A series of novel bis(phenoxy)phthalimidine-containing poly(amide-imide)s III were synthesized by the direct polycondensation of 3,3-bis[4-(4-aminophenoxy)phenyl]phthalimidine (BAPP) with various aromatic bis(trimellitimide)s in N-methyl-2-pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. Poly(amide-imide)s III, having inherent viscosities up to 1.36 dL/g, were obtained in quantitative yields. All resulting polymers showed an amorphous nature and were readily soluble in polar solvents such as NMP and N,N-dimethylacetamide. All the soluble poly(amide-imide)s afforded transparent, flexible, and tough films. The glass transition temperatures of these polymers were in the range of 267-322 degrees C and the 10% weight loss temperatures were above 490 degrees C in nitrogen. Some properties of poly(amide-imide)s III were compared with those of the corresponding isomeric poly(amide-imide)s III' prepared from 3,3-[4-(4-trimellitimidophenoxy)phenyl]phthalimidine and various aromatic diamines. (C) 1996 John Wiley & Sons, Inc.
