Thioethers are secondary antioxidants that function by the decomposition of hydroperoxide intermediates in the oxidation process. They most effective at moderate temperatures and in the solid phase. Thioethers provide excellent protection during end use at elevated temperatures, serving to reduce discoloration and improve the retention of useful mechanical properties.
Combinations of thioethers with hindered phenols are often strongly synergistic. These systems represent the state-of-the-art for the long-term thermal stabilization of many types of plastics.