New poly(amide‐imide) syntheses, 19 . Preparation and properties of poly(amide‐imide)s derived from N ‐phenyl‐3,3‐bis[4‐(4‐aminophenoxy)phenyl]‐1‐oxoisoindoline and various bis(trimellitimide)s

A series of novel bis(phenoxy)‐1‐oxoisoindoline‐containing poly(amide‐imide)s 3 were synthesized by the direct polycondensations of N ‐phenyl‐3,3‐bis[4‐(4‐aminophenoxy)‐phenyl]‐1‐oxoisoindoline ( 1m , NPBA) 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 1,06 dL/g were obtained in quantitative yields. Most of the resulting polymers showed an amorphous nature and were readily soluble in polar solvent such as NMP and N , N ‐dimethylacetamide. All of the soluble poly(amide‐imide)s afforded transparent, flexible, and tough films. The glass transition temperatures of these polymers were in the range of 277–327°C, and the 10% weight loss temperatures were above 500°C in nitrogen. The properties of poly(amideimide)s 3 were compared with those of the corresponding isomeric poly(amide‐imide)s 3 ′ prepared from NPBA and various aromatic diamines.