The fractionation of polyelectrolytes by adsorption onto ionic crystals

Abstract

During the adsorption of polydisperse nonionic polymers at the solid/liquid interface, it has been previously observed that there has been preferential adsorption of high- or low-molecular-weight fractions. Here the fractionation of polyelectrolytes on adsorption onto BaSO4 crystals has been studied, using both HPGPC and NMR techniques. For sodium polyacrylate and sodium carboxymethyl cellulose (SCMC), low-molecular-weight molecules were preferentially adsorbed. In addition SCMC molecules having a higher degree of substitution were preferentially adsorbed. This may be a result of the method of preparation of SCMC in which the lower molecular weight molecules have the highest degree of substitution. © 1982.