The aim of this work is to use a recently developed statistical model of dispersions with non-hydrodynamic interactions (Dagreou et al., 2002) to describe the linear viscoelastic properties of suspensions of rigid hairy particles in a polymeric matrix., We first present numerical simulations of our model applied to this system; we demonstrate that taking physical interactions into account allows one to predict the complex relaxation behaviour of filled polymers. We then compare the statistical model to experimental results on suspensions of grafted silica particles in a polystyrene matrix and show that they are in reasonable agreement up to volume fractions close to percolation.