Influence of temperature on the solution rheology of cellulose in 1-ethyl-3-methylimidazolium chloride/dimethyl sulfoxide

Abstract

Rheological properties of cellulose solutions in 1-ethyl-3-methylimidazolium chloride/dimethyl sulfoxide ([Emim]Cl/DMSO, 7/3, w/w) in a wide range of concentration and temperature were investigated. The viscosity of cellulose/[Emim]Cl/DMSO solution agrees well with the complex viscosity suggesting Cox-Merz law is valid for the solution. The viscosity contributed by cellulose (eta (0)-eta (s) ) and cellulose concentration (c) scales as (eta (0)-eta (s) )similar to c (n) with n in the range of 2.00-1.57 and 4.52-3.79 in semidilute unentangled and semidilute entangled regimes, respectively, in the temperature of 25-100 A degrees C. Intrinsic viscosity of the solutions remains constant at temperature below 60 A degrees C and decreases linearly with the increase of temperature above 60 A degrees C. The activation energy of cellulose/[Emim]Cl/DMSO solution increases with the increase in cellulose concentration. The chain dynamics of cellulose in [Emim]Cl/DMSO follows Zimm model and Rouse model in dilute regime (lower than 0.5 wt%) and semidilute unentangled regime (between 0.5 and 2 wt%), respectively.