New poly(amide‐imide) syntheses. V. Preparation and properties of poly(amide‐imide)s based on the diimide—diacid condensed from 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane and trimellitic anhydride

Abstract A dicarboxylic acid ( 1 ) bearing two pre‐formed imide rings, was prepared from the condensation of 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane and trimellitic anhydride. A new family of poly(amide‐imide)s having inherent viscosities of 0.53–1.68 dL/g was prepared by the triphenyl phosphite activated polycondensation from the diimide—diacid I with various aromatic diamines in a medium consisting of N ‐methyl‐2‐pyrolidone (NMP), pyridine, and calcium chloride. 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 poly(amide‐imide)s were in the range of 237–293°C and the 10% weight loss temperatures were above 508°C in nitrogen. © 1993 John Wiley & Sons, Inc.