A series of novel bis(phenoxy)phthalide-containing poly(amide-imide)s 3 were synthesized via direct polycondensation of 3,3-bis[4-(4-aminophenoxy)phenyl] phthalide (BAPP) with various aromatic bis(trimellitimide)s 2 in N-methyl-2-pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. Poly(amide-imide)s 3 having inherent viscosities up to 1,68 dL/g were obtained in quantitative yields. Most of the 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 237-292 degrees C and the 10% weight loss temperatures were above 500 degrees C in nitrogen. The properties of poly(amide-imide)s 3 were compared with those of the corresponding isomeric poly(amide-imide)s 3' prepared from 3,3-[4-(4-trimellitimidophenoxy)phenyl]-phthalide and various aromatic diamines.
