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PITTSBURGH UNIV PA SCHOOL OF ENGINEERING
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Inorganic polymers were first synthesized during the latter part of the last century, but commercial development was slow initially. The polysiloxanes have been exploited successfully since the late 1940s. Amongst other uses they are now being developed as precursors for silicon nitrides and silicon carbides in high temperature applications. More recently polyphosphazenes, a rapidly growing new class of polymers since the mid 1960s, have received much attention. These polymers represent the first important new class of semiorganic plastics since the siloxanes. They have great potential and may in time prove to be even more useful than the polysiloxanes since many of these materials are also liquid-crystal formers. Besides, a single cyclic monomeric precursor has been used to synthesize a very large number of homo and copolymers whose properties may be varied at will via side group substitution to obtain polymers that are crystalline, elastomeric or foams and thermosets are required. Some of these materials are growing in technological importance despite their cost. The purpose of this paper is to select and discuss polymers primarily from these two inorganic classes and to highlight some aspects of their thermal stability, toxicity or lack of, morphology and structure-property relationships that are challenging academically and developing industrially in our time.
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