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

4,4'-Diamino-3,3'-dimethyldiphenylmethane was used to prepare polyimides in an attempt to achieve good organo-solubility and light color. Polyimides b ased on this diamine and three conventional aromatic dianhydrides were prep ared by solution polycondensation followed by chemical imidization. They po ssess good solubility in aprotonic polar organic solvents such as N-methyl 2-pyrrolidone, N,N-dimethyl acetamide, and m-cresol. Polyimide from 4,4'-di amino-3,3'-dimethyldiphenylmethane and diphenylether-3,3',4,4'-tetracarboxy lic acid dianhydride is even soluble in common solvents such as tetrahydrof uran and chloroform. Polyimides exhibit high transmittance at wavelengths a bove 400 nm. The glass transition temperature of polyimide from 4,4'-diamin o-3,3'-dimethyldiphenylmethane and pyromellitic dianhydride is 370 degrees C, while that from 4,4'-diamino-3,3'-dimethyldiphenylmethane and diphenylet her-3,3',4,4'-tetracarboxylic acid dianhydride is about 260 degrees C. The initial thermal decomposition temperatures of these polyimides are 520-540 degrees C. (C) 1999 John Wiley & Sons, Inc.