1. The Development of Heat Resistant Epoxy Resin for Industrial Applications
Cadence Luchsinger and David A. Rider*
Departments of Chemistry and Engineering Technology, Western Washington University
Additives
Acknowledgments and Funding Future Work
Introduction
100 200 300 400 500 600 700 800 900
0
10
20
30
40
50
60
70
80
90
100
%Mass
Temperature (C)
Cured WB400-HT-386 Resin
Cured Epoxy Resin with Oxazolidone Additive Synthesis 1
Cured Epoxy Resin with Oxazolidone Additive Synthesis 2
Cured Epoxy Resin with Oxazolidone Additive Synthesis 3
Cured Epoxy Resin with Oxazolidone Additive Synthesis 4
Cured Epoxy Resin with Oxazolidone Additive Synthesis 5
Cured Phenolic Resin
200 300 400 500 600 700 800 900
0
10
20
30
40
50
60
70
80
90
100
%Mass
Temperature (C)
WB-400 + HT-386
WB400 + 95% HT-386/ 5% TBAB
WB-400 + 90% HT-386/ 10% TBAB
WB-400 + 85% HT-386/ 15% TBAB
4000 3500 3000 2500 2000 1500 1000 500
30
40
50
60
70
80
90
100
%Transmittance
Wavenumbers
Pure TBAB
Pure DGEBA
Synthesis 1 of Epoxy Resin with Oxazolidone Additive
Synthesis 2 of Epoxy Resin with Oxazolidone Additive
Synthesis 3 of Epoxy Resin with Oxazolidone Additive
Synthesis 4 of Epoxy Resin with Oxazolidone Resin
4000 3500 3000 2500 2000 1500 1000 500
70
75
80
85
90
95
100
%Transmittance
Wavenumbers
WB-400 + HT-386
WB-400 + 95% HT 386/ 5% TBAB
WB-400 + 90% HT-386/10% TBAB
WB-400 + 85% HT-386/ %15 TBAB
WB-400 + 80% HT-386/ 20% TBAB
My research has involved studying epoxy resin systems to be used in industry. I first conducted solubility tests on
the separate components of the resin systems (epoxy is made up of an epoxy resin and an amine hardener) to
determine the correct solvents to be used during my research for both clean-up as well as to know how the resins
interact with different compounds, which gave me an idea of their structures. A TGA test was then run to compare
the percent weight lost when heated of the resin used currently by Zodiac Aerospace and the epoxy resin system;
this test revealed the necessity for a thermal stabilizer for both resin systems being studied. I then chose the resin
systems from those donated that would be most effective for use by Zodiac Aerospace because their solubility
results showed they would dissolve in the solvent currently used by the company, and made formulations of the
resins in order to test how they would cure under different conditions. The data compiled was analyzed and
showed that the epoxy system needed an additive that would slow the time it took to cure. Currently I am
analyzing the effects of various additives on the thermal and structural characteristics of the resin systems with
the goal of having a prototype of a resin ready for industrial use.
Abstract
Various chemicals in use in industry currently may be slowly phased out of use
because of tighter regulations made as science develops further. In order to be
compliant and have the utmost safety for the workers and customers in contact with
these chemicals, companies begin researching alternatives years in advance of the
higher regulations. Zodiac Aerospace currently uses phenol formaldehyde, a resin that
is likely to be slowly phased out of use within the next 50 years. My research has
focused on finding a replacement resin that will not only meet or exceed Zodiac’s high
standards for tensile strength, low vertical burn, low heat release, and low smoke
density, but also conform to the future restrictions made on chemical usage.
Tests on which the resins must be able to meet or exceed phenolic
formaldehyde5
Vertical Burn:
Burn Length: Distance from original specimen edge to farthest evidence of damage
to test specimen due to that area’s combustion
Extinguish time (Flame Time): Time in seconds specimen continues to flame after
burner is removed from underneath the specimen
Heat Release Test:
The measure of the amount of heat energy evolved by a material when burned
At least 3 specimens of a specific size are used for each material
They are conditioned at ~70oF and ~50% relative humidity for 24 hours prior to the
test, then wrapped in aluminum foil
Specimen is put into a heating chamber and heated for 5 min.
Data is used to determine max heat release rate during 5 min.
Smoke Density:
Specific Optical Density: Dimensionless measurement of the amount of smoke
produced per unit area by a material when burned
Procedure: Smoke emitted by a specimen accumulates in a sealed chamber, light
is measured as it is shot through the smoke and the result is used to compute the
amount of smoke in the chamber and thus the amount of smoke emitted by the
specimen.
Synthesis of an Epoxy Resin1
Figure 1. Bisphenol A reacts with epichlorohydrin in NaOH, opening the epoxide ring
(from which epoxy gets its name) to form a cross-linked epoxy chain that can be
cured using various hardeners.
The Components of a Cured Epoxy System:
Resin and Hardener1
Figure 2. A generic epoxy resin system is made up of a specific ratio of epoxy resin to
amine hardener that combine to form a cross-linked compound that cures within
hours of mixing, where the R groups vary depending on the applications of the
system.
