ENHANCING THE PERFORMANCE OF AN EPOXY RESIN USING OLIGOMERIC
AMIDE ADDITIVES
A Dissertation by
Janet de los Reyes
Master of Science, Wichita State University, 2009
Submitted to the Department of Chemistry
and the faculty of the Graduate School of
Wichita State University
in partial fulfillment of
the requirements for the degree of
Doctor of Philosophy
May 2012
i
© Copyright 2012 by Janet de los Reyes
All Rights Reserved
ii
ENHANCING THE PERFORMANCE OF AN EPOXY RESIN USING OLIGOMERIC
AMIDE ADDITIVES
The following faculty members have examined the final copy of this thesis for form and content,
and recommended that it be accepted in partial fulfillment of the requirement for the degree of
with a major in Chemistry.
David M. Eichhorn , Co-Chair
William T. K. Stevenson (deceased), Committee Chair
Moriah Beck, Committee Member
Denis H. Burns, Committee Member
Suresh Raju Keshavanarayana, Committee Member
Donald Paul Rillema, Committee Member
iii
ACKNOWLEDGMENTS
First of all, I would like to thank our Maker, for I am nothing if not for Him.
I feel deeply indebted to Dr. William Stevenson for giving me an opportunity to work in
his group. I am very grateful for his guidance and intellectual inputs in this research. He will
always be cherished. I am very thankful to Dr. David Eichhorn for taking me as an advisee after
Dr. Stevenson’s death. I also extend my gratitude to the members of my committee, Dr. Moriah
Beck, Dr. Dennis Burns, Dr. Suresh Raju Keshavanarayana and Dr. Donald Rillema for their
comments and inputs for this dissertation.
I want to express my gratitude to Mrinal Agrecha, and Stacy Wolf who helped me
conduct some mechanical testings and Matt Opliger who performed some viscoelastic property
tests.
My sincere appreciation is extended to my former groupmates, Anusha Dissanayake, Dr.
Irish Gibson, Dr. Joel Flores, Dr. Rama Gandikota, Amanda Alliband, Ritu Gurung, Roxanne Uy
and Van Anh Hoang for all their help and making work enjoyable.
Finally, I would like to thank my family and friends for their constant encouragement and
support, and occasional positive distractions that helped me kept me sane as I was working on
this project. ☺
iv
ABSTRACT
An antiplasticizer is any chemical that when added, reduces the free volume of a polymer
thereby restricting the polymeric chain motions. This type of additive usually increases the
modulus and strength but can compromise other important properties such as glass transition
temperature and thermal degradation profile.
Oligomeric amide additives, which when mixed with TGDDM and DDS, react to form
strong hydrogen bonds and reduce the free volume in the system, were synthesized. The
nonaromatic additives, especially those that have shorter methylene sequences, had low
solubility in the resin, while the mixed amide oligomer additive have better solubility. The effect
of these additives to enhance mechanical properties was tested by tensile testing and fracture
toughness measurement. Compact tension results indicated that the additives improved the
resins’ resistance to crack propagation. In general, when the additive is shorter and additive
loading is lower, the material performs better. No general conclusion can be arrived at from the
tensile testing due to the variablility of results caused by unavoidable imperfections incurred
during specimen preparation. The cure kinetics of the resin was studied using Differential
Scanning Calorimetry. Dynamic temperature scanning DSC indicated that the cure reaction was
not affected significantly by these additives. However, an increase in activation energy was
observed. TMA experiments on resins with nonaromatic additives indicated that the additives
slightly increased the softening temperature while DMA experiments on resins with mixed amide
oligomers show that the additives slightly increase the glass transition temperature. TGA
experiments on resins with mixed amide oligomers indicated that the additives did not introduce
significant changes in thermal stability.
v
TABLE OF CONTENTS
Chapter
Page
TABLE OF CONTENTS............................................................................................................... vi
LISTOF FIGURES ........................................................................................................................ ix
LIST OF TABLES........................................................................................................................ xii
LIST OF ABBREVIATIONS...................................................................................................... xiv
CHAPTER 1 ................................................................................................................................. 1
INTRODUCTION .............................................................................................................. 1
1.1
Epoxy-Amine Curing...................................................................................... 4
1.2
Free Volume ................................................................................................... 6
1.3
Hydrogen bonds .............................................................................................. 8
1.4
Related Studies ............................................................................................... 9
1.5
Controlling Average Chain Length of Oligomers ........................................ 12
1.6
Intrinsic Viscosity ......................................................................................... 13
1.7
Mechanical Properties................................................................................... 14
1.8
Overview of the Study .................................................................................. 16
CHAPTER 2 ............................................................................................................................... 19
EXPERIMENTAL............................................................................................................ 19
2.1
Introduction.................................................................................................. 19
2.2
Mixing of Resin and the Curing Agent........................................................ 19
2.3
The Additives................................................................................................ 20
2.4
Synthesis of Additives .................................................................................. 21
2.4.1 The Materials ........................................................................................... 21
2.4.2
Synthesis of Nylon-Like Oligomers ........................................................ 22
2.4.3 Synthesis of Mixed Aliphatic-Aromatic Amide Oligomers ........................ 23
2.5
2.6
2.7
2.8
2.9
Preparation of Resin with Additives............................................................. 24
The Cure Cycle ............................................................................................. 25
Intrinsic Viscosity Measurements................................................................. 25
Molecular Weight Determination ................................................................. 27
Fourier-Transform Infrared Spectroscopy .................................................... 27
vi
TABLE OF CONTENTS (Continued)
Chapter
Page
2.10 Nuclear Magnetic Resonance (NMR)........................................................... 28
2.11 Tensile Testing.............................................................................................. 28
2.12 Fracture Toughness Test ............................................................................... 30
2.13 Dynamic Mechanical Analysis ..................................................................... 32
2.14 Thermo Mechanical Analysis ....................................................................... 32
2.15 Thermogravimetric Analysis ........................................................................ 33
2.16 Differential Scanning Calorimetry................................................................ 33
CHAPTER 3 ............................................................................................................................... 36
RESULTS AND DISCUUSION: NON-AROMATIC ADDITIVES............................... 36
3.2
FTIR.............................................................................................................. 37
1
H NMR ........................................................................................................ 39
3.3
3.4
Solubility Test............................................................................................... 42
3.5
Intrinsic Viscosity ......................................................................................... 43
3.6
Curing of Resin ............................................................................................. 45
3.7
Curing with Oligomer................................................................................... 48
3.8
Tensile test .................................................................................................... 49
3.9
Tensile Testing of Resins Using New Cure Cycle ....................................... 53
3.10 Thermomechanical Analysis........................................................................ 56
3.11 Conclusion ................................................................................................... 58
CHAPTER 4 ............................................................................................................................... 59
RESULTS AND DISCUSSION: MIXED AMIDE ADDITIVES ................................... 59
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4. 9
Introduction................................................................................................... 59
Infrared Spectroscopy ................................................................................... 61
Proton and 13C NMR..................................................................................... 63
Intrinsic Viscosity (IV) ................................................................................. 70
Tensile Test................................................................................................... 73
Fracture Toughness....................................................................................... 82
Differential Scanning Calorimetry................................................................ 86
Dynamic Mechanical Analysis ..................................................................... 93
Thermogravimetric Analysis ........................................................................ 95
vii
TABLE OF CONTENTS (Continued)
Chapter
Page
4.10 Conclusion .................................................................................................... 97
CHAPTER 5 ............................................................................................................................... 99
CONCLUSIONS............................................................................................................... 99
REFERENCES ........................................................................................................................... 102
APPENDICES ............................................................................................................................ 105
A. Infrared Spectra of the Additives..…...……………………………………..106
B. NMR Spectra of the Additive……..………………………………………..113
C. Intrinsic Viscosity and GPC Plots…...……………………………………..122
D. Tensile Test Results………………………………………………………...127
E. Fracture Toughness Results………………………………………………...161
F. Differential Calorimetry Plots……………………………………………...189
viii
LISTOF FIGURES
Figure
Page
Figure 1.1
The growing use of composites in aircrafts ............................................................ 2
Figure 1.2
The chemical structures of DDS and TGDDM....................................................... 3
Figure 1.3
Development of cure for an epoxy resin system.6 .................................................. 5
Figure 1.4
The reactions involved in resin curing.................................................................... 6
Figure 1.5
Dissipation of energy through disruption of hydrogen bonds. ............................... 9
Figure 1.6
Chemical Structure of EPPHAA........................................................................... 10
Figure 1.7
A Stress-Strain Curve. The slope of the straight initial part of the curve “a” is
taken as the Young’s modulus. ............................................................................ 15
Figure 2.1
Reaction of amine and acid chloride to form amide. ............................................ 21
Figure 2.2
Representative repeat unit for the 10,12 oligomer prepared using a C10 diacid
chloride and a C12 diamine. ................................................................................. 21
Figure 2.3
The chemical Structures of the diamines a. p-phenylenediamine, b. mphenylenediamine and c. 4,4’-methylene dianiline. ............................................. 24
Figure 2.4
The Ubbelohde dilution viscometer...................................................................... 26
Figure 2.5
Dogbone dimensions of ASTM D638 Type IV.................................................... 29
Figure 2.6
Dimensions of compact tension specimen............................................................ 31
Figure 3.1
Scheme for the synthesis of Nylon 6,6 ................................................................. 36
Figure 3.2
FTIR spectrum of nylon 6,6 Xn =6....................................................................... 38
Figure 3.3
The acid carbonyl peak in the FTIR of nylon 6,6 Xn =6...................................... 38
Figure 3.4
1
Figure 3.6
13
H NMR spectrum of Nylon 6,6 Xn=3.67 ............................................................ 39
C NMR spectrum for Nylon 6,6 Xn=3.67 .......................................................... 41
ix
LIST OF FIGURES (Continued)
Figure
Figure 3.7
Page
Solubilities of different nylon oligomers in (1) 90% formic acid (2) m-cresol (3)
DMF and (4) DMAc. (CD = completely dissolved, PD = partially dissolved and
ND = not dissolved) .............................................................................................. 43
Figure 3.8
Intrinsic Viscosity of Nylon 6,6 Xn=6.................................................................. 44
Figure 3.9
Stress-strain curves of control specimens made by Method III. ........................... 47
Figure 3.10
Linear initial part of the stress-strain curve of specimen 1 made by Method III.. 47
Figure 3.11
Comparing TMA output for nylon 10,12 Xn=3.67 and control. .......................... 57
Figure 4.1
The chemical structures of the monomers and the corresponding names of their
oligomers............................................................................................................... 59
Figure 4.2
Scheme for the synthesis of MDA10 .................................................................... 60
Figure 4.4
FTIR Spectrum of MPDA10 Xn=3.67, an enlargement of the carbonyl area. ..... 62
Figure 4.5
Proton NMR Spectrum of MPDA10 Xn=3.67 ..................................................... 64
Figure 4.6
Expansion of aromatic region of MPDA10 Xn=3.67 proton NMR spectrum...... 65
Figure 4.7
Chemical structure of MPDA10 Xn=5 with assigned carbon numbers................ 65
Figure 4.8
13
Figure 4.9
Expanded aliphatic region of C13NMR spectrum of MPDA10 Xn=3.67 ............. 67
Figure 4.10
Expanded aromatic region of C13NMR spectrum of MPDA10 Xn=3.67............. 68
Figure 4.11
Expanded carbonyl region of 13C NMR spectrum of MPDA10 Xn=3.67 ............ 68
Figure 4.12
Intrinsic viscosity plot for MDA10 Xn=5............................................................. 70
Figure 4.13
Gel Permeation Chromatography of MDA10....................................................... 72
Figure 4.14
Stress-strain curves of MDA10 Xn=3.67 3% ....................................................... 74
Figure 4.15
Initial portion of the stress-strain curve of Control resin specimen 1................... 74
Figure 4.16
Tensile testing curves of MPDA10 Xn=3.67 at 3 % loading. .............................. 76
Figure 4.17
Initial portion of tensile testing curve of MPDA10 Xn=3.67 3% specimen 1...... 76
C NMR spectrum of MPDA10 Xn=3.67............................................................ 67
x
LIST OF FIGURES (Continued)
Figure
Page
Figure 4.18
Fracture toughness test load-strain curve of control resin specimen 1. ................ 83
Figure 4.19
Plot of Control resin Degree of Cure vs. Temperature Summary......................... 87
Figure 4.20
Plot of Resin with MDA10 Xn=3.67 degree of cure vs. temperature summary... 88
Figure 4.21
Comparison of control resin and resin with MPDA10 Xn=3.67 @ 5oC/min
heating rate............................................................................................................ 88
Figure 4.22
Summary of rate of cure vs temperature for the control resin at different heating
rates. ...................................................................................................................... 89
Figure 4.23
Summary of rate of cure vs temperature for the resin containing MDA10 Xn=3.67
at 3% load at different heating rates. .................................................................... 90
Figure 4.24
Plot for ln rate of cure vs 1/T for 0.05 degree of cure of control resin. ................ 91
Figure 4.25
Activation energy vs degree of cure of Control and 3 % MDA10 Xn=3.67 ........ 92
Figure 4.26
DMA of MPDA10 Xn=3.67 3%........................................................................... 93
Figure 4.27
Comparing Tangent Delta from DMA scans. ....................................................... 94
Figure 4.28
Change of weight percent of control resin and resin with MPDA10 Xn=3.67
additive with time at 4 ºC/min heating rate. ......................................................... 96
xi
LIST OF TABLES
Table
Page
Table 1.1
Typical Tensile Strength, Elongation and Tensile Modulus of Polymers. ............. 8
Table 2.3
The dimensions of the dogbones........................................................................... 29
Table 3.1
Experimental and predicted chemical shifts for Nylon 6,6 Xn=3.67 ................... 40
Table 3.2
Corresponding MW of Nylon 2 Intrinsic viscosities and their 6,6 oligomer........ 45
Table 3.3
The calculated a parameters of the nylon 6,6 oligomers. ..................................... 45
Table 3.4
The tensile results for Control, made with and without acetone as solvent.......... 48
Table 3.5
Formulation of nylon 6,6 oligomers ..................................................................... 50
Table 3.6
Stiffness of dogbones made with different oligomer additives at 3% load. ......... 51
Table 3.7
Stress at break of dogbones made with different oligomer additives @ 3% load. 52
Table 3.8
Strain at break of dogbones made with different oligomer additives. ................. 53
Table 3.9
Stiffness of the dogbones with different nylon oligomers at 5% load. ................. 54
Table 3.10
Stress at break of the dogbones with different nylon oligomers at 5% load......... 55
Table 3.11
Strain at break of the dogbones with different nylon oligomers at 5% load......... 56
Table 3.12
Softening temperatures of control resin, resins with nylon 10,12 Xn=3.67 5% and
10% determined by TMA. .................................................................................... 57
Table 4.1
The number average degrees polymerization of MDA10 and their corresponding
reagent ratios......................................................................................................... 61
Table 4.2
Experimental and Predicted chemical shifts for MPDA10 Xn=3.67.................... 66
Table 4.3
Assignment of carbon numbers and chemical shifts in the 13C NMR of MPDA10
Xn=3.67 ................................................................................................................ 69
Table 4.4
Summary of results for intrinsic viscosity experiments........................................ 71
Table 4.5
Summary of gel permeation chromatography results. .......................................... 73
Table 4.6
Tensile testing summary for control resins........................................................... 75
xii
LIST OF TABLES (Continued)
Table
Page
Table 4.7
Tensile Testing summary for MPDA10 Xn=3.67 at 3% load. ............................. 77
Table 4.8
Formulations of resins tested. ............................................................................... 78
Table 4.9
Tensile Testing Summary for resins containing MPDA10................................... 79
Table 4.10
Tensile testing summary for resins containing MDA10. ...................................... 80
Table 4.11
Tensile Testing summary for resins containing PPDA10..................................... 81
Table 4.12
T-test calculation results ....................................................................................... 82
Table 4.13
Fracture toughness for control specimens............................................................. 83
Table 4.14
Fracture Toughness of Resins with MDA10 additives. ........................................ 84
Table 4.15
Fracture toughness tests results for resins with PPDA10 additives...................... 85
Table 4.16
Fracture toughness tests results for resins with MPDA10 additives..................... 85
Table 4.17
Comparison of the three best resins from each type of additive........................... 86
Table 4.18
Comparison of High-Temperature DMA of MDA10 and MPDA10 Xn=3.67. ... 95
Table 4.19
Summary of weight degradation for control and resins with MPDA10 Xn=3.67.96
xiii
LIST OF ABBREVIATIONS
ASTM
American Society for Testing and Materials
DBu
1, 8-diazobicycloundec-7-ene base
DDS
Diaminodiphenyl sulphone
DMAc
N,N - Dimethyl acetamide
DMF
N,N - Dimethylformamide
DMMP
Dimethyl methyl phosphate solvent
EHPC
Ethyl 4-hydroxy phenyl carbamate reagent
EPPHAA
Reaction product of 4-hydroxyacetanilide and 1, 2-epoxy-3-phenoxypropane
HP-3-PU
1-(4-hydroxyphenyl)-3-propyl urea
IV
Intrinsic Viscosity
MDA
Methylene diamine
MPDA
Meta phenylene diamine
MY720
Commerical name for tetragylcidyl diaminodiphenylmethane resin
PHR
Parts per hundred parts resin
PPDA
Para phenylene diamine curative
TGDDM
Tetraglycidyl diaminodiphenylmethane resin
VCDHAA
Reaction product of vinylcyclohexene dioxide and 4-hydroxyacetanilide
VCD-EHPC
Ethyl 4-(2-(7-oxa-bicyclo[4.1.0]heptan-3-yl)-2-hydroxyethoxy)phenyl carbamate
xiv
CHAPTER 1
INTRODUCTION
Epoxy resins are widely used thermosetting plastics possessing properties that are easily
altered and tailored. For this reason they have found applications in different fields such as
adhesives, coatings, electrical and electronic, and structural applications.
The most important application of epoxy resins in the aerospace industry is in the
fabrication of fiber reinforced composites for use in structural applications. They constitute the
matrix in long fiber reinforced composites. They are used as such for the following reasons: they
are light-weight, impregnation of reinforcing fiber is easy, and it has excellent adhesion to the
reinforcing fiber.
Figure 1.1 shows that the use of composites in both military and commercial aircrafts is
steadily growing.1 They are much preferred over other structural components such as metals
because of the following properties: they are lightweight, have high strength compared to weight,
are corrosion resistant, have low thermal conductivity which makes them good insulators, are
non-electrically conductive, and have dimensional stability which means they are resistant to
expansion and contraction due to temperature changes. They are also radar transparent. This
property plays a key role in stealth bombers.2
The military aircrafts V-22 and Eurofighter, which presently have the highest composite
percentage of 80%, are lightweight and very agile. On the other hand, the Boeing 787, formerly
known as Boeing 7E7, which was first launched in 2009 has a composition of 50% composite
(the highest among the commercial planes), 20% aluminum, 15% titanium, 10% steel, and 5%
other materials.3 It uses 20% less fuel than an aircraft with a comparable size making it very
economical.
1
Figure 1.1
The growing use of composites in aircrafts
Although the resin matrix in a composite may appear to have unimportant mechanical
properties due to the presence of reinforcing fibers, matrices are also subjected to tensile stresses.
Since the matrix is what holds the fibers together in a composite, when it fails the whole
composite’s strength and performance are greatly affected and could cause the whole composite
to fail. Since epoxy resins are inherently brittle, much research has been conducted on improving
their resistance to mechanical failures.
Many epoxy composites used in the aerospace industry are based on N,N,N’,N’tetraglycidyl-4,4’-diaminodiphenylmethane (TGDDM) resin and diaminodiphenyl sulphone
(DDS) curative (Figure 1.2) as matrix components. These composites have high mechanical
properties and can be used at high temperatures due to their high glass transition temperatures.
TGDDM, commercially known as MY720 resin, is a semi-solid and therefore requires only
minor modifications to obtain good physical properties in the prepreg. DDS is used as the
2
aromatic amine curative because the electron-withdrawing sulfone group provides latency,
molecular fit and relatively stable epoxy/amine links,4-5 which, when combined with TGDDM,
give excellent initial mechanical properties.
O
O
S
H 2N
NH 2
4,4-Diamino diphenyl sulfone or DDS (resin curing agent)
O
N
N
O
O
O
N,N,N’,N’-tetraglycidyl-4,4’-diaminodiphenylmethane or TGDDM or MY720
Figure 1.2
The chemical structures of DDS and TGDDM
Even though TGDDM/DDS systems provide high mechanical properties due to a high
crosslink density, they are inherently brittle materials and have poor resistance to crack
propagation. They are known to fail by the growth of internal flaws and micro voids that
consolidate into cracks. TGDDM/DDS based composites also have been recorded to have very
low fracture toughness values. Various chemical additives have been developed that would
improve the fracture toughness and the tensile strength of these systems without having adverse
effects on other properties such as the glass transition temperature (Tg) and solvent resistance.
Compounds having terminal amine functionality are often used as additives as they can easily
react with the epoxide groups of the resin.
3
1.1
Epoxy-Amine Curing
The process of curing epoxy resins involves reaction of monomeric or oligomeric
polyfunctional epoxide molecules with a curing agent (which is usually an amine compound) and
catalyst, to form a highly crosslinked, rigid structure. The curing takes place in stages.6 The first
stage involves combining the epoxy resin and curing agent. The resin is a viscous liquid and the
curing agent is either a liquid or a low-temperature melting solid. When combined and after a
catalyst is added and heated, the curing agent and resin react, accompanied by release of
additional heat which helps to increase the speed of reaction. The second stage results in the
formation of linear chains of combined curing agent and epoxy resin. At this stage, the material
is still liquid but its viscosity increases rapidly. Continued heating causes the linear chains to
crosslink to form a network with a very high molecular mass. At this stage of cure (third stage),
the material is a strong solid gel. The final stage is carried out at a more elevated temperature to
push the crosslinking process to completion. The product is a very strong, chemically resistant
material. A representation of the curing process is shown in Figure 1.3.
4
Development of cure for an epoxy resin system.6
Figure 1.3
The mechanism of epoxy-amine curing has been widely studied. There are three basic
reactions 4,7-8 (Figure 1.4) First is (1) attack of the primary amine lone pair on the least hindered
methylene of the epoxide, opening the ring and producing a secondary amine and a hydroxyl
group; (2) the secondary amine reacts further with another epoxide to form a tertiary amine and
another hydroxyl group; (3) the hydroxyl groups of the products in reactions (1) and (2) react
with any excess epoxide to form an ether linkage.
1) Epoxy – Primary Amine
OH
O
NH2
+
H2C
CH
NH
5
CH2
CH
2) Epoxy-Secondary Amine
OH
O
+
NH
H2C
N
CH
CH2
CH
3) Etherification
CH2
CH2
CH2
CH
O
H2 C
CH
HO
Figure 1.4
CH2
O
+
OH
CH
H2C
CH
The reactions involved in resin curing.
Reaction 2 is slower than reaction 1 due to steric factors in the secondary amine. The
tendency of the etherification reaction to take place depends on the temperature and the basicity
of the diamine and increases with the initial ratio of epoxy/amine.7 It is insignificant if the
reactants are mixed in stoichiometric amounts or with an excess of the amine. It occurs at high
temperatures and advanced degrees of cure, especially if the epoxy is in excess in the mixture.
This leads to a more brittle resin, therefore this reaction is unwanted.
1.2
Free Volume
Chain flexibility is a major factor in establishing polymer properties such as stiffness,
strength, glass transition and melting temperature, and thermal stability. The more flexible the
polymer chains are, the easier it is for the segments to acquire translational motion. If the
polymer chains are stiff, the bulk polymer will have high stiffness, glass transition and melting
temperature and will be more thermally stable. With an appropriate packing of polymer chains,
intermolecular forces of attraction can exert an effect on holding the chains together and thus
6
help make the chains less flexible. Good packing occurs when the polymer chains have structural
regularity, symmetry, compactness and a certain degree of flexibility. 9
The influence of packing on the properties of polymers can be explained by the concept
of free volume. Free volume may be considered as the unoccupied volume by the atomic species
of the material. The bigger the free volume, the bigger the space for polymer segment mobility
and the easier it is for polymer molecules to slip from one another. Therefore free volume
determines any physical or mechanical property of a polymer that is dependent on the ability of a
polymer to physically respond or move in response to external stress.10
This has led to the idea of antiplasticizing polymers by using small compounds as
additives to fill the free volume or introduce attractive forces such as hydrogen bonds to make
polymer chains less mobile, and therefore improve stiffness and tensile strength. The early
attempts at antiplasticization involved adding low molecular weight compounds to
polycarbonates, polyesters, and poly(sulfone ether) as reported by Jackson and Caldwell in 1967.
10-13
When a low molecular weight material is added to a polymer the resultant free volume of
the system, f, can be described by the relationship
f = V1f1 + V2f2 + KV1V2
where V1 is the volume fraction of the polymer and f1 is the fractional free volume of the
polymer, while V2 and f2 refer to the additive. K is an interaction parameter.12-14 The free volume
decreases when f2 is small and K is a large negative number which coincides with the additive as
a stiff polar molecule able to form strong interactions with the polymer. In such a case
antiplasticization occurs, thereby stiffening the polymer.
7
1.3
Hydrogen bonds
As mentioned before, secondary forces have influence on flexibility and therefore play a
significant part in the polymer’s properties. Polar functionalities in polymer chains or side groups
can lead to interchain secondary bonding. These forces can result in a higher tensile strength and
melting point. These hydrogen bonds are the reason for the high tensile strength and melting
point of polyacrylic acid, nylon 6, and polyamide-imide. (Table 1.1) Polyamide-imide and nylon
6 both contain amide and carbonyl groups and polyacrylic acid contains hydroxyl groups that can
form hydrogen bonds between adjacent chains.14
Table 1.1
Typical Tensile Strength, Elongation and Tensile Modulus of Polymers.
