Competitive adsorption of PVA and PAA on alumina surface

A variety of organic polymer is used in ceramic processing as binders and dispersants, etc. Their adsorption on the surface of ceramic particles as well as their effect on rheology of ceramic slurry are an important topic in studies on ceramic processing. In systems containing two or more kinds of polymers, the adsorption as well as the function of a specific polymer can be affected by other coexisting polymers. This paper reports the competitive adsorption of PVA and PAA in the alumina system. The original roles of the former and the latter are binder and dispersant, respectively. Various slurries were prepared by changing the adding order of these organic additives. The slurry viscosity was measured with a rotary viscometer. Adsorption of PVA on the alumina surface was found to be hindered markedly by the presence of PAA. However, that of PAA was not affected by the presence of PVA. Clearly, the adsorption of PVA on solid surface is much weaker than that of PAA.