Studies of surface adsorbability of sodium carboxymethyl cellulose onto nylon 6 fiber byζ-potential method

Abstract

The surface adsorption behavior of a polyelectrolyte, sodium carboxymethyl cellulose (Na-CMC), onto Nylon 6 fiber was studied by measuringζ-potential of the fiber in acidic aqueous solutions (pH 3) of the polyelectrolyte. The amount of Na-CMC adsorbed per unit area of the fiber surface was calculated from theζ-potential. With the increase in the Na-CMC concentration, the sign of theζ-potential of the fiber rapidly changed from positive to negative and thereafter the negative values approached to the saturation values, and the amount of adsorption of the polyelectrolyte (expressed in g/cm2-fiber) increased also. These results may possibly be attributed mainly to the formation of the electrostatic bond between the fiber and the Na-CMC. The maximum amount of adsorption of the polyelectrolyte,A s , decreased with the increase in the degree of polymerization. The slope,a, of theA s vs. molecular weight,M, curve was equal to or less than zero. It was, therefore, suggested that the polyelectrolyte lay flat on the fiber surface with the same dimension as that in the solution.