Concentrated emulsions. 3. Studies on the influence of continuous-phase viscosity, volume fraction, droplet size, and temperature on emulsion viscosity

Abstract

Explosive-type emulsions with internal-phase fractions from 0.74 to 0.92 were studied to quantify the effects of average droplet size, continuous-phase viscosity, volume fraction, and temperature on emulsion viscosity measured at low rates of shear. Plots of emulsion viscosity vs volume fraction of the dispersed phase (0) were obtained at 80 °C for two different emulsions varying in continuous-phase composition, but having constant droplet size profiles. Emulsion viscosity increased steeply as the internal phase increased, but varied inversely with average droplet radius. The effect of droplet size became more prominent at higher values of <t>. The viscosity of the emulsion (when corrected for the viscosity of the continuous phase) increased approximately linearly with increased internal phase when drop size distribution was held constant. A mathematical analysis is given that ascribes the increase to droplet distortion. At low shear, the studied emulsions exhibited Boltzmann temperature dependence to flow (2Ja = 2-6 kcal/mol) with breaks at 22 and 72 °C. The continuous phase also exhibited a break at 22 °C.

A Combined Plasmachemical and Emulsion Templating Approach for Actuated Macroporous Scaffolds

“…Apart from the mediating effect of surfactants, the stability of conventional water in oil microemulsions can also be enhanced by increasing the viscosity of the organic phase 59. For the case of pulsed plasma deposited poly(vinylbenzyl chloride), although these films are not sufficiently flexible at room temperature to form emulsions, the plasmachemical layer can be considered to become a highly viscous organic phase at elevated temperatures.…”

Highly permeable macroporous polymers via controlled agitation of emulsion templates

“…This is likely to be caused by the increase in the viscosity and average density of the emulsion templates with increasing internal phase volume. It has been reported that there are several factors affecting the viscosity of emulsions; emulsion viscosity increases with higher internal phase volume and decreasing droplet size[40].…”

A Kinetic Study of a Modified Fine Coal Agglomeration Process

“…Therefore, the internal, dispersed droplets are deformed and take the shape of polyhedra separated only by thin layers of the continuous phase, meaning that, HIP emulsions effectively have a liquid-in-liquid foam type structure [16]. As HIP emulsions are so highly concentrated with tightly packed water droplets, they can have very high viscosities and therefore usually behave more like gels, rather than liquids [17]. Another defining property, which was the basis for the selection of these emulsions for use in this work, is that an emulsion may be made almost entirely from one liquid but exhibit the surface properties of another liquid [16].…”