Assessment of the dispersibility of surfactant‐treated titanium dioxide powders for compounding with polyethylene

Abstract A strategy involving the use of anionic surfactants to compatibilize titanium dioxide powders with nonpolar polymers has been applied to facilitate the dispersion of these powders into polymer composites. The methodology first involves the adsorption of surfactant onto the powder within aqueous dispersions. Surfactantcoated powders are then removed from the dispersion and dried. The cohesivity and some surface properties of the surfactant‐coated powders were measured and compared to that of the uncoated powders. Dispersion experiments of titania agglomerates in polyethylene were performed in a rotating cone‐and‐plate device set within a temperature controlled oven. The titania agglomerates dispersed by an erosion mechanism in which small fragments detached from the surface of the parent agglomerate. The erosion rate was higher for the surfactant treated powders in comparison to uncoated powders. The links between the enhanced erosion rates and the surfactant coating were investigated in terms of the cohesivity of the powders, the penetration of the polymer into the agglomerates, and the interactions between the powders and the polymer media that govern wetting and the transmission of hydrodynamic stress.