The structure and stability of oxidised polybutadiene

Abstract

Polybutadiene has been oxidised at 0–20°C for periods from one day up to several months and also at elevated temperatures. Microstructural changes in the polymer due to oxidation have been followed by ir and uv spectroscopy. Oxidised samples of the polymer have been degraded in nitrogen or in vacuum under programmed heating conditions by TG, DSC and thermal volatilisation analysis (TVA). In TVA degradations, non-condensable gaseous products have been studied by adsorption TVA, condensable volatile products have been separated by subambient TVA for identification, cold ring fraction materials have been examined spectroscopically and the ir spectrum of the polymer residue, after degradation to 440°C, has also been obtained. From this considerable amount of data it has been possible to propose structures present in oxidised polybutadienes and to suggest some degradative processes involved in the subsequent thermal degradation. Oxidation leads to a considerable lowering of the threshold temperature for the main decomposition process; in samples oxidised at low temperatures, an additional early stage of degradation, commencing near 100°C, is found, due to peroxide decomposition.