FULLY AROMATIC COPOLY(ESTER-IMIDE)S WITH HIGH THERMAL-STABILITY

Fully aromatic copoly(ester-imide)s of various compositions were synth esized in bulk by conversion of N-(3-acetoxyphenyl)trimellitic acid im ide and N-(2-methyl-4-acetoxyphenyl)trimellitic acid imide with 4-acet oxybenzoic acid as comonomer. The solid state properties, the melting and phase behaviour of the copoly(ester-imide)s differ largely, but al l of them show high thermal stability. Some of the copoly(ester-imide) s form mesophases in the melt. Most of the investigated copoly(ester-i mide)s of N-(3-acetoxyphenyl)trimellitic acid imide and 4-acetoxybenzo ic acid and some of the ternary systems could be processed from the me lt. Copoly(ester-imide)s of N-(2-methyl-4-acetoxyphenyl)trimellitic ac id imide and 4-acetoxybenzoic acid, however, do not melt before rapid degradation at temperatures above 480 degrees C.