Ionic strength control of sulfated cellulose nanocrystal suspension viscosity

Abstract

The effect of added electrolyte on the viscosity behavior of 3–9 wt% cellulose nanocrystals (CNC) suspensions was investigated for three different grades of CNCs extracted from wood pulp with sulfuric acid at increasing hydrolysis temperature. The viscosity of aqueous CNC suspensions decreases significantly when small amounts of electrolyte are added because of a reduction in electroviscous effects caused by compression of the electrical double layer surrounding the particles. As the ionic strength increases further, the suspension viscosity reaches a minimum and then increases again with the formation of an attractive gel.