Polymer Type
Ultimate Tensile Strength Elongation Tensile Modulus
(MPa)
(%)
(GPa)
Acrylonitrile Butadiene Styrene
40
30
2.3
Polyacrylic Acid
70
5
3.2
Nylon 6
70
90
1.8
Polyamide-Imide
110
6
4.5
Polycarbonate
70
100
2.6
Polyethylene, HDPE
15
500
0.8
Polyethylene Terephthalate (PET)
55
125
2.7
Polypropylene
40
100
1.9
Polystyrene
40
7
3
To propagate a crack in a polymeric material, energy must be available to at least equal
the surface energy of the two new surfaces produced by the growth of the crack.15 If attractive
8
forces such as hydrogen bonds are present, part of the available crack energy G will also be
dissipated to break the hydrogen bonds. This means to increase the crack length, a greater
amount of crack energy is needed because part of it, which is equal to the hydrogen bonding
energy, H, is spent to disrupt the hydrogen bonds. (Figure 1.5)
Crack
Energy G
N C
H O
O H
C N
Figure 1.5
1.4
N C
H O
Q = H bonding energy
Crack
Energy G - Q
O H
C N
Dissipation of energy through disruption of hydrogen bonds.
Related Studies
Since epoxy resins are brittle yet used as matrices for composites, several studies about
improving their mechanical properties have been conducted. Modifying polymers by the use of
an additive is more cost effective and flexible than switching to a more expensive polymer due to
the range of additives that can be formulated. Therefore, numerous studies have been conducted
to develop additives that improve the physical and mechanical properties of epoxy resins. Many
antiplasticizer additives first reported were characterized by their bulky, stiff structure due to the
idea that stiffening is governed by the ability to fill free volume, thereby reducing chain mobility.
Haldankar reported that a compound that has a flat, compact structure and has a polar
group like the phthalimide group in N-(2,3-epoxypropyl) phthalimide is an effective
antiplasticizer in the diglycidyl bisphenol-A (DGEBA, EPON 828) – methylenediamine resin
system because it can facilitate good packing.16 In the same paper, the dependence of modulus
9
on free volume of the epoxy resin system was reported. The modulus increased as the free
volume decreased. The free volume was calculated as the difference between specific volume
and occupied volume, with the occupied volume being determined by the extrapolation of the
rubbery coefficient of thermal expansion data to zero Kelvin.
McLean reported successful development of a range of additives that improve the
strength (up to 60%) and stiffness (up to 70%) of amine cured epoxy resins, as well as improving
the ability of the specimens to yield before fracture using EPPHAA (Figure 1.6) as a
representative of the series, which is a reaction product of epoxyphenoxy propane and 4hydroxyacetanilide.17 However, there were decreases of glass transition temperatures in the
epoxy resins. The fracture toughness values for EPPHAA-containing samples were strongly
strain-rate dependent. There was a significant increase in the toughness at low testing rates
however.
O
NH
O
O
OH
Figure 1.6
Chemical Structure of EPPHAA
In another paper, Garton, et al. reported that EPPHAA and VCDHAA (a reaction product
of vinylcyclohexene dioxide and 4-hydroxyacetanilide) increase the tensile modulus of
conventional epoxy-amine systems by over 60% and tensile strength by over 50% while
producing a ductile mode of failure.18 They found a reduction in the free volume by adding these
compounds to the resin system at low strains and that such hinders polymer segmental motion
10
and so increases the modulus. However, resin systems also exhibit a very low Poisson’s ratio and
strains about 5% cause an increase in free volume sufficient that ductile failure can occur. It was
also reported that the coefficients of thermal expansion and water uptake of the resins were
reduced.
However, it was reported by Zerda that a small, non-aromatic molecule, dimethyl methyl
phosphate (DMMP) was still capable of enhancing mechanical properties of the diglycidyl ether
of bisphenol-A (EPON 825 from Shell) through antiplasticization.19 It was found that 10 pph
yielded maximum mechanical properties enhancements. Both the tensile strength and modulus
increased by 2%. It was also reported that the introduction of DMMP resulted in flammability
enhancements.
On the other hand, Don described an antiplasticization behavior in the polycaprolactone
(PCL)/polycarbonate (PC) – modified epoxy system, cured with an aromatic amine up to 15
parts modifier.20 This means that a high molecular weight polymer can also serve as an
antiplasticizer in the same manner as a low molecular weight compound. The initial modulus
increased and the fracture toughness and the elongation at break decreased with the addition of
the PCL/PC modifier with only a slight decrease in glass transition temperature with modifier
content up to 15 phr.2 It is found in his research that the formation of hydrogen bonding between
the carbonyl groups of PCL/PC and the hydroxyl groups in the epoxy leads to antiplasticization.
It is thought that a strong interaction is probably leading to a decrease in the free volume of the
matrix. The FTIR analysis indicated appreciable hydrogen bonding between the carbonyl groups
not only in PC but also in PCL with the hydroxyl groups in the epoxies.
In general, an additive, no matter how small or large, bulky or not can still act as an
antiplasticizer as long as it either has strong interaction toward the polymer or can fill the free
11
volume. And also, unfortunately, improving one property of a resin can be achieved sometimes
only at the expense of another.15,16 Usually, the use of an additive is very property-specific in
nature.
1.5
Controlling Average Chain Length of Oligomers
Synthesizing oligomeric additives with multi-hydrogen bonding capable functionalities of
different lengths can be achieved by using a concept introduced by Carother in step-growth
polymerization. The average chain lengths of polymers or oligomers can be controlled by
adjusting the stoichiometric mole ratios of the reactants.
In a linear polymer composed of equimolar mixtures of two monomers, the number
average degree of polymerization, X n (which relates to average chain length) is given by the
Carother’s equation9:
Xn =
1
1− p
(1)
where p is the extent of reaction. If one of the monomers is stoichiometrically in excess, the
relationship between the extent of stoichiometric imbalance (r) and X n , for this type of reaction
is given by the modified Carother’s equation:
Xn =
1+ r
1 + r − 2rp
(2)
where r is the mole ratio of functional groups of monomers or reactants. If p 1, that is the
reaction approaches completion or loss of all of one type functional group, the modified
Carother’s equation relating X n to r simplifies to
Xn =
1+ r
1− r
(3)
12
Based on this equation, the average chain length can be estimated by adjusting the
stoichiometric imbalance, r.
The number average molecular weight, M n of the polymer is calculated by multiplying
the number average degree of polymerization by the molecular weight, M o , of the repeating unit.
(4)
M n = X nMo
If a diamine and a dicarbocylic acid or diacid chloride are used as monomers in a
condensation reaction, using this idea, oligomeric amides of different lengths can be made.
1.6
Intrinsic Viscosity
The viscosity of a polymer solution is dependent on the concentration and the average
molecular size of the sample and therefore the molecular weight of the polymer.
The intrinsic viscosity, also known as limiting viscosity number [η ] , of a polymer gives a
measure of the volume of the solvated polymer coil. It constitutes an accepted marker of chain
length which may be converted to an absolute value of molecular weight if Mark-HouwinkSakurada constants are available.21
The viscosity average molecular weight, M v , is related to viscosity through the MarkHouwink equation, [η ] = KM vα , where [η ] is intrinsic viscosity for the polymer/solvent system
and the α and K are empirical constants for the particular system where α is dependent on the
polymer-solvent pair and temperature.22
The intrinsic viscosity number is the limiting value of the specific viscosity/concentration
ratio extrapolated to zero concentration. To measure it, viscosities at different concentrations are
determined and then viscosity at zero concentration is extrapolated.
13
Experimentally, [η ] can be determined by measurements of flow times of solvent (to)
with a series of dilute polymers of known concentration (tc) in a viscometer. Specific viscosity is
calculated as follows:9
η sp =
ηc − ηo tc − to
=
ηo
to
(1)
Based on the Huggin’s equation
η sp
c
2
= [η ] + k 1 [η ] c
(2)
where c is the concentration of dilute polymer solution and k1 is a positive constant. The intrinsic
viscosity can be determined by plotting
η sp
c
against c and extrapolating to zero concentration.
When [η ] is determined, the Mv can then be calculated using the Mark-Houwink equation
if the empirical constants are known. However, based on the equation, even without knowing the
values of these constants, it can be said that when [η ] increases Mv of the polymer also increases.
1.7
Mechanical Properties
How a resin matrix in a composite responds to external stress is a huge concern in the
aerospace industry. Mechanical testing includes, amongst other tests, the measuring of ultimate
strength, Young’s modulus and fracture toughness. Ultimate strength is defined as the maximum
tensile stress which a material is capable of developing. Stress is defined as the intensity
(measured per unit area) of the internal distributed forces, or components of force, which resist a
change within a body.23 It may be calculated based on the original dimensions of the cross
section of the body. The modulus of elasticity or Young’s modulus, E, a measure of stiffness, is
the ability of a material to resist deformation when stress is applied. It is represented by the slope
of the initial straight segment of the stress-strain curve obtained from a uniaxial tension test.
14
(Figure 1.7) Strain is the deformation of a material’s dimensions when stress is applied or
simply, elongation.
These properties can be measured by stress-strain tests, the most common of which is the
uniaxial tensile test. In stress-strain tests the buildup of force is measured as the material is being
deformed at a constant rate. The tensile test used in this research is described in the American
a
Yield Stress
Stress
Society for Testing and Materials (ASTM) D638 -02 (Type IV) method.24
Strain
Figure 1.7
An example of a stress-strain Curve. The slope of the straight initial part of
the curve “a” is taken as the Young’s modulus.
In general, plastics that are:
a. Soft, weak – have low modulus of elasticity, yield point and elongation at break.
b. Hard, brittle – have high modulus of elasticity, no well defined yield point and low
strain at break.
15
c. Soft, tough – have low modulus of elasticity, low yield point and high strain at break
d. Hard, strong – have high modulus of elasticity, yield point and moderate stress and
strain at break
e. Hard, tough – have high modulus of elasticity, yield point, stress and strain at break.
Brittle failure, otherwise known as fracture starts from nucleation and propagation of
imperfections such as micro and macro cracks. These cracks can propagate, that is, to increase its
surface area if there is sufficient energy to form new surfaces. The energy needed to form new
surface is called fracture energy.20 The fracture energy needed for the formation of a new
fracture surface is defined as
(1)
δτ = GδS
Where G is the energy released per unit area of the crack (rate of elastic strain energy release)
and δS the crack growth increment. .
There are different techniques used to measure fracture toughness and each uses a
different geometry. They are the double-cantilever beam, impact test and compact tension. This
research employed the use of compact tension for measuring mode-1 fracture toughness (opening
mode).
1.8
Overview of the Study
The goal of this research was to synthesize additives that can enhance the mechanical
properties of the MY720-DDS resin system. The additives would have functional groups which
can form hydrogen bonds. It was expected that these additives will fill free volume and that
added hydrogen bonds would yield additional attractive forces to the hydroxyl group of the
epoxies thereby antiplasticizing the resin system. It was also hoped that these hydrogen bonds
16
would act as energy absorbers during crack propagation thereby increasing the fracture
toughness of the resin system.
The type of compounds that were explored were short chain amide oligomers since the
amide functional group has a carbonyl and N-H group that can form hydrogen bonds. The
additives were designed to be amine terminated so that they could react with the epoxies of the
resin.
The first part of the research was spent on exploring amine-terminated nylon-like
oligomers produced from reacting non-aromatic diacid chlorides and diamines while the second
part was spent on exploring mixed oligomeric amides produced from reacting non-aromatic
diacid chlorides and aromatic diamines. This is the general structure of the additives that were
used in this research:
where n= 3-9.
Different types of oligomers were made by varying the monomers used and different
oligomer lengths were made by adjusting the stoichiometric imbalance of the monomers. The
additives were characterized by FTIR and NMR. The variation of average chain lengths and
average molecular weight were verified via intrinsic viscosity experiments and gel permeation
chromatography, respectively.
The effects of the additives on modulus and strength were studied, as well as how the
properties change at various loads through tensile testing and on fracture toughness through
compact tension. The glass transition temperatures and softening temperatures of the resins were
studied by dynamic mechanical analysis and thermomechanical analysis. The degradation of the
17
resins with temperature was conducted through thermogravimetric analysis. And lastly, how the
additives affect the kinetics of the resin curing was studied by differential scanning calorimetry.
18
CHAPTER 2
EXPERIMENTAL
2.1
Introduction
The properties of additive-containing resins were compared to those of a control resin.
This control resin is made from MY720 and the curing agent DDS. The formulation was based
on a commercial resin called 934 Resin, which was known to contain MY720, DDS and traces of
the catalyst, BF3. The DDS in 934 Resin is slightly in excess to make sure all epoxy
functionalities in the resin are reacted to form a network, and also to prevent etherification
reactions. The 934 Resin contains a catalyst, BF3, which enables the resin to cure at a fast rate
even at low temperatures. Since in this study, there was no need to cure the resins at low
temperatures, BF3 was not used but higher curing temperatures were employed. The properties of
the cured resin proved to be similar to those of the resin cured with a catalyst. It is stiff, has high
glass transition temperature and is somewhat brittle.
2.2
Mixing of Resin and the Curing Agent
It was necessary that the base resin mixture was formulated in order to achieve best
properties so that a proper comparison can be made with the additive enhanced resin mixture. In
this research, three methods of preparing the base resin (control resin) were attempted over a
large number of experiments.
1. The DDS powder was added to the resin in a paddle mixer and the mixture was heated.
2. The DDS powder was added to the resin in a high shear mixer and the mixture was heated.
3. The DDS powder was dissolved in acetone and added to the warmed resin in a high shear
mixer. A stir bar was then added, and the mixture was stirred and warmed in a heated oil bath
19
under vacuum. The temperature of the resin was raised to keep the mixture fluid as acetone
was lost by vacuum pumping. Acetone was chosen to be the solvent in this method because it
is the only low boiling point solvent in which it would dissolve.
It was observed in Methods 1 and 2 that the DDS did not mix homogeneously with the
resin. Resins made from Method 1 and 2 have undissolved particles which would act as nuclei
for crack propagation. On the other hand, it was observed that Method 3 produces a
homogeneous mixture and at 140 oC it is flowing and can be poured into a mould. Method 3,
therefore, was used as the mxing method for all resins in this study.
2.3
The Additives
The molecules that were synthesized to be used as additives were aliphatic amide nylon-
like oligomers and mixed aliphatic-aromatic amide oligomers. Their linkages, -CONH- can
hydrogen bond and they can be synthesized in a way that they are going to be amino groupterminated (-NH2) so that they could react with the epoxy groups of the resin.
The additives synthesized in this research were based on the reaction product of diamines
and aliphatic linear diacid chlorides. The peptide linkage may be produced in a number of ways.
However, the reaction between an aliphatic amine and an acid chloride is one of the simplest and
easiest to control experimentally. The reagents are simply mixed at room temperature with
solvent and a strong bulky base to remove the HCl by-product. The reaction is inexpensive, a
low temperature reaction and yields hydrogen bonding capable and thermally stable amide
oligomers. The reaction is illustrated in Figure 2.1 below.
20
O
C
H2N
Cl
(-HCl)
Figure 2.1
O
H
C
N
Reaction of amine and acid chloride to form amide.
A representative of the additives made for this work - the reaction product of a C10
diacid chloride, i.e. a diacid chloride with ten carbon atoms, and a C12 diamine, that is a diamine
with twelve carbon atoms - is reproduced below in Figure 2.2. This additive is classified as a
saturated oligomer 10,12 where m is the number of repeating units.
H
H
[
[
O
N
H
Figure 2.2
H
N
N
O
H
m
Representative repeat unit for the 10,12 oligomer prepared using a C10
diacid chloride and a C12 diamine.
2.4
Synthesis of Additives
2.4.1
The Materials
The materials used in the additive syntheses are the following: 1,6-diaminohexane (98%,
Acros Organics), 1,8-diaminooctane (98%, Acros Organics), 1,10-diaminododecane (97%,
Aldrich), 1,12-diaminododecane (98%, Aldrich), p-phenylenediamine (99%, Acros Organics),
m-phenylenediamine (98%, Aldrich), methylenedianiline (97%, Acros Organics), adipoyl
chloride (98%, Acros Organics), sebacoyl chloride (97%, Aldrich), 1,12-dodecanedioyl
21
dichloride (98%, Acros Organics), N,N-dimethylacetamide (99%, Acros Organics) and 1,8diazabicyclo[5.4.0]undec-7-ene (98%, Aldrich).
2.4.2
Synthesis of Nylon-Like Oligomers
The system was flushed with nitrogen to remove water and water vapor. The diamine was
dissolved in an aprotic solvent, N,N-dimethylacetamide (DMAc) in a flask. A bulky base, 1,8diazabicyclo[5.4.0]undec-7-ene (DBU) was added. The diacid chloride in the same solvent was
added slowly with stirring. The reaction was allowed to proceed for at least an hour. Finally, the
reaction mixture was removed and added to a large excess of acidified distilled water to
precipitate the product. The product was filtered off and added to fresh water, then stirred
overnight to remove impurities, then filtered and vacuum dried.
The diamine was always in excess so that the oligomer was amine terminated and can
easily react into the polymerizing resin mixture. The number of moles of the deficient
functionality , in this instance, diacid chloride in the reaction flask is denoted as “A” and the
number of moles of diamine, the excess functionality, is “B”. Assuming that the reaction has
proceeded to completion, the relationship between the extent of stoichiometric imbalance (r) and
their theoretical average chain length, X n , for this class of reaction is X n =
1+ r
, as discussed in
1− r
Chapter 1.5 .The average molecular weight is calculated as, M n = X n × M o , where Mo is the
average of the masses of the reacting monomers.
e.g. If A= 1 and B= 1.25
r = A/B = 0.8
and therefore, Xn= 9
22
The nylon-like oligomers synthesized are listed in Table 2.1 below with their
corresponding theoretical average chain lengths and their theoretical average molecular weights.
Table 2.1
List of nylon-like oligomers used as additives.
material
#C in
moles moles
#C in
theoretical Theoretical
r
Diacid
diacid diamine
Diamine
Xn
Mn
(=A/B)
Chloride
"A"
"B"
(1+r)/(1-r) Xn*Mo
oligomer 6,6
6
6
1
1.75
0.57
3.67
415.25
oligomer 6,6
6
6
1
1.5
0.67
5
565.74
oligomer 6,6
6
6
1
1.4
0.71
6
678.89
oligomer 6,8
6
8
1
1.5
0.67
5
635.87
oligomer 10,8
10
8
1
1.5
0.67
5
776.13
oligomer 6,12
6
12
1
1.75
0.57
3.67
569.68
oligomer 6,12
6
12
1
1.5
0.67
5
776.13
oligomer 10,12
10
12
1
1.75
0.57
3.67
672.63
oligomer 10,12
10
12
1
1.5
0.67
5
916.39
oligomer 12,12
12
12
1
1.75
0.57
5
724.11
oligomer 12,12
12
12
1
1.5
0.67
5
986.52
2.4.3 Synthesis of Mixed Aliphatic-Aromatic Amide Oligomers
The mixed aliphatic-aromatic oligomers were made in the same way as the aliphatic
oligomers were synthesized except for PPDA which had to be mixed with the solvent DMAc and
heated to dissolve because it was less soluble in the chosen solvent.
The diacid chloride used was sebacoyl chloride (C10) and there were three diamine
compounds used to react it with, namely, p-phenylenediamine (PPDA), m-phenylenediamine
(MPDA) and 4,4’-methylenedianiline (MDA). See Figure 2.3 for their chemical structures.
23
a.
b.
H2N
NH2
H2N
c.
NH2
H2N
Figure 2.3
NH2
The chemical Structures of the diamines a. p-phenylenediamine, b. mphenylenediamine and c. 4,4’-methylene dianiline.
The mixed amide oligomer additives that were synthesized are listed in Table 2.2 below.
Table 2.2
Synthesized mixed amide oligomers.
Additive
MPDA10
MPDA10
PPDA10
PPDA10
PPDA10
MDA10
MDA10
MDA10
2.5
#C in
Diacid
Chloride
10
10
10
10
10
10
10
10
moles
diacid
"A"
moles
r
theoretical Theoretical
diamine
(=A/B)
Xn
Mn
"B"
1
1
1
1
1
1
1
1
1.75
1.5
1.75
1.5
1.25
1.75
1.5
1.25
0.57
0.67
0.57
0.67
0.57
0.80
0.67
0.80
(1+r)/(1-r) Xn*Mo
3.67
503.41
5
685.84
3.67
503.41
5
685.84
9
1234.51
3.67
668.77
5
911.14
9
1640.04
Preparation of Resin with Additives
It was found that the additives did not easily dissolve into the resin mixtures. To ensure
dissolution, the MY720 resin, additive and acetone (solvent) were mixed at room temperature
using a high shear mixer for about one hour. Once the additive was mixed thoroughly with the
resin to form a homogenous mixture, the curing agent, DDS, was added and the mixture was
stirred again using the high shear mixer. Then the mixture was heated in an oil bath under rotary
pump vacuum to remove acetone. The temperature of the mixture was gradually increased so
that the mixture remained fluid as acetone was being pumped out. Once the temperature reached
140 oC, the resin was poured into a mould and cured.
24
2.6
The Cure Cycle
After the resin and curing agent have been mixed and heated, the mixture is then poured
into a stainless steel mould and then cured.
As discussed in Chapter 1, the epoxy-amine reaction involves two main reactions. First,
is the reaction of a primary amine with an epoxy group to form a secondary amine and the
second one is the reaction of the secondary amine with an epoxy group which is a slower
reaction and needs a higher temperature to form the network. The cure cycle of the resin used
two heating steps at substantially higher temperatures.
Two cure cycles were tried in this research. The first one was carried out by an initial
cure cycle of 2 h @ 140oC followed by 2h @ 200oC in a programmable, digital, forced air oven.
It was shown by DSC that it only cures the resin to 90%. The cure percentage did not meet the
acceptable degree for stability purposes which is around 95%26 so another cure cycle was
attempted, which was 2 hrs at 140oC and the second heating step was still at 200oC but prolonged
for 4 hrs. This cure cycle resulted in 97% resin cure and thus was used in all subsequent
experiments. The % cure was calculated using the following formula:
φuncured − φ cured
x100 = %
φuncured
cure, where Фuncured (535.6 J/g) is the heat required to fully cure an uncured resin and Фcured is the
residual heat of cure determined by DSC (53.9 J/g for resin cured at 2 hours at 140 oC and 2
hours at 200 oC and 17.1 J/g for resin cured for 2 hours at 140 oC and 4 hours at 200 oC).
2.7
Intrinsic Viscosity Measurements
In order to determine whether or not there was some control achieved over the average
molecular weight of the polyamide oligomer by adjusting the ratio of diacid to diamine, oligomer
fractions were characterized by dilute solution viscometry.
25
About 1 g of sample was dissolved in either filtered 90% formic acid (for nylon-like) or
filtered m-cresol (for aromatic additives) in a 25 mL volumetric flask. The flask of solution along
with a stock solution of 90% formic acid and Ubbelohde viscometer (Figure 2.4) were then
placed in a water bath held at 25oC. A 10 mL portion of the solution was placed in the
viscometer through tube 1. Tube 3 was then covered, while the solution was sucked from tube 2
using a rubber bulb until the solution filled the bulb above line A. The stopper at tube 3 was then
released and at the same time, the suction from tube 2 was released. The solution flows back
down and flow time of the solution from line A to line B, t, was taken. This process was done in
three trials and the average flow time was calculated.
The solution in the viscometer was then diluted by adding 2 ml of the solvent
quantitatively. The solution was allowed to mix and the temperature to equilibrate by blowing air
using a rubber bulb. The same process of elution was done in three trials and the average flow
time was calculated. The solution was successively diluted with 2 ml of solvent and for each
dilution the time of flow was measured for 3-4 times to determine the average flow time at
different concentration of additive.
1
2
3
A
B
Figure 2.4
The Ubbelohde dilution viscometer.
26
2.8
Molecular Weight Determination
The molecular weight and polydispersity index, that is, a measure of molecular weight
distribution of polymers and oligomers can be determined by GPC. This technique involves
separating the polymers or oligomers based on their hydrodynamic size. The sample solution is
passed through a column packed with a porous material. The smaller molecules can penetrate
more into the pores and therefore are more retained and eluted at a longer time. The larger
molecules on the other hand, can penetrate less into the pores and therefore passes through the
column in a less hindered route and are eluted faster.
This technique is done by first performing a calibration using a series of standards of
known molecular weight. The retention time for these standards is then used to create a
calibration curve. The standard used in the GPC was polystyrene. The additives were studied via
GPC using DMAc with 5 g/L LiBr as eluent, with PSS GRAM 10:m, 30Å, 8x50mm as
precolumn, PSS GRAM, 10:m, 30 Å, 8x300mm, PSS GRAM, 10:m, 100 Å, 8x300mm and PSS
GRAM, 10:m, 3000 Å, 8x300mm as columns, with temperature held at 70 oC and flow rate at
1.0 mL/min.
2.9
Fourier-Transform Infrared Spectroscopy
Infrared spectroscopy can often give an idea of what functionalities are present in
additives. The presence of the amide I band, the amide carbonyl peak (a strong peak that usually
appears around 1640 cm-1) and amide II band (the C-N stretching peak for an amide, a medium
band which appears around 1540 cm-1) were all sought to confirm the formation of amide
groups. This technique can also determine if there were unreacted monomer reactants. If
unreacted acid chloride exists a peak around 1815-1770 cm-1 would be observed or if hydrolyzed
unreacted acid chloride is present, a peak around 1640 cm-1 would be observed.
27
About 3 mg of additive was mixed with 300 mg of pre-dried KBr. The mixture was
pressed into a disc then subjected to FTIR using a Nicolet Avatar 360 FTIR.
2.10
Nuclear Magnetic Resonance (NMR)
NMR is an important tool in elucidating chemical structures of organic compounds. The
synthesized additives are fairly large, thus insoluble in most NMR solvents. However, the
additives were soluble in trifluoroacetic acid-d1 and thus this solvent was used for all H-NMR
and CNMR runs.
