Thermo-oxidative degradation of polyamides and polyimides

Abstract

It has been shown [1, 2] that, in the degradation of aromatic polyamides (PA) with hetero-groups in the chain, their resistance to the thermo-oxidative action is determined not so much by the rate of the primary acts of decomposition as by the intensity with which secondary processes occur. Clearly this conclusion may equally relate to polypyromellitimides (PPI). On this basis it must be considered that, despite the abundance of information on the degradation of aromatic PA and PPI which exists in the literature [3], the data cannot be used as a foundation for selecting polymeric materials in a suitable way for real conditions of use, since most of these data are the result of investigations in vacuum or an inert atmosphere. We therefore considered it desirable to investigate the kinetics of the thermo-oxidative degradation of a number of PA and PPI over a wide temperature range.