Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 10, pp. 1800−1804.
Pleiades Publishing, Ltd., 2011.
Original Russian Text © V.E. Smirnova, E.N. Popova, V.M. Svetlichnyi, L.A. Myagkova, A.N. Orekhov, V.E. Yudin, A.M. Muzafarov, E.A. Tatarinova, 2011,
published in Zhurnal Prikladnoi Khimii, 2011, Vol. 84, No. 10, pp. 1708−1712.
AND POLYMERIC MATERIALS
Effect of Thermal Aging on the Mechanical Characteristics
of a Composite of a Polyimide with an Organosilicon Resin
V. E. Smirnova
, E. N. Popova
, V. M. Svetlichnyi
, L. A. Myagkova
A. N. Orekhov
, V. E. Yudin
, A. M. Muzafarov
, and E. A. Tatarinova
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Enikolopov Institute of Synthetic Polymeric Materials, Russian Academy of Sciences, Moscow, Russia
Received April 22, 2011
Abstract—The effect exerted by thermal aging in air at 350°С on the thermal and mechanical properties of composite
ﬁ lms prepared on the basis of heat-resistant polyimide PM and non-ﬁ lm-forming polymethylphenylsiloxane (PMPS)
was examined. The phase segregation of polymeric composites of various compositions and the thermal aging
rate were evaluated.
One of priority problems of the modern materials
science is the development of new highly heat-resistant
polymeric binders and improvement of the characteristics
of the existing binders. These materials are essential for
the successful development of many branches of modern
engineering, such as aviation and aerospace industry, ship
building, electronics, instrument-making, and certain
special branches of electrical engineering. An important
property of heat-resistant binders, in particular, of
polyimide binders, is that the mechanical characteristics
of ﬁ brous composite materials based on them can be
preserved for a long time at high temperatures. As
we showed in , the composites (glass- and carbon-
reinforced plastics) based on a series of polyimide
binders after keeping in air for 100 h at 350°C preserve
their initial mechanical characteristics to 60% at best. At
the same time, it is known [2, 3] that glass-reinforced
plastics based on organosilicon binders, though exhibiting
relatively low mechanical characteristics (strength, crack
resistance), have enhanced heat and ﬂ ame resistance, so
that preservation of their performance at temperatures
exceeding 350°С can be expected.
In this study we examined the possibility of combining
the components and preparing composite binders based on
polymethylphenylsiloxane (PMPS) binder and one of the
most heat-resistant polymers, poly(4,4'-oxydiphenylene)
pyromellitimide (PM), whose specimens preserve high
mechanical properties in a wide temperature interval .
In the composite binders, the heat resistance of PMPS, on
the one hand, and the high mechanical characteristics of
heat-resistant polyimide PM, on the other hand, should
be utilized to maximum possible extent. The PM/PMPS
composites were prepared and studied both as film
materials (to avoid possible additional effect of glass
ﬁ bers in the course of studying the heat resistance) and
as glass-reinforced plastics.
Polymethylphenylsiloxane polymer was prepared by
hydrolytic polycondensation of a mixture of phenyl- and
methyltrialkoxysilanes in acetic acid :
In the course of the reaction, we attained complete
conversion of the alkoxy groups and obtained PMPS
samples with the molecular weight of 2800 (GPC data,
polystyrene references), hydroxy group content of 5 wt %,
and gel time of 2 min at 200°C.