A kinetic model for silica-filled rubber reinforcement

The competition between filler-filler interaction and filler-rubber interaction during the dispersion process of silica-filled rubber has been investigated. Several complementary techniques were carried out going from local observations of the dispersion to a global view given from linear and nonlinear rheological measurements in order to lead to a better estimation of the dispersion kinetics. It has been shown that reinforcement evolves with mixing time. A direct link between the bound rubber amount and reinforcement indicators was found, revealing a replacement of strong filler-filler interactions by weak rubber-filler ones. As a result, rheological reinforcement can be cast under the form of a universal power law by introducing an effective interacting surface between fillers. Finally, a kinetic model of the rubber reinforcement has been developed on the basis of the competition between filler dispersion mechanism and rubber physical adsorption.