Rheological properties of high concentrations of carboxymethyl cellulose solutions

The study was concerned with measurements of steady-state parameters, the transient shear stress response, and the yield stress of carboxymethyl cellulose (CIVIC) solutions at high concentrations. Tests also included thixotropic and viscoelastic behavior and dynamic responses. The concentrations ranged by weight from 5 to 8% of CMC. The steady-state shear flow showed that at higher shear rates the viscosities of CMC solutions tend to he less dependent on the concentration. The solutions showed rheopectic behavior for very small shear rates. No yield stress was detected. Measurements recorded the thixotropic behavior. At higher stress values, nonlinear viscoelastic effects were detected. Dynamic viscosities measured in a dynamic test were higher than were the shear viscosities at the same concentrations. (C) 2001 John Wiley & Sons, Inc.