Approximately 0.1 mg of additive was dissolved in about 1.0 mL of deuterated
trifluoroacetic acid and analyzed in a Varian Mercury 300MHz instrument. Samples were
subjected to both 1H and 13C NMR spectroscopy. The results were compared to those generated
by the NMR spectra predictor, ACD/Labs. The chemical structure is drawn using the software
and the NMR spectra can be predicted by the software using HOSE code and neural net
algorithms to provide the most chemical shifts. It can also predict positions of chemical shifts in
different solvents.
2.11
Tensile Testing
Tensile testing is considered as the most fundamental type of mechanical test that can be
performed on a material. It is simple and relatively inexpensive. By pulling, the material reacts to
forces being applied in tension and its strength and its extension can be measured.
In preparing tensile specimens, the heated uncured resin (refer to Chapter 2.3) was
poured into a dogbone-shaped stainless steel mould, which was pre-treated with silicone mould
release agent and cured (refer to Chapter 2.5). The dimensions of the dogbones are shown in
Figure 2.5 and Table 2.3, in accordance with ASTM D638 Type IV.25
28
.
Figure 2.5
Table 2.3
Dogbone dimensions of ASTM D638 Type IV.
The dimensions of the dogbones.
Dimensions
mm
W- Width of the narrow section
6
L – Length of the narrow section
33
WO – Width overall
19
LO – Length overall
115
G – Gauge length
25
D – Distance between grips
65
R – Radius of fillet
14
RO
25
T - Thickness
3
The sides of the dogbones were smoothened using very fine aluminum oxide sandpaper
to achieve uniformity on their surfaces and eliminate imperfections especially on their thin
29
bodies. The width and thickness of the narrow section were measured using a vernier caliper.
The dogbone specimen was pulled using an Instron Tensile Tester machine. A clip-on strain
extensometer was used to measure strain. The specimen was stretched at a speed of 5 mm/min
[about 0.2 in. /min] in accordance with ASTM D638-02. Force and elongation were measured
and used to calculate stress (σ) and strain (ε). Stress (σ) was calculated by dividing the force at
each time step by the cross sectional area of the narrowest section of the specimen. Strain (ε) was
obtained by measuring the extension of a gage length of 1 inch.
2.12
Fracture Toughness Test
Fracture toughness is a material’s property which describes the ability of a material to
resist fracture. It is indicated by the amount of energy required to propagate a preexisting flaw. It
is very important since flaws are not completely unavoidable in the processing and flaws lead to
premature fracture.
To determine the fracture toughness of the resins, compact tension specimens were made.
The resins were cured the same way as the tensile specimen but cured in a rectangular mould
with a thickness of 1/4 inch. The cured resins were then cut using a band saw and press drilled to
form rectangular-like specimens as shown in Figure 2.6 using the same dimensions described by
Cottington.27
30
Thickness: 0.64- 1 cm, 0.3 ≤ a/W ≤ 0.7 cm, hole diameter: 0.4 -0.5 cm
Figure 2.6
Dimensions of compact tension specimen.
The specimens were tested using the same Instron Tensile tester for tensile testing but
using fixtures at a testing rate of 0.5 in/min .The force at break of each specimen was recordeded
to calculate the fracture energy in J/m2 using the equation below.
Y 2 P@a
FractureEnergy (G ) =
EW 2b 2
Where Y - Geometrical factor
P - load at break in pascals (N/m2)
a - Crack length in meters
E - Elastic modulus in pascals (determined from tensile test)
W- Hole to edge distance in meters
b - Thickness in meters
31
The fracture toughness was then calculated as (√(E*G)) with units of Pa*m1/2.
2.13
Dynamic Mechanical Analysis
Dynamic mechanical analysis is a thermo analytical technique that can be used to study
viscoelastic properties of a material. The sample is subjected to a low sinusoidal stress and the
resulting strain is measured. The storage modulus and loss modulus can be determined as a
function of temperature or time as the polymer is deformed under the oscillating force. The shear
elastic modulus (G’) is used to determine the stiffness of the material.28 The shear loss modulus
(G”) sheds light on the viscous damping and energy dissipation properties of the material. DMA
is also used to determine the glass transition temperature or α transition of a material.
Cured samples were shaped into 1 inch by 0.25 inch and were sent to National Institute
for Aviation Research (NIAR) for DMA. The samples were tested using TA DMA Q800 with a
test fixture of 20 mm, 3-point bent clamp with 15 micrometers oscillating amplitude. Samples
were tested at 1 Hz at a ramp rate of 5 ºC/min from 100 ºC to 300 ºC to determine the alpha
transition and -140 ºC to 30 ºC to determine the beta transition. In DMA, an oscillating force is
applied to a sample of material and the resulting displacement of the sample is measured.
The sample deforms under the load. From this, the stiffness of the sample can be
determined, and the sample modulus can be calculated. By scanning the temperature during
DMA, the abrupt change in modulus due to the transition from glassy to rubbery state, the glass
transition temperature is determined.
2.14
Thermo Mechanical Analysis
Thermo Mechanical Analysis is used to determine the glass transition temperature and
thermal expansion coefficients of materials. It measures the physical dimension change of a
sample due to thermal expansion or indentation at the softening point as a function of
temperature and time. The glass transition (Tg) of a polymer corresponds to the thermal transition
32
of the material from a brittle glassy state at lower temperature to a rubbery state at higher
temperatures. By interpolating the straight line portions of the graph, a value for Tg can be
obtained.
Samples of the cured resin were sent to National Institute for Aviation Research. The
samples were shaped into little squares with the dimensions of 0.25 in. x 0.25 in. and tested using
TA TMA Q400 at a constant load of 1 N and ramped from 100-280 oC, at 5 oC/min.
2.15
Thermogravimetric Analysis
It is important to study how a material degrades with temperature in order to determine
the range of temperatures at which the material is stable. The effect of the additives on the
degradation pattern of the resin was studied by thermogravimetric analysis (TGA). In this
method, the weight of a sample is measured as the material is heated. The percentage weight loss
is recorded against sample temperature. The weight loss curve can be easily differentiated to
achieve a
vs T rate curve.
The samples were prepared by pulverizing using a cryogenic grinder and were sent to
NIAR for TGA. Each sample was tested by placing on a basket-shaped platinum pan and heated
from 30 oC to 750 oC at heating rates of 1, 2, 4, 7 and 10 oC/min under nitrogen atmosphere.
2.16
Differential Scanning Calorimetry
Differential Scanning Calorimetry (DSC) measures the heat flow that accompanies phase
transitions and chemical reactions. In this research, DSC was used to study the kinetics of resin
cure by determining the relationship between degree of cure (α) and the rate of cure (dα/dt) of
the samples as a function of temperature and calculating the activation energy for the cure
reaction (Ea).
The general formula for rate of reaction for epoxy cure is;28
33
(1)
dα
= kf (α )
dt
where α is the degree of cure, t is the reaction time, k is the reaction constant and f(α) is a
function of degree of cure. Usually, k shows an Arrhenius type temperature dependence
(2)
k = Ae
 − Ea 


 RT 
where A is the pre-exponential factor, Ea is the activation energy of cure, R is the universal gas
constant (8.314 J/mol K) and T is the temperature in Kelvin.
Therefore,
 − Ea 


(3)

dα
= A f (α )e  RT
dt
However,
(4)
dα
dα
=Φ
dt
dT
where Φ is the heating rate. Substituting equation 4 into 3 gives,
− Ea
(5)
dα
Φ
= Af (α )e RT
dT
Taking the logarithm of the above variables results gives,
(6)
ln{Φ
E
dα
} = (ln A + ln f (α )) − a
dT
RT
At a constant α, ( lnA + ln f (α) ) is a constant and ln{Φ
Therefore in ln{Φ
dα
} becomes proportional to 1/T.
dT
dα
} vs 1/temperature plots, m= -Ea/R
dT
The activation energy of cure can then be estimated for values of α from 0.05 to 0.95, thus can
show any changes in the reaction mechanism at different α’s.
34
The effect of the additives on the kinetics of the curing of the resin was studied. About 710 mg of the uncured resin was loaded in a T-Zero aluminum DSC pan and sealed with T-Zero
aluminum lid. For all DSC experiments the sample was equilibrated at 30 oC and then ramped
from 30 oC to 350 oC at a specific rate using TA Q2000, which was pre-calibrated with a
sapphire calibration disc. This process was done for the following heating rates ranging from 120 oC/min. To verify whether the resin was fully cured after the first heating, the resin sample
was cooled down to 30 oC at a rate of 30 oC/min and reheated to 400 oC at 10 oC/min. No excess
exotherm was observed for all samples, so it was concluded that all resins were fully cured after
the first heating.
TA universal analysis software was used to analyze DSC results. The degree of cure (α)
was calculated by dividing the area of the cure exotherm at that point by the total exotherm area
times 100. The degree of cure intervals of 0.05 was differentiated with respect to time using
Origin software, which yielded rate of cure at that value of α. Plots of rate of cure vs temperature
were constructed for each heating rate using Microsoft Excel. Summary graphs for degree of
cure (α) and rate of cure vs temperature were then generated using Microsoft Excel to determine
the effect of heating rate on the above two factors. Logarithms of rate of cure vs 1/temperature
plots for each degree of cure ranging from 0.05 to 0.95 were constructed. Activation energy of
the curing at different values of α was then calculated using the gradients of these plots.
35
CHAPTER 3
RESULTS AND DISCUUSION: NON-AROMATIC ADDITIVES
3.1
Synthesis of Oligomers
The first additives synthesized in this research were a set of nylon-like molecules based
on the reaction products of aliphatic linear diamines and aliphatic linear diacid chlorides. The
oligomers were synthesized by using the following representative scheme shown in Figure 3.1.
o
Cl
Cl
+
DMAc
H 2N
NH 2
DBU
o
O
N
H
H 2N
N
H
O
Figure 3.1
H
+ DBU•HCl
N
H
n
Scheme for the synthesis of Nylon 6,6
The amine reactant added to the reaction mixture was in slight excess. Hence, the
oligomer products were amine terminated at both ends. Since control over stoichiometry was a
crucial aspect of the reaction, the conditions of the synthesis were controlled in such a way that
none of the monomers would be lost to side reactions.
Since one of the monomers is a diamine and the other monomer is a diacid chloride,
using a protic solvent in the synthesis was not an option. The acidic hydrogen of the solvent
would react with the amine and the diacid choride is very sensitive towards nucleophiles. The
solvent used DMAc, is an aprotic polar solvent. DMAc was a good choice since it hydrolyzes in
acidified water and therefore can be washed away easily from the oligomer product.
36
The addition of base, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was needed to react
with HCl produced in the reaction to prevent the amino groups from reacting with the HCl so
produced to form salts that will not react with the acid chloride. Furthermore, if the amine chain
ends are present as the salts, this would also prevent the oligomers from eventually reacting with
epoxy groups in the resin. The DBU base is very bulky and its basic nitrogen is sufficiently
sterically hindered that it will not itself react with the diacid chloride. The use of a smaller bulky
base such as triethylamine (TEA) was attempted, however the oligomers precipitated out in the
middle of the reaction leading to poor control over molecular weight. The solubility of the
oligomers in DMAc/DBU mixture was better compared with DMAc/TEA.
The oligomer produced in the reaction was isolated by precipitation by addition of
acidified water with stirring. DBU was washed off by filtering the precipitated oligomeracidified water mixture and additional washing with acidified water.
3.2
FTIR
The IR spectrum for nylon 6,6 Xn =6 oligomer, reproduced in Figure 3.2 (all other
spectra are shown in Appendix A) reveals a strong carbonyl amide I band at 1637 cm-1 and
medium amide II band at 1539 cm-1, which is due to C-N bending. The large peak at 3320 cm-1
also confirms the presence of N-H stretching of the amides. The medium absorption peak at 3295
cm-1 is due to amide hydrogen bonded N-H, further confirming this hypothesis.
An enlargement of the carbonyl section shows a little hump around 1750 cm-1 (Figure
3.3) This means that the additive has a negligible amount of acid impurity which was a product
of the hydrolysis of the diacid chloride. This also means that the oligomer is not acid-terminated,
and therefore, is amine-terminated.
37
Nylon 6,6 Xn=6
2.50
2.00
Amide I
absorbance
1.50
Amide II
1.00
0.50
0.00
4000
3500
3000
2500
2000
1500
1000
500
-
wavenumber (cm )
Figure 3.2
FTIR spectrum of nylon 6,6 Xn =6.
Nylon 6,6 Xn=6
2.50
2.00
absorbance
1.50
1.00
Acid C=O
0.50
0.00
1800
1750
1700
1650
1600
-
wavenumber (cm )
Figure 3.3
The acid carbonyl peak in the FTIR of nylon 6,6 Xn =6.
38
1550
1500
3.3
1
H NMR
The proton and
13
C spectra obtained for Nylon 6,6 Xn=3.67, are reproduced below in
Figure 3.4 and Figure 3.6. All other NMR spectra are given in Appendix B.
Trifluoroacetic acid
NH
1
Figure 3.4
H NMR spectrum of Nylon 6,6 Xn=3.67
Shifts observed in the NMR spectra were compared to modelled shifts generated using
ACDLABS (9.0) software. Figure 3.5 shows the structure of Nylon 6,6 Xn=3.
O
H2 N
10
9
8
7
6
5
4
NH
3
2
11
12
O
13
14
16
15
NH
17
18
19
20
21
22
NH2
23 24
1
Figure 3.5 Chemical structure of Nylon 6,6 Xn=3 with numbered atoms.
39
Table 3.1
Experimental and predicted chemical shifts for Nylon 6,6 Xn=3.67
Carbon number
assignment on Figure 3.5
Chemical shift generated
by ACD software/ ppm
6, 20
1.30
Chemical shift observed
experimentally in Figure
3.4/ ppm
1.55
8,22
1.50
1.80
5,19
1.58
1.90
12
1.69
2.65
11,14
2.21
2.75
9,23
2.54
3.40
4,18
3.07
3.60
It was observed that the spectra predicted from ACD software and those that were
observed experimentally were similar, however, the peaks show up more downfield in the
experimentally determined one. However, the chemical shifts obtained using ACD software were
predicted using methanol-D as the solvent while the samples were dissolved in trifluoroacetic
acid which is a more polar solvent than chloroform and therefore the peaks were observed
further downfield.
Seven prominent peaks, excluding the peak at 11.7 ppm, which is from the solvent
deuterated trifluoroacetic acid, were observed in the experimental spectrum and are consistent
with the ACD predicted spectrum. The small broad NH peak observed at 6.85 ppm is way
downfield compared to the one predicted in ACD which is at 5.25 ppm. This is probably
observed because the NH groups in the additive forms hydrogen bonds with the solvent.
Small peaks found at 2.2, 3.5, and 3.8 ppm indicates the presence of traces of DBU.
40
The 13C NMR spectrum (Figure3.6) of nylon 6,6 Xn = 3.67 was difficult to interpret. See
Figure 3.6, Based on the structure in Figure 3.5 the 8 methylene carbon atoms are expected to be
seen in the spectrum. However, the sample was a mixture of nylon 6,6 oligomers. The Xn was
3.67 but this is only the theoretical average length. This means longer and shorter chains are
present in the mixture. And the presence of longer chains result in the appearance of quite a
number of peaks in the spectrum. However it can still be pointed out that the sample has a
carbonyl peak at 181 ppm which is quite high compared to a normal amide carbonyl. The
downfield shift is caused by extensive hydrogen bonding among the carbonyl groups. The peak
at 44.96 ppm is the peak for carbon atoms next to nitrogen atoms and the peak at 36.21 ppm is
the peak for the carbon atom next to a carbonyl. The peaks at 50 ppm and 55 ppm are due to the
pressence of DBU which means that DBU was not completely removed by washing.
Nylon 6,6 Xn=3.67
4000
3500
Trifluoroacetic
acid
absorbance
3000
2500
DBU
2000
1500
1000
500
0
200
180
160
140
120
100
80
60
40
ppm
Figure 3.6
13
C NMR spectrum for Nylon 6,6 Xn=3.67
41
20
0
3.4
Solubility Test
Nylon polymer is known to be insoluble in most solvents. Its solubility is suppressed by
the polar amide groups. Molecular dissolution requires strong interaction between the solvent
and the amide groups to disrupt the inter-chain hydrogen bonding of the amide groups.
Moreover, the hydrophobic interactions of the methylene sequences must also be loosened. The
most common solvents for nylon 6,6 are strong oxy-acids such as H2SO4 and formic acid and
solvents having solubility parameters close to its own like phenols (e.g. phenol and cresols).
Nylon 6,6 possesses solubility parameters29 (Hildebrand) of δd=18.62, δp=5.11, and δh=12.28 (δ
in MPa1/2). Solubility parameters for m-cresol are δd=18.0, δp=5.1, and δh=12.9.
Because the synthesized oligomers have a range of lengths of methylene sequences and
low molecular weights they might not have the same solubility as long chain nylon 6,6.
Therefore, solubility had to be tested before performing experiments which would require
dissolution, such as intrinsic viscosity (IV). The solubility of nylon-like oligomers in 90% formic
acid and m-cresol were tested. These two are commonly used in IV experiments for nylon 6,6.
Solubility in DMF and DMAc were also of interest since DMAc was used as the solvent in the
synthesis and DMF is a close relative. All oligomers were soluble in m-cresol. This means that
the solubility parameters of the other oligomers must also be close to the parameters of m-cresol.
The solubility in 90% formic acid decreases as the methylene sequences gets longer (Figure 3.7).
The same behavior was also observed concerning the solubility of the additives in DMAc and
DMF. It is commonly known that as the polymer chain length increases, in order to maintain
solubility, the difference in solubility parameter between the polymer and solvent must be
lessened.
42
CD
1
CD
2
PD
3
PD
4
CD
1
a. Nylon 6,6
CD
1
CD
2
CD
2
PD
3
PD
4
ND
3
ND
4
b. Nylon 6,8
PD
4
PD
3
PD
1
CD
2
d. Nylon 10,12
c. Nylon 6,12
PD
1
CD
2
ND
3
ND
4
e. Nylon 12,12
Figure 3.7
3.5
Solubilities of different nylon oligomers in (1) 90% formic acid (2) m-cresol
(3) DMF and (4) DMAc. (CD = completely dissolved, PD = partially dissolved
and ND = not dissolved)
Intrinsic Viscosity
Intrinsic viscosity (IV) experiments were conducted to determine whether there was some
control of the oligomer length by adjusting the mole to mole ratio of diacid chloride to diamine.
The nylon 6,6 aditive was soluble in 90% formic acid and thus this solvent was used for IV
experiments.
Figure 3.8 shows the plot of specific viscosity divided by concentraion versus
concentration for nylon 6,6, where the y-intercept of the equation of the curve was taken as the
intrinsic viscosity of the oligomer.
43
Nylon 6,6 Xn=6
30
Intrinsic Viscosity
25
y = 866.63x + 10.664
2
R = 0.9736
nsp/C
20
15
10
5
0
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
C (g/ml)
Figure 3.8
Intrinsic Viscosity of Nylon 6,6 Xn=6
Since the Mark-Houwink-Sakurada parameters of Nylon 6,6 in formic acid at
25oC are known from the literature (K= 11.0 x 10-2 mL/g and a = 0.72),29 the molecular weights
of the oligomers can be estimated by using the Mark-Houwink equation, [η ] = KM va as discussed
in Chapter 1.5. However, this is not going to give the true average mass since the parameter is
experimentally determined for nylon polymers of high average masses. The α parameter gets
closer to the value of theta (θ), 0.5, as the polymer chain length is reduced. Theta is a condition at
which the polymer coils act like ideal chains, assuming exactly their random walk coil
dimensions. Corresponding molecular weights calculated from the equation using the parameters
for nylon 6,6 and the molecular weights when α =0.5 and α =0.72 are listed in Table 3.2.
Formula weight is calculated as X n x Mo, where Mo is the weight of the repeating unit.
44
Table 3.2
Corresponding MW of Nylon 2 Intrinsic viscosities and their 6,6 oligomer.
Oligomer
Nylon 6,6
Nylon 6,6
Nylon 6,6
Xn
3.67
5
6
IV
(mL/g)
2.9283
5.1931
10.6640
MW/g
(α=0.72)
708.67
2228.78
9398.42
MW/g
(α=0.72)
95.38
211.37
574.20
Formula
Weight
415
565
678
From the results it is apparent that when either a value is used the average polymer
molecular weight or chain length increases with the theoretical X n . Therefore, we are exerting a
modicum of control over average molecular weight, M n , by adjusting the ratio of the diamine to
diacid chloride in the additive synthesis reactor.
When the α values are calculated from the intrinsic viscosities and the formula weight it
can be noted that the α parameter does approach 0.5 (Table 3.3). This further proves that
adjusting the monomer ratio indeed controls the average chain length of the oligomers. As the
X n is reduced, the α value approaches its theta (θ) value of 0.5.
Table 3.3
The calculated a parameters of the nylon 6,6 oligomers.
Oligomer
Nylon 6,6
Nylon 6,6
Nylon 6,6
3.6
Xn IV (g/ml) Formula Weight
3.67 2.9283
414.71
5
5.1931
565
6
10.664
678
Calculated a
0.54
0.60
0.70
Curing of Resin
Making dogbones was not a straightforward process. Sometimes the cured specimens
contained bubbles and these specimens had to be discarded. It was thought that the bubbles were
caused by residual acetone, the solvent that was used in mixing the resin and curative,
evaporating as the resin is cured in the mould. This would mean that acetone was not completely
removed by vacuum pumping prior to curing. To address this issue, three alternative methods of
45
preparing the resin mixture were tested as described in Chapter 2.2. In Method I, the MY720
resin and the DDS were heated and mixed in a paddle mixer - upon reaching 140 oC, the resin
mixture was poured into a mould. Method II uses a shear mixer instead of a paddle mixer. And
lastly, in Method III, the resin and the DDS are dissolved in acetone then heated and mixed. (See
Chapter 2.2 for more detailed procedure.) After achieving a homogeneous mixture, the acetone
was pumped off while heated until the temperature is 140 oC, poured into a mould and then
cured.
Mixing the curing agent DDS with the MY720 without a solvent turned out to be difficult
even with heating and the use of a paddle mixer or shear mixer. The mixture could not be
homogenized. The cured dogbones made by these methods had some observable undissolved
curing agent. Mixing was much easier when solvent was used (Method III). The mixture with
acetone was heated and stirred. When the temperature of the oil bath reached 140 oC and the
acetone was pumped off, the mixture became viscous but could still be poured into the mould.
The cured dogbone resin looked clear and free from undissolved particles. Tensile tests were
performed on these dogbones and their stress-strain curves were generated. An example of these
plots are shown on Figure 3.9 which are generated using the dogbones that were made using
Method III.
The slopes of the initial straight line of the curves (slope from 0% to 0.5% straight
arbitrarily chosen) were taken as the moduli and the average modulus was calculated. An
example of this is shown in Figure 3.10, i.e. from the initial part of the curve of specimen 1 of
control resin made by Method III.
46
Tensile Testing Curves for Control Resin (Method III)
6.00E+07
5.00E+07
sp 1
sp2
stress (Pa)
4.00E+07
sp3
sp4
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
strain (%)
Figure 3.9
Stress-strain curves of control specimens made by Method III.
Control Resin Specimen 1 (Method III)
2.00E+07
stress (Pa)
1.80E+07
1.60E+07
y = 33944286.6692x + 361418.5040
1.40E+07
R = 0.9997
2
1.20E+07
1.00E+07
8.00E+06
6.00E+06
4.00E+06
2.00E+06
0.00E+00
0.00
0.10
0.20
0.30
0.40
0.50
strain (%)
Figure 3.10 Linear initial part of the stress-strain curve of specimen 1 made by Method
III.
47
The averages of the tensile results for the dogbones are listed on Table 3.4.
Table 3.4
The tensile results for Control, made with and without acetone as solvent.
Average
Stress at
Break
(Mpa)
Std.Dev
(MPa)
Material
Control
Method
III
34.0856
1.4112
Control
Method I
34.5058
0.7034
%
change
1.2328
Average
Stiffness
(Mpa)
Std.
Dev
(Mpa)
48.5179
1.6434
30.6917
5.5058
%
Change
Average
Strain
to Break
0.0159
(1.590%)
-36.7415
0.00928
(0.928%)
Std. Dev
%
Change
0.00126
(0.126%)
0.00200
(0.200%)
-41.6352
The undissolved particles in the resin cured without the use of solvent (Method I) had
become nuclei for crack formation, thus the resins failed at a low stress. Its stiffness is 36.7% and
strain to break is 41.6% lower than the ones made using Method III. No resins made using
Method II were tested because none of the dogbones made were suitable for testing. Some were
already broken in the mould.
It is apparent that the use of acetone in mixing of the resin made things easier and
resulted in specimens with better properties. So even though this method sometimes produced
bubbles in the specimens, it is still used for all succeeding experiments. Samples containing
bubbles in the test zone were discarded. Those that had few surface bubbles were recovered by
surface smoothing with sandpaper.
3.7
Curing with Oligomer
The amine to epoxy mole to mole ratio was kept constant at 1.1:1 for all resin systems
including systems with additive. The amount of amine terminated additive loaded to the resin
was also taken into account when adjusting stoichiometry.
48
There were some issues regarding the solubility of oligomers with shorter methylene
segments, namely nylon 6,6, nylon 6,8 and nylon 10,8 in the base resin. These oligomers did not
completely dissolve during mixing with the base resin, DDS, and acetone prior to curing even at
140 oC. As a result cured resins made with the previously mentioned additives possessed some
visible particles throughout the cured resin. However, mixtures made using nylon 6,12, nylon
10,12 and nylon 12,12 oligomers were more homogeneous. These longer segment oligomers
produced a more homogenous cured resin. These resins were a little opaque but with no visible
particles. It was also observed that the longer the oligomer (keeping the structure fixed) the more
opaque was the final cured resin. In some instances, we were completely unable to mix resin
with additive. For example, mixing powdered nylon 6,6 oligomers with resin dissolved in
acetone overnight prior to adding the DDS curative was attempted. With heating or without
heating the nylon 6,6 type would not dissolve.
