Viscometric behavior of hydroxyethyl cellulose in aqueous solutions of some imidazolium ionic liquids

In this work, viscosity of hydroxyethyl cellulose in aqueous solutions of ionic liquids, 1-butyl-3-methyl imidazolium bromide, 1-hexyl-3-methyl imidazolium bromide and 1-octyl-3-methyl imidazolium bromide were measured at temperature range of T = 288.15-308.15 K. Some hydrodynamic and thermodynamic parameters such as intrinsic viscosity, polymer-solvent interaction parameter and second virial coefficient were calculated using viscosity data. Obtained results reveal that thermodynamic quality of aqueous solutions of ionic liquids for hydroxyethyl cellulose decreases with increasing temperature and addition of ionic liquids. The flow activation energy was found from the linearization of Arrhenius equation and correlated in terms of polymer concentration. From sign of the initial slope of the activation energy versus polymer concentration at zero concentration, it is concluded that thermodynamic quality of aqueous solutions of ionic liquids are reduced by increasing temperature.