High shear rate flow behavior of xanthan gum dispersions

Abstract The high shear rate flow behavior of aqueous xanthan gum dispersions of 0.05, 0.10, 0.25, 0.50 and 1.0% w/w concentration, was determined at 5, 15, 25 and 35°C by capillary rheometry. Viscosity declined with increasing shear rates and approached a constant infinite shear viscosity, over a shear rate range of 1000–250 000/s. This viscosity decline was modeled using non-linear regression to relate apparent viscosity to shear stress and infinite shear viscosity. Arrhenius and Huggins models were then used to describe the variation of infinite shear viscosity with temperature and concentration respectively. Multiple regression was used to express the logarithm of infinite shear viscosity as a function of the logarithm of concentration and reciprocal of the absolute temperature. Examination of the data revealed that xanthan solution viscosities at high rates of shear were less dependent on gum concentration than on solvent viscosity.