RHEOLOGICAL STUDY OF MAGNETIC PARTICLE DISPERSION

The rheological properties of an acicular magnetic particle dispersion, as well as those of a platelet particle dispersion, were studied. The relative viscosity, reduced viscosity and yield value of the dispersion were redefined using the analogy of those of polymer solution to characterize dispersion rheology. The volume fraction of the solid component, which consists of the core particle and the polymer adsorbed layer, is a dominant factor in determining dispersion rheology, independent of the kind of solvent. The magnitude of interparticle interaction, which is indicated by the magnitude of relative viscosity or that of reduced viscosity, is notable when the volume fraction of the solid component is higher than 20%. The yield value rises at a lower volume fraction than do the relative viscosity or the reduced viscosity.