Study on Rheological Properties of Sodium Carboxymethyl Cellulose in the presence of mixed surfactants and Electrolytes

Abstract

The effect of mixed surfactant systems of CTAB (cationic) and IGEPAL – CO 890 (non ionic) as well as different electrolytes i.e. NaCl, Na2SO4, and NaH2PO4 on the flow rheological properties of CMC has been studied. Initially various properties such as CMC values, surface excess, β interaction parameter and area of the molecule are calculated for mixed surfactant systems in the ratio of 7:3 and 3:7 (CTAB to IGEPAL CO -890) and also in the presence of electrolytes at 150mmol at low value of mixed surfactants. Low values of CMC were observed for mixed surfactant systems due to higher synergistic effect and minimum surface tension value is also low for the mixed surfactant solution compared to that of the pure surfactants. Later flow rheological properties of carboxymethyl cellulose i.e. change in viscosity and shear stress for a wide range of shear rate in the presence of surfactants and electrolytes were observed. It was observed that at low shear rate viscosity values were higher and with increasing shear rate the values decreases. It was also observed that with increase in surfactant values and valency of electrolytes the shear stress decreases due to adsorption of surfactant molecules in between the polymer molecules which results in disruption of the structured molecules