Curing of epoxidized natural rubber with <i>p</i>‐phenylenediamine

Abstract

Abstract The curing of epoxidized natural rubber with p ‐phenylenediamine catalyzed by bisphenol A was investigated. The curing reaction was found to be first order with respect to the amine and to have an activation energy of 67.5 kJ/mol. Vulcanizates of tensile strength 12.5–16.0 MPa were obtained at cure times of 30–75 min at 180°C. The amine‐cured vulcanizate was observed to be more rigid than the sulfur‐cured one at room temperature consistent with its relatively high T g . Stress‐strain analysis and dynamic mechanical properties indicated that the high T g of the amine‐cured vulcanizate could be attributed to the bulky amine crosslinks and hydrogen bonding effect of bisphenol A. © 1994 John Wiley &amp; Sons, Inc.