Viscosity of Concentrated Dispersions of Spherical Particles in the Framework of a Structural Model

Within the framework of the structural rheological model, viscosity curves are examined for four types of colloidal dispersions of spherical particles, varying in dispersity and composition of the dispersion medium. The study analyzes rheological curves using three types of coordinate axes. Rheological equations of the structural rheological model are used to approximate the data over specific shear rate intervals. At high shear rates, the experimental data align well with the generalized flow equation, indicating that aggregates disintegrate under the influence of tensile hydrodynamic forces. At low shear rates, a rheological equation accounting for additional aggregate formation due to compressive hydrodynamic forces should be applied. The coefficients (parameters) of the rheological equations for the examined colloidal dispersions are consistent with the predictions of the structural rheological model, confirming a common flow mechanism for these dispersions.