Semicrystalline polyimides as matrices for carbon-fiber reinforced plastics

A fusible poly(imide), poly{[4,4'-bis(4"-N-phenoxy)diphenyl]imido-1,3-bis(3,4-dicarboxyphenoxy)benzene}, capable of crystallization upon cooling from melt was synthesized. The crystallization of poly(imide) was shown to be enhanced in its blends with bis(imides) that model the structure of its repeating unit or one of its fragments, diamine or acidic, Semicrystalline poly(imide) compositions which may serve as matrices for carbon-fiber reinforced plastics were obtained, As compared with an amorphous poly(imide), the use of a crystallizable poly(imide) leads to an increase in the heat resistance of a carbon-fiber reinforced plastic by almost 100degreesC and allows one to achieve a twofold increase in the elastic shear modulus.