3.8
Tensile test
The first resins prepared for tensile test were cured using the cure cycle 2 hours at 140oC
and 2 hours at 200 oC because it was not known yet that this cure cycle only cured about 90% of
the resin. The resins prepared in this cure cycle are listed in Table 3.5 and their formulations are
also given in the same table.
49
Table 3.5
Formulation of nylon 6,6 oligomers.
material
moles
diacid
"A"
moles
diamine
"B"
r (=A/B)
theoretical
Xn
(1+r)/(1-r)
MY720-DDS
g DDS/ g
MY720
g additive/
1g of
MY720
0.6472
0
1.1
Amine
NH/epoxy
nylon 6,6 Xn=3.67
1
1.75
0.57
3.67
0.6173
0.05
1.1
nylon 6,6 Xn=5
1
1.5
0.67
5
0.6253
0.05
1.1
nylon 6,6 Xn=6
1
1.4
0.71
6
0.6289
0.05
1.1
nylon 6,8 Xn=5
1
1.5
0.67
5
0.6277
0.05
1.1
nylon 10,8 Xn=5
1
1.5
0.67
5
0.6308
0.05
1.1
nylon 6,12 Xn=3.67
1
1.75
0.57
3.67
0.6254
0.05
1.1
nylon 6,12 Xn=5
1
1.5
0.67
5
0.6312
0.05
1.1
nylon 10,12 Xn=3.67
1
1.75
0.57
3.67
0.6287
0.05
1.1
nylon 10,12 Xn=5
1
1.5
0.67
5
0.6337
0.05
1.1
nylon 12,12 Xn=3.67
1
1.75
0.57
3.67
0.6301
0.05
1.1
nylon 12,12 Xn=5
1
1.5
0.67
5
0.6346
0.05
1.1
Stress-strain curves for these resins are shown in Appendix B.
The results of the tensile tests are given in Tables 3.6-3.8. In general, the stiffness of the
resin increased when fortified with the nylon additives. It can be noted in Table 3.6 that as the
theoretical Xn increases, the stiffness decreases, see results for resins #2, #3, and #4 for nylon
6,6, resins #7 and #8 for nylon 6,12 and resins #9 and #10 for nylon 10,12. However, resins #11
and #12 nylon 12,12 have an opposite trend.
50
Table 3.6
Stiffness of dogbones made with different oligomer additives at 3% load.
1
Material
Control
Xn
(Theoretical)
(1+r)/(1-r)
X
Stiffness
Average
Standard
Stiffness %
(MPa)
deviation (MPa) Change
31.3225
0.9334
X
2
Nylon 6,6
3.67
33.4132
0.5452
6.6748
3
Nylon 6,6
5
30.4412
1.3864
-2.8136
4
Nylon 6,6
6
30.2533
0.0593
-3.4135
5
Nylon 6,8
5
32.2860
1.2824
3.0761
6
Nylon 10,8
5
31.7545
1.1859
1.3792
7
Nylon 6,12
3.67
34.0990
1.7906
8.8642
8
Nylon 6,12
5
33.9584
1.6408
8.4153
9
Nylon 10,12
3.67
33.8266
0.8405
7.9946
10
Nylon 10,12
5
33.4612
0.3593
6.8280
11
Nylon 12,12
3.67
32.1563
0.2433
2.6534
12
Nylon 12,12
5
32.1751
0.2574
2.7220
Resins #2-6 failed at stresses a lot lower than that of the control resin (Table 3.7). It was
expected that these resins would fail at a lower stress than the control because of the presence of
undissolved particles in the cured resin. These particles served as nuclei for crack formation.
However, generally, for resins #7-12, which had better dissolution in the resin mixture, those
with Xn =3.67 oligomers failed at stresses higher than those which are fortified with Xn =5 and
that of the control. This shows that the oligomers with higher methylene content have a positive
effect on the resin in terms of strength. However, increasing the theoretical chain length had an
adverse effect. We believe that this is related to solubility issues. The longer the theoretical
average chain lengths the less soluble the oligomer is in the resin mixture.
51
Table 3.7
load.
1
Stress at break of dogbones made with different oligomer additives @ 3%
Material
Control
Stress at Break
Xn
% Change
Standard
(Theoretical)
(1+r)/(1-r) Average (MPa) Deviation (Mpa)
X
67.6899
5.9206
2
Nylon 6,6
3.67
37.0206
5.3071 -45.308532
3
Nylon 6,6
5
25.1346
0.7279
4
Nylon 6,6
6
26.0263
2.2538 -61.550689
5
Nylon 6,8
5
19.8043
2.6305 -70.742607
6
Nylon 10,8
5
40.6702
3.2257 -39.916856
7
Nylon 6,12
3.67
76.8637
10.3891
13.5527
8
Nylon 6,12
5
69.4538
0.7230
2.6059
9
Nylon 10,12
3.67
84.3584
8.8296 24.624796
10
Nylon 10,12
5
66.9616
8.3421
-1.0759
11
Nylon 12,12
3.67
75.3148
13.7355
11.2645
12
Nylon 12,12
5
65.6532
5.3717
-3.0089
-62.86802
The results for strain-to-break tensile experiments summarized in Table 3.8 show
congruence with stress at break. Resins #2-5 in Table 3.8 exhibit lower strains compared to the
control while resins #7, 9 and 11 which were all resins with Xn =3.67 had extended longer than
the control when they failed and are higher compared to their analogs with Xn =5. We believe
that this is again solubility related. Due to the presence of the undissolved particles, resins #1-6
do not take long to elongate before they break.
52
Table 3.8
Strain at break of dogbones made with different oligomer additives.
Xn
Material
3.9
1
Control
2
(Theoretical)
(1+r)/(1-r)
Strain at Break
Standard Deviation
% Change
X
0.02 70 (2.702%)
0.003399 (0.3399%)
Nylon 6,6
3.67
0.01 40 (1.400%)
0.001414 (0.414%)
-48.1481
3
Nylon 6,6
5
0.0 120 (1.20%)
0.007482 (0.748%)
-55.5556
4
Nylon 6,6
6
0.0 123 (1.23%)
0.007307 (0.731%)
-54.4444
5
Nylon 6,8
5
0.00 59 (0.590%)
0.000781 (0.0781%)
-78.1481
6
Nylon 10,8
5
0.0 137 (1.37%)
0.001155 (0.116%)
-49.2593
7
Nylon 6,12
3.67
0.0 277 (2.77%)
0.002887 (0.289%)
2.5926
8
Nylon 6,12
5
0.026 (2.6%)
0.0002828 (0.0283%)
-3.7037
9
Nylon 10,12
3.67
0.0 333 (3.33%)
0.005686 (0.569%)
23.3333
10 Nylon 10,12
11 Nylon 12,12
5
0.024 19 (2.419%)
0.003965 (0.396%)
-10.4074
3.67
0.02 908 (2.93%)
0.007578 (0.758%)
7.7037
12 Nylon 12,12
5
0.02 448 (2.45%)
0.002602 (0.260%)
-9.3333
Tensile Testing of Resins Using New Cure Cycle
Since it was found out previously that oligomers of nylon 10,12 and nylon 12,12 have
some positive effects on the mechanical properties of the MY720 resin, dogbone resins fortified
with 5% of these oligomers were made using the new cure cycle, 2 hours at 140 oC and 4 hours
at 200 oC and then tensile testing was performed. Table 3.9 shows the stiffness of the resin with
additives. Stiffness decreased by a small percentage apart from nylon 12,12 Xn=3 at 5% load.
No general pattern can be concluded in terms of the effect of Xn of the oligomer.
53
Table 3.9
Stiffness of the dogbones with different nylon oligomers at 5% load.
material
MY720-DDS control
stiffness
standard
average deviation
(MPa)
(MPa)
34.0856 1.4112
Stiffness
%
change
Nylon 10,12 Xn=3 5%
32.2651
0.4462
-5.3410
Nylon 10,12 Xn=3.67 5%
33.4695
0.8089
-1.8075
Nylon 10,12 Xn=5 5%
33.9174
0.0535
-0.4936
Nylon 12,12 Xn=3 5%
34.7467
1.3209
1.9395
Nylon12,12 Xn=3.67 5%
31.8300
0.2477
-6.6173
Nylon 12,12 Xn=5 5%
32.8598
0.6410
-3.5962
The effect of the additives on stress at break is shown in Table 3.10. It can be seen that all
of the resins with additive broke at stresses higher than that of the control with nylon 10,12
Xn=3.67 improving the resin by 57.9%. However, no general trend could be concluded based on
the results.
54
Table 3.10
Stress at break of the dogbones with different nylon oligomers at 5% load.
stress at break
control
Nylon 10,12
Xn=3 5%
Nylon 10,12
Xn=3.67 5%
Nylon 10,12
Xn=5 5%
Nylon 12,12
Xn=3 5%
Nylon12,12
Xn=3.67 5%
Nylon 12,12
Xn=5 5%
stress at
break %
change
average
(MPa)
48.5179
standard
deviation
(MPa)
1.6434
67.3995
3.4096
38.9168
76.5965
7.8769
57.8727
62.8425
7.7879
29.5244
72.6986
1.6213
49.8387
65.1828
8.0533
34.3478
68.1505
7.1093
40.4646
material
The results for the comparison of strain at break are shown on Table 3.11 The extensions
at break of the resins with additive were higher than that of the control. This means that the resin
had become less crack sensitive. Nylon 10,12 Xn=3.67 increased the strain at break by 92.4%.
Again no trend can be concluded in terms of the effect of structure of additive or Xn .
55
Table 3.11
Strain at break of the dogbones with different nylon oligomers at 5% load.
strain at break
material
Control
Nylon 10,12 Xn=3 5%
Nylon 10,12 Xn=3.67 5%
Nylon 10,12 Xn=5 5%
Nylon 12,12 Xn=3 3%
Nylon 12,12 Xn=3.67 5%
Nylon 12,12 Xn=5 5%
Average
0.01590 (1.590%)
0.02530 (2.523%)
0.03059 (3.059%)
0.02249 (2.249%)
0.02674 (2.674%)
0.02417 (2.417%)
0.02497 (2.497%)
standard deviation
0.01260 (0.1260%)
0.001959 (0.195%)
0.005296 (0.53%)
0.004031 (0.403%)
0.001725 (0.172%)
0.003571 (0.357%)
0.004972 (0.497%)
extension at
break %
change
59.1195
92.3899
41.4465
68.1761
52.0126
57.0440
In general the addition of nylon 10,12 and nylon 12,12 oligomers improved the properties
of the resin. Both the stress at break and extension at break were increased with a minimal
decrease in stiffness except for nylon 12,12 Xn=3 at 3% load because it improved all three
properties studied. No general trend could be established and this could be because it was hard to
control uniformity of the specimens. Achieving perfect specimens was hard because most of the
times the specimens would contain gas bubbles.
3.10
Thermomechanical Analysis
Thermomechanical analysis (TMA) can determine the softening temperature of a
material. The TMA results for the cured resin, resins with 5% load and 10% load of nylon 10,12
Xn =3.67 are shown in Figure 3.12. It was determined that the softening temperature of the
fortified resins were higher than that of the control.
Softening temperature is affected by the strength of the intermolecular forces of attraction
in the material. The stronger the forces the higher the temperature required to soften. The
additives in the resin are capable of hydrogen bonding which is the strongest among all
intermolecular forces. So these hydrogen bonds were responsible for making the resin more
resistant to softening.
56
It is interesting that the softening temperatures of the resin with 5% and 10% additive
were about the same. This might be brought about by the opposing effect of the decrease in
crystallinity of the resin when more of the additive is loaded. Although the additives are creating
hydrogen bonds, the crystallinity of the material decreases as more of the additive is added.
TMA: Resins with Nylon 10,12 Xn=3.67 vs Control Resin
200
0
µm
-200
Control
-400
Nylon 10,12 Xn=3.67 5%
Nylon 10,12 Xn=3.67 10%
-600
-800
-1000
0
50
100
150
200
250
300
350
400
Temperature (°C)
Figure 3.11
Comparing TMA output for nylon 10,12 Xn=3.67 and control.
Table 3.12
Softening temperatures of control resin, resins with nylon 10,12 Xn=3.67 5%
and 10% determined by TMA.
TMA (Tm)
Sample #
Control Resin
Resin with Nylon 10,12 Xn=367 5%
Resin with Nylon 10,12 Xn=367 10%
57
Dimension Change
Tm [°C]
Tm [°F]
326.58
619.84
331.28
628.30
330.81
627.46
3.11
Conclusion
The additives synthesized are amide oligomers and are amine terminated as suggested by
FTIR and NMR results. The length of the oligomers can be somewhat controlled by adjusting the
mole ratio of the reacting monomers. The additives did not easily homogenize with the resin
especially the additives that contain monomers with shorter methylene sequences, resulting in
deterioration of mechanical properties of the resin.
Nylon 10,12 and Nylon 12,12 additives improved the tensile strength and increased the
strain to break of the resin. It can be said that these nylon oligomers apparently did create
hydrogen bonds as reflected by the increase in the softening temperature and the increase in
tensile strength of the resin when compared to control.
Because of the low solubility of the additives in the resin, the research went into the
direction of exploring additives with lesser crystallinity but with some bulky groups that may
help make the resin stiffer. These oligomers are going to be discussed in the next chapter.
58
CHAPTER 4
RESULTS AND DISCUSSION: MIXED AMIDE ADDITIVES
4.1
Introduction
In chapter 3, it was concluded that the nylon-like oligomers were too crystalline and thus
solvating in the resin was a problem. To address this issue, the research went into the direction of
using less crystalline oligoamides. As dicussed in Chapter 3, it was determined that the longer
the methylene sequence in the oligomer, the more soluble the oligomer becomes in the resin,
resulting in a cured resin with better mechanical performance. Based on those ideas, the new set
of oligomers explored were mixed oligoamides made from a diacid chloride with long methylene
sequence, sebacoyl chloride (C10) and aromatic diamines, namely methylenedianiline (MDA),
p-phenylenediamine (PPDA) and m-phenylenediamine (MPDA). These aromatic diamines have
bulky and rigid rings that makes the additive less crystalline.
The nomenclature of their
corresponding oligomers is shown in Figure 4.1.
O
a.
+
H2N
NH2
Cl
Sebacoyl Chloride
MDA
H2N
MDA10
Cl
MPDA10
Cl
PPDA10
O
O
NH2
b.
Cl
+
Cl
Sebacoyl Chloride
MPDA
O
O
c.
H2N
NH2
PPDA
Figure 4.1
+
Cl
Sebacoyl Chloride
O
The chemical structures of the monomers and the corresponding names of
their oligomers.
59
Synthesis of Oligomers
The synthesis scheme for MDA10, as a representative for this new set of oligomers is
shown in Figure 4.2. The synthesis is very similar to the synthesis of nylon-like oligomers in
Chapter 3. N.N-dimethylacetamide is still used as the solvent and DBU is still used as base to
neutralize HCl produced in the reaction.
O
+
H2N
DBU•HCl
HCl
NH2
Cl
Cl
O
O
+
NH
H2N
NH H
NH
O
Where n= 2.67, 4 and 8
Figure 4.2
DMAc
DBU
n
Scheme for the synthesis of MDA10
The different number average degrees of polymerization ( Xn ) or simply the theoretical
chain lengths of the additive were made by adjusting the monomer ratios. For MDA10, for
example, see Table 4.1. The corresponding theoretical molecular masses are also listed below.
The number average molecular weight (Mn) was also calculated by multiplying Xn with Mo,
where Mo is the average mass of the two monomers sebacoyl chloride and the diamine. Different
theoretical chain lengths of MPDA10 and PPDA10 oligomers were also preapared in the same
manner.
60
Table 4.1
The number average degrees polymerization of MDA10 and their
corresponding reagent ratios.
Ratio Theoretical Theoretical
Oligomer Moles Sebacoylc Moles
Chloride (A)
MDA (B) r=A/B
Mn = Xn *M0
Xn
MDA10
MDA10
MDA10
4.2
1
1
1
1.75
1.5
1.25
0.57
0.67
0.80
3.67
5
9
661.49
901.21
1162.18
Infrared Spectroscopy
Figure 4.3 below is a representative IR spectrum of the additives. All other spectra are
given in Appendix A. The MDA10 Xn=3.67 IR spectrum reveals a carbonyl amide I band at
1660 cm-1 and medium amide II band at 1540 cm-1, which is due to C-N bending.. The medium
absorption peak at 3295 cm-1 is due to amide hydrogen bonded N-H. This showed that the
additive has an amide functionality. Enlargement of the carbonyl area in Figure 4.4 shows the
absence of a band around 1750 cm-1 which means that the product was free from acid impurity, a
hydrolysis of the diacid chloride. This also means that the oligomer is not acid-terminated. The
large peak around 1610 cm-1 is due to carbon to carbon aromatic double bond.
61
IR Spectrum of MPDA10 Xn=3.67
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
4000
3600
3200
2800
2400
2000
1600
1200
800
400
wavenumber (cm-)
Figure 4.3
FTIR Spectrum of MPDA10 Xn=3.67
IR Spectrum of MPDA10 Xn=3.67
1.20
1.00
absorbance
0.80
0.60
No Acid C=O
0.40
0.20
0.00
1800
1700
1600
1500
-
wavenumber (cm )
Figure 4.4
FTIR Spectrum of MPDA10 Xn=3.67, an enlargement of the carbonyl area.
62
4.3
Proton and 13C NMR
The 1H NMR spectrum of MPDA10 Xn =3.67 in deuterated trifluoroacetic acid is
reproduced in Figure 4.5. The spectrum shows three prominent peaks in the aliphatic region and
bunched up peaks in the aromatic region which is expanded in Figure 4.6. The spectrum was
compared to the one predicted by ACDLabs NMR simulator for MPDA10 Xn=5 (Figure 4.7).
The experimental and predicted spectra were comparable despite the fact that the simulation was
predicted in methanol-d. The chemical shifts of the experimental result were more downfield
because trifluoroacetic acid is more polar than methanol. Their chemical shifts are listed in
Table 4.2. Peaks at 2.754 ppm are due to protons 11, 18, 31 and 38 which are closest to electron
withrawing carbonyl groups. Protons 13, 14, 15, 16, 33, 34, 35 and 36 have have about the same
high field chemical environments and thus their peaks are bunched up at 1.484 ppm. The peak
for protons 12, 17, 32 and 37 is at 1.890 ppm. The NH peaks are shifted to very low field region.
The experimental NMR spectrum shows two faint peaks around 9.037 and 9.379 ppm, which are
due to the NH groups, while the software’s prediction is at 5.14 ppm. The large downfield shift
shows that there is extensive hydrogen bonding interaction between the solvent and the oligomer.
Of the two NH peaks, the one that is more deshielded should be due to the NH that is involved in
the amide bond.
63
Proton NMR Spectrum of MPDA10 Xn=3.67
12
11
10
9
8
7
6
5
4
3
2
1
0
ppm
Figure 4.5
Proton NMR Spectrum of MPDA10 Xn=3.67
ACD HNMR predictor software indicates that there are seven peaks in the aromatic
region of the ACD spectrum. These correspond to the seven peaks observed in the experimental
spectrum. The CH groups belonging to the terminal benzene rings appear more upfield than
those from the central aromatic group. This is because the terminal benzene rings are connected
to highly electron donating NH2 groups, whereas the central aromatic ring is connected to two
amide groups that are less electron donating. When considering the terminal benzene rings of our
additive, the ortho and para positions (with respect to NH2) are negatively charged due to the
mesomeric effect of the NH2 and NHCO groups attached to it. Therefore those CH groups
resonate at a position more upfield when compared to the CH group in the meta position. This
trend is observed in the chemical shifts observed for the ACDLABS generated spectrum as well.
When considering the central benzene ring of the prepared additive, NHCO is electron donating
and therefore the ortho and para positions in relation to the two substituted positions have high
electron density making them more upfield than the meta CH. This trend is again similar in the
spectrum predicted by ACDLABS.
64
Proton NMR Spectrum of MPDA10 Xn=3.67 (expanded aromatic region)
9
8
7
ppm
Figure 4.6
Expansion of aromatic region of MPDA10 Xn=3.67 proton NMR spectrum.
46
5
6
1
H2N
O
4
10
9
3
2
7
N
12
11
14
13
16
15
NH
18
17
NH
23
19 21 22
31
24 28 29
8
H
8a
Figure 4.7
O
33
32
35
34
40
39
37
36
47
38
42
NH
41
O
20
27
25
26
O
30
Chemical structure of MPDA10 Xn=5 with assigned carbon numbers.
65
45
44
43
NH2
48
Table 4.2
Experimental and Predicted chemical shifts for MPDA10 Xn=3.67
Carbon/Nitrogen
numbers From
Figure 4.7
13, 16, 33, 36
Chemical shift
generated by ACD
software (ppm)
1.38
Experimental
Chemical shift
(ppm)
1.484
14, 15, 34, 35
1.34
1.484
12, 17, 32, 37
1.82
1.890
18, 31
2.19
2.754
11, 38
2.23
2.754
2, 43
6.43
7.435
6, 45
6.99
7.438
4, 47
7.00
7.500
5, 46
7.15
7.520
25, 27
7.28
7.560
26
7.39
7.900
23
7.96
8.131
7, 48
5.14
9.073
8, 21, 28, 41
5.14
9.379
In the aliphatic region of the spectrum of MPDA10 Xn=3.67 there are also peaks at 3.523
and 3.665 ppm due to the methyl groups of incompletely removed DMAc solvent. These 2 peaks
confirm trace amounts of DMAc present in the mixture (which can be confirmed by the carbonyl
peak in the 13C NMR spectrum). The small peaks with chemical shifts 2.23, 2.31, 3.50, 3.64 and
3.71 ppm are due to incompletely removed DBU.
The experimental
13
C spectrum for MPDA10 Xn=3.67 additive is shown in Figure 4.8,
the aliphatic region is expanded in Figure 4.9 and the expanded aromatic region is shown in
Figure 4.10.
66
CNMR Spectrum of MPDA10 Xn=3.67
200
180
160
140
120
100
80
60
40
20
0
ppm
Figure 4.8
13
C NMR spectrum of MPDA10 Xn=3.67
CNMR Spectrum of MPDA10 Xn=3.67 (Expnaded Methylene Region)
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
ppm
Figure 4.9
Expanded aliphatic region of C13NMR spectrum of MPDA10 Xn=3.67
67
CNMR Spectrum of MPDA10 Xn=3.67 ( Expanded Aromatic Regoin)
15000
10000
5000
0
140
135
130
125
120
115
ppm
Figure 4.10
Expanded aromatic region of C13NMR spectrum of MPDA10 Xn=3.67
Expanded Carbonyl Region of C13 Spectrum of MPDA10 Xn=3.67
15000
10000
5000
0
185
184
183
182
181
180
179
178
177
176
175
ppm
Figure 4.11
Expanded carbonyl region of 13C NMR spectrum of MPDA10 Xn=3.67
68
Table 4.3
Assignment of carbon numbers and chemical shifts in the 13C NMR of
MPDA10 Xn=3.67
Carbon numbers in
Figure 4.7
1, 44
Predicted Chemical shift
generated by ACD software
(ppm)
139.22
Experimental Chemical
shift observed (ppm)
139.896
2, 43
117.79
119.675
3, 44
138.80
133.205
4, 47
114.70
124.002
5. 46
130.02
131.008
6, 45
114.70
125.230
9, 39
171.68
180.943
19. 29
171.68
180.380
11, 18, 31, 38
37.63
37.986
12, 17, 32, 37
25.60
28.074
13, 16, 33, 36
29.43
30.835
14, 15, 34, 35
27.56
30.657
22, 24
138.80
137.741
23
117.79
119.859
25, 27
129.62
125.8
26
130.02
132.669
The observed experimental chemical shifts correlate to those predicted by ACD software.
Observed shifts are slightly more downfield due to the fact that samples were dissolved in highly
polar trifluoroacetic acid. Shifts from ACD C13NMR predictor software were predicted in
methanol as solvent. The experimental spectrum indicates traces of impurities. The tiny peak at
176.963 ppm is most likely due to DMAc. The two peaks at 180.943 and 180.380 ppm are due to
the oligomer’s carbonyl groups. The aromatic region of the experimentally obtained spectrum
shows 10 peaks, which is consistent with the structure. The most downfield of these are C1 and
C44 which give a peak at 139.896 ppm. The remainder of the aromatic peaks and their chemical
shifts are listed in Table 4.3.
The peak at 39.644 ppm observed in the experimentally obtained spectrum could be due
to methyl groups attached to the nitrogen atom of DMAc. The peak at 19.108 ppm is due to the
methyl group attached to the carbon of DMAc. The peak at 37.986 ppm is the most deshielded
69
carbon of the oligomer and it is due to carbons 11, 18, 31,38 of Figure 4.7. All the other peaks
can be attributed to DBU and DMAc that is present in the mixture.
The NMR spectra of the other oligomers are given in Appendix B.
4.4
Intrinsic Viscosity (IV)
The reduced specific viscosity plot obtained for MPDA10 Xn=5 is shown in Figure 4.12.
All other IV plots are given in Appendix C. By extrapolating the plot to C=0, the intrinsic
viscosity is estimated to be 16.482 mL/g of oligomer. The intrinsic viscosity experiments for
MPDA10 and MDA10 additives were done using filtered m-cresol as the solvent since the
additive is not very soluble in 90% formic acid.
Intrinsic Viscosity Plot for MPDA10 Xn=5
26
24
y = 153.82x + 16.482
nsp/C
22
2
R = 0.9824
20
18
16
14
12
10
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
0.040
0.045
0.050
C (g/ml)
Figure 4.12
Intrinsic viscosity plot for MDA10 Xn=5
The intrinsic viscosity values obtained for the additives are summarized in Table 4.4
below.
