Synthesis and properties of poly(amide-imide)s based on the diimide-diacid condensed from 2,2′bis(4-aminophenoxy)biphenyl and trimellitic anhydride

A new dicarboxylic acid having a kinked structure was synthesized from the condensation of 2,2'-bis(4-aminophenoxy)biphenyl and trimellitic anhydride. A series of biphenyl-2,2'-diyl-containing aromatic poly(amide-imide)s having inherent viscosities of 0.23-0.94 dL/g was prepared by the triphenyl phosphite activated polycondensation from the diimide-diacid II with various aromatic diamines in a medium consisting of N-methyl-2-pyrrolidone (NMP), pyridine, and calcium chloride. Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents including NMP and N,N-dimethylacetamide (DMAc). Transparent, flexible, and tough films of these polymers could be cast from DMAc or NMP solutions. The glass transition temperatures of these polymers were in the range of 227-261 degrees C and the 10% weight loss temperatures were above 520 degrees C in nitrogen. (C) 1998 John Wiley & Sons, Inc.