Synthesis and characterization of aromatic polyimide containing 3,6-diamino-9-alkylcarbazole and aromatic tetracarboxylic dianhydrides

New soluble polyimides with inherent viscosities of 0.25-0.62 dl g(-1) were synthesized from 3,6-diamino-9-alkylcarbazole and various aromatic tetracarboxylic dianhydrides by the conventional two-step method, including ring-opening polyaddition and subsequent thermally cyclodehydration. Most of the polyimides having hexyl alkyl chains were soluble in N-methylpyrrolidinone and in-cresol, while the polymers having ethyl chains were not soluble in organic solvents. The glass transition temperatures and 10% weight loss temperatures under argon of the polyimides having hexyl chains were in the ranges 232-269degreesC and 485-518degreesC, respectively.