Lodz University of Technology, Poland
Radiation methods of polymer modification:
Hybride crosslinking of butadiene – acrylonitrile
rubber
MS. KATARZYNA BANDZIERZ
PROF. DARIUSZ BIELIŃSKI
Ionizing radiation
 Any kind of radiation (electromagnetic, corposcular or mixture
of both), which carry enough energy to break chemical bonds,
separate electrons from parent atoms and molecules –
cause ionization of irradiated matter.
Secondary
electron
Ionizing radiation
 Any kind of radiation (electromagnetic, corposcular or mixture
of both), which carry enough energy to break chemical bonds,
separate electrons from parent atoms and molecules –
cause ionization of irradiated matter.
Secondary
electron
 Radiation engineering – involves practical application of chemical
reactions (and biological and physcical processes) initiated with
ioniznig radiation.
Electron beam (EB) as a form of ionizing radiation
Electron accelerator Elektronica ELU-6E
(Institute of Applied Radiation Chemistry, Lodz University of Technology)
Operating pulpit and control cabinet of
electron accelarator
Linear electron accelerator
Radiation modification of polymers
 curing of surface layers leading to surface modification
 grafting (of bulk material or surface)
 chain-scissioning for recycling purposes
 crosslinking of polymer materials (including heat-shrink
products and hydrogels)
… and many others
Crosslinking of polymers
 Crosslinking – process of forming bonds (crosslinks) between
macromolecules’ chains, which leads to three-dimentional
polymer network.
 Crosslinking
is fundamental and indispensable process
in polymer processing !
Radiation crosslinking – scheme
Advantages of radiation crosslinking
 Simplicity to control network density
 Irradiation process can be carried out in room temperature
(or either lower or higher), in air or another medium of choice
(e. g. inert gas atmosphere)
 Comparing to products crosslinked ‘classically’ – thermally, general
improvement of properties occurs
 Radiation crosslinking do not create residual stress in material
(as thermal crosslinking do)
 The method is fast, efficient and inexpensive, defined as
“green process”
A uthor’s own research
Radiation
crosslinking
of ‘neat’ NBR
Thermal
crosslinking
of NBR with
sulfur
crosslinking
system
Radiation
crosslinkin of
NBR with sulfur
crosslinking
system
Results – crosslinking of nitrile rubber
H2
C
C
H
*
Network density [mol/cm3]
C
H2
*
H
C
m
n
C
Density of network as a function of ionizing
radiation dose
radiation crosslinking
H2
C
H
C
N
radiation and thermal crosslinking
5.E-04
4.E-04
3.E-04
Network density of
sample crosslinked solely
thermally:
2.E-04
1.E-04
2,2 ∙ 10-4 [mol/cm3]
0.E+00
0
50
100
150
200
250
300
350
Dose [kGy]
material composition: NBR (100 phr), MBTS (1,5 phr), S8 (2 phr), ZnO (5 phr), stearic acid (1 phr), silica Aerosil A380 (40 phr)
Results – mechanical properties of composite
Mechanical properties of composites (presented by tensile
strenght)
radiation crosslinking
radiation and thermal crosslinking
thermal crosslinking
Tensile strenght [MPa]
35
30
200 kGy
25
100 kGy
20
15
250 kGy
150 kGy
150 kGy
200 kGy
250 kGy
100 kGy
10
5
0
0.E+00
1.E-04
2.E-04
3.E-04
4.E-04
5.E-04
6.E-04
Network density [mol/cm3]
material composition: NBR (100 phr), MBTS (1,5 phr), S8 (2 phr), ZnO (5 phr), stearic acid (1 phr), silica Aerosil A380 (40 phr)
Results – hybride structure of crosslinks
Participation of various types of crosslinks in NBR rubber structure
C-C and monosulphide crosslinks
disulphide crosslinks
polysulphide crosslinks
Network density [mol/cm3]
5.E-04
4.E-04
3.E-04
2.E-04
1.E-04
0.E+00
thermal
kGy 150 kGy 200 kGy 250 kGy
100
______________________________
kGy 150 kGy 200 kGy 250 kGy 100
_______________________________
radiation crosslinking
radiation and thermal crosslinking crosslinking
material composition: NBR (100 phr), MBTS (1,5 phr), S8 (2 phr), ZnO (5 phr), stearic acid (1 phr), silica Aerosil A380 (40 phr)
Summary
 Radiation modyfication of polymers (including radiation crosslinking) is
highly useful method to enhance properties of polymers
 The radiation modification can be run under precise control, so that
properties can be ‘tailord’ for specific end-use of material
 Results of autors’ research show that upon radiation crosslinking of
nitrile rubber, hybride network structure can be obtained and the
general properties of such material are better than of ‘classically’ –
thermaly crosslinked
 The process of radiation crosslinking of nitrile rubber is a promising
alternative for up-till-now used method of thermal crosslinking and
can be used in industry
THANK YOU FOR YOUR ATTENTION
Contact: katarzyna.bandzierz@gmail.com
MS. Katarzyna Bandzierz
Institute of Polymer and Dye Technology
Faculty of Chemistry
Lodz University of Technology, Poland