Is it a polymer?
Intrinsic Viscosity
Intrinsic viscosity, [η], is a vital parameter that tells us whether or not the
material is a polymer in solution. A polymer in solution will have an
intrinsic viscosity greater than one
What did we do?
Test Method
 sp 
 1   s 
[ ]  lim red   lim 

lim

 C 0  
C 0
C 0
C
C



s


The viscosity of the sample cooked at 88 °C dissolved in water was
investigated for different concentrations. (see graph) The intercept can be
estimated to be [η].
Objective:
Viscometry of sample
cooked at 88 0C.
[η] = 1.27 ± 0.11
TGA
Thermo-gram of percent
weight vs. temperature
Measurements of three
different samples cooked at
different temperatures were
made and compared with
glycerol. Around the
temperature glycerol starts
decomposing at 160 0C, none
of the three samples loose
any mass and decompose yet.
Commercial polymers should be designed for environmental sustainability. Desirable traits are
biodegradability and production from cost-effective raw materials with sustainable sources. Our goal
is to investigate the following parameters of a potentially biodegradable polymer created from
sustainable raw materials:
•Physical, chemical and structural properties
•Degradability and environmental impact
•Usefulness as a replacement technology
DSC
Thermo-gram of heat flow
vs. temperature
The heat flow is plotted
against the temperature
change. From the second
run of the sample, there is
Tg observed at 100.6 0C.
From the first run of the
glycerol, there is a reaction
observed around 180 0C.
What are we working on?
How did we do it?
Implementation
Area of study: Polyglycerol Tartarate (PGT)
Because our team members are not the only ones investigating this material, it was agreed that we would focus on materials created from glycerol
and tartaric acid cooked above 80 °C. Last year’s team determined the optimal reaction stoichiometry as a 3:2 tartaric acid to glycerol molar ratio.
Thus, our main variables are the cooking time and temperature.
Foaming Phenomenon
88
°C
120
°C
These samples were cooked for 22 hours in a vacuum oven using silicone muffin cups. The only
difference is their cooking temperature.
What are its application?
Two forms of the polymer were tested:
•Water soluble material cooked at 120 °C
•Water insoluble material cooked at 140
°C
Tests will be done against three controls:
•RAS with nothing added
•RAS with un-biodegradable polymer
(HDPE from a milk jug)
•RAS with compostable polymer
(Polylactic Acid)
All 5 tests were done in triplicate, for a total of
15 runs (see left)
Data acquisition
•For all 15 runs, bi-daily air samples were taken via a
1-ml syringe (see right)
• The samples were analyzed by gas chromatographer
and then, GC outputs were converted to CO2
percentage based on the constructed calibration
curves of air and CO2
Why is this special?
Shear modulus (G’) and
loss modulus (G’’)
Starting material was
prepared with (3:7.5 mass
ratio of glycerol and
tartaric acid. Starting
material and cooked
sample behaves very
similar up to 120 0C.
It’s brown and smelly, but it’s
not what you think it is. Really
folks, it’s just microbes.
Shake flask tray holding what will be our 15
runs.
•A major consequence of higher cooking temperature is ‘foaming’
Water byproduct escapes as steam until the viscosity of the material
becomes so high that it instead forms bubbles that cannot escape
•Investigations in this phenomenon have included chemical additives
and time-lapse photography
Rheometry
•A few ASTM tests say that if after six months 70% of
a material’s carbon has been converted to CO2, the
material can be classified as biodegradable
•Because the timeframe for ASTM tests are exceed the
scope of this course, a modified test was designed
under the mentorship of Dr. Christine Kelly.
•To encourage the material to biodegrade, we will put
the material in the presence of Return Activated Sludge
(RAS) from Corvallis’ municipal water treatment
facility. (see right)
The results:
Inconclusive
Taking a sample from a flask
with modified stopper
Housing insulation
•Because the product foams naturally, insulation presents a
natural course to begin investigating applications
•Commercial insulation is cheap, so we have some pretty
tough parameters to beat.
•First we had to figure out how to make an insulator:
R-value at 1.5” (ft2•°F•hr/BTU)
10
Density (g/ml)
Recommendations
0.18
9
0.16
8
• Operating temperature
0.14
7
• Particle size of polymers
• Measurement method
• Duration of experiment
0.12
6
0.1
5
0.08
4
0.06
3
0.04
2
0.02
1
0
0
EPS
EPS
PGT
PGT
Comparison of of properties of EPS and PGT: Experimentation with blowing agents may yet produce properties
closer to commercial insulation.
G’ and G’’ of the
sample sheared at 120
0C and 1400C.
The percent carbon originally in the sample vs. carbon dioxide percentage vs. elapsed time. In this
analysis, all carbon dioxide in the head space of the flask was assumed to come from the added
polymer, even though it may have instead originated as yeast or glucose. CB, polylactic acid was
added in to the pre-treated sludge a week after other test batches were added.
1st Attempt
Acknowledgements:
Thanks to Dr. Skip for his direction, guidance and instruction, lending us a viscometer, and
letting us use the vacuum oven and polymer characterization equipment
Thanks to David Hackleman and Don Jackson for their experience and advice
Thanks to Christine Kelly for her expertise and design ingenuity
Thanks to Heather Paris, Birdie Cornyn and Jan Trinkel for sharing samples and experience
Thanks to Staci Van Norman for training us on lab equipment
Lastly, thanks to Dr. Harding for his guidance and support
A reaction may be
occurring between
these temperatures.
2nd Attempt
EPS insulation (left) and PGT 2nd attempt (right)