Investigation of the Stabilizing Action of Mixtures of Fullerene C60 with Known Antioxidants in the Thermo-oxidative Degradation of Polystyrene

Abstract

Investigations have been made on the effects of double mixtures of C60 with well-known antioxidants (amines, phenols, S- and P-containing compounds, Ph3Sb) on the thermo-oxidative degradation of PS by DSC method under oxygen. The influence of mixtures on the temperature of the onset of polymer degradation, T 0, has been studied. The effects of concentration of C60 on the value of the temperature limit of inhibition of PS thermo-oxidative degradation by known antioxidants, T 0 max, have been investigated. It has been shown that mixtures of C60 with Ph3Sb and phenyl-β-naphthylamine have a synergistic effect upon T 0. At a total concentration of 1.4 × 10−2mol/kg, the maximum value of T 0 is observed at a molar C60: compound ratio of 3:4 and 1:2.5 for the mixtures of C60 with Ph3Sb and phenyl-β-naphthylamine, respectively. Addition of C60 to these compounds leads to an increase in T 0 max for Ph3Sb and phenyl-β-naphthylamine. The suggestion was made that in the case of mixtures of C60 with Ph3Sb, the synergistic effect is Associated with different mechanisms of stabilizing action of the components on PS degradation, namely C60 reacts with alkyl and oxygen-containing radicals with the formation of more stable compounds while Ph3Sb decomposes polymeric and fullerene-containing peroxides and hydroperoxides. The decomposition of Ph3Sb was investigated by DSC method under oxygen. The temperature of the onset of Ph3Sb degradation was shown to be 362.5°C. It was concluded that further investigations are necessary for understanding the synergistic action of mixture of C60 with phenyl-β-naphthylamine in the thermo-oxidative degradation of PS.