Curing of Rubber via Oxa-Michael Reaction toward Significantly Increased Aging Resistance

An epoxidized natural rubber was successfully cured with zinc diacrylate (ZDA). A nonconventional curing mechanism via oxa-Michael addition between hydroxyl and acryloyl was revealed. Such a cured elastomer was found to be highly resistant to heat/oxygen aging, and such an outcome is closely related to the relatively lower concentration of epoxides and the absence of sulfides in the ZDA-cured composites. The present method provides a unique insight for developing aging-resistant diene-based elastomers which are generally heat/oxygen susceptible.