Crosslinking of Epoxidized Natural Rubber by Dicarboxylic Acids: An Alternative to Standard Vulcanization

Summary It is demonstrated that epoxidized natural rubber (ENR) may be efficiently crosslinked by dicarboxylic acids in presence of 1,2‐dimethylimidazole. The activation mechanism of the crosslinking involves the formation of an imidazolium dicarboxylate salt. The formation of ester bridges is ascertained by solid‐state NMR spectroscopy. Due to different epoxidation levels, blends of ENRs can be selectively crosslinked, giving rise to semi‐interpenetrated networks.