LC-POLYIMIDES .22. THERMOTROPIC POLY(AMIDE-IMIDE)S DERIVED FROM NEW BISIMIDE SPACERS AND BIPHENYL 4,4'-DICARBOXYLIC ACIDS

A new class of diamine spacers was synthesized from alpha,omega-diaminoalkanes and 4-nitrophthalic anhydride. The resulting alpha,omega-bis(4-aminophthalimido)alkanes were polycondensed with terephthaloylchloride, 2-phenylthioterephthaloylchloride, naphthalene-2, 6-dicarboxylic acid dichloride, and 4,4'-biphenyl dicarboxylic acid dichloride. Most poly(amide-imide)s proved to be semicrystalline, forming a smectic layer structure in the solid state. Yet only the poly( amide-imide)s derived from 4,4'-biphenyl dicarboxylic acid are thermotropic and form a smectic and a nematic LC-phase. Due to the high temperatures employed, the reversibility of the phase transitions suffers from thermal degradation.