I would like to thank Zodiac Aerospace as a whole, HOS-Technik, Dr. David Rider, Kalin
Karich, Decomp Composites, Axson Technologies, James Delpinto, Kevin Bussard, Hla
Win-Piazza, Ryan Hackler, Nicki Larson, Nicki Hoekstra, JCATI, AMSEC, Polly Berseth,
SciTech, Charlie Wandler, Sean Cavanaugh, and the other members of the Zodiac
Research Team for their help with furthering our research.
References
• Synthesize epoxy resins with benzyl alcohol
additive
• Test resins for mechanical and thermal stability and
compare results to phenolic resin used by Zodiac
• Analyze findings and decide if further additives are
necessary
• Finalize formulation for industrial application
Oxazolidone: Incorporates
aromatic rings into the
backbone of the epoxy,
increasing thermal stability
because of higher density
as well as intermolecular
forces holding the
molecules together.3
Figure 3. The molecular
structure of an oxazolidone;
the R group is where the
additive is connected with
the epoxy resin system.
Benzyl Alcohol: Lessens
the cross-linking of the
epoxy structure to
lengthen the curing time,
prolonging the amount of
time it can be processed
industrially2.
Figure 4. The molecular
structure of benzyl
alcohol.
Resin or
Hardener
Result in
acetone
Result in
ethanol/methanol
Result in
chloroform
Result in
hexanes
HT-386
clear,
completely
dissolved
dissolved clear, dissolved
dissolved,
clear
SC-150-N
milky, some
chunks
milky, no chunks
slightly milky,
appears totally
dissolved
milky, two
layers
HT-9234
yellow, clear,
no chunks
orange, clear, no
chunks
yellow,
dissolved
2 layers
HTR-212
clear,
completely
dissolved
not dissolved at all,
separation (2
layers)
bubbles,
slightly yellow,
appears totally
dissolved
not
dissolved,
2 layers
HTR-350
clear,
completely
dissolved
not dissolved at all,
separation (2
layers)
dissolved
slightly
soluble,
not totally
WB-400
some bubbles,
appears
dissolved
milky, all liquid,
homogeneous
bubbles, clear,
totally
dissolved
slightly
soluble,
not totally
Resin + Hardener
% epoxy in
formula
% ethanol in
formula
initial appearance of
formula
appearance
at 1hr
appearance at
2r-4hr
appearance at
5hr
apearance at 6
hr
appearance at
23hrs
Formulation:
HT386+WB400
30 70
totally clear, some
bubbles, some yellow,
dissolved
dissolved,
clear, some
yellow
same as at 1 hr
possibly
beginning to
cure slightly,
some flakes
appear, very
viscous
much more
viscous, but
stir bar still
spins well
fully cured at
bottom, hazy
opaque liquid at
top
Formulation:
HT386+WB400
10 90
clear, bubbles, no color,
dissolved
dissolved,
clear
same as at 1 hr
definite flakes,
not viscous
flakes, but not
many and not
viscous
cured a little
around the top
and the stir bar
but still a lot
dissolved
Table 1. Solubility tests performed on epoxy resins and
hardeners dissolved in different solvents. WB-400 resin
and the hardener HT-386 were soluble in solvents
currently in use at Zodiac Aerospace, so they were chosen
to be further tested.
Table 2. WB-400 and HT-386 were mixed together under different percentages of resin and hardener to solvent; data
was taken every hour for 6 hours and then at the 23rd hour to determine the state of cure the resin system had
reached. The results showed that the resin system cured too quickly for use by Zodiac Aerospace in its current state, so
a cure retarding agent must be added to the epoxy.
Solvent Tests and Resin Formulations
TGA Test Results of Synthesized Resins with Oxazolidone Additive
IR Results of Synthesized Resins with Oxazolidone Additive
Figure 5. The IR of various epoxy resins
synthesized with oxazolidone under an
N2 environment with a tetrabutyl
ammonium bromide catalyst (TBAB).
Figure 6. The IR of various epoxy resins
synthesized with oxazolidone under an
open-air environment without a TBAB
catalyst.
Figure 7. TGA test results of various epoxy resins
synthesized with oxazolidone under an N2 environment
with a tetrabutyl ammonium bromide catalyst (TBAB).
Figure 8. TGA test results of various epoxy resins synthesized
with oxazolidone + amine hardener under an O2
environment without a TBAB catalyst.
Analysis of IR Results3
Formulations of Epoxy Resin and Hardener
1. Dewprashadd, B; Eisenbraun E. Journal Of Chemical Education, 1994,
71, 290-294.
2. Le Craz, S.; Pethrick, R. International Journal of Polymeric Materials.
2011, 60, 441-455.
3. Mathur, R.; Prajapati, K.;Varshne, A. Advances in Applied Science
Research 2012. 2553-2560.
4. Patel, B.; Patel, H. International Journal of Polymeric Materials and
Polymeric Biomaterials. 2012, 62, 455-461.
5. Zodiac Aerospace. 2013.
• According to literature,
oxazolidone presents a
peak around 1754 cm-1
• This peak can be seen in
some of the syntheses, but
appears absent in others
• This indicates an improper
synthesis
• An epoxy peak can be seen
at around 910 cm-1 in all
syntheses, indicating epoxy
compounds were present