PREPARATION AND CHARACTERIZATION OF COLORLESS ALTERNATE POLY(AMIDE-IMIDE)S BASED ON TRIMELLITIC ANHYDRIDE AND M-PHENYLENEDIAMINE

Alternate copoly(amide-imide) was synthesized from two aromatic diamin es and trimellitic anhydride (TMA). When the diamine was m-phenylenedi amine (m-PDA), the resulted poly(amide-imide) [P(A-alt-I)] was found t o be of light colour. Specifically, when nt-PDA was located between tw o amide groups in the P(A-alt-I) chain, the P(A-alt-I) was colourless. Using triphenyl phosphite (TPP) and pyridine as condensing agents, a series of P(A-alt-I)s (series III) containing m-PDA was synthesized th rough direct polycondensation of an aromatic dicarboxylic acid (IIb) p repared from m-PDA and TMA, as well as various aromatic diamines. The isomeric series of P(A-alt-I)s (series IV) was synthesized from diacid monomers that had been prepared from various diamines and TMA, as wel l as m-PDA. The colour (yellow) of P(A-alt-I)s IV was lighter than tha t of the isomeric series of P(A-alt-I)s III. The 24 P(A-alt-I)s (serie s III and series IV) had inherent viscosities ranging 1.01-1.88 dl g(- 1). The tensile strengths, elongations to break and initial moduli of the films were 86-112 MPa, 6%-42% and 1.74-2.81 GPa, respectively, and most of the films had yielding. Polymers of Series IV had glass trans ition temperatures 228 degrees C-293 degrees C, which were higher than those of Series III ranging 223 degrees C-278 degrees C. The 10% weig ht loss temperatures in nitrogen of these two series were similar in t he range 472 degrees C-561 degrees C. (C) 1998 Elsevier Science Ltd. A ll rights reserved.