SEMIRIGID HOMOPOLY(IMIDE-CARBONATE)S AND COPOLY(IMIDE-CARBONATE)S BASED ON 3,4,3'',4''-P-TERPHENYLTETRACARBOXDIIMIDE

Novel thermotropic liquid crystalline (LC) semirigid home- and copoly( imidecarbonate)s composed of a 3,4,3'',4''-p-terphenyltetracarboxdiimi de ring and aliphatic chains were prepared by melt polycondensation of a dihexanol derivative of 3,4,3'',4''-p-terphenyltetracarboxdiimide a nd/or a dioxydihexanol of biphenyl taken in a definite molar ratio wit h hexamethylene diphenyl dicarbonate in the presence of zinc acetate, and their thermal and mesogenic properties were evaluated. The assigne d structures of polymers were characterized by FT-IR and C-13 NMR spec troscopy, and elemental analyses. DSC and TG-DTA measurements, polariz ing microscope observations of textures and temperature-dependent x-ra y analyses demonstrated that the polymers have wider LC temperature ra nges (nematic phase) than analogous semirigid poly(ester-imide)s and a re thermally stable up to 300 degrees C in air.