Synthesis and curing of epoxy-anhydride polymers modified with an oxirane of the tetrahydroquinoline series

Article abstract of DOI:10.1134/S1070427211090230

Epoxy-anhydride polymers were prepared from diphenylolpropane diglycidyl ether and isomethyltetrahydrophthalic anhydride in the presence of a chemical modifier, oxirane of the tetrahydroquinoline series. The kinetics of the reaction of the modifier with t

Full text of DOI:10.1134/S1070427211090230

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 9, pp. 1596−1599. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © M.S. Fedoseev, V.A. Glushkov, L.F. Derzhavinskaya, G.F. Krainova, T.G. Tiunova, 2011, published in Zhurnal Prikladnoi Khimii,
2011, Vol. 84, No. 9, pp. 1547−1550.
MACROMOLECULAR COMPOUNDS
AND POLYMERIC MATERIALS
Synthesis and Curing of Epoxy–Anhydride Polymers
Modified with an Oxirane
of the Tetrahydroquinoline Series
M. S. Fedoseev, V. A. Glushkov, L. F. Derzhavinskaya,
G. F. Krainova, and T. G. Tiunova
Institute of Technical Chemistry, Ural Branch, Russian Academy of Sciences, Perm, Russia
Received May 19, 2011
Abstract—Epoxy–anhydride polymers were prepared from diphenylolpropane diglycidyl ether and
isomethyltetrahydrophthalic anhydride in the presence of a chemical modifier, oxirane of the tetrahydroquinoline
series. The kinetics of the reaction of the modifier with the anhydride and the curing kinetics of the polymeric
compound containing the modifier were studied. The thermal properties and water absorption of the polymers
after their curing and structure formation were determined.
DOI: 10.1134/S1070427211090230
Thanks to a favorable combination of physicome-
chanical, adhesion, and insulation properties, polymeric
materials based on epoxy binders are widely used in
spacecraft engineering, in aircraft, machine, and ship
building, in radio electronics, in building, and in homes
[1]. One of the drawbacks of many epoxy materials is
low water resistance. They absorb up to 8–10% water,
which impairs their heat resistance [2, 3].
examined the properties of the products.
EXPERIMENTAL
We used vinylimidazole produced by Alfa Aesar
(Lancaster). The melting point of the oxirane (OTQ)
was determined with a PTP device. Thin-layer
chromatography was performed with Sorbfil silica gel
plates. The chromatograms were visualized under UV
light. The IR spectrum was recorded with a Bruker IFS
66ps Fourier spectrometer (mull in mineral oil); the
1Н and 13С NMR spectra, with a Varian Mercury+300
spectrometer (300 and 75 MHz), solvent CDCl3, internal
references HMDS and residual solvent signal (CHCl3,
13C NMR, δ = 77.0 ppm); and the mass spectrum, with
an Agilent 6890N device equipped with an MSD 5975В
mass detector. Elemental analysis was performed with
a Leco CHNS 9321P device.
One of possible ways to enhance the water resistance
of polymers is introduction into their structure of
hydrophobic chemical modifiers that do not cause phase
segregation of the system in the course of the synthesis,
do not give rise to thermodynamic and aggregative
instability of the system [4, 5], and do not deteriorate
the physicomechanical and thermal properties of the
material under the action of elevated temperatures
and strains. It was shown [5] that the water resistance
of epoxy–anhydride polymers is enhanced by their
modification with polyfluoroalkyl glycidyl ethers in the
course of curing.
1,2-Epoxy-8-fluoro-4-phenyl-5-trifluoroacetyl-
3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline
(OTQ, mixture of diastereomers) was synthesized
by epoxidation of the corresponding olefin with
m-chloroperoxybenzoic acid (MCPBA), following the
In this study we prepared epoxy–anhydride polymers
modified with an oxirane of the tetrahydroquinoline
series, containing fluorine atoms in the molecule, and
1596

