Influence of polyvinyl alcohol/zirconium polycation interactions on the properties of aqueous alumina suspensions

This paper presents and describes the interactions occurring in polyvinyl-alcohol-containing alumina suspensions containing different multivalent cations. The influence of Mg (+II), Ca (+II), Al (+III) and Zr (+IV) cations was studied systematically by means of surface potential, viscosity, sedimentation and adsorption measurement techniques. The results were compared with the results obtained for a monovalent reference (K (+I)). Whereas for Mg (+II), Ca (+II) and Al (+III) the interactions can be explained by compression of the electric double layer or formation of hydroxides, Zr (+IV) shows a unique affinity for polyvinyl alcohol. This interaction yields a significant improvement in suspension flowability and sedimentation stability. Moreover this specific interaction is independent of t he solid surface. Thus the stabilizing effect of polyvinyl alcohol/Zr (+IV) can be combined with the effect of a polyacrylate dispersant