Rheological properties of ionic liquid solutions of xanthan

Dynamic viscoelasticity and steady shear flow of ionic liquid solutions of xanthan were examined. Concentrated solutions of xanthan were prepared using 1-butyl-3-methylimidazolium acetate as the solvent. The solutions exhibited the viscoelastic behavior typical of polymer solutions with the entanglement coupling. The absolute value of the complex viscosity and the steady shear viscosity agreed quite well, namely the Cox-Merz rule held, when the terminal flow behavior was observed in the dynamic viscoelasticity and the zero-shear viscosity was able to be determined. The molecular weight between entanglements for xanthan in the molten state was estimated to be 1.7 x 10(4), being significantly greater than that for cellulose.