Rheological study of sodium carboxymethylcellulose: Effect of concentration and molecular weight

Abstract

This study deals with the rheological behavior of sodium carboxymethylcellulose (Na-CMC) using a rheological analysis. The rheological properties of Na-CMC in aqueous solution, at different mass concentrations (0.7, 0.9, 1.1, 1.3 and 1.5 wt%) and types including carboxymethylcellulose high viscosity (CMC HV), medium viscosity (CMC MV) and low viscosity (CMC LV), were investigated using a large deformation rheological measurements (0–700 s−1). The rheological behavior of CMC HV and CMC MV solutions was shear-thinning without yield stress. The flow curves were modeled by Ostwald de Waele and Cross laws (R2 > 0.99). The same models were used for fitting flow curves of various samples of CMC LV suspension but we noticed shear thickening behavior. On the contrary of the CMC HV and CMC MV, and according to the power law model, the flow index of CMC LV was increased with raising in concentration. The consistency of Na-CMC solution at 0.7w.% were 0.5 × 10−3, 0.039 and 0.252 Pa·s, and at 1.5%-CMC were 0.5 × 10−3, 0.065 and 3.162 Pa·s, for respectively CMC LV, CMC MV and CMC HV