Viscoelastic Behavior of Cellulose Nano-Fiber Suspension Possessing Effectively Controlled Inter-Particle Interactions

Abstract

Linear viscoelastic behavior of cellulose nano-fiber (CNF) suspension dispersed in concentrated aqueous sucrose solution at the concentration of 60 wt% was investigated. Because the strong inter-particle interaction due to many hydrogen bonds formed between hydroxy groups on the surface of dispersed CNF particles is quite effectively reduced by using the concentrated aqueous sucrose solution as a dispersion medium, the viscoelastic behavior observed in the suspension clearly demonstrated a flow region showing fundamental viscoelastic parameters such as the zero-shear viscosity, steady state compliance, and the average relaxation time as functions of the concentration of CNF particles. A theoretical model for monodisperse rigid rod particle suspensions proposed by Doi and Edwards was slightly modified and expanded to rigid rodlike particle suspensions with a relatively broad particle length distribution, and was successfully applied to the obtained viscoelastic behavior of the CNF suspension.