Use of the Hysteresis Loop Method to Study Thixotropic Suspensions. Part 2. Acetylene Black in Hydrazine and Pyrogenic Silica in Liquids of Varying Polarity

摘要

The hysteresis loop method was used to study the flow properties of suspensions of acetylene black in hydrazine and of pyrogenic silica in n-decane, hydrazine, unsymmetrical dimethylhydrazine, n-propyl and isopropyl alcohols, and water. It was found that the acetylene black/hydrazine system behaved ideally, in that the plastic viscosity and yield stress values of these suspensions followed Arrhenius' law at low concentrations and Weltman and Green's equation at higher concentrations. Of the silica suspensions tested, only the pyrogenic silica/n-decane system exhibited the same exponential dependence of plastic viscosity and yield stress on concentration as was found for the ideal thixotropic suspensions. The remaining silica suspensions either broke down irreversibly under high shear conditions or were otherwise unsuitable for study by the hysteresis loop method. (Author)