Comparison of the thermal and thermo oxidative stability of polycarbonate, polyphenylene oxide, polysulphone and two polyarylates

It has been shown that polysulphone is appreciably more stable to thermal and thermaloxidative breakdown than polycarbonate, the polyarylates, prepared from the condensation of terephthaloyl chloride/bisphenol A and terephthaloyl chloride/phenolphthalein, and polyphenylene oxide. The latter four polymers differ little in their thermal stabilities but regarding thermo‐oxidation, while the three polyesters are comparable, minor differences being attributable to the relative stability of the phenylene linking groups, polyphenylene oxide is markedly less stable. This has been explained as being due to the oxidisability of the pendant methyl groups in polyphenylene oxide. Also, it is noted that this polymer may be considered as being composed of potential antioxidant units and accordingly is liable to oxidative breakdown.