The Rheological Properties of Concentrated Suspensions. I. Some Theoretical Considerations Based on a Network Model

Abstract

Abstract The rheological properties of concentrated suspensions have been considered theoretically by the use of a network model in which the particles are linked at random by thermal and mechanical actions. The effects of particle size, the viscosity of the medium and the mean free energy of the activation for breaking links between particles have been taken into account in the calculation of the number of interparticle links. The links between particles have been conveniently distinguished into two kinds in stationary states: the primary links, which are elongated without the separation of neighboring particles in an instant, and the secondary links, which are broken and reformed reversibly in an instant. The primary links originate from circular structures in the flocculates. The dynamic properties at very small deformations and the stationary flow properties have been derived theoretically as functions of the concentration and of the frequency or the rate of shear by assuming a generalized Maxwell model modified by Eyring’s non-linear viscous elements. The correlation of the dynamic properties and the stationary flow properties and the dependence of the dynamic properties on amplitude have been considered theoretically by the use of the present network model.