Preparation and properties of organo-soluble polyimides based on 4,4?-diamino-3,3-dimethyldiphenylmethane and conventional dianhydrides

Abstract

4,4′-Diamino-3,3′-dimethyldiphenylmethane was used to prepare polyimides in an attempt to achieve good organo-solubility and light color. Polyimides based on this diamine and three conventional aromatic dianhydrides were prepared by solution polycondensation followed by chemical imidization. They possess good solubility in aprotonic polar organic solvents such as N-methyl 2-pyrrolidone, N,N-dimethyl acetamide, and m-cresol. Polyimide from 4,4′-diamino-3,3′-dimethyldiphenylmethane and diphenylether-3,3′,4,4′-tetracarboxylic acid dianhydride is even soluble in common solvents such as tetrahydrofuran and chloroform. Polyimides exhibit high transmittance at wavelengths above 400 nm. The glass transition temperature of polyimide from 4,4′-diamino-3,3′-dimethyldiphenylmethane and pyromellitic dianhydride is 370°C, while that from 4,4′-diamino-3,3′-dimethyldiphenylmethane and diphenylether-3,3′,4,4′-tetracarboxylic acid dianhydride is about 260°C. The initial thermal decomposition temperatures of these polyimides are 520–540°C. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1299–1304, 1999