Structure analyses of polybutadiene rubber crosslinked with unsaturated carboxylate using contrast variation small-angle neutron scattering

We studied the structure of polybutadiene rubber (BR) crosslinked with zinc diacrylate (ZDA) to elucidate the structure of the high crosslink density BR (HC-BR) using a contrast variation small-angle neutron scattering (CV-SANS) method. The careful analysis revealed the existence of a HC-BR layer around the ZDA aggregates. This is the first time quantitative structural analysis of the HC-BR layer in this rubber material has been performed. In addition, the network structure of the HC-BR layer in the rubber matrix is responsible for the high mechanical modulus of the rubber.