VISCOELASTIC BEHAVIOR OF SEMISOLID W O EMULSION SYSTEMS/

In the present article, the viscoelastic behaviour of creams containin g silicone surfactant was investigated. The creams prepared by own pre scription were highly concentrated emulsion systems of white petrolatu m. Methyl cellulose hydrosols were incorporated instead of purified wa ter for facilitation and acceleration of the cold emulsification proce ss and for improving the spreadability of the creams. Rheological eval uation was carried out under continuous and oscillatory flow condition s. All systems exhibited shear thinning behaviour: in the presence of methyl cellulose hydrosols the apparent viscosity increased, indicatin g more ordered internal structure. Oscillation experiments at an ampli tude within previously determined linear viscoelastic area showed typi cal viscoelastic behaviour. The incorporation of methyl cellulose hydr osol increased the viscous response of the system more than the elasti c one. A simultaneous decrease in droplet size was confirmed using low temperature differential scanning calorimetry and transmission electr on microscopy.