Elucidation of Viscosity Reduction Mechanism of Nano Alumina Suspensions with Fructose Addition by DSC

Abstract

Control of the rheological properties of the nanoparticle suspensions is challenging. In this study influence of the solids content and the fructose addition on the viscosity of nano alumina suspensions have been investigated by low temperature differential scanning calorimetry (LT‐DSC), rheometry, and zeta potential measurements. Analysis of the water melting events in LT‐DSC revealed useful information for explaining the rheological behavior of the nanoparticle suspensions. It was shown that the bound water layer has a negligible effect on the viscosity of micrometer‐size particle suspension while it increases the effective solid content of alumina nanoparticle suspensions significantly leading to high viscosities. The presence of fructose modifies the bound water layer, decreases the effective solids content, hence resulting in viscosity reduction. Fructose addition lowers the pH of the suspension, but has a negligible effect on the zeta potential. The origin of the bound water, and electrostatic and steric effects of the fructose addition on the viscosity are discussed.