Journal of Polymer Science Part A: Polymer Chemistry, Vol.37, No.8, 1183-1188, 1999
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 (BPADA) 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 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 degrees C by DSC, and 5% weight loss temperatures were above 400 degrees C in both air and nitrogen. Flexible films cast from DMAc were light yellow, transparent, and tough.