Synthesis and characterization of thermoset imidazolium bromide ionomers

Elastomeric ionomers are prepared via halide displacement from brominated poly(isobutylene-co-isoprene) (BIIR) with various imidazole-based nucleophiles. Reaction of BIIR with imidazole or 1,1′(1,4-butanediyl)bis(imidazole) in a single-step, solvent-free elastomer compounding approach is used to synthesize thermoset derivatives, in addition to a two-step process involving reaction of BIIR with 1-vinylimidazole (VIm), followed by peroxide-initiated cross-linking. The physical properties of these ionomeric thermosets are the product of their covalent and ionic networks. Ion-pair aggregation contributes significantly to dynamic storage modulus and low-strain static tensile modulus, but extensive relaxation of this labile network minimizes its influence over timescales larger than 1 min. The adhesive properties and antibacterial activity against E. coli provided by these ionomers are also demonstrated.