Aspects of poly(p-phenylene sulfide) degradation and stabilization. Part 1. Influence of polymer end groups on exposure induced coloration

In this paper we reviewed some of our work on the photo induced coloration of Poly(p‐phenylene sulfide) (PPS) and compared it to recent results obtained from the thermal treatment of resins that varied in molecular weight and ionic content. The results from this study suggest that coloration of amorphous PPS films after UV irradiation is caused by products different from those that cause coloration in semicrystalline PPS after thermoxidation. In addition, we found that polymer end group chemistry and resin molecular weights play important roles in the thermoxidative coloration of PPS, but only nominally influence the photooxidative coloration of the resin. PPS coloration may arise from the accumulation of specific, colored products (e.g., phenyl‐phenyl moieties) and the possible presence of intermolecular aggregates. The mechanism and extent by which these structures occur in UV irradiated or heated PPS are likely dependent upon the polymer morphology of the samples tested.