Design, Synthesis, and Characterization of Bismaleimide Co-Curing Elastomers

Isobutylene-rich elastomers bearing functional groups that engage N-arylmaleimides in C–H bond addition and/or alternating copolymerization are described. While inactive to cross-linking when treated at high temperature with peroxide alone, these co-curing elastomers can be cross-linked substantially when combined with bismaleimide coagents such as N,N′-m-phenylenedimaleimide (BMI). Poly(isobutylene-co-isoprene) (IIR) samples containing relatively high amounts of residual isoprene unsaturation are shown to provide relatively low coagent cure reactivity, whereas IIR derivatives bearing pendant polyether or vinyl ether functionality are shown to provide exceptional cross-linking rates and extents when treated with identical BMI formulations. The design of such co-curing elastomers is discussed, along with the physical properties of the resulting vulcanizates.