THERMOTROPIC LIQUID-CRYSTALLINE AROMATIC-ALIPHATIC POLYIMIDES .3. POLY(IMIDE-CARBONATE)S COMPOSED OF 3,4 3',4'-BIPHENYLDICARBOXIMIDE/

mega-hydroxyalkyl)-3,4:3',4'-biphenyldicarboximide (l = 3, 6) were pre pared by a two-step reaction (via intermediates) of 3,4:3',4'-biphenyl tetracarboxylic dianhydride and omega-amino-alcohols. Polycondensation of dihydroxyalkyl derivatives of the 3,4:3',4'-biphenyldicarboximide (l = 3, 6) and/or biphenyl with alkylene bis(phenylcarbonate)s (m = 3, 6) afforded poly(imide-carbonate)s with high molecular weights in hig h yields, which were characterized by FT-IR and NMR measurements and e lemental analyses and showed good solubilities in organic solvents. Th e mesogenic properties of the polymers were evaluated by means of diff erential scanning calorimetry (DSC), observation in the polarizing mic roscope equipped with a hot stage and by means of powder X-ray diffrac tion. The DSC curves of the imide unit rich polymers without annealing only display glass transition steps. The curves after annealing, howe ver, show some endotherms. The polarizing microscope observation and X -ray analyses indicated that the homo- and copolymers from the 3,4:3', 4'-biphenyldicarboximide derivative with longer methylene chains (l = 6) form nematic liquid-crystalline mesophases.