ABSTRACT
The sensitivity of viscosity to small changes in particle interactions makes rheology a valuable tool for theoretical studies of dispersions. Rheology can elucidate particle interactions, the effect of dispersants and adsorbed polymers, the flocculation of dispersions, and the relationships governing flow of dispersions under stress. Rheological measurements can be classified into two main categories: measurements involving only a small deformation of the system, measurements involving an extensive deformation, such as a steady shear stress. The sentiment that it is difficult to obtain reliable rheological information on concentrated dispersions and to interpret data has been shared by Ilic and Phan-Thien. Rheological measurements of concentrated suspensions are complicated by the velocity gradient anomalies at solid boundaries in suspensions caused by inhomogeneous stress fields or direct fluid-wall interactions. Many commercially important polymers are made by suspension or emulsion polymerization in an aqueous or organic medium and coagulated to form a bulk polymer or used as dispersion, formulated with various ingredients and additives.