SYNTHESIS AND CURING OF EPOXY–ANHYDRIDE POLYMERS
1597
procedure described in [6]:
4.01, N 3.71. C20H15NO2F4. Calculated, %: С 63.33, Н 3.09,
N 3.72.
As a system for modification, we chose an epoxy
binder based on diphenylolpropane diglycidyl ether
(ED-20) and a curing agent, isomethyltetrahydrophthalic
anhydride (IMTHPA), in combination with the reaction
catalyst, 2,4,6-tris(dimethylaminomethyl)phenol. The
kinetics of the reaction of IMTHPAwith the modifier was
studied by DSC with a DSC 822e calorimeter (Mettler
Toledo, Switzerland). The reaction was performed in
the dynamic mode in the temperature interval 20–300°С
at a heating rate of 5 deg min–1. In the thermograms
we recorded the reaction onset temperature Тo and the
reaction maximum temperature Тmax. From the DSC
results, we calculated the thermal effect of the reaction.
The results of studying the reaction are given in Table 1.
For comparison, we present the kinetic parameters for
the reaction of IMTHPA with phenyl glycidyl ether
(PGE). The modifier of the quinoline series reacts
with IMTHPA in the temperature interval 122–166°С
with a small thermal effect (42 J g–1) to form esters.
The compound of simpler structure, PGE, reacts with
IMTHPA only in the presence of an active catalyst,
vinylimidazole (1 wt %).
To a solution of 0.5 g (1.30 mmol) 8-fluoro-4-
phenyl-5-trifluoroacetyl-3a,4,5,9b-tetrahydro-3H-
cyclopenta[c]quinoline (synthesized by the method
described in [7]) in 10 ml of dichloromethane, prepared
at 0°C, we added dropwise with stirring a cooled solution
of 0.95 g (5.5 mmol) of m-chloroperoxybenzoic acid in
10 ml of dichloromethane. The mixture was stirred for
1 h at 10°С and for 6 h at room temperature, until the
starting compound fully disappeared (TLC monitoring).
The reaction mixture was washed with a 10% Na2SO3
solution (3 × 20 ml) to decompose excess per acid) and
then with a 5% Na2CO3 solution. The crude epoxide
obtained after drying over sodium sulfate and distillation
of the solvent was subjected to chromatography on
a silica gel column (eluent hexane–ethyl acetate, 1 :
1), followed by recrystallization from ethanol. Yield
0.40 g (78%), colorless crystals, mp 152–154°С, Rf 0.61
Curing of the epoxy–anhydride compound in the
presence of 10 wt % modifier in the temperature interval
found for the reaction of IMTHPA with the modifier
yields a network polymer. The structure of the node of
its chemical network is shown in the scheme.
1
(Sorbfil plates, hexane–ethyl acetate, 1 : 1). H NMR
spectra, δ, ppm (CDCl3): 0.99 m (1Н, НaxС3), 1.63 m
(1Н, НeqС3), 3.21 m (1Н, НС3а), 3.40 m (2Н, НС1 and
НС2), 3.99 d (1Н, НС4, J = 2.4 Hz), 5.95 d (1Н, НС9b,
J = 10.8 Hz), 6.79 m (2Н, Нarom), 7.04 m (1Н, Нarom),
7.14–7.30 m (5Н, Нarom). 13С NMR spectrum, δC, ppm
(CDCl3): 29.83, 38.71, 56.44, 57.08, 57.62, 113.35,
113.67, 114.20, 11450, 118.32, 127.59, 127.80, 128.45,
131.71, 135.48, 137.92, 155.82, 156.31, 159.84, 163.14.
Mass spectrum: m/z 377 (M+). Found, %: С 63.65, Н
The physicomechanical characteristics of the
polymer specimens prepared in the form of blades
(nominal tensile strength σ, relative critical deformation
ε) were determined at 25 ± 2°С and extension velocity
of 0.056 s–1 with an Instron 3565 tensile-testing machine
(the United Kingdom) in accordance with GOST (State
Scheme.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 84 No. 9 2011