70
Table 4.4
Summary of results for intrinsic viscosity experiments.
Additive
Xn
Intrinsic viscosity (mL/g)
MPDA10
3.67
14.327
5
16.482
9
16.844
3.67
19.808
5
22.112
9
27.165
MDA10
It is apparent that there is a control over the intrinsic viscosity by adjusting the theoretical
number average degree of polymerization, Xn. The intrinsic viscosity increases with Xn. This
indicates that by controlling the molar ratio of reactants, the oligomer can be lengthened or
shortened. No intrinsic viscosity experiments were performed on PPDA10 additives due to
difficulty of finding a suitable solvent. They are only partially soluble in m-cresol and in 90%
formic acid.
4.4
Gel Permeation Chromatography
The gel permeation chromatography results support our conclusion from intrinsic
viscosity experiments. GPC chromatograms of MDA10 additives are shown in Figure 4.13 while
GPC chromatograms for the MPDA10 additives are shown in Appendix C. PPDA10 additives
were not sent for GPC since a good solvent was not found.
The chromatograms show the mass distribution of the three additives. There is a shift
towards higher masses as Xn increases.
71
GPC for MDA10
1.00
0.90
MDA10 Xn=3.67
MDA10 Xn=5
MDA10 Xn=9
0.80
W(log M)
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
1.00E+01
1.00E+02
1.00E+03
1.00E+04
1.00E+05
1.00E+06
Molar Mass (Da)
Figure 4.13
Gel Permeation Chromatography of MDA10
The average molecular weight, Mw (or weight average molecular weight) of the MDA10
and MPDA10 additives are listed in Table 4.5.The results show that adjusting the theoretical Xn
indeed controls the molecular weight of the additives. The polydispersity index, D of each type
of oligomer, which relates to the range of distribution of weights, is also given in the table. All of
them are above 2 which are typical for condensation polymerization. The chromatogram of
MDA10 Xn=5 looks like it has more low molecular weight species (most probably due to DBU
and DMAc impurities) compared to the other two. Since it has more impurities, its dispersity
index is higher than the rest of the additives.
72
Table 4.5
Summary of gel permeation chromatography results.
Oligomer
MDA10
MPDA10
4.5
Xn
Mw (Dalton)
D
3.67
5115
4.41
5
8770
7.34
9
9551
3.06
3.67
6320
2.17
5
7830
2.87
9
15200
3.11
Tensile Test
Stress-strain curves such as Figure 4.14 were plotted and the stress at break, strain to
break and moduli which were taken from the slope of the initial portion of the curves such as
Figure 4.15, were determined. All other plots are given in Appendix D. Four control resins were
tested and the summary of results are given in Table 4.6.
73
Tensile Testing Curves for Control Resin
6.00E+07
5.00E+07
sp 1
sp2
stress (Pa)
4.00E+07
sp3
sp4
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
strain (% )
Figure 4.14 Stress-strain curves of MDA10 Xn=3.67 3%
Control Resin Sample 1
2.00E+07
1.80E+07
1.60E+07
y = 33944286.6692x + 361418.5040
1.40E+07
R = 0.9997
stress (Pa)
2
1.20E+07
1.00E+07
8.00E+06
6.00E+06
4.00E+06
2.00E+06
0.00E+00
0.00
0.10
0.20
0.30
0.40
0.50
strain (% )
Figure 4.15
Initial portion of the stress-strain curve of Control resin specimen 1.
74
Table 4.6
Tensile testing summary for control resins.
Specimen
1
2
3
4
Ave
Stdev
% RSD
modulus (MPa) Strain to failure (%)
33.9443
1.676
33.2176
1.567
36.1218
1.421
33.0587
1.696
34.0856
1.590
1.4112
0.126
4.1402
7.931
stress at break (MPa)
50.2620
47.5573
46.7422
49.5101
48.5179
1.6434
3.3872
The low average ultimate strength to break from the above experiments indicates that
MY720 and DDS forms a brittle material. The percentage relative standard deviation (RSD) for
the modulus and stress at break are fairly low, indicating a consistent sample preparation.
However, the strain to failure shows a high %RSD and this could be due to imperfections such as
bubbles on the specimens that would affect crack formation.
The tensile curves of resin specimens containing MPDA10 Xn=3.67 at a loading of 3%
are shown in Figure 4.16 and the initial portion of the first specimen is shown in Figure 4.17.
The summary of results is given in Table 4.7. All other tensile testing plots and results are given
in Appendix D.
75
Tensile Testing Curves of MPDA10 Xn=3.67 3% Specimens
7.0E+07
6.0E+07
sp1
sp2
sp3
sp4
stress (Pa)
5.0E+07
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.5
1
1.5
2
2.5
strain %
Figure 4.16
Tensile testing curves of MPDA10 Xn=3.67 at 3 % loading.
Initial Portion of MPDA10 Xn=3.67 3% Specimen 1
2.0E+07
1.8E+07
y = 35,686,956.1411x + 608,338.3224
1.6E+07
R2 = 0.9997
stress (Pa)
1.4E+07
1.2E+07
1.0E+07
8.0E+06
6.0E+06
4.0E+06
2.0E+06
0.0E+00
0
0.1
0.2
0.3
0.4
0.5
strain %
Figure 4.17
Initial portion of tensile testing curve of MPDA10 Xn=3.67 3% specimen 1.
76
Table 4.7
Tensile Testing summary for MPDA10 Xn=3.67 at 3% load.
Specimen Modulus (MPa)
1
2
3
4
Ave
Stdev
Strain to Failure (%)
35.6870
35.9517
33.8357
36.0078
35.3705
1.0328
1.691
2.020
1.530
1.719
1.740
0.2044
Stress at Break (MPa)
54.0702
63.4879
48.2066
55.1947
55.2398
6.2946
MPDA10 Xn=3.67 at 3% loading gives a 3.77% improvement on modulus, 13.85%
improvement on stress at break and gives a 9.43% increase on strain to failure when compared to
control. This suggests that the material has become stronger and less brittle upon addition of the
additive.
The resins listed in Table 4.8 were tested. The formulations of the resins tested are given
in the same table. The amount of curing agent added is adjusted to the type of oligomer and
oligomer loading used.
77
Table 4.8
Formulations of resins tested.
material
moles
diacid
"A"
moles
diamine
"B"
r
(=A/B)
Theoretical
Xn
(1+r)/(1-r)
MY720-DDS control
w/ solvent
g
DDS/g
MY720
g
additive/
g of
MY720
N-H in
additive
/epoxy
0.6472
0
1.1
MPDA10 XN=3.67 3%
1
1.75
0.57
3.67
0.5729
0.03
1.1
MPDA10 XN=3.67 5%
1
1.75
0.57
3.67
0.5768
0.05
1.1
MPDA10 XN=5 3%
1
1.5
0.67
5
0.5768
0.03
1.1
MDA10 Xn =3.67 3%
1
1.75
0.57
3.67
0.5765
0.03
1.1
MDA10 XN=3.67 5%
1
1.75
0.57
3.67
0.5689
0.05
1.1
MDA10 XN=3.67 10%
1
1.75
0.57
3.67
0.5504
0.10
1.1
MDA10 Xn=5 3%
1
1.5
0.67
5
0.5795
0.03
1.1
MDA10 Xn=5 5%
1
1.5
0.67
5
0.5740
0.05
1.1
MDA10 Xn=9 3%
1
1.25
0.8
9
0.5831
0.03
1.1
MDA10 Xn=9 5%
1
1.25
0.8
9
0.5801
0.05
1.1
MDA10 Xn=9 10%
1
1.25
0.8
9
0.5725
0.10
1.1
PPDA10 Xn=3.67 3%
PPDA10 Xn=3.67 5%
1
1
1.75
1.75
0.57
0.57
3.67
3.67
0.5729
0.5630
0.03
0.05
1.1
1.1
PPDA10 Xn=3.67 10%
1
1.75
0.57
3.67
0.5384
0.10
1.1
PPDA10 Xn=5 3%
1
1.5
0.67
5
0.5768
0.03
1.1
PPDA10 Xn=5 5%
1
1.5
0.67
5
0.5696
0.05
1.1
PPDA10 Xn=5 10%
1
1.5
0.67
5
0.5515
0.10
1.1
PPDA10 Xn=9 3%
1
1.35
0.8
9
0.5817
0.03
1.1
MDA10 XN=9 5%
1
1.25
0.8
9
0.5776
0.05
1.1
The tensile test results for resins with MPDA10 additives are given in Table 4.9.
Attempts to prepare several resins with MPDA10 additives were made, however only resins
containing MPDA10 Xn=3.67 at 3% and 5% loading and MPDA10 Xn=5% were successfully
made. The others have imperfections not tolerable for testing. Moreover, it was decided not to
pursue attempting to prepare again the resins that were unsuccessfully made because based on
the results the mechanical property deteriorates as % load and Xn are increased.
78
Table 4.9
Material
MY720DDS
control w/
solvent
MPDA10
Xn=3.67
3%
MPDA10
Xn=3.67
5%
MPDA10
Xn=5 3%
Tensile Testing Summary for resins containing MPDA10.
No of
samples
tested
Stiffness
Ave
(MPa)
StDev
(MPa)
34.0856
1.4112
35.3705
1.0328
35.21
35.1162
%
change
stress at break
Ave
(MPa)
StDev
(MPa)
%
change
Strain at break
Ave
StDev
0.01590
(1.590%)
0.00126
(0.126%)
%
change
48.5179
1.6434
3.7696
55.2398
6.2946
13.8545
0.0174
(1.74%)
0.00204
(0.204%)
9.4340
0.8260
3.2976
42.2310
8.1233
-12.9579
0.01301
(1.301%)
0.00305
(0.305%)
-18.1761
1.3063
3.0236
38.2780
9.8276
-21.1054
0.01170
(1.1697%)
0.00371
(0.3708%)
-26.4969
4
4
4
3
Among the three resins containing MPDA10, the Xn=3.67, with 3% loading is the only
one that shows improvement. There was a 3.77 % increase in modulus, 13.85% in stress at break
and 9.34% in strain at break. This means that the material has become stronger and stiffer.
However, the resins with 5% MPDA10 Xn=3.67 and 3% MPDA10 Xn=5 show improvement
only in modulus and show deterioration in stress at break and strain at break.
The results for resins with MDA10 additives are given in Table 4.10. Resin MDA10
Xn=9 at 5% loading gave the best result. The additive has improved 1.59% in modulus, 56.61%
stress at break and 58.30% strain at break. It can be noted that resins with 5% loading gave the
most improvement for all three Xns. This could be because resins having 5% additive have more
hydrogen bonds than those that only have 3% and resins having 10% additives have solubility
issues. Undissolved additive can act as nucleus that starts crack propagation. As for the effect of
the Xn, no conclusion can be arrived at since there is no consistent pattern; either increasing or
decreasing property measurement is observed.
79
Table 4.10
Tensile testing summary for resins containing MDA10.
Stiffness
No of
samples
tested
Ave
(MPa)
StDev
(MPa)
MY720DDS control
w/ solvent
4
34.0856
1.4112
MDA10
Xn=3.67 3%
34.1093
0.8667
7
32.7234
Material
MDA10
Xn=3.67 5%
MDA10
Xn=3.67
10%
MDA10
Xn=5 3%
MDA10
Xn=5 5%
MDA10
Xn=9 3%
MDA10
Xn=9 5%
MDA10
Xn=9 10%
%
change
stress at break
strain at break
ave
StDev
%
change
-11.0722
0.0159
(1.59%)
0.01367
(1.367%)
0.0126
(0.126%)
0.00159
(0.159%)
-14.1139
6.3819
23.5808
0.02128
(2.128%)
0.002865
(0.287%)
33.8634
40.0822
5.3990
-17.3868
0.01234
(1.234%)
0.00178
(0.178%)
-22.3899
6.9496
44.6762
1.1815
-7.9181
0.01335
(1.335%)
0.001067
(0.011%)
-16.0377
0.5098
1.4666
47.8403
8.1951
-1.3966
0.0163
(1.53%)
0.00347
(0.347%)
-3.7736
34.9359
1.3248
2.4946
45.3621
1.9981
-6.5044
0.01418
(1.418%)
0.00222
(0.222%)
-10.8176
34.6280
2.5493
1.5913
75.9837
2.5167
56.6096
0.02517
(2.517%)
0.00368
(0.368%)
58.3019
34.7171
2.0688
1.8527
55.9826
10.955
15.3855
0.01872
(1.872%)
0.00491
(0.491%)
17.7358
Ave
(MPa)
StDev
(MPa)
48.5179
1.6434
0.0695
43.1459
3.8543
0.5060
-3.9964
59.9588
34.6935
1.9574
1.7835
36.4544
1.1120
34.5855
% change
4
5
3
4
3
4
5
The results for resins with PPDA10 additives are shown in Table 4.11. The resins that
gave the best results among them are those that contain 5% PPDA10 Xn=3.67 and 5% PPDA10
Xn=5, showing increase in modulus, stress at break and strain to failure. The resin with PPDA10
Xn=9 at 5% loading had greater stress at break and strain at break improvement than the Xn=5,
however the material is less stiff. The resins that showed improvement on tensile strength also
showed an increase in strain-to-failure which indicates that the additives have a toughening
effect. The PPDA10 additives are consistent with the MDA10 additives that resins with 5%
additives are best in all three Xns. And as expected, resins with 10% loading of additive show
80
very poor mechanical properties due to solubility issues. As for the effect of Xn on the three
mechanical properties, no general trend can be arrived at.
Table 4.11
Tensile Testing summary for resins containing PPDA10.
Number
of
samples
tested
average
(MPa)
Standard
deviation
(MPa)
MY720DDS control
4
34.0856
1.4112
PPDA10
Xn=3.67 3%
33.7534
1.3193
5
35.4719
35.5554
Material
PPDA10
Xn=3.67 5%
PPDA10
Xn=3.67
10%
PPDA10
Xn=5 3%
PPDA10
Xn=5 5%
PPDA10
Xn=5 10%
PPDA10
Xn=9 3%
PPDA10
Xn=9 5%
Stiffness
Stiffness
% change
stress at break
strain at break
stress at
break %
change
average
Standard
deviation
Extension
at break
% change
0.0126
(0.126%)
0.00196
(0.196%)
18.3019
Average
(MPa)
standard
deviation
(MPa)
48.5179
1.6434
-0.9747
55.2709
3.388851
13.9187
0.0159
(1.59%)
0.01881
(1.881%)
0.5827
4.0670
57.7422
7.747524
19.0121
0.0187
(1.87%)
0.00335
(0.335%)
17.6101
0.7181
4.3120
38.4683
1.332717
-20.7131
0.01132
(1.132%)
0.00017
(0.017%)
-29.9874
4
3
33.5802
1.5652
-1.4828
53.6544
9.556974
10.5868
0.01823
(1.823%)
0.00492
(0.492%)
14.6541
34.7140
1.6147
1.8436
59.7335
1.3237
23.1164
0.02001
(2.001%)
0.0001
(0.01%)
25.8491
35.0071
1.0232
2.7035
49.7156
3.4654
2.4686
0.01597
(1.597%)
0.00472
(0.472%)
35.0655
1.0791
2.8749
46.4452
10.30997
-4.2721
0.01458
(1.458%)
0.00421
(0.421%)
-8.3019
33.5841
0.6073
-1.4173
56.9832
13.1904
14.8558
0.02023
(2.022%)
0.006130
(0.613%)
27.1698
5
4
0.4403
4
4
4
Among all the resins tested the MDA10 Xn=9 at 5% loading gave the best mechanical
property improvement.
To determine whether the percent changes listed in Tables 4.9-4.11 are significant, the
results were analyzed through T-test at 95% confidence interval. The values were calculated and
listed in Table 4.12.
81
Table 4.12
T-test calculation results
Resin with:
MPDA10 Xn=3.67 3%
MPDA10 Xn=3.67 5%
MPDA10 Xn=5 3%
MDA10 Xn=3.67 3%
MDA10 Xn=3.67 5%
MDA10 Xn=3.67 10%
MDA10 Xn=5 3%
MDA10 Xn=5 5%
MDA10 Xn=9 3%
MDA10 Xn=9 5%
MDA10 Xn=9 10%
PPDA10 Xn=3.67 3%
PPDA10 Xn=3.67 5%
PPDA10 Xn=3.67 10%
PPDA10 Xn=5 3%
PPDA10 Xn=5 5%
PPDA10 Xn=5 10%
PPDA10 Xn=9 3%
PPDA10 Xn=9 5%
DF
6
6
5
9
6
7
5
6
5
6
7
7
6
5
7
6
6
6
6
t (table
value)
Stiffness
1.9432
1.4695
1.9432
1.3753
2.0150
0.9848
1.8331
0.0350
1.9432
1.6661
1.8946
0.5195
2.0150
2.3861
1.9432
0.6663
2.0150
0.8083
1.9432
0.3723
1.8946
0.5183
1.8946
0.3643
1.9432
1.8160
2.0150
1.6258
1.8946
0.5019
1.9432
0.5861
1.9432
1.0573
1.9432
1.1032
1.9432
0.6529
Calculated t
stress at
break
2.0665
1.5171
2.1132
2.6075
3.4721
2.9794
3.4076
0.1621
2.3035
18.2755
1.3325
3.6231
2.3294
8.6184
1.0483
10.5299
0.6246
0.3971
1.2737
strain-tofailure
1.2512
1.7515
2.1639
2.3906
3.4379
3.3625
2.1115
0.2167
1.317
4.7664
1.1126
2.5581
1.5646
6.1072
0.9118
6.5034
0.0287
0.6007
1.3838
Note: Results in red are greater than t (table value) and therefore the difference of these results
from the control are significant.
4.6
Fracture Toughness
The load-strain plot for the first control specimen and the summary table for the
calculation of fracture toughness are shown in Figure 4.18 and Table 4.13. The rest of the plots
for the control resin are in Appendix E.
82
Control Resin Specimen 1
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
Crosshead Displacement (cm)
Figure 4.18
Fracture toughness test load-strain curve of control resin specimen 1.
Table 4.13
Fracture toughness for control specimens.
control
1
2
3
4
5
6
Average
STDEV
% RSD
geometrical
factor, Y
23.14615
23.14615
23.14615
23.14615
23.14615
23.14615
Fracture
load P
(N)
207.32
208.87
230.05
227.95
205.16
193.39
crack
length a
(m)
0.0026
0.0024
0.0028
0.0027
0.0030
0.0034
elastic
modulus E
(Pa)
34085597.75
34085597.75
34085597.75
34085597.75
34085597.75
34085597.75
hole
to
edge
fracture
fracture
dist W thickness
energy
toughness
(m)
(J/m2)
(Mpa*m1/2)
b (m)
0.025
0.0064 1498679.19
1.5322
0.025
0.0064 1266426.78
1.4879
0.025
0.0064 1749935.54
1.7610
0.025
0.0064 1630029.55
1.7198
0.025
0.0064 1509593.72
1.6256
0.025
0.0064 1499269.52
1.6313
1.6263
0.10
6.4
The average fracture toughness of the control was found to be 1.6263 MPa*m1/2 The
fracture toughness results of the resins with MDA10 additives are given in Table 4.14. All resins
with MDA10 additive tested showed improvement in fracture toughness. The additive that
improved the resin’s fracture toughness the most is MDA10 Xn=3.67 at 3% load, increasing the
fracture toughness by 26.62%. Fracture toughness of resins with additives with 3% additive load
83
have higher fracture toughness compared to the ones with 5% load. It can be observed from the
resin with 5% additives that the fracture toughness decreases with Xn.
Table 4.14
Fracture Toughness of Resins with MDA10 additives.
material
control
MDA10 Xn=3.67 3%
MDA10 Xn=3.67 5%
MDA10 Xn=5 3%
MDA10 Xn=5 5%
MDA10 Xn=9 5%
ave fracture toughness
(MPa*m1/2)
1.6263
2.0592
2.0471
1.9783
1.8529
1.8362
%RSD
6.44
7.33
5.52
7.30
10.81
7.83
% change
26.62
25.87
21.64
13.94
12.91
no. of
specimens
6
4
4
3
4
6
The fracture toughness test for resins containing PPDA10 additives are given in Table
4.15.
All PPDA10 additives also showed improvements. Just like the resin-MDA10 additives
series, the PPDA10 Xn=3.67 at 3% load gave the greatest improvement, increasing the fracture
toughness by 33.93%. Resins with Xn=3.67 and Xn=9 additives also follow the same trend as
the resins with MDA10 additives where the fracture toughness of resins with 3% additive have
higher average fracture toughness than the corresponding resins with 5% load. For resins with
3% load, fracture toughness decreases with additive Xn. The result for resins with PPDA10
Xn=5 at 5% showed an increase of 29.88%, which is inconsistent with trend.
84
Table 4.15
Fracture toughness tests results for resins with PPDA10 additives.
material
control
PPDA10 Xn=3.67 3%
PPDA10 Xn=3.67 5%
PPDA10 Xn=5 3%
PPDA10 Xn=5 5%
PPDA10 Xn=9 3%
PPDA10 Xn=9 5%
ave fracture toughness
(MPa*m1/2)
1.6263
2.1781
1.9658
1.8726
2.1122
1.8246
1.7886
%RSD
6.44
8.63
4.06
4.87
5.08
7.32
2.57
%
change
33.93
20.88
15.14
29.88
12.19
9.98
no. of
specimens
6
6
4
6
4
6
5
Compact tension specimens were also made for resins with MPDA10 additives that were
tested for tensiles. The results are given in Table 4.16.
Table 4.16
Fracture toughness tests results for resins with MPDA10 additives.
material
control
MPDA10 Xn=3.67 3%
MPDA10 Xn=3.67 5%
MPDA10 Xn=5 3%
ave fracture toughness
(MPa*m1/2)
1.6263
1.9567
1.8906
1.8381
%RSD
6.44
8.80
6.73
5.04
% change
20.32
16.25
13.02
no. of
specimens
6
5
6
3
MPDA10 Xn=3.67 at 3% load gave the most improvement among the three additives
showing 20.32% increase in fracture toughness. The average fracture toughness of resins with
3% Xn=3.67 is higher than the resins with 5% additive load and resins with 3% of MPDA10
Xn=5. .
The results show that the additives indeed introduce secondary forces of attraction
between chains in the resin causing the fracture toughness to increase. Two general trends can be
observed. First, increasing the additive load decreases the fracture toughness. This is attributed to
the solubility of the additive in the resin. The additives are not very soluble at higher loads. So
the higher percentage additive the more likely it is that a fraction of the additive will not
85
dissolve. Undissolved particles can act as nuclei in crack propagation and thus leads to the
decrease in fracture toughness. A second observation is that fracture toughness decreases with
Xn. This observation can be attributed to decrease in resin crosslink density as well as the
decrease of solubility of the additves in the resin as the size of the additives increase.
Comparison of resins containing MDA10, MPDA10 and PPDA10 all having an Xn=3.67
and at 3% load are given in Table 4.17. PPDA10 Xn=3.67 at 3% load gave the greatest
improvement among the three. The PPDA10 is less bulky compared to MDA10 and has a more
linear structure than MPDA10 and thus creates a better fit for formation of hydrogen bonds.
Table 4.17
Comparison of the three best resins from each type of additive.
material
control
MDA10 Xn=3.67 3%
MPDA10 Xn=3.67 3%
PPDA19 Xn=3.67 3%
4.7
ave fracture
toughness
(MPa*m1/2)
1.6263
2.0592
1.9567
2.1781
%RSD
6.44
7.33
8.80
8.63
% change
26.62
20.32
33.93
no. of
specimens
6
4
5
6
Differential Scanning Calorimetry
Data generated from dynamic temperature scanning were used to construct plots for the
degree of cure (α) as a function of temperature over a range of heating rates from 1 °C/min to 20
°C/min. A summary of plots of α vs T obtained for the control resin is shown in Figure 4.19. The
cure reaction shifts to higher temperatures at higher heating rates. At slower heating rates such as
1 and 2 ºC/min the cure is complete by 230 ºC. At higher heating rates such as 20 ºC/min, curing
is not completed until 286.1 ºC.
At slower heating rates, the molecules have sufficient time to unravel, rearrange
themselves and react. However, at faster heating rates molecules are not given sufficient time
therefore will need to be heated to higher temperatures in order to react and form a network.
86
Similar curves were plotted for resin containing MDA10 Xn=3.67 at a 3% load. Again,
the area percentage values generated by the DSC instrument for plots of heat flow vs temperature
were used to calculate the degree of cure. Plots of degree of cure as a function of temperature at
different heating rates (1 ºC/min to 20 ºC/min) were constructed. These plots are summarized in
Figure 4.20.
The cure reaction also shifts to higher temperatures as the heating rate increases. At lower
heating rates of 1 ºC/min, the cure reaction is completed by 243 ºC. However, at higher heating
rates, 20 ºC/min for instance, the temperature must be raised up to 293.1 ºC to completely cure
the resin mixture. These temperatures are not very different from those obtained for the control
resin. A comparison plot in Figure 4.21 shows the additive has no significant effect on the
ultimate curing temperatures.
Control Resin Degree of Cure vs Temperature Summary
1.2
1
1C/min
2C/min
3C/min
4C/min
Degree of Cure
0.8
5C/min
7C/min
10C/min
15C/min
20C/min
0.6
0.4
0.2
0
100
120
140
160
180
200
220
240
260
280
300
Temperature (ºC)
Figure 4.19
Plot of Control resin Degree of Cure vs. Temperature Summary
87
Resin with MDA10 Xn=3.67 Degree of Cure vs Temperature Summary
1.2
1C/min
1
2C/min
3C/min
Degree of Cure
0.8
4C/min
5C/min
0.6
7C/min
10C/min
15C/min
0.4
20C/min
0.2
0
100
Figure 4.20
120
140
160
180
200
220
Temperature (ºC)
240
260
280
300
Plot of Resin with MDA10 Xn=3.67 degree of cure vs. temperature summary.
