Polypyromellitimides based on carbazole and substituted carbazoles

Polypyromellitimides have been synthesized from carbazole and N-benzylcarbazole by a two-step procedure involving ring-opening polyaddition with pyromellitic dianhydride and subsequent thermal cyclodehydration. The physicochemical, thermal and dielectric properties of the polymers have been studied. The various N-substituents, such as N-methyl and N-benzyl groups of the carbazole moieties, exert some influence on the overall thermal and dielectric properties of the polyimides. The influence has been rationalized in terms of gross structural characteristics.