Structural changes occurring in polyindigoides under thermal and thermo-oxidative degradation

Abstract

When polyindigoides are subjected to heating in a vacuum the chemical structure of the polymers remains largely intact up to 430–450°; the onset of oxidative degradation is observed at 300–310°, in air. Thermal degradation primarily affects the end groups and to a lesser extent, some of the main chain bonds; the degradation is accompanied by the formation of crosslinked structures and by superstructural changes leading to an extreme type of relationship between electrical properties and the temperature of heat treatment. The thermo-oxidative degradation primarily involves oxidative scission of the central double bond. The main parallel reactions in polyindigo are those of dehydration and hydrolysis.