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

Abstract

We studied the structure of polybutadiene rubber (BR) crosslinked with zinc diacrylate (ZDA) to elucidate the structure of the high crosslink density BR using a contrast variation small-angle neutron scattering (CV-SANS) method. SPP(q), SZZ(q) and SPZ(q), which correspond to the partial scattering functions of the self-correlation of BR, the self-correlation of ZDA aggregates and the cross-correlation between BR and ZDA aggregates, respectively, were successfully evaluated using CV-SANS. A model function assuming a hierarchical structure consisting of spheres with broad size distributions was used to describe the SZZ(q), and the careful analysis of SPZ(q) revealed the existence of a HC-BR layer around the ZDA aggregates owing to an inhomogeneous crosslinked structure in the BR matrix. 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. 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.