Specific features of thermooxidation of thermoresistant heterochain polymers

摘要

Works, performed in Russian Institute for Plastics and Russian Research and Production Company "Polyplastic" during the last 15 years concerning aromatic heterochain polymers (PHA) ageing and stabilisation, were analysed. Specific features of high-temperature (300-400 deg) oxidation in melt and solid-phase (150-200 deg) oxidation of PHA were outlined. General regularities in thermooxidation of aromatic and aliphatic-aromatic polyimides, polyesterimides, poly(phenyl-quinoxalines),polysuphones, etc. are brought out. It has been shown that PHA degrades according to the radial-chain mechanism, but the process differs from that of aliphatic polymers by the presence of initiation acts. Thermally realised electron-excited states of polymers and molecular complexes with oxygen are shown up as the most probable structures. Besides deceleration of thermooxidative ageing, phosphorus-containing additives increase radiation resistance of, for example, polyimides and poly(alkyl terephthalates): the extraction rate of aromatic rings radiation destruction CH_4-product two-fold reduces.