ONE-POT SYNTHESIS OF POLY(AMIDE-IMIDE)S DERIVED FROM TRIMELLITIC ACIDMONOESTERS AND MULTIRING AROMATIC DIAMINES

Aromatic processable poly(amide-imide)s have been prepared according t o the Yamazaki and Higashi phosphorylation reaction from flexible arom atic diamines and a mixture of isomeric 1,2,4-benzenetricarboxylic aci d monoethylesters following a novel ''one-pot'' procedure. The polymer ization was performed in 1-methyl-2-pyrrolidone/LiCl solutions using t riphenylphosphite and pyridine as condensing agents to form amide bond s. Cyclization of the intermediate poly(amide-amic ethylester) occurre d by eliminating ethanol under the polymerization conditions used, thu s leading to the formation of imide rings. The influence of several pa rameters which regulate the degree of polymerization and the formation of the imide rings, such as reaction temperature, triphenylphosphite/ monomers molar ratio, and pyridine concentration was carefully investi gated. In particular, the catalytic activity of pyridine in the imidiz ation reaction has been demonstrated. C-13-NMR spectroscopy has been u sed to show the absence of constitutional regularity in the prepared P AIs thus indicating equal reactivity toward polycondensation of the tw o different carboxyl groups of the 1,2,4-benzenetricarboxylic acid mon oethylesters. (C) 1996 John Wiley & Sons, Inc.