Degree of cure vs Temperature of Control Resin
and Resin with MDA10 Xn=3.67 @ 20 ºC/min
1.2
Degree of Cure
1
control
0.8
with additive
0.6
0.4
0.2
0
100
150
200
250
300
350
Temperature (ºC)
Figure 4.21
Comparison of control resin and resin with MPDA10 Xn=3.67 @ 5oC/min
heating rate.
88
Using the software, Origin, the plots for degree of cure vs temperature were differentiated
with respect to time to construct plots of rate of cure
dα
as a function of temperature. A
dT
summary of rate of cure vs temperature plots obtained for the control resin at heating rates
ranging from 1 ºC/min to 20 ºC/min is shown in Figure 4.22.
Control Rate of Cure vs Temperature Summary
4.00E-01
3.50E-01
1cmin
2cmin
3cmin
4cmin
5cmin
7cmin
10cmin
15cmin
20cmin
Rate of Cure
3.00E-01
2.50E-01
2.00E-01
1.50E-01
1.00E-01
5.00E-02
0.00E+00
100
120
140
160
180
200
220
240
260
280
300
Temperature (ºC)
Figure 4.22
Summary of rate of cure vs temperature for the control resin at different
heating rates.
It is observed that the rate of cure increases with heating rate. It can also be observed
from the plot that the maximum shifted to higher temperature at higher heating rates. Figure 4.23
summarizes the rate of cure as a function of temperature at heating rates ranging from 1 ºC/min
to 20 ºC/min for control resin containing MDA10, Xn=3.67 additive at 3% load. The rate of cure
profile is very similar to that of the control resin. The rate of cure increases as the heating rate is
increased. The temperature at which the highest cure rate is achieved also increases with
89
increasing heating rate. This means that the additive MDA10, Xn=3.67 at 3% load does not alter
the rate of cure significantly.
Resin Containing MDA10 Xn=3.67 at 3% load Rate of Cure vs
Temperature Summary
4.00E-01
1C/min
2C/min
3C/min
3.50E-01
Rate of Cure
3.00E-01
4C/min
5C/min
7C/min
10C/min
15C/min
2.50E-01
2.00E-01
20C/min
1.50E-01
1.00E-01
5.00E-02
0.00E+00
100
120
140
160
180
200
220
240
260
280
300
Temperature (ºC)
Figure 4.23
Summary of rate of cure vs temperature for the resin containing MDA10
Xn=3.67 at 3% load at different heating rates.
Using the data above, plots of ln (rate of cure) against 1/temperature (K) were
constructed at different degrees of cure ranging from 0.05 to 0.95. A typical plot of ln rate of
cure vs 1/temperature for the control resin is reproduced in Figure 4.24. The remaining plots are
given in Appendix F.
90
ln Rate of Cure vs. 1/T for 0.05 Degree of Cure
0
ln rate of cure
-1
-2
-3
-4
y = -7,687.090x + 13.718
2
-5
R = 0.987
-6
0.0021
Figure 4.24
0.00215
0.0022
0.00225
0.0023
1/T (1/K)
0.00235
0.0024
0.00245
Plot for ln rate of cure vs 1/T for 0.05 degree of cure of control resin.
The slope of each graph was multiplied by the gas constant (8.314 J/mol K) to obtain the
activation energy for each degree of cure. The calculated activation energies were plotted against
degree of cure for each resin system (Figure 4.25).
91
Activation Energy Comaprison
Acivation Energy (J/mol)
140000
120000
100000
80000
60000
40000
control
20000
with 3% MDA10 Xn=3.67
0
0
0.2
0.4
0.6
0.8
1
Degree of Cure
Figure 4.25
Activation energy vs degree of cure of Control and 3 % MDA10 Xn=3.67
The activation energy of the control slightly decreases during the curing process. This is
because during the curing process hydroxyl groups are formed and these hydroxyl groups
catalyze the process. However, towards the end of the curing process, the activation energy
increases because at this point the resin is already very viscous and has already formed a network
Therefore, it would be harder for the reacting functional groups to meet and react.
The comparison suggests that addition of the additive increases the activation energy of
the curing process. This is probably due to the secondary forces brought by the additives. The
interchain attraction brought by the additive makes it more difficult for chains to move and
functional groups to meet and react.
92
4.8
Dynamic Mechanical Analysis
The storage modulus, G’ was plotted on a linear scale to observe the drop off in G’ at
higher temperatures. Tan (δ)
max
is an easier method of determining Tg and is more accurate.
Figure 4.26 compares the storage modulus of resin systems containing MPDA10 Xn=3.67 and
MDA10 Xn=3.67 additives with fixed chain lengths, Xn=3.67. The storage modulus vs
temperature is compared against that measured for the control resin. Resins with additives at 3%
have higher storage moduli at lower temperatures than the control. However at higher
temperatures their storage moduli are about the same.
Storage Modulus (MPa)
Comparing Storage Modulus
3010
Control
2510
MPDA10 Xn=3.67
3%
MDA10 Xn=3.67
3%
MDA10 Xn=5 3%
2010
1510
1010
510
10
0
50
100
150
200
250
Temperature (°C)
Figure 4.26
DMA of MPDA10 Xn=3.67 3%
93
300
350
400
Figure 4.27 compares the tangent delta values of resin system containing MPDA10 and MDA10
additives with fixed chain lengths, Xn=3.67.
Comparing Tangent Delta
1
0.9
Tangent Delta
0.8
Control
0.7
MPDA10 Xn=3.67 3%
0.6
MDA10 Xn=3.67 3%
0.5
MDA10 Xn=3.67 5%
0.4
0.3
0.2
0.1
0
140
160
180
200
220
240
260
280
300
Temperature (C)
Figure 4.27
Comparing Tangent Delta from DMA scans.
The results of Figure 4.26 and Figure 4.27 are summarized in Table 4.18. Addition of an
additive slightly increased the glass transition temperature of the control resin. The percent
change ranges from 0.70-1.41 are too low and insignificant from application stand point.
However, the slight increase in Tg suggests that the additives have slightly decreased the resin’s
free volume. MPDA10 Xn=3.67 has a slightly greater effect than MPDA10 Xn=3.67. This is
because MPDA10 has a less bulky structure than MDA10 and therefore can form a more
94
crystalline structure with the resin. As the loading of MDA10 Xn=3.67 is increased, the cross
link density of the resin decreases causing a minimal decrease in the Tg.
Table 4.18
Comparison of High-Temperature DMA of MDA10 and MPDA10 Xn=3.67.
Sample
Control
MDA10 Xn=3.67 3%
MDA10 Xn=3.67 5%
MPDA10 Xn=3.67 3%
4. 9
Onset Storage Modulus
% Change
(Based on
Tg
Tg
Tg in
[°C]
[°F]
Celcius)
234.88 454.78
236.52 457.74
0.70
236.35 457.43
0.63
238.19 460.74
1.41
Peak of Tangent Delta
% Change
(Based on
Tg
Tg
Tg in
[°C]
[°F]
Celcius)
251.7 485.06
253.62 488.52
0.76
253.57 488.43
0.74
253.71 488.68
0.80
Thermogravimetric Analysis
TGA plots for the control and resin containing MPDA10 Xn=3.67 at loadings of 3%, 5%,
and 10% and were constructed in Figure 4.28, obtained using a heating rate of 4 ºC/min and inert
atmosphere.
TGA MPDA10 Xn=3.67 (4C per min)
120
Weight Percent (%)
100
control
3%
80
5%
10%
60
40
20
0
0
100
200
300
400
500
Temperature (Celcius)
95
600
700
800
Figure 4.28
Change of weight percent of control resin and resin with MPDA10 Xn=3.67
additive with time at 4 ºC/min heating rate.
The onset and endset temperatures of degradation for the control resin, heated at 4
ºC/min, were found to be 325.57 ºC and 393.49 ºC respectively. During this degradation a weight
change of 41.54% was observed. Upon heating resin mixtures containing MPDA10, Xn=3.67 at
loadings of 3%, 5% and 10% at the same heating rate, the degradation onset temperatures were
found to be 313.90 ºC, 305.55 ºC and 307.57 ºC with weight degradation of 39.13%, 39.61%
and 43.41% respectively. The results are summarized on Table 4.19
Table 4.19
Summary of weight degradation for control and resins with MPDA10
Xn=3.67.
MPDA10 Xn=3.67 Heating Rate = 4 C/mim
Onset
Endset
Additive Load
Temperature
Temperature
Degredation
TO [°C] TO [°F] TE [°C] TE [°F]
∆ Weight (%)
Control (0%)
325.57 618.03
393.49
740.28
41.54
3%
313.90 597.02
399.22
750.60
39.13
5%
305.55 581.99
401.96
755.53
39.61
10%
307.57 585.63
418.34
785.01
43.41
The onset of degradation has been shifted towards lower temperatures, lowering the
thermal stability of the resin mixture. This is probably due to the decrease of crosslink density of
the resin as the percentage of additive is increased. The percentage weight change also remains
approximately the same as that of the control resin, indicating that no new degradation processes
occur by the addition of the additive to the resin.
96
4.10
Conclusion
MDA10, MPDA10 and PPDA10 oligomers were synthesized and characterized. From
FTIR and NMR results the oligomers were proven to contain amide groups. Intrinsic viscosity
experiments and GPC show that there was some control over the chain length of the oligomer by
adjusting the ratio of reacting monomers.
Fracture toughness tests show that all oligomers tested improved the toughness of the
resin suggesting that the hydrogen bonds of the amide groups added resistance towards crack
propagation. It is observed that the resins containing 3% have greater fracture toughness than the
resins containing 5% additive. The decrease in toughness can attributed to the solubility of the
additives into the resin since they are not very soluble at higher loading.
From the tensile tests, it can be observed that the best resins from the tests have a
moderate load of additive, which is at 5%. From 3% to 5% the mechanical performance
improves which suggests that the more hydrogen bonds (from the additive) introduced, the
stronger and stiffer the resin becomes. However, when the load is at 10%, the mechanical
performance deteriorates. Again this behavior is attributed to solubility of the additives to the
resin additives. At 10% loading, some of the additives are not dissolved in the resin and will
initiate crack propagation during the testing
The additives slightly increase the glass transition temperature of the resin based on
dynamic mechanical analysis results. This suggests that the additives are causing the resin
molecules to be more compact thus, decreasing the free volume and becoming less mobile. This
most likely was caused by formation of hydrogen bonds by the amide groups in the oligomer.
The increase in the glass transition temperature is only minimal, however, the goal of using
97
additives that does not decrease the glass transition temperature of the resin was at least
achieved.
From the thermal degradation analysis, it can be concluded that the additives do not lead
to new degradation processes. Even though addition of the additives slightly decreases the onset
of degradation temperatures, the change is insignificant and the percentage weight change also
remains approximately the same as that of the control resin.
The results from differential scanning calorimetry suggest that addition of additive
increases the activation energy of the curing process. This is most likely caused hydrogen bonds
of the amide groups of the additive. The hydrogen bonds gave the material more rigid and less
resistant to movements making the resin more viscous during the curing process making it more
difficult for the reactive groups to meet.
98
CHAPTER 5
CONCLUSIONS
The goal of this research was to synthesize hydrogen bonding additives that can enhance
the mechanical properties of the MY720-DDS resin system. It was hoped that these additives
will fill free volume to antiplasticize the resin (increasing stiffness and strength); the hydrogen
bonds would yield additional attractive forces thereby making the resin more resistant to crack
propagation; and lastly that these additives would not have adverse effect on other important
resin properties such as glass transition temperature and thermal degradation resistance.
Oligomeric amides additives were synthesized by reacting diamine monomers and diacid
chloride via condensation polymerization. The amide (–CONH-) group is capable of hydrogen
bonding. Oligomers with different number average degree of polymerization, Xn (i.e. related to
average chain length) were synthesized. FTIR and NMR studied proved that the additives have
amide functionalities. Intrinsic viscosity experiments and gel permeation chromatography results
proved that there is a control over chain length by adjusting the reacting monomer ratio.
The first part of the research focused on non-aromatic additives. Dog bone-shaped resins
with additives of different Xn and at different additive loadings were prepared via the cure cycle
2 hours at 120 oC and 2 hours at 200 oC. It was noticed that the additives are not very soluble in
the resin. Some resins are very brittle due to the presence of undissolved additives. Some of them
were already broken and discovered upon dismantling of the mould. The good and better
specimens were used for tensile testing. It was noticed out that the performance of the cured
resin was better when the additive has a longer methylene sequence. It was also found that the
resins were only 90% cured using the cure cycle. The cure cycle was then adjusted to 2 hours at
120 oC and 4 hours at 200 oC and it resulted in 97% completion, which exceeds the industry
99
requirement of 95%. All the succeeding resins were then cured using the new cure cycle. The
resins with additives in general, using the new cycle increased the tensile strength and strain to
break but slightly decreased the stiffness with the exception of the resin with 5% Nylon 12,12
Xn=3 where all tensile strength, strain-to-failure and stiffness increased. The additives therefore,
were more of plasticizers than antiplasticizers.
TMA experiment, runs on resins with Nylon 10,12 Xn=3.67 additives and control resin
show that the additive increases the softening temperature. This behavior can be attributed to the
hydrogen bonds introduced by the additives to the resin. The polymer chains do not move as
easily with the additive due to the additional presence of forces of attraction.
Since solubility was an issue, the research went into a new direction and explored
additives that were less crystalline but have bulky groups to introduce some sort of rigidity to
hopefully improve the resins stiffness. Mixed amide oligomers were synthesized. These additives
were more soluble in the resin compared to the non-aromatics. In general, the resins with
moderate additive loading (5%) are better than those that have 3% and 10% loading.
Resins containing 5% and 10% MDA10 Xn=9, 5% PPDA10 Xn=3.67, and 5% and 10%
PPDA10 Xn=5 improved all the three mechanical parameters stiffness, tensile strength and strain
to failure. The best resins were the ones containing 5% MDA10 Xn=9 (1.6% stiffness, 56.6%
tensile strength and 58.3% strain to failure increase). However, resins containing 5% PPDA10
Xn=3.67 has an increase of 4.1% stiffness, 19.0% tensile strength and 17.6% strain–to-failure
has a greater increase in stiffness. However, the variability of the results in general were a little
high. This is because producing a perfect specimen was hard to achieve. Imperfections like
bubbles sometimes cannot be eliminated
100
Fracture toughness tests show that the additives increase the resins’ resistance to crack
propagation. Resins containing 3% have greater fracture toughness than the resins containing 5%
additive and fracture toughness decreases with Xn. The decrease in toughness can attributed to
the solubility of the additives into the resin since they are not very soluble at higher loading or
when the additive becomes longer.
The additives MDA10 Xn=3.67 at 3% and 5% loading and MPDA10 Xn=3.67 at 3%
loading slightly increase the glass transition temperature indicating that the hydrogen bonds
made the resin polymer chains less mobile. Thermal degradation analysis shows that the
additives do not lead to new degradation processes. Differential scanning calorimetry runs show
that the MDA10 Xn=3.67 additive at 3% loading increases the activation energy of the curing
process. This is most likely by caused hydrogen bonds of the amide groups of the additive. The
hydrogen bonds gave the material more rigidity and more resistance to movement making the
resin more viscous during the curing process and making it more difficult for the reactive groups
to meet.
Additives that improved the performance of MY720 resin were synthesized. These
additives did not compromise the other important properties of the resin such as glass transition
temperature and thermal degradation pattern and do not alter the curing process of the resin.
101
REFERENCES
102
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18. Garton. A. The Journal of Adhesion, 1989, 29, 13-26.
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104
APPENDICES
105
APPENDIX A
Infrared spectra of additives
Nylon 6,6 Xn=3
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3,950
3,450
2,950
2,450
1,950
1,450
950
450
1,450
950
450
wavenumber (cm-1 )
Nylon 6,6 Xn=5
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3,950
3,450
2,950
2,450
1,950
-1
wavenumber (cm )
106
APPENDIX A (Continued)
Nylon 6,6 Xn=6
2.50
2.00
absorbance
1.50
1.00
0.50
0.00
4000
3500
3000
2500
2000
1500
1000
500
1,450
950
450
1,450
950
450
-1
wavenumber (cm )
Nylon 8,10 Xn=6
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3,950
3,450
2,950
2,450
1,950
-1
wavenumber (cm )
Nylon 6,12 Xn=3
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3,950
3,450
2,950
2,450
1,950
-1
wavenumber (cm )
107
APPENDIX A (Continued)
Nylon 6,12 Xn=5
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3,950
3,450
2,950
2,450
1,950
1,450
950
450
1,450
950
450
1,450
950
450
-1
wavenumber (cm )
Nylon 10,12 Xn=3
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3,950
3,450
2,950
2,450
1,950
-1
wavenumber (cm )
Nylon 10,12 Xn=3.67
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3,950
3,450
2,950
2,450
1,950
-1
wavenumber (cm )
108
APPENDIX A (Continued)
Nylon 10,12 Xn= 5
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3,950
3,450
2,950
2,450
1,950
1,450
950
450
1,450
950
450
-1
wavenumber (cm )
Nylon 12,12 Xn=3
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3,950
3,450
2,950
2,450
1,950
-1
wavenumber (cm )
109
APPENDIX A (Continued)
MDA10 Xn=3.67
1.20
1.00
Absorbance
0.80
0.60
0.40
0.20
0.00
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
1,450
950
450
Wavenumber (cm- )
MDA10 Xn=5
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3,950
3,450
2,950
2,450
1,950
-1
wavenumber (cm )
110
APPENDIX A (Continued)
MDA10 Xn=9
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3,950
3,450
2,950
2,450
1,950
1,450
950
450
-1
wavenumber (cm )
MPDA10 Xn=3.67
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
4000
3600
3200
2800
2400
2000
1600
1200
800
400
1600
1200
800
400
wavenumber (cm-)
MPDA10 Xn=5
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
4000
3600
3200
2800
2400
2000
wavenumber
111
APPENDIX A (Continued)
MPDA10 Xn=9
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
4000
3600
3200
2800
2400
2000
1600
1200
800
400
wavenumber
PPDA10 Xn=3.67
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3950
3450
2950
2450
1950
1450
950
450
1450
950
450
wavenumber
PPDA10 Xn=5
1.20
1.00
absorbance
0.80
0.60
0.40
0.20
0.00
3950
3450
2950
2450
1950
wavenumber
112
APPENDIX B
NMR SPECTRA
a. 1H NMR
1
H NMR Spectrum of MDA10 Xn=3.67
12
11
10
9
8
7
6
5
4
3
2
1
0
ppm
1
H NMR Spectrum of MDA10 Xn=5
12
11
10
9
8
7
6
ppm
113
5
4
3
2
1
0
APPENDIX B (Continued)
1
HNMR Spectrum of MDA10 Xn=9
12
11
10
9
8
7
6
5
4
3
2
1
0
ppm
1
H NMR Spectrum of MPDA10 Xn=3.67
1000
900
800
700
600
500
400
300
200
100
0
12
11
10
9
8
7
6
5
4
3
2
1
0
ppm
1
H NMR Spectrum of MPDA10 Xn=5
800
700
600
500
400
300
200
100
0
12
11
10
9
8
7
6
ppm
114
5
4
3
2
1
0
APPENDIX B (Continued)
1
H NMR Spectrum of MPDA10 Xn=9
1000
900
800
700
600
500
400
300
200
100
0
12
11
10
9
8
7
6
5
4
3
2
1
0
2
1
0
2
1
0
ppm
1
H NMR Spectrum of PPDA10 Xn=3.67
120
100
80
60
40
20
0
12
11
10
9
8
7
6
5
4
3
ppm
1H NMR Spectrum of PPDA10 Xn=9
1000
900
800
700
600
500
400
300
200
100
0
12
11
10
9
8
7
6
ppm
115
5
4
3
APPENDIX B (Continued)
b. 13C NMR Spectra
13
C NMR Spectrum of MDA10 Xn=3.67
1000000
800000
600000
400000
200000
0
200
180
160
140
120
100
80
60
40
20
0
ppm
13
Expanded C NMR Spectrum of MDA10 Xn=3.67
140000
120000
100000
80000
60000
40000
20000
0
200
180
160
140
120
100
ppm
116
80
60
40
20
0
APPENDIX B (Continued)
13
C NMR Spectrum of MDA10 Xn=5
1200000
1000000
800000
600000
400000
200000
0
200
180
160
140
120
100
80
60
40
20
0
ppm
13
C NMR Spectrum of MDA10 Xn=9
900000
800000
700000
600000
500000
400000
300000
200000
100000
0
200
180
160
140
120
100
80
60
40
20
0
ppm
13
Expanded CNMR Spectrum of MDA10 Xn=9
250000
200000
150000
100000
50000
0
200
180
160
140
120
100
ppm
117
80
60
40
20
0
APPENDIX B (Continued)
13
C NMR Spectrum of MPDA10 Xn=3.67
120000
100000
80000
60000
40000
20000
0
200
180
160
140
120
100
80
60
40
20
0
ppm
13
Expanded C NMR Spectrum of MPDA10 Xn=3.67
40000
35000
30000
25000
20000
15000
10000
5000
0
200
180
160
140
120
100
80
60
40
20
0
20
0
ppm
13
C NMR Spectrum MPDA10 Xn=5
600000
500000
400000
300000
200000
100000
0
200
180
160
140
120
100
ppm
118
80
60
40
APPENDIX B (Continued)
13
Expanded C NMR Spectrum MPDA10 Xn=5
100000
90000
80000
70000
60000
50000
40000
30000
20000
10000
0
200
180
160
140
120
100
80
60
40
20
0
ppm
13
C NMR Spectrum of MPDA10 Xn=9
800000
700000
600000
