Rheology of chitosan-kaolin dispersions

Rheological properties of kaolin dispersions have been analyzed as a function of kaolin/chitosan mass ratio. Zeta potential measurements characterized the particles as negatively charged, resulting in the feasibility of chitosan (a cationic polyelectrolyte) adsorption on their surface. The rheological behavior of the dispersions was markedly pseudoplastic and a simple power-law was not able to describe it. The pseudoplastic character of the dispersions was a function of the shear rate, decreasing with its increase. The decrease in pseudoplasticity was related to the disruption of interparticle interactions by shear.