Silica-paraffin and kaolin-paraffin dispersions: Use of rheological and calorimetric methods to investigate the nature of their dispersed microstructure units

摘要

The yield stress and enthalpy of the wetting of silica-paraffin and kaolin-paraffin dispersions were measured as a function of the volumetric concentration θ of the dispersed colloidal powders after having performed a careful analysis of their macro-meso microstructure. The evolution and stability of the corresponding microstructure units is strongly linked to the shape of the τ 0 versus θ and ΔH versus θ curves. The percolation threshold θτ_0 and θΔH values are fairly equal for each dispersion. These values were observed to be 9% and 18% for silica-paraffin and kaolin-paraffin dispersions, respectively. Two different paths of microstructural evolution were identified for the silica-paraffin and the kaolin-paraffin dispersions with respect to particle shape and size. The stability of the silica-paraffin microstructure units was greater than that corresponding to the kaolin-paraffin ones.