RHEOLOGICAL STUDIES ON MACALOID DISPERSIONS .2. EFFECT OF SURFACE-ACTIVE AGENTS

The effect of sodium lauryl sulphate, cetrimide and Tween(R) 20 on the theological characteristics of macaloid dispersions was studied, The theological study included investigations of consistency, thixotropic breakdown and structural recovery in the stationary state. The consist ency of macaloid dispersions was found to increase in presence of thes e surfactants, This increase is, in general, proportional to the conce ntration of the surfactant. The swelling properties of macaloid is sup pressed by surfactants in a manner proportional to their concentration . The thixotropic breakdown induced by increasing shear rate is genera lly increased by surfactants, while that by shearing is affected diffe rently by the different surfactant concentrations. The rate of structu ral recovery is slightly affected by sodium lauryl sulphate and cetrim ide. In presence of Tween 20, it is slightly affected by low surfactan t concentrations and is lowered by the high ones.