In order to improve the mechanical characteristics of silicone polymer, silica particulate filler can be dispersed in the continuous phase. During the dispersion process, silicone is adsorbed on the particle surfaces, and at the same time, the particles are submitted to breakage and erosion phenomena, modifying therefore their particle size distribution (PSD). A numerical tool, that can simulate the evolution of the silica PSD in polydimethylsiloxane (PDMS) during dispersion, and allows an a priori knowledge of the evolution of the suspension properties, is developed. The comparison between experimental and calculated PSD as well as process viscosity values is presented. The advantage of such a modelization lies in the prediction of the final product properties, or in the design and optimization of a process for obtaining a desired product. This approach also shows the effect of the particle porosity on the product characteristics evolution during the dispersion process. The influence of parameters such as the filler quantity, the stirring speed or the number of silanols sites on the silica surface is also investigated. (c) 2006 Elsevier Ltd. All rights reserved.