1598
FEDOSEEV et al.
Table 1. Kinetic parameters of the reaction of IMTHPA with
the modifiers
introduction of the oxirane of the tetrahydroquinoline
series into the compound made it more hydrophobic
and, correspondingly, reduced the moisture absorption
by the polymers by a factor of approximately 2.
To
Tmax
Modifier
Catalyst
Q, J g–1
°С
It seemed necessary to evaluate the heat resistance
of the polymers whose moisture content was reduced by
introducing a fluorinated modifier. The thermal oxidative
stability of the polymers was studied with a Q-1500D
derivatograph (МОМ, Hungary). Programmed heating
of the samples (100 mg) was performed at a rate of
20 deg min–1 to 1000°С in air. As reference we used
calcined aluminum oxide. The sensitivity was as follows:
DTA 500 μV and DTG 2.5 mV. The results of thermal
gravimetric analysis of the polymers, characterizing the
thermal oxidative degradation, are given in Table 3.
OTQ
PGE
No catalyst
122
100
166
150
42
Vinylimidazole
410
Table 2. Physicomechanical properties and moisture
absorption of cured epoxy polymers modified with oxirane of
the tetrahydroquinoline series
Moisture
Our results show that the heat resistance of the
polymers modified with fluorinated OTQ is high, with
50% weight loss observed at 400°C and 75–80% weight
loss, at 650°С.
Modifier
σ, MPa ε, %
Tg, °С
absorption, %,
in 24 h
OTQ
PGE
67
59
53
12
10
9
104
86
0.138
0.456
0.260
It should be noted that, with respect to the heat
resistance in the temperature range 300–400°С, the
modified polymers are similar to the polymers without
modifiers. At the temperature increased to 650°С, the
polymer with the modifier is more heat-resistant. This
is apparently due to the fact that the polymer modified
with OTQ has higher cross-linking density and,
correspondingly, higher tensile strength (Table 2) and
higher heat resistance.
No modifier
99
DEG-1
63
11
84
0.352
Table 3. Results of thermal gravimetric analysis of the
polymers
Temperature, °C, of
Residue at
indicated weight loss, %
Modifier
650°C,
wt %
5
10
50
CONCLUSIONS
OTQ
310
307
340
322
400
370
19
14
(1) An oxirane of the tetrahydroquinoline series was
synthesized. Its structure was confirmed by the Н and
13С NMR data.
No modifier
1
(2)The temperature interval and thermal effects of the
reactions of oxiranes with isomethyltetrahydrophthalic
anhydride were determined.
Standard) 270–75. The glass transition point Тg was
determined by thermomechanical analysis with a UIP-
70 device. Analysis was performed in the temperature
interval 20–250°С at a scanning rate of 0.08 deg s–1. The
water absorption was determined from the specimen
weight gain in cold water. The results are given in
Table 2.
(3) Introduction of the oxirane into the epoxy
compounds as structural modifier enhances the
moisture resistance by a factor of approximately 2 and
allows preparation of the polymers with high levels of
physicomechanical properties and heat resistance.
We found that OTQ positively affects the
formation of the polymeric matrix of the binder.
The cured polymers exhibit high physicomechanical
characteristics, not inferior to those of the polymers
prepared without modifiers and in the presence of PGE
and DEG-1 (aliphatic epoxy resin). At the same time,
ACKNOWLEDGMENTS
The study was financially supported by the Ural
Branch of the Russian Academy of Sciences (project
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 84 No. 9 2011

SYNTHESIS AND CURING OF EPOXY–ANHYDRIDE POLYMERS
1599
3. Johucock, P. and Tudgey, G.F., Brit. Polym. J., 1986,
“Development of Physicochemical Principles for the
Preparation of Heat- and Moisture-Resistant Polymeric
Materials with Improved Elastic and Deformation
Characteristics”).
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4. Kobets, L.P. and Deev, I.G., Ross. Khim. Zh., 2010, vol. 44,
no. 1, pp. 67–78.
5. Fedoseev, M.S., Derzhavinskaya, L.F., Karmanov, V.I., et
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