The Action of Antiozonants in Rubber

Abstract

Abstract Rubbers with olefinic double bonds, and rubber goods based on them, are destroyed by ozone. Crack formation can be retarded by adding antiozonants. The mechanism of the antiozonant effect has not yet been fully explained. The mechanism by which bis-(1,2,3,6-tetrahydrobenzaldehyde)-pentaerythrityl acetal (AFS), a nonstaining antiozonant, hinders the ozonation of polychloroprene has been described. AFS competes with the double bonds in the polymer for the available ozone. Additionally, the resulting ozonization products prevent the ozone from penetrating into the polymer matrix. This mechanism was corroborated by carrying out kinetic measurements of the competing reactions in solution and in the rubber. The findings were confirmed by studying model substances with basic structures identical to AFS but with modified active groups.