Destruction of polymers with benzoxazole and imide fragments in the main chain

Thermal and thermooxidative destruction of polyimidobenzoxazoles having the same ratio of imide and benzoxazole cycles was studied. The benzoxazole cycle was shown to be more thermally stable than the imide cycle. It has been concluded from the composition of the products of polymer decomposition and the kinetics of their formation that both in vacuum and in the presence of oxygen decomposition of the polymer by a radical mechanism predominates. Above 550°C there is slight hydrolytic decomposition of the benzoxazole fragments of the chain.