In Situ Characterisation of Dispersion Process of Silica in an Elastomer Matrix Submitted to Shear, Impact of a Filler Treatment

The dispersion of a filler immersed in a polymer flow submitted to shear is the result of the counterbalance between hydrodynamic forces acting on the agglomerate and its cohesive forces. The nature of the filler, its surface treatment or its degree of infiltration by the polymer should impact its cohesivity. To better understand the influence of these parameters on dispersion, direct observations of dispersion mechanisms under shear were carried out on raw silica, silica treated with a covering agent and fully infiltrated silica agglomerates. Dispersion mechanisms and critical stresses for dispersion were determined and found to be different in those three cases.