Oxidative degradation of a polyimide film: II. Studies using hydrazine hydrate

Abstract Treatment of a polypyromellitimide with hydrazine hydrate yields the biscyclohydrazide of pyromellitic dianhydride and the diamine originally used in the preparation. This reagent was, therefore, employed in a study of oxidised poly‐N,N′‐(4,4′‐diphenylether)pyromellitimide film in an attempt to elucidate the structural changes which had taken place. The most important process appeared to be cleavage of the aryl‐ether bond followed by reactions leading to the formation of polyaromatic aggregates. Breakdown of the imide ring structure also occurred.