Structure analyses of rubber-filler systems by contrast variation SANS

Abstract

The network structures in rubber containing silica particles have investigated with contrast variation small-angle neutron scattering (SANS) method. The contrast variation SANS for the rubber specimens swollen by the solvents having various scattering length densities yielded partial scattering functions: the scattering function for polymer-polymer correlation Spp (q), the scattering function for silica-silica correlation Sss(q), and the scattering function for polymer-silica correlation SPS(q). The analyses of the partial scattering functions explored the following features:(1) Silica particles form aggregates consisting of several silica particles, and (2) there are relatively dense polymer layers around silica aggregates. Several characteristic parameters are estimated from the analyses, such as the size of aggregates, the thickness of layers, the volume fractions of polymer of layers and matrix, and the correlation length of the matrix network. This result suggests that the contrast variation SANS is a powerful tool of the analyses of the structures of the rubber-filler systems.