EFFECT OF PAA ADSORPTION ON STABILITY AND RHEOLOGY OF TIO2 DISPERSIONS

The specific modification of the interfacial properties of finely dispersed TiO2-powders by adsorbing surface-active substances (polyacrylic acid) causes a change of dispersity and flow behaviour of TiO2 suspensions. Without polyacrylic acid the pH value mainly determines the state of charge and, consequently, the granulometric and rheological properties of the system. Addition of a polyelectrolyte leads to a higher content of fine grains and a lower viscosity of high-concentrated TiO2-suspensions. It turned out that an effective improvement of the properties of the solid suspensions investigated depends on definite amounts of polyacrylic acid and definite pH ranges as well.