Polyimidazopyrrolones and related polymers. II. Polyimidazopyrrolones from aromatic dianhydrides and 3,3′-dichloro-5,5′-diaminobenzidine

The preparation of 3,3′-dichloro-5,5′-diaminobenzidine and its polymeric reaction products with pyromellitic dianhydride and 3,4,3′,4′-benzophenonetetracarboxylic dianhydride are described. The soluble amine–acid–amide form of the polymer is stable at higher concentrations than the corresponding polymers from 3,3′-diaminobenzidine or 3,3′,4,4′-tetraaminodiphenyl ether. Infrared spectra indicate that polybenzimidazopyrrolone structure is formed after cure. The preparation and properties of films and glass-reinforced laminates prepared from the polymers are described.