500000
400000
300000
200000
100000
0
200
180
160
140
120
100
80
60
40
20
0
20
0
ppm
13
Expanded C NMR Spectrum of MPDA10 Xn=9
200000
180000
160000
140000
120000
100000
80000
60000
40000
20000
0
200
180
160
140
120
100
ppm
119
80
60
40
APPENDIX B (Continued)
13
C NMR Spectrum of PPDA10 Xn=3.67
700000
600000
500000
400000
300000
200000
100000
0
200
180
160
140
120
100
80
60
40
20
0
ppm
13
Expanded C NMR Spectrum of PPDA10 Xn=3.67
200000
180000
160000
140000
120000
100000
80000
60000
40000
20000
0
200
180
160
140
120
100
80
60
40
20
0
ppm
13
C NMR Spectrum of PPDA10 Xn=9
1000000
900000
800000
700000
600000
500000
400000
300000
200000
100000
0
200
180
160
140
120
100
ppm
120
80
60
40
20
0
APPENDIX B (Continued)
13
Expanded C NMR Spectrum of PPDA10 Xn=9
50000
45000
40000
35000
30000
25000
20000
15000
10000
5000
0
200
180
160
140
120
100
ppm
121
80
60
40
20
0
APPENDIX C
INTRINSIC VISCOSITY
Nsp/C vs C for Nylon 6,6 Xn=3.67
16
y = 686.2x + 2.9283
14
2
R = 0.946
12
Nsp/C
10
8
6
4
2
0
0
0.005
0.01
0.015
0.02
C (g/ml)
nsp/C vs C Nylon 6,6 Xn=5
16
14
y = 622.2896x + 5.1931
12
2
R = 0.9418
nsp/C
10
8
6
4
2
0
0
0.002
0.004
0.006
0.008
0.01
C (g/ml)
122
0.012
0.014
0.016
0.018
APPENDIX C (Continued)
Nsp/C vs C for Nylon 6,6 Xn=6
30
25
y = 866.63x + 10.664
2
R = 0.9736
nsp/C
20
15
10
5
0
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
C (g/ml)
Nsp/C vs C for MDA10 Xn=3.67
35
30
nsp/C (ml/g)
25
y = 382.06x + 19.808
20
2
R = 0.9812
15
10
5
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
C (g/ml)
Nsp/C vs C for MDA10 Xn=5
45
40
y = 392.07x + 22.112
35
R = 0.9989
2
nsp/C
30
25
20
15
10
5
0
0
0.005
0.01
0.015
0.02
0.025
C (g/ml)
123
0.03
0.035
0.04
0.045
APPENDIX C (Continued)
Nsp/C vs C for MDA10 Xn=9
45
40
35
nsp/C
30
y = 453.24x + 27.165
25
2
R = 0.9826
20
15
10
5
0
0.000
0.005
0.010
0.015
C (g/ml)
0.020
0.025
0.030
Nsp/C vs C for MPDA10 Xn=3.67
25
20
y = 182.5x + 14.327
2
R = 0.577
nsp/C
15
10
5
0
0.000
0.010
0.020
0.030
0.040
0.050
C (g/ml)
Nsp/C vs C for MPDA10 Xn=5
26
24
nsp/C
22
y = 153.82x + 16.482
R2 = 0.9824
20
18
16
14
12
10
0.000
0.010
0.020
C (g/ml)
124
0.030
0.040
0.050
APPENDIX C (Continued)
Nsp/C vs C for MPDA10 Xn=9
25
20
y = 99.824x + 16.844
2
nsp/C
R = 0.9821
15
10
5
0
0.000
0.010
0.020
0.030
0.040
0.050
0.060
C (g/ml)
GPC for MPDA10
1.0
0.9
MPDA10 Xn=3.67
MPDA10 Xn=5
MPDA10 Xn=9
0.8
0.7
W(log M)
0.6
t
0.5
0.4
0.3
0.2
0.1
0.0
1.00E+02
1.00E+03
1.00E+04
Molar Mass (Da)
125
1.00E+05
1.00E+06
APPENDIX C (Continued)
GPC for MDA10
1.00
0.90
MDA10 Xn=3.67
MDA10 Xn=5
MDA10 Xn=9
0.80
W(log M)
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
1.00E+01
1.00E+02
1.00E+03
1.00E+04
Molar Mass (Da)
126
1.00E+05
1.00E+06
APPENDIX D
TENSILE TEST RESULTS
a. For Specimens Cured for 2 hours at 140 ºC and 2 hours at 200 ºC
Tensile Testing Curves for Specimens Containing 5% Nylon 6,6 Xn = 3.67
Specimens Containing 5% Nylon 6,6 Xn=3.67
4.50E+07
4.00E+07
Stress (MPa)
3.50E+07
sp 1
sp 2
3.00E+07
2.50E+07
2.00E+07
1.50E+07
1.00E+07
5.00E+06
0.00E+00
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Strain (%)
Tensile Testing Summary for Specimens Containing 5% Nylon 6,6 Xn = 3.67
Nylon 6,6 Xn = 3.67 5%
specimen stress (MPa)
strain (%)
modulus (MPa)
sp 1
40.7732
1.351
33.5287
sp 2
32.2679
1.042
33.4529
ave
36.5206
1.197
33.4908
st dev
6.0142
0.218
0.0536
% RSD
16.4679
18.261
0.1600
127
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 6,6 Xn = 5
Specimens Containing 5% Nylon 6,6 Xn=5
2.50E+07
stress (Pa)
2.00E+07
sp1
sp2
1.50E+07
sp3
1.00E+07
5.00E+06
0.00E+00
0
0.2
0.4
0.6
0.8
strain (%)
Tensile Testing Summary for Specimens Containing 5% Nylon 6,6 Xn = 5
Specimen
sp 1
sp 2
sp 3
ave
st dev
% RSD
Nylon 6,6 Xn = 5 5%
stress (MPa)
strain (%)
22.5451
0.702
20.5422
0.63
23.2582
0.73
22.1152
0.6873
1.4081
0.0516
6.3672
7.5055
128
modulus (MPa)
33.7170
33.0620
33.1545
33.3112
0.3545
1.0642
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 6,8 Xn = 5
Specimens Containing 5% Nylon 6,8 Xn=5
Stress (Pa)
2.50E+07
2.00E+07
sp 1
sp 2
1.50E+07
sp 3
1.00E+07
5.00E+06
0.00E+00
0
0.1
0.2
0.3
0.4
0.5
0.6
Strain (%)
Tensile Testing Summary for Specimens Containing 5% Nylon 6,8 Xn = 5
specimen
1
2
3
ave
stdev
% RSD
modulus (MPa)
33.4971
31.2711
32.4586
32.4089
1.1138
3.4368
strain (%)
0.653
0.538
0.632
0.6077
0.0612
10.0779
129
stress (MPa)
21.7459
16.8106
20.8506
19.8024
2.6293
13.2779
0.7
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 6,12 Xn = 3.67
Specimens Containing 5% Nylon 6,12 Xn = 3.67
7.00E+07
stress (Pa)
6.00E+07
5.00E+07
sp 1
4.00E+07
sp 2
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.5
1
1.5
2
2.5
strain (%)
Tensile Testing Summary for Specimens Containing 5% Nylon 6,12 Xn = 3.67
Specimen
sp 1
sp 2
Ave
st dev
% RSD
Nylon 6,12 Xn = 3.67 5%
stress (MPa)
strain (%)
Modulus (MPa)
63.8586
2.503
30.5020
50.5676
2.152
29.1099
57.2131
2.3275
29.8060
9.3981
0.2482
0.9844
16.426574
10.66357
3.302661
130
3
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 6,12 Xn = 5
Specimens Containing 5% Nylon 6,12 Xn=5
8.E+07
7.E+07
stress (Pa)
6.E+07
5.E+07
sp1
sp2
4.E+07
3.E+07
2.E+07
1.E+07
0.E+00
0
0.5
1
1.5
2
2.5
strain %
Tensile Testing Summary for Specimens Containing 5% Nylon 6,12 Xn = 5
Containing 5% Nylon 6,12 Xn = 5
sample stress (MPa)
strain (%)
modulus MPa)
sp 1
68.5274
2.603
35.1186
sp 2
68.9426
2.620
32.7982
ave
68.7350
2.6115
33.9584
st dev
0.2936
0.0120
1.6408
% rsd
0.4271
0.460
4.8318
131
3
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 10,12 Xn = 3.67
Specimens Containing 5% Nylon 10,12 Xn=3.67
Stress (MPa)
1.00E+08
9.00E+07
sp1
8.00E+07
sp 2
7.00E+07
sp 3
sp 4
6.00E+07
5.00E+07
4.00E+07
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Strain (%)
Tensile Testing Summary for Specimens Containing 5% Nylon 6,12 Xn = 3.67
sample
sp 1
sp 2
sp 3
sp 4
ave
st dev
% RSD
Nylon 10, 12 Xn = 3.67 5%
stress (MPa)
strain (%)
modulus (MPa)
74.3288
2.748
34.4210
90.9595
3.840
32.9011
65.3933
2.499
32.0302
87.7869
3.541
34.0632
79.6171
3.157
33.3539
11.9119
0.636
1.0953
14.9614
20.152
3.2839
132
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 10,12 Xn = 5
Specimens Containing 5% Nylon 10,12 Xn=5
8.00E+07
7.00E+07
Stress (Pa)
6.00E+07
5.00E+07
sp 1
sp 2
4.00E+07
sp 3
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.5
1
1.5
2
2.5
Strain (%)
Tensile Testing Summary for Specimens Containing 5% Nylon 10,12 Xn = 5
nylon 10,12 Xn=5
specimen stress (MPa)
strain (%)
modulus (MPa)
sp 1
71.4643
2.602
33.2409
sp 2
72.0848
2.691
33.2669
sp 3
57.3356
1.964
33.8758
Ave
66.9616
2.419
33.4612
st dev
8.3421
0.397
0.3593
% RSD
12.4580
16.393
1.0738
133
3
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 12,12 Xn = 3.67
Specimens Containing 5% Nylon 12,12 Xn=3.67
1.00E+08
stress (Pa)
8.00E+07
sp 2
sp 3
sp 4
6.00E+07
4.00E+07
2.00E+07
0.00E+00
0
1
2
strain (%)
3
Tensile Testing Summary for Specimens Containing 5% Nylon 12,12 Xn = 3.67
specimen
sp 1
sp 2
sp 3
Ave
st dev
% RSD
nylon 12,12 Xn=3.67 5%
stress (MPa)
strain (%) modulus (MPa)
64.6362
2.353
32.0030
70.4983
2.645
32.0235
90.8098
3.787
32.4342
75.3148
2.928
32.1536
13.7355
0.758
0.2433
18.2374
25.879
0.7566
134
4
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 12,12 Xn = 5
Specimens Containing 5% Nylon 12,12 Xn=5
8.00E+07
sp 1
sp 2
sp 3
7.00E+07
Stress (MPa)
6.00E+07
5.00E+07
4.00E+07
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.5
1
1.5
2
2.5
Strain (%)
Tensile Testing Summary for Specimens Containing 5% Nylon 12,12 Xn = 5
nylon 12,12 Xn=5 5%
specimen stress (MPa) strain (%)
modulus (MPa)
sp 1
69.6994
2.663
32.4721
sp 2
67.7015
2.523
32.0355
sp 3
59.5587
2.159
32.0177
ave
65.6532
2.448
32.1751
st dev
5.3717
0.260
0.2574
% RSD
8.1819
10.626
0.7999
135
3
APPENDIX D (Continued)
b. Tensile Test Results for resins cured for 2 hrs at 140 ⁰C and 4 hours at 200 ⁰C
Tensile Testing Curves for Specimens Containing 5% Nylon 10,12 Xn = 3
Specimens Containing 5% Nylon 10,12 Xn=3
8.00E+07
7.00E+07
stress (Pa)
6.00E+07
sp1
sp2
sp3
5.00E+07
4.00E+07
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.5
1
1.5
strain (%)
2
2.5
Tensile Testing Summary for Specimens Containing 5% Nylon 10,12, Xn = 3
nylon 10,12 Xn=3 2h at 140C 4h at 200C
Specimen stress (MPa)
strain (%)
Modulus (MPa)
sp 1
64.9886
2.391
32.5807
sp 2
69.8105
2.668
31.9496
sp 3
45.1569
1.445
34.5777
Ave
59.9853
2.1680
33.0360
st dev
13.0662
0.6413
1.3719
% RSD
21.7823
29.5789
4.1528
136
3
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 10,12 Xn = 3.67
Specimens Containing 5% Nylon 10,12 Xn=3.67
9.00E+07
8.00E+07
sp 1
7.00E+07
sp 2
stress (Pa)
6.00E+07
sp 3
5.00E+07
4.00E+07
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.5
1
1.5
2
2.5
3
3.5
strain (%)
Tensile Testing Summary for Specimens Containing 5% Nylon 10,12 Xn = 3.67
nylon 10,12 Xn=3.67 2h at 140C 4h at 200C
Specimen stress (MPa)
Strain (%)
modulus (MPa)
sp 1
68.3478
2.559
32.6462
sp 2
77.4019
3.005
33.9737
sp 3
84.0397
3.614
33.0546
Ave
76.5965
3.059
33.2248
st dev
7.8769
0.530
0.6799
% RSD
10.2836
17.311
2.0464
137
4
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 10,12 Xn = 5
Specimens Containing 5% Nylon 10,12 Xn=5
8.00E+07
7.00E+07
stress (Pa)
6.00E+07
5.00E+07
4.00E+07
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.5
1
1.5
2
2.5
strain (%)
Tensile Testing Summary for Specimens Containing 5% Nylon 10,12 Xn = 5
nylon 10,12 Xn=5 2h at 140C 4h at 200C
specimen Stress (MPa) strain (%)
modulus (MPa)
sp 1
68.3493
2.534
33.9516
sp 2
29.8793
2.691
34.0191
ave
st dev
49.1143
27.2024
2.6125
0.1110
138
33.9854
0.0477
3
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 12,12 Xn = 3
Specimens Containing 5% Nylon 12,12 X=3
8.00E+07
7.00E+07
Stress (Pa)
6.00E+07
sp 1
5.00E+07
sp 2
4.00E+07
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.5
1
1.5
2
2.5
Strain %
Tensile Testing Summary for Specimens Containing 5% Nylon 12,12 Xn = 3
Specimen
sp 1
sp 2
ave
st dev
% RSD
nylon 12,12 Xn=3 2h at 140C 4h at 200C
stress (MPa)
strain (%)
modulus (MPa)
71.5521
2.552
35.6807
73.8450
2.796
33.8127
72.6986
2.6740
34.7467
1.6213
0.1725
1.3209
2.230217192
6.452283269
3.801445543
139
3
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 12,12 Xn = 3.67
Specimens Containing 5% Nylon12,12 Xn = 3.67
8.00E+07
7.00E+07
sp 1
sp 2
sp 3
stress (Pa)
6.00E+07
5.00E+07
4.00E+07
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.5
1
1.5
2
2.5
strain (%)
Tensile Testing Summary for Specimens Containing 5% Nylon 12,12 Xn = 3.67
Nylon 12,12Xn = 3.67 5%
Specimen stress (MPa)
strain (%)
modulus (MPa)
sp 1
70.8773
2.67
32.0052
sp 2
39.9186
1.36
30.8887
sp 3
59.4882
2.165
31.6549
Ave
56.7614
2.065
31.5163
st dev
15.6585
0.661
0.5710
% RSD
27.5865
31.995
1.8118
140
3
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% Nylon 12,12 Xn = 5
Specimens Containing 5% Nylon 12,12 Xn=5
9.00E+07
sp 1
sp 2
sp3
8.00E+07
stress (Pa)
7.00E+07
6.00E+07
5.00E+07
4.00E+07
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.5
1
1.5
2
2.5
3
strain %
Tensile Testing Summary for Specimens Containing 5% Nylon 12,12 Xn = 5
Nylon 12,12 Xn = 5 5%
specimen stress (MPa)
strain (%)
Modulus (MPa)
sp 1
76.3364
3.056
32.2354
sp 2
63.5238
2.105
32.8278
sp 3
64.5912
2.329
33.5162
Ave
68.1505
2.497
32.8598
st dev
7.1093
0.497
0.6410
% RSD
10.4317
19.914
1.9507
141
3.5
APPENDIX D (Continued)
d. Tensile Testing Results for Specimens Containing MDA10, MPDA10 and PPDA10
Oligomers
Tensile Testing Curves for Specimens Containing 10% MDA10 Xn=3.67
Specimens Containing 3% MDA10 Xn=3.67
6.0E+07
5.0E+07
sp1
sp2
sp3
sp4
sp5
sp6
sp7
stress (Pa)
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
strain %
Tensile Testing Summary for Specimens Containing 3% MDA10 Xn=3.67
specimen
1
2
3
4
5
6
7
ave
stdev
% RSD
modulus (MPa)
33.8336
33.5845
34.2566
33.9762
34.2275
35.8359
33.0508
34.1093
0.8666
2.5408
strain (%)
1.368
1.269
1.291
1.557
1.362
1.138
1.585
1.367
0.159
11.622
142
stress (MPa)
42.8236
39.8232
40.9951
48.5604
43.5227
38.4628
47.8336
43.1459
3.8543
8.9333
1.8
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% MDA10 Xn=3.67
Specimens with 5% MDA10 Xn=3.67
8.0E+07
7.0E+07
sp1
6.0E+07
stress (Pa)
sp2
5.0E+07
sp3
sp4
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.5
1
1.5
2
2.5
strain %
Tensile Testing Summary for Specimens Containing 5% MDA10 Xn=3.67
Specimen
1
2
3
4
ave
stdev
%RSD
modulus (MPa)
33.1941
32.0142
32.7554
32.9298
32.7234
0.5060
1.5464
strain to failure (%)
1.922
2.612
1.948
2.028
2.1275
0.326
15.329
143
stress at break (MPa)
55.6028
69.4020
56.6752
58.1551
59.9588
6.3819
10.6437
3
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 10% MDA10 Xn=3.67
Specimens Containing 10% MDA10 Xn=3.67
6.0E+07
sp1
5.0E+07
sp2
sp3
4.0E+07
stress (Pa)
sp4
sp5
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.2
0.4
0.6
0.8
1
1.2
1.4
strain %
Tensile Testing Summary for Specimens Containing 10% MDA10 Xn=3.67
Specimen Modulus (MPa) strain to failure (%)
stress at break (MPa)
1
36.9211
0.98
35.1407
2
36.5445
1.468
49.2595
3
33.1914
1.296
39.7964
4
34.2304
1.173
37.9162
5
32.5800
1.252
38.2985
ave
34.6935
1.234
40.0822
stdev
1.9574
0.178
5.3990
%RSD
5.6421
14.451
13.4698
144
1.6
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 3% MDA10 Xn=5
Specimens Containing 3% MDA10 Xn=5
5.0E+07
stress (Pa)
4.5E+07
4.0E+07
sp1
3.5E+07
sp2
3.0E+07
sp3
2.5E+07
2.0E+07
1.5E+07
1.0E+07
5.0E+06
0.0E+00
0
0.2
0.4
0.6
0.8
1
1.2
1.4
strain %
Tensile Testing Summary for Specimens Containing 3% MDA10 Xn=5
specimen modulus (MPa) strain to failure (%)
stress at break (MPa)
1
36.4612
1.390
45.9595
2
35.3390
1.403
45.4694
3
37.5630
1.212
42.5996
ave
36.4544
1.335
44.6762
stdev
1.1120
0.107
1.8150
% RSD
3.0505
7.994
4.0625
145
1.6
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% MDA10 Xn=5
Specimens Containing 5% MDA10 Xn=5
4.5E+07
4.0E+07
sp1
sp2
sp3
sp4
3.5E+07
stress (Pa)
3.0E+07
2.5E+07
2.0E+07
1.5E+07
1.0E+07
5.0E+06
0.0E+00
0
0.2
0.4
0.6
0.8
1
1.2
strain %
Tensile Testing Summary for Specimens Containing 5% MDA10 Xn=5
sample modulus (MPa) Strain to failure (%)
stress at break (MPa)
1
34.4491
1.310
42.2216
2
34.9568
1.475
47.2632
3
35.0137
1.299
42.2669
4
33.9222
2.037
59.6095
Ave
34.5855
1.530
47.8403
stdev
0.5098
0.347
8.1951
% RSD
1.4741
22.695
17.1302
146
1.4
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 3% MDA10 Xn=9
Specimens Containing 3% MDA10 Xn=9
6.0E+07
5.0E+07
sp1
sp2
4.0E+07
stress (Pa)
sp3
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
strain %
Tensile Testing Summary for Specimens Containing 3% MDA10 Xn=9
Specimen Modulus (MPa) strain (%)
1
36.2114
2
33.5668
3
35.0296
ave
34.9359
stdev
1.3248
% RSD
3.7920
147
1.163
1.523
1.567
1.418
0.222
15.634
stress at break (MPa)
39.5324
46.9286
49.6253
45.3621
5.2256
11.5198
1.8
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% MDA10 Xn=9
Specimens Containing 5% MDA10 Xn=9
9.0E+07
8.0E+07
sp1
stress (Pa)
7.0E+07
sp2
6.0E+07
sp3
5.0E+07
sp4
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.5
1
1.5
2
2.5
3
strain %
Tensile Testing Summary for Specimens Containing 5% MDA10 Xn=9
strain (%)
Specimen modulus (MPa)
1
36.7700
2
36.7993
3
33.1452
4
31.8003
ave
34.6287
stdev
2.5493
% RSD
7.3619
148
2.466
2.559
3.010
3.240
2.819
0.368
13.050
stress at break (MPa)
72.8903
75.7899
76.2144
79.0401
75.9837
2.5167
3.3122
3.5
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 10% MDA10 Xn=9
Specimens Containing 10% MDA10 Xn=9
8.0E+07
7.0E+07
sp1
sp2
5.0E+07
sp3
4.0E+07
sp5
stress (Pa)
6.0E+07
sp4
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.5
1
1.5
2
strain %
Tensile Testing Summary for Specimens Containing 10% MDA10 Xn=9
sample modulus (MPa)
strain (%)
1
38.0369
2
34.7003
3
34.6780
4
32.4633
5
33.7085
ave
34.7174
stdev
2.0688
% RSD
5.9590
149
1.378
2.328
1.302
2.162
2.192
1.872
0.491
26.210
stress at break (MPa)
47.4443
69.7930
42.4859
59.6200
60.5699
55.9826
10.9552
19.5689
2.5
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 3% MPDA10 Xn=3.67
Specimens Containing 3% MPDA10 Xn=3.67
7.0E+07
6.0E+07
sp1
sp2
sp3
sp4
stress (Pa)
5.0E+07
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.5
1
1.5
2
strain %
Tensile Testing Summary for Specimens Containing 3% MPDA10 Xn=3.67
Specimen modulus (MPa)
strain (%)
1
35.6870
2
35.9517
3
33.8357
4
36.0078
Ave
35.3705
stdev
1.0328
% RSD
2.9199
150
1.691
2.020
1.530
1.719
1.740
0.204
11.747
stress at break (MPa)
54.0702
63.4879
48.2066
55.1947
55.2398
6.2946
11.3951
2.5
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% MPDA10 Xn=3.67
Specimens Containing 5% MPDA10 Xn=3.67
6.0E+07
sp1
sp2
sp3
sp4
5.0E+07
stress (Pa)
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
strain %
Tensile Testing Summary for Specimens Containing 3% MPDA10 Xn=3.67
Specimen modulus (MPa) Strain (%)
1
34.7244
2
35.6717
3
34.3274
4
36.1150
Ave
35.2096
Stdev
0.8260
% RSD
2.3460
151
0.951
1.245
1.693
1.313
1.301
0.305
23.468
stress at break (MPa)
31.9386
41.5788
51.6853
43.7212
42.2310
8.1233
19.2354
1.8
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 3% MPDA10 Xn=5
Specimens Containing 3% MPDA10 Xn=5
5.0E+07
4.5E+07
sp1
sp2
sp3
4.0E+07
stress (Pa)
3.5E+07
3.0E+07
2.5E+07
2.0E+07
1.5E+07
1.0E+07
5.0E+06
0.0E+00
0
0.2
0.4
0.6
0.8
1
1.2
1.4
strain %
Tensile Testing Summary for Specimens Containing 3% MPDA10 Xn=3.67
Specimen strain (%)
stress (MPa)
modulus (Mpa)
1
1.277
41.7537
34.8148
2
0.757
27.1849
36.5468
3
1.475
45.8956
33.9869
ave
1.170
38.278
35.1162
stdev
0.371
9.8276
1.3063
% RSD
31.705
25.6743
3.7199
152
1.6
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 3% PPDA10 Xn=3.67
Specimens Containing 3% PPDA10 Xn=3.67
7.0E+07
6.0E+07
sp1
sp2
sp3
sp4
sp5
stress (Pa)
5.0E+07
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.5
1
1.5
2
strain %
Tensile Testing Summary for Specimens Containing 3% PPDA10 Xn=3.67
Specimen
1
2
3
4
5
ave
stdev
% RSD
modulus (Mpa)
strain %
Stress (Mpa)
35.8097
1.636
52.9495
33.2881
1.829
54.0202
33.8838
2.051
58.5377
32.1790
1.778
51.6643
33.6062
2.109
59.1830
33.7534
1.881
55.2709
1.3193
0.196
3.3889
3.9086
10.441
6.1313
153
2.5
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% PPDA10 Xn=3.67
Specimens Containing 5% PPDA10 Xn=3.67
8.0E+07
7.0E+07
sp1
sp2
sp3
sp4
stress (Pa)
6.0E+07
5.0E+07
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.5
1
1.5
2
strain %
Tensile Testing Summary for Specimens Containing 5% PPDA10 Xn=3.67
Specimen modulus (MPa)
strain %
stress (MPa)
1
36.1325
1.704
54.5014
2
35.7912
1.541
50.3034
3
34.9861
2.316
68.4302
4
34.9777
1.903
57.7337
ave
35.4719
1.866
57.7422
stdev
0.5827
0.335
7.7475
% RSD
1.6427
17.928
13.4174
154
2.5
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 10% PPDA10 Xn=3.67
Specimens Containing 10% PPDA10 Xn=3.67
4.5E+07
4.0E+07
sp1
3.5E+07
sp2
stress (Pa)
3.0E+07
sp3
2.5E+07
2.0E+07
1.5E+07
1.0E+07
5.0E+06
0.0E+00
0
0.2
0.4
0.6
0.8
1
1.2
strain %
Tensile Testing Summary for Specimens Containing 10% PPDA10 Xn=3.67
specimens strain %
stress (MPa)
modulus (MPa)
1
1.118
37.01552
34.7453
2
1.127
38.75530
35.8071
3
1.151
39.63420
36.1137
ave
1.132
38.46834
35.5554
stdev
0.017
1.3327
0.7181
% RSD
1.507
3.4645
2.0196
155
1.4
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 3% PPDA10 Xn=5
Specimens Containing 3% PPDA10 Xn=5
7.0E+07
6.0E+07
sp1
sp2
sp3
sp4
sp5
stress (Pa)
5.0E+07
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.5
1
1.5
2
2.5
strain %
Tensile Testing Summary for Specimens Containing 3% PPDA10 Xn=5
Specimen modulus (MPa) strain %
stress (MPa)
1
34.9193
1.242
40.32238
2
35.3081
1.570
50.06721
3
33.6436
1.747
52.61501
4
31.7737
2.173
60.14417
5
32.2561
2.383
65.12327
ave
33.5802
1.823
53.6544
stdev
1.5652
0.459
9.5570
% RSD
4.6611
25.189
17.8121
156
3
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% PPDA10 Xn=5
Specimens Containing 5% PPDA10 Xn=5
6.0E+07
5.0E+07
sp1
sp2
sp3
sp4
stress (Pa)
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
strain %
Tensile Testing Summary for Specimens Containing 5% PPDA10 Xn=5
Specimen strain %
stress (MPa)
modulus (MPa)
1
1.377
44.2704
35.3012
2
1.655
51.9385
35.6315
3
1.456
45.5443
33.9393
4
1.429
45.5165
34.8249
ave
1.479
46.8175
34.9242
stdev
0.122
3.4654
0.7354
% RSD
8.225
7.4018
2.1057
157
1.8
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 10% PPDA10 Xn=5
Specimens Containing 10% PPDA10 Xn=5
Stress (Pa)
7.00E+07
6.00E+07
Sp 1
Sp 2
5.00E+07
Sp 3
Sp 4
4.00E+07
3.00E+07
2.00E+07
1.00E+07
0.00E+00
0
0.5
1
1.5
2
Strain %
Tensile Testing Summary for Specimens Containing 10% PPDA10 Xn=5
specimen strain (%)
stress (MPa)
modulus (MPa)
1
2.008
58.7975
33.5722
2
1.994
60.6695
35.8558
3
1.102
37.4085
35.6084
4
1.285
41.9867
34.9919
ave
1.597
49.7156
35.0071
stdev
0.472
11.7427
1.0232
% RSD
29.563
23.6197
2.9229
158
2.5
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 3% PPDA10 Xn=9
Specimens Containing 3% PPDA10 Xn=9
6.0E+07
5.0E+07
sp1
sp2
sp3
sp4
stress (Pa)
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
strain %
Tensile Testing Summary for Specimens Containing 3% PPDA10 Xn=9
Specimen modulus (MPa) Strain ( %)
stress (MPa)
1
33.7138
1.860
55.1534
2
34.7895
1.774
55.2160
3
35.5154
1.022
35.1204
4
36.2434
1.175
40.2908
