Effect of D―sorbitol on Rheology of Aqueous Alumina Suspensions with Poly(Acrylic Acid)

Effect of D―sorbitol addition on rheological properties of aqueous alumina suspensions dispersed with poly (acrylic acid) (PAA) was investigated. The results showed that for the aqueous alumina suspensions with 30vol%?40vol% solids loadings, small amount of D―sorbitol can significantly enhance the stability of alumina suspensions with PAA at pH=9.0. When the total amount of dispersant was 0.5wt% and the concentration of D―sorbitol was 20%, the viscosity of suspensions was the lowest. In addition, the suspensions dispersed with binary dispersant were less sensitive to ionic strength than the suspensions containing just the PAA. The role of PAA and D―sorbitol in the alumina suspensions was characterized by FTIR spectroscope. Based on the rheology and FTIR measurements, a schematic model was established to depict the mechanism for the effect of D―sorbitol in the presence of PAA. D―Sorbitol was absorbed both on alumina surface and the absorbed PAA, leading to an enhanced steric hindrance thus resulting better stability of the suspensions.