Temperature limit of inhibition of thermo- oxidative degradation of polystyrene and poly(methyl methacrylate) by antioxidants

Abstract Investigation has been made on the influence of aromatic and sterically hindered amines, sterically hindered phenols, S- and P-containing compounds on the thermo-oxidative degradation of PS and PMMA by a DSC method under oxygen. The oxidative degradation of antioxidants themselves has been studied under the identical conditions. The dependences of the temperature of the onset of degradation of the polymers on antioxidant concentrations have been obtained. It has been shown that the upper temperature limit of inhibition of the thermo-oxidative degradation of PS and PMMA by well-known effective antioxidants is in the range 280–295°C and depends insignificantly on the chemical structure of polymer. The suggestion was made that the value of the temperature limit of inhibition depends to a great extent on intensive oxidative decomposition of antioxidant itself.