Oscillatory, creep and steady flow behavior of Xanthan‐thickened oil‐in‐water emulsions

Abstract

AbstractThe rheological behavior of xanthan gum–thickened oil‐in‐water emulsions is studied with a cone‐and‐plate system using a constant‐stress rheometer. Xanthan gum solutions and xanthan‐thickened oil‐in‐water emulsions are strongly shear‐thinning and viscoelastic in nature. The effects of polymer and oil concentrations on the rheological behavior of emulsions are investigated. The relative viscosity for the thickened emulsions, at any given oil concentration, increases with an increase in the shear rate, whereas the unthickened emulsions show the opposite trend. The theoretical models give reasonable predictions for the relative viscosity, storage modulus, and loss modulus of xan‐than‐thickened emulsions. The ratio of storage to loss moduli increases considerably with the increase in polymer and oil concentrations. The creep/recovery experiments confirm that the xanthan‐thickened emulsions are highly viscoelastic in nature and that the degree of elasticity increase with the increase in polymer and oil concentrations.