ave
35.0655
1.458
46.4452
stdev
1.0791
0.421
10.3100
% RSD
3.0773
28.878
22.1982
159
1.8
2
APPENDIX D (Continued)
Tensile Testing Curves for Specimens Containing 5% PPDA10 Xn=9
Specimens Containing 5% MDA10 Xn=9
8.0E+07
7.0E+07
sp1
sp2
sp3
sp4
6.0E+07
stress (Pa)
5.0E+07
4.0E+07
3.0E+07
2.0E+07
1.0E+07
0.0E+00
0
0.5
1
1.5
2
2.5
strain %
Tensile Testing Summary for Specimens Containing 5% PPDA10 Xn=9
Specimen strain (%)
stress (MPa)
Modulus (MPa)
1
1.588
47.5440
33.7188
2
1.424
44.2970
34.3718
3
2.693
71.7302
32.9774
4
2.384
64.3618
33.2683
ave
2.022
56.9832
33.5841
stdev
0.613
13.1904
0.6073
% RSD
30.312
23.1478
1.8083
160
3
APPENDIX E
FRACTURE TOUGHNESS
Stress-Strain Curves of Control Resins
Control Resin Specimen 2
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
Crosshead Displacement (cm)
Control Resin Specimen 3
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
Crosshead Displacement (cm)
161
0.03
0.035
0.04
APPENDIX E (Continued)
Control Resin Specimen 4
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
Crosshead Displacement (cm)
Control Resin Specimen 5
250
Load (N)
200
150
100
50
0
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0.02
Crosshead Displacement (cm)
Control Resin Specimen 6
250
Load (N)
200
150
100
50
0
0
0.002
0.004
0.006
0.008
Crosshead Displacement (cm)
162
0.01
0.012
0.014
APPENDIX E (Continued)
Stress-Strain Curves for Resins Containing 3% MDA10 Xn=3.67
Fracture Toughness Test for MDA10 Xn=3.67 3% Specimen 1
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
Crosshead Displacement (cm)
Fracture Toughness Test for MDA10 Xn=3.67 3% Specimen 2
2.5E+02
Load (N)
2.0E+02
1.5E+02
1.0E+02
5.0E+01
0.0E+00
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
Fracture Toughness Test for MDA10 Xn=3.67 3% Specimen 4
3.0E+02
2.5E+02
Load (N)
2.0E+02
1.5E+02
1.0E+02
5.0E+01
0.0E+00
0
0.005
0.01
0.015
0.02
Crosshead Displacement (cm)
163
0.025
0.03
0.035
APPENDIX E (Continued)
Summary of Fracture Toughness Test on Resins Containing 3% MDA10 Xn=3.67
MDA10
Xn=3.67
3%
Specimen
1
2
3
4
average
std dev
% RSD
geometrical
factor
23.146148
23.146148
23.146148
23.146148
fracture
load (N)
P
224.45
243.84
318.79
269.17
crack
length a
(m)
0.00331
0.00349
0.00235
0.00277
elastic
modulus E
(Pa)
34109276.87
34109276.87
34109276.87
34109276.87
hole to
edge
dist W
(m)
0.025
0.025
0.025
0.025
thickness
b (m)
0.0064
0.0064
0.0064
0.0064
fracture
energy
(J/m2)
102308.36
127318.49
146523.94
123132.56
Stress-Strain Curves for Resins Containing 5% MDA10 Xn=3.67
Fracture Tougness Test for MDA10 Xn=3.67 5% Specimen 1
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
Fracture Tougness Test for MDA10 Xn=3.67 5% Specimen 2
400
350
Load (N)
300
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
Crosshead Displacement (cm)
164
0.03
0.035
0.04
0.045
Fracture
toughness
(MPa*m1/2)
1.8681
2.0839
2.2356
2.0494
2.0592
0.15
7.33
APPENDIX E (Continued)
Fracture Tougness Test for MDA10 Xn=3.67 5% Specimen 3
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
Fracture Tougness Test for MDA10 Xn=3.67 5% Specimen 4
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
Crosshead Displacement (cm)
Summary of Fracture Toughness Test for Resins Containing 5% MDA10 Xn=3.67
MDA10
Xn=3.67
5%
Specimen
1
2
3
4
average
std dev
% RSD
geometrical
factor
23.14614784
23.14614784
23.14614784
23.14614784
fracture
load (N)
P
272.93
385.96
278.13
238.70
crack
length a
(m)
0.00270
0.00153
0.00259
0.00305
elastic
modulus E
(Pa)
32723385.49
32723385.49
32723385.49
32723385.49
165
hole to
edge
dist W
(m)
0.025
0.025
0.025
0.025
thickness
b (m)
0.0064
0.0064
0.0064
0.0064
fracture
toughness
(J/m2)
128623.20
145758.65
127888.10
111141.36
128352.83
14136.08
11.01
Fracture
Toughness
(MPa*m1/2)
2.0516
2.1840
2.0457
1.9071
2.0471
0.11
5.52
APPENDIX E (Continued)
Stress-Strain Curves for Resin Containing 3% MDA10 Xn=5
Fracture Toughness for MDA10 Xn=5 3% Specimen 1
400
350
Load (N)
300
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
Crosshead Displacement (cm)
Fracture Toughness for MDA10 Xn=5 3% Specimen 2
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
Crosshead Dispalcement (cm)
Fracture Toughness for MDA10 Xn=5 3% Specimen 3
300
250
Load (N)
200
150
100
50
0
0
0.002
0.004
0.006
0.008
0.01
0.012
Crosshead Dispalcement (cm)
166
0.014
0.016
0.018
APPENDIX E (Continued)
Summary of Fracture Toughness Test for Resins Containing 3% MDA10 Xn=5
MDA10
Xn=3.67
3%
Specimen
geometrical
factor
fracture
load
(Pa) P
crack
length
a (m)
elastic
modulus E
(Pa)
hole to
edge dist
W (m)
thickness
b (m)
1
23.14615
360.53
0.0014
2
23.14615
327.46
3
23.14615
267.78
fracture
energy
(J/m2)
36454413.14
0.025
0.0064
105957.58
1.965355
0.0015
36454413.14
0.025
0.0064
92954.43
1.840815
0.0030
36454413.14
0.025
0.0064
124316.49
2.128822
Fracture
Toughness
(MPa*m1/2)
average
1.9783
std dev
0.14
% RSD
7.30
Stress-Strain Curves for Resins Containing 5% MDA10 Xn=5
Fracture Toughness Test for MDA10 Xn=5 5% Specimen 1
70
60
Load (N)
50
40
30
20
10
0
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
Crosshead Displacement (cm)
Fracture Toughness Test for MDA10 Xn=5 5% Specimen 2
140
120
Load (N)
100
80
60
40
20
0
0
0.01
0.02
0.03
0.04
Crosshead Displacement (cm)
167
0.05
0.06
0.07
APPENDIX E (Continued)
Fracture Toughness Test for MDA10 Xn=5 5% Specimen 3
100
90
80
Load (N)
70
60
50
40
30
20
10
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.05
0.018
0.02
Crosshead Displacement (cm)
Fracture Toughness Test for MDA10 Xn=5 5% Specimen 4
300
250
Load (N)
200
150
100
50
0
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
Crosshead Displacement (cm)
Summary of Fracture Toughness Test for Resins Containing 5% MDA10 Xn=5
MDA10
Xn=5
5%
geometrical
factor, Y
fracture
load (N)
P
crack
length a
(m)
1
23.14615
77.33
0.0320
2
23.14615
321.27
3
23.14615
4
23.14615
elastic
modulus E
(Pa)
hole to
edge dist
W (m)
thickness
b (m)
34585453.93
0.025
0.0064
115777.48
2.001054
0.00180
34585453.93
0.025
0.0064
112418.64
1.971814
98.79
0.0120
34585453.93
0.025
0.0064
70683.86
1.563532
277.01
0.00219
34585453.93
0.025
0.0064
101686.51
1.875333
average
fracture
toughness
(J/m2)
fracture
toughness
(MPa*m1/2)
1.8529
std dev
0.20
% RSD
10.81
168
APPENDIX E (Continued)
Stress-Strain Curves for Resins Containing 5% MDA10 Xn=9
Fracture Toughness for MDA10 Xn=9 5% Specimen 1
400
350
Load (N)
300
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
Fracture Toughness for MDA10 Xn=9 5% Specimen 2
400
350
Load (N)
300
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.05
Crosshead Displacement (cm)
Fracture Toughness for MDA10 Xn=9 5% Specimen 3
400
350
Load (N)
300
250
200
150
100
50
0
0
0.01
0.02
0.03
Crosshead Dispalcement (cm)
169
0.04
0.05
0.06
APPENDIX E (Continued)
Fracture Toughness for MDA10 Xn=9 5% Specimen 4
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.045
0.05
Crosshead Displacement (cm)
Fracture Toughness for MDA10 Xn=9 3% Specimen 5
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
Crosshead Displacement (cm)
Fracture Toughness for MDA10 Xn=9 3% Specimen 6
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
Crosshead Displacement(cm)
170
0.025
0.03
0.035
APPENDIX E (Continued)
Summary of Fracture Toughness Test on Resins Containing 5% MDA10 Xn=9
MDA10
Xn=9
5%
geometrical
factor, Y
fracture
load (N)
P
crack
length a
(m)
elastic
modulus E
(Pa)
hole to
edge dist
W (m)
thickness
b (m)
1
23.14615
360.04
0.0011
2
23.14615
353.33
3
23.14615
4
5
6
fracture
energy
(J/m2)
fracture
toughness
(Pa*m1/2)
34628706.08
0.025
0.0064
86172.14
1.7274
0.0013
34628706.08
0.025
0.0064
95064.26
1.8144
361.15
0.0013
34628706.08
0.025
0.0064
99319.94
1.8545
23.14615
283.75
0.0024
34628706.08
0.025
0.0064
115317.00
1.9983
23.14615
260.77
0.0028
34628706.08
0.025
0.0064
114247.71
1.9890
23.14615
313.17
0.0013
34628706.08
0.025
0.0064
77050.43
1.6334
average
1.8362
std dev
0.14
% RSD
7.83
Stress-Strain Curves for Resins Containing 3% MPDA10 Xn=3.67
Fracture Toughness for MPDA10 Xn = 3.67 3% Specimen 1
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
Crosshead Displacement (cm)
171
0.02
0.025
APPENDIX E (Continued)
Fracture Toughness for MPDA10 Xn = 3.67 3% Specimen 2
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
Fracture Toughness for MPDA10 Xn = 3.67 3% Specimen 3
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
Crosshead Displacement (cm)
Fracture Toughness for MPDA10 Xn = 3.67 3% Specimen 4
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
Crosshoead Displacement (cm)
172
0.025
0.03
0.035
APPENDIX E (Continued)
Fracture Toughness for MPDA10 Xn = 3.67 3% Specimen 5
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
Summary of Fracture Toughness Test on Resins Containing 3% MPDA10 Xn=3.67
hole to
edge
dist W
(m)
thickness
b (m)
35370539.97
0.025
0.0064
97388.93
1.8560
0.00299
35370539.97
0.025
0.0064
105449.91
1.9313
238.16
0.00289
35370539.97
0.025
0.0064
96988.07
1.8522
23.14614784
305.71
0.00261
35370539.97
0.025
0.0064
144322.90
2.2594
23.14614784
267.02
0.00238
35370539.97
0.025
0.0064
100403.25
1.8845
MPDA10
Xn=3.67
3%
fracture
load (N)
P
crack
length a
(m)
elastic
modulus E
(Pa)
geometrical
factor, Y
1
23.14614784
217.48
0.00348
2
23.14614784
244.15
3
23.14614784
4
5
fracture
energy
(J/m2)
fracture
toughness
(Pa*m1/2)
average
1.9567
std dev
0.17
% RSD
8.80
Stress-Strain Curves for Resins Containing 3% MPDA10 Xn=9
173
APPENDIX E (Continued)
Fracture Toughness For MPDA10 Xn = 3.67 5% Specimen 1
400
350
300
Load (N)
250
200
150
100
50
0
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0.02
Crosshead Displacement (cm)
Fracture Toughness For MPDA10 Xn = 3.67 5% Specimen 2
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
Crosshead Displacement (cm)
0.02
0.025
Fracture Toughness For MPDA10 Xn = 3.67 5% Specimen 3
400
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
Crosshead Displacement (cm)
174
0.02
0.025
APPENDIX E (Continued)
Fracture Toughness For MPDA10 Xn = 3.67 5% Specimen 4
300
250
Load (N)
200
150
100
50
0
0
0.002
0.004
0.006
0.008
Crosshead Displacement (cm)
0.01
0.012
Fracture Toughness For MPDA10 Xn = 3.67 5% Specimen 5
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
Crosshead Displacement (cm)
0.02
0.025
Fracture Toughness For MPDA10 Xn = 3.67 5% Specimen 6
450
400
350
Load (N)
300
250
200
150
100
50
0
0
0.01
0.02
0.03
0.04
Crosshead Displacement (cm)
175
0.05
0.06
0.07
APPENDIX E (Continued)
Summary of Fracture Toughness Test on Resins Containing 5% MPDA10 Xn=3.67
MPDA10
Xn=3.67
5%
1
2
3
4
5
6
average
std dev
% RSD
geometrical
factor, Y
23.14615
23.14615
23.14615
23.14615
23.14615
23.14615
fracture
load
(N) P
352.13
299.68
363.42
253.30
323.87
324.45
crack
length a
(m)
0.0015
0.0019
0.0012
0.0027
0.00194
0.0013
elastic
modulus E
(Pa)
35209621.42
35209621.42
35209621.42
35209621.42
35209621.42
35209621.42
hole to
edge
dist W
(m)
0.025
0.025
0.025
0.025
0.025
0.025
thickness
b (m)
0.0064
0.0064
0.0064
0.0064
0.0064
0.0064
fracture
energy
(J/m2)
110549.16
101423.12
94200.97
102969.09
120948.90
81335.96
101904.53
13573.46
13.32
Stress-Strain Curves for Resins Containing 3% PPDA10 Xn=3.67
Fracture Toughness for PPDA10 Xn=3.67 3% Specimen 1
250
Load (N)
200
150
100
50
0
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=3.67 3% Specimen 2
400
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
Crosshead Displacement (cm)
176
0.02
0.025
Fracture
toughness
(Pa*m1/2)
1.9729
1.8897
1.8212
1.9041
2.0636
1.6923
1.8906
0.13
6.73
APPENDIX E (Continued)
Fracture Toughness for PPDA10 Xn=3.67 3% Specimen 3
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=3.67 3% Specimen 4
600
500
Load (N)
400
300
200
100
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
Summary of Fracture Toughness Test for Resins Containing 3% PPDA10 Xn=3.67
PPDA10
Xn=3.67
3%
hole to
edge dist
W (m)
thickness
b (m)
fracture
toughness
(J/m2)
fracture
toughness
(Pa*m1/2)
33753364.41
0.025
0.0064
124471.35
2.0497
0.00155
33753364.41
0.025
0.0064
120758.32
2.0189
319.25
0.0023
33753364.41
0.025
0.0064
145346.17
2.2149
480.69
0.00122
33753364.41
0.025
0.0064
174778.87
2.4289
geometrical
factor, Y
fracture
load
(N) P
crack
length a
(m)
elastic
modulus E
(Pa)
1
23.14615
207.782
0.00465
2
23.14615
354.48
3
23.14615
4
23.14615
average
2.1781
std dev
0.19
% RSD
8.63
177
APPENDIX E (Continued)
Stress- Strain Curves for Resins Containing 5% PPDA10 Xn=3.67
Fracture Toughness for PPDA10 Xn=3.67 5% Specimen 1
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=3.67 5% Specimen 2
400
350
Load (N)
300
250
200
150
100
50
0
0
0.01
0.02
0.03
0.04
0.05
0.06
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=3.67 5% Specimen 3
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
178
0.04
0.045
0.05
APPENDIX E (Continued)
Fracture Toughness for PPDA10 Xn=3.67 5% Specimen 4
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
Crosshead Displacement (cm)
0.035
0.04
0.045
Summary of Fracture Toughness Test for Resins Containing 5% PPDA10 Xn=3.67
PPDA10
Xn=3.67
5%
elastic
modulus E
(Pa)
hole to
edge dist
W (m)
fracture
load (N)
P
crack
length a
(m)
1
23.14615
217.33
0.0036
35471875.43
0.025
0.0064
99478.72
1.8785
2
23.14615
347.19
0.0015
35471875.43
0.025
0.0064
106674.77
1.9452
3
23.14615
304.30
0.0020
35471875.43
0.025
0.0064
109261.52
1.9687
4
23.14615
312.37
0.0021
35471875.43
0.025
0.0064
120892.39
2.0708
thickness
b (m)
fracture
toughness
(J/m2)
fracture
toughness
(Pa*m1/2)
geometrical
factor, Y
average
1.9658
std dev
0.08
% RSD
4.06
179
APPENDIX E (Continued)
Stress-Strain Curves for Resins Containing 3% PPDA10 Xn=5
Fracture Toughness for PPDA10 Xn = 5 3% Specimen 1
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn = 5 3% Specimen 2
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn = 5 3% Specimen 3
300
250
Load (N)
200
150
100
50
0
0
0.01
0.02
0.03
0.04
Crosshead Displacement (cm)
180
0.05
0.06
APPENDIX E (Continued)
Fracture Toughness for PPDA10 Xn = 5 3% Specimen 4
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.05
0.04
0.045
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn = 5 3% Specimen 5
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
Summary of Fracture Toughness Test for Resins Containing 3% PPDA10 Xn=5
PPDA10
Xn=5
3%
geometrical
factor, Y
fracture
load P
(N)
crack
length
a (m)
elastic
modulus E
(Pa)
hole to
edge dist
W (m)
thickness
b (m)
fracture
toughness
(J/m2)
fracture
toughness
(MPa*m1/2)
1
23.14615
245.03
0.0027
33580167.25
0.025
0.0064
101029.92
1.8419
2
23.14615
281.99
0.0019
33580167.25
0.025
0.0064
94159.58
1.7782
3
23.14615
255.75
0.0024
33580167.25
0.025
0.0064
97830.09
1.8125
4
23.14615
326.06
0.0018
33580167.25
0.025
0.0064
119265.00
2.0012
5
23.14615
272.19
0.0024
33580167.25
0.025
0.0064
110810.06
1.9290
average
1.8726
std dev
0.09
% RSD
4.87
181
APPENDIX E (Continued)
Stress-Strain Curves for Resins Containing 5% PPDA10 Xn=5
Fracture Toughness for PPDA10 Xn=5 5% Specimen 1
400
350
Load (N))
300
250
200
150
100
50
0
0
0.01
0.02
0.03
0.04
0.05
0.06
0.05
0.06
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=5 5% Specimen 2
250
Load (N)
200
150
100
50
0
0
0.01
0.02
0.03
0.04
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=5 5% Specimen 3
400
350
Load (N)
300
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
Crosshead Displacement (cm)
182
0.03
0.035
0.04
0.045
APPENDIX E (Continued)
Fracture Toughness for PPDA10 Xn=5 5% Specimen 4
300
250
Load (N)
200
150
100
50
0
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=5 5% Specimen 5
250
Load (N)
200
150
100
50
0
0
0.01
0.02
0.03
0.04
0.05
0.06
Crosshead Displacement (cm)
Summary of Fracture Toughness Test on Resins Containing 5% PPDA10 Xn=5
PPDA10
Xn=5
5%
geometrical
factor, Y
fracture
load
(N) P
crack
length a
(m)
1
23.14615
354.96
0.0017
2
23.14615
230.50
3
23.14615
4
5
elastic
modulus E
(Pa)
hole to
edge dist
W (m)
thickness
b (m)
34924215.12
0.025
0.0064
128351.51
2.1172
0.0036
34924215.12
0.025
0.0064
114609.84
2.0007
337.21
0.0022
34924215.12
0.025
0.0064
149901.91
2.2881
23.14615
241.40
0.0035
34924215.12
0.025
0.0064
122216.86
2.0660
23.14615
234.27
0.0038
34924215.12
0.025
0.0064
124966.85
2.0891
average
128009.39
2.1122
std dev
13245.36
0.11
% RSD
10.35
5.08
183
fracture
energy
(J/m2)
fracture
toughness
(MPa*m1/2)
APPENDIX E (Continued)
Stress-Strain Curves for Resins Containing 3% PPDA10 Xn=9
Fracture Toughness for PPDA10 Xn=9 3% Specimen 1
300
250
Load (N)
200
150
100
50
0
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0.02
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=9 3% Specimen 2
400
350
Load (N)
300
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=9 3% Specimen 3
300
250
Load (N)
200
150
100
50
0
0
0.002
0.004
0.006
0.008
0.01
0.012
Crosshead Displacement (cm)
184
0.014
0.016
0.018
0.02
APPENDIX E (Continued)
Fracture Toughness for PPDA10 Xn=9 3% Specimen 4
400
350
Load (N)
300
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=9 3% Specimen 5
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=9 3% Specimen 6
350
300
Load (N)
250
200
150
100
50
0
0
0.005
0.01
0.015
Crosshead Displacement (cm)
185
0.02
0.025
0.03
APPENDIX E (Continued)
Summary of Fracture Toughness Test for Resins Containing 3% PPDA10 Xn=9
PPDA10
Xn=9
3%
geometrical
factor, Y
fracture
load (N)
P
crack
length a
(m)
elastic
modulus E
(Pa)
hole to
edge dist
W (m)
thickness
b (m)
fracture
toughness
(J/m2)
fracture
toughness
(MPa*m1/2)
1
23.14615
266.17
0.00215
35065514.88
0.025
0.0064
90907.06
1.7854
2
23.14615
351.65
0.00148
35065514.88
0.025
0.0064
109224.80
1.9570
3
23.14615
247.82
0.00235
35065514.88
0.025
0.0064
86136.07
1.7379
4
23.14615
339.11
0.00170
35065514.88
0.025
0.0064
116670.76
2.0227
5
23.14615
274.28
0.00181
35065514.88
0.025
0.0064
81262.26
1.6880
6
23.14615
332.89
0.00133
35065514.88
0.025
0.0064
87963.19
1.7563
average
1.8246
std dev
0.13
% RSD
7.32
Stress Strain Curves for Resins Containing 5% PPDA10 Xn=9
Fracture Toughness for PPDA10 Xn=9 5% Specimen 1
400
350
Load (N)
300
250
200
150
100
50
0
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0.02
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=9 5% Specimen 2
300
250
Load (N)
200
150
100
50
0
0
0.005
0.01
0.015
Crosshead Displacement (cm)
186
0.02
0.025
APPENDIX E (Continued)
Fracture Toughness for PPDA10 Xn=9 5% Specimen 3
300
250
Load (N)
200
150
100
50
0
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=9 5% Specimen 4
400
350
Load (N)
300
250
200
150
100
50
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Crosshead Displacement (cm)
Fracture Toughness for PPDA10 Xn=9 5% Specimen 5
400
350
Load (N)
300
250
200
150
100
50
0
0
0.005
0.01
0.015
Crosshead Displacement (cm)
187
0.02
0.025
0.03
APPENDIX E (Continued)
Summary of Fracture Toughness Test of Resins Containing 5% PPDA10 Xn=9
PPDA10
Xn=9
5%
hole to
edge
dist W
(m)
thickness
b (m)
0.025
0.0064
geometrical
factor, Y
fracture
load P
(N)
crack
length a
(m)
elastic
modulus E
(Pa)
fracture
toughness
(J/m2)
1
23.14615
335.28
0.00125
2114713.10
2
23.14615
279.71
0.00205
1674548.75
0.025
0.0064
2004363.63
1.8320
3
23.14615
252.77
0.0024
1894792.73
0.025
0.0064
1693658.10
1.7914
4
23.14615
377.89
0.00111
1772602.21
0.025
0.0064
1871417.84
1.8213
5
23.14615
348.71
0.00125
2106793.70
0.025
0.0064
1509811.92
1.7835
1390524.99
Fracture
toughness
(MPa*m1/2)
1.7148
average
1.7886
std dev
0.05
% RSD
2.57
188
APPENDIX F
DIFFERENTIAL CALORIMETRY PLOTS
Degree of cure vs Temperature of Control Resin and
Resin Containing 3% MDA10 Xn=3.67 at 1 ºC/min
1.2
Degree of Cure
1
0.8
0.6
control
with additive
0.4
0.2
0
100
120
140
160
180
200
220
240
260
280
Temperature (ºC)
Degree of cure vs Temperature of Control Resin and Resin
Containing 3% MDA10 Xn=3.67 at 2 ºC/min
1.2
Degree of Cure
1
0.8
control
with additive
0.6
0.4
0.2
0
100
120
140
160
180
200
Temperature (ºC)
189
220
240
260
APPENDIX F (Continued)
Degree of cure vs Temperature of Control Resin and
Resin Containing 3% MDA10 Xn=3.67 at 3 ºC/min
1.2
Degree of Cure
1
0.8
0.6
0.4
control
with additive
0.2
0
100
120
140
160
180
200
220
240
260
280
Temperature (ºC)
1.2
Degree of Cure vs Temperature of Control Resin and
Resin Containing 3% MDA10 Xn=3.67 at 4 ºC/min
Degree of Cure
1
0.8
0.6
control
with additive
0.4
0.2
0
100
150
200
Temperature (ºC)
190
250
300
APPENDIX F (Continued)
1.2
Degree of Cure vs Temperature of Control Resin and
Resin Containing 3% MDA10 Xn=3.67 at 7 @5 ºC/min
Degree of Cure
1
0.8
0.6
control
with additive
0.4
0.2
0
100
150
200
250
300
Temperature (ºC)
1.2
Degree of cure vs Temperature of Control Resin and
Resin with MDA10 Xn=3.67 @10 ºC/min
Degree of Cure
1
0.8
0.6
0.4
control
0.2
with additive
0
100
150
200
Temperature (ºC)
191
250
300
APPENDIX F (Continued)
1.2
Degree of cure vs Temperature of Control Resin and
Resin with MDA10 Xn=3.67 @15 ºC/min
1
Degree of Cure
0.8
0.6
control
with additive
0.4
0.2
0
100
-0.2
150
200
250
300
Temperature (ºC)
Degree of cure vs Temperature of Control Resin
and Resin with MDA10 Xn=3.67 @ 20 ºC/min
1.2
Degree of Cure
1
control
0.8
with additive
0.6
0.4
0.2
0
100
150
200
250
Temperature (ºC)
192
300
350