Chemical Inhibition of Ozone Degradation of SBR

The standard rubber antioxidant types which are capable of imparting ozone resistance to SBR vulcanizates are summarized. The 6-ethoxy-l,2-dihydro-2,2,4-trimethylquinoline and para phenylenediamines are shown to represent the most active structures. Steric, mesomeric, and resonance effects are shown to be important in imparting high levels of antiozone activity. When electronegative groups are substituted in an active structure, antiozone effectiveness is greatly reduced. Antiozonant activity is attributed to efficient stopping of ozone-induced free radical chain reactions in the polymeric structure.