Abstract
Stearic acid dispersions in the aqueous phase stabilized by sodium stearate or potassium stearate have been examined by their flow and creep curves. The flow curves, obtained by using a Couett type viscometer, showed hysteresis loops between "up" and "down" curves. The creep curves suggested that the systems can be represented by a mechanical model of one Voigt unit in series with a Maxwell unit. The compliances increased sharply with decreasing weight fraction of dispersed phase from 0.10 to 0.05, and also showed an increase by ageing over several weeks after the preparation. These rheological properties may be explained by the presence of a network structure of the soap micelles solubilized partially by fatty acid, in the aqueous phase.
