Aerospace & Defense Technology - December 2021 - 29

Tech Briefs
dation at temperatures below 1000°C.
To stymie this material degradation, an
EBC was applied to all specimens composed
of a 5 mil Si bond coat and a 10
mil Yb2Si2O7 topcoat. Application of the
coating may have other benefits such as
filling pores remaining from the meltinfiltration
process. The EBC is assumed
to maintain a uniform dry film thickness
and infinitesimal load carry. Finally,
SiC has a high strength to density
ratio which is ideal for any aircraft application
due to weight reduction without
sacrificing strength.
This work was done by Thaddeus M.
Williams for the Air Force Institute of Technology.
For more information, download
the Technical Support Package (free
white paper) at www.aerodefensetech.
com/tsp under the Manufacturing &
Materials category. AFIT-0002
Bio-Based Polyurethane Containing Isosorbide for Use in
Composites and Coatings
Formulating polyurethane that can be used in composites or coatings containing isosorbide as part or
all of the polyol phase and can be easily molded or cast into a film at ambient conditions.
Army Research Laboratory, Aberdeen Proving Ground, Maryland
I
sosorbide is a renewable material derived
from sorbitol, which is obtained
from glucose. Isosorbide (DianhydroD-glucitol)
is a nontoxic diol produced
from bio-based feedstocks that is
biodegradable and thermally stable.
The purpose of this research is to formulate
polyurethane for use in composites
or coatings that contain isosorbide
as part or all of the polyol phase
and can be easily molded or cast into a
film at ambient conditions. This research
also explores the possibility of
using isosorbide as a drop-in replacement
for a commercial polyol in a
polyurethane formulation. The raw
materials used in this study are detailed
in the accompanying table.
Isosorbide is a nontoxic diol and a
white solid at room temperature. Two
diols were selected to use as a solvent
with isosorbide. The first diol was
dipropylene glycol (DPG), a mixture of
three isomeric chemical compounds,
and the second was ethylene glycol
(EG), a liquid organic compound.
Glycerol, a polyol, was selected because
it is polyfuntional, containing 3hydroxyl
groups, and is bio-based.
Isosorbide was dissolved in the diols
individually and in blends with glycerol
at various levels. The Thinky ARE250
conditioning mixer and Aquasonic
sonicator 75D were used to create homogeneous
blends of isosorbide at various
percentages with the carrier
diols/polyol.
The first method included 1-3 mixing
cycles at 2,000 rpm for 10 minutes
SUMMARY OF RAW MATERIALS
Molecular or
Equivalent
Product Name
Dianhydro-D-glucitol (Isosorbide) (IS)
Dipropylene Glycol (DPG), mixture of
3 isomeric chemical compounds
Ethylene Glycol (1,2-Ethanediol) (EG)
Glycerol Andhydrous
Triethylamine (TEA)
Dabco 33-LV (33% TEDA and 67% DPG)
Surfynol DF-178 Defoamer (HAP-free and
alkylphenol ethoxylated free)
BYK-023 Silicone defoamer for
aqueous systems
Tolylene-2,4-diisocyanate (TDI)
(Toluene-2,4-di-isocyante)
Hexamethylene diisocyanate (HDI)
Bayhydrol XP 7110E
Bayhydur 303, Water-dipersible
Desmodur E 744
Desmodur L 67 BA
Desmodur L 75
Aerospace & Defense Technology, December 2021 www.aerodefensetech.com
Intro
Cov
ToC
+
-
A
µ
Chemical Type
diol
diol
diol
polyol
catalyst
catalyst
defoamer
defoamer
Aromatic
diisocyanate
Aliphatic
diisocyanate
Hydroxyl-functional
polyurethane
dispersion (PUD)
Aliphatic polyisocyanate
based on HDI
Aromatic polyisocyanate
based on MDI
Aromatic polyisocyanate
based on TDI
Aromatic polyisocyanate
based on TDI
n/a
n/a
n/a
n/a
n/a
1100
equivalent wt.218.0
equivalent wt. 179
equivalent wt. 350
equivalent wt. 315
n/a
n/a
n/a
n/a
n/a
29
C8H12N2O2
168.19
822-06-0
Formula
C6H10O4
C6H14O3
C2H6O2
C3H8O3
C6H15N
n/a
n/a
n/a
C9H6N2O2
Weight (g/mol) CAS-No.
146.14
652-67-5
134.2
62.07
92.09
101.19
n/a
n/a
n/a
174.16
2565-71-8
107-21-1
56-81-5
121-44-8
n/a
n/a
n/a
584-84-9
È
http://www.aerodefensetech.com/tsp http://www.aerodefensetech.com http://info.hotims.com/79420-922

Aerospace & Defense Technology - December 2021

Table of Contents for the Digital Edition of Aerospace & Defense Technology - December 2021

Aerospace & Defense Technology - December 2021 - Intro
Aerospace & Defense Technology - December 2021 - Sponsor
Aerospace & Defense Technology - December 2021 - Cov1
Aerospace & Defense Technology - December 2021 - Cov2
Aerospace & Defense Technology - December 2021 - 1
Aerospace & Defense Technology - December 2021 - 2
Aerospace & Defense Technology - December 2021 - 3
Aerospace & Defense Technology - December 2021 - 4
Aerospace & Defense Technology - December 2021 - 5
Aerospace & Defense Technology - December 2021 - 6
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Aerospace & Defense Technology - December 2021 - 12
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Aerospace & Defense Technology - December 2021 - 28
Aerospace & Defense Technology - December 2021 - 29
Aerospace & Defense Technology - December 2021 - 30
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Aerospace & Defense Technology - December 2021 - 39
Aerospace & Defense Technology - December 2021 - 40
Aerospace & Defense Technology - December 2021 - Cov3
Aerospace & Defense Technology - December 2021 - Cov4
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