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

A new one-pot procedure for imide-acid monomer synthesis and polymerization is reported for four new poly(amide-imide)s. Bisphenol A dianhydride (BPAD A) was reacted with twice the molar amount of 3-aminobenzoic acid (3ABA) or 3-amino-methylbenzoic acid (3A4MBA) in 1-methyl-2-pyrrolidinone (NMP) and toluene mixture, and the amic acid intermediates cyclized in solution to gi ve two diimide-containing dicarboxylic acid monomers. Without isolation, th e diacid monomers were then polymerized with either 1,3-diaminomesitylene ( DAM) or 1,5-diaminonaphthalene (1,5NAPda) using triphenyl phosphite-activat ion to give a series of four soluble poly(amide-imide)s, PAI. Isolation and purification of the dicarboxylic acid monomers was not necessary for forma tion of high molecular weight polymers as indicated by intrinsic viscositie s 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 degr ees C by DSC, and 5% weight loss temperatures were above 400 degrees C in b oth air and nitrogen. Flexible films cast from DMAc were light yellow, tran sparent, and tough. (C) 1999 John Wiley & Sons, Inc.