Rheological investigation of a stabilised suspension of calcium carbonate

This thesis is a continuation of work started by Riley who observed anomalies in the rheological behaviour of concentrated suspensions of calcium carbonate stabilised by polyacrylate (Dispex N40) exposed to steady shear. The present work consists of a detailed investigation of the same system under condition of oscillatory shear from which non-linear behaviour was observed. Using the model of Green and Revlin and analysing the data by means of harmonic analysis the elastic and viscous moduli of the system were determined as the functions of strain, strain rate and concentration. The thesis reviews theories of linear and non-linear behaviour of dispersed systems and attempts to relate the results obtained to this theory. In order to do this measurements and calculations were made of the degree of the colloidal stabilities of the dispersions used.