Soluble poly(amide-imide)s prepared by one-pot solution condensation

Abstract

A new one-pot procedure for imide–acid monomer synthesis and polymerization is reported for four new poly(amide–imide)s. Bisphenol A dianhydride (BPADA) was reacted with twice the molar amount of 3-aminobenzoic acid (3ABA) or 3-amino-4-methylbenzoic acid (3A4MBA) in 1-methyl-2-pyrrolidinone (NMP) and toluene mixture, and the amic acid intermediates cyclized in solution to give two diimide-containing dicarboxylic acid monomers. Without isolation, the diacid monomers were then polymerized with either 1,3-diaminomesitylene (DAM) or 1,5-diaminonaphthalene (1,5NAPda) using triphenyl phosphite-activation to give a series of four soluble poly(amide–imide)s, PAI. Isolation and purification of the dicarboxylic acid monomers was not necessary for formation of high molecular weight polymers as indicated by intrinsic viscosities of 0.64–1.04 dL/g determined in N,N-dimethylacetamide (DMAc). All of the PAI were soluble in polar aprotic solvents such as NMP, DMAc, and dimethyl sulfoxide (DMSO). Glass transition temperatures ranged from 243 to 279°C by DSC, and 5% weight loss temperatures were above 400°C in both air and nitrogen. Flexible films cast from DMAc were light yellow, transparent, and tough. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1183–1188, 1999