Thermal degradation of a polyphenylimide‐quinoxaline in air and under vacuum

Abstract

AbstractThree samples of poly{2,2′‐[N,N′‐bis(1,4‐phenylene)benzophenone‐3,3′,4,4′‐tetracarboxylimide‐6,6′‐bis(3‐phenyl‐quinoxaline)]} (PPIQ), were prepared, differing in molecular weights and polymer chain endings. Their thermal degradation in vacuo and in air was determined by isothermal weight loss measurements. As in the case of poly‐[2,2′‐(1,4‐phenylene)‐6,6′‐bis(3‐phenylquinoxaline)] (PPQ), the temperature coefficients of thermal degradation in air were independent of molecular weight. However, in contrast, the temperature coefficients were independent of the type of polymer endgroups. It is, therefore, concluded that, contrary to amino‐terminated PPQ's, polymer chain‐end unzipping of PPIQ is of minor importance during thermal‐oxidative degradation.