Preparation and electrochemical characterization of sulfonated interpolymer of polyethylene and styrene-divinylbenzene copolymer membranes

Preformed interpolymer films of polyethylene and styrene-divinylbenzene copolymer subjected to chemical treatment for various time intervals, in the presence of chlorosulfonic acid and ethylene dichloride mixture of different composition, have been used as membranes in these investigations. Membrane potential and conductance measurements have been carried out in sodium chloride solutions of different concentrations, to investigate the relationship between the concentration of the fixed ionic site and the electrochemical characteristics