Studies on carboxymethyl cellulose. Viscosity dependence on polymer concentration and electrolyte content

Viscosity behaviour of sodium carboxymethyl cellulose (NaCMC) in water has been examined. The data obtained are treated with Fuoss, Liberti‐Stivala, Jones‐Dole‐Fuoss, and Yuan et al., empirical as well as semiempirical relations to understand the polyelectrolytic character of NaCMC. The results obtained are compared with other polyelectrolytes. The effect of added salt, like sodium chloride, on the viscosity of NaCMC solution also has been reported. Isoionic dillution experiments have been carried out to determine the degree of ionization of the polyelectrolyte, which reveals a little dependence of the degree of free counterions on the concentration of carboxymethyl cellulose (CMC) solutions. This leads to the conclusion that the polyion gets dilated because of the osmotic effect caused on diluting the polyelectrolyte solution. Furthermore, it has been found that the theory of Oosawa accounting the additivity rule adequately explains the viscosity behaviour of CMC in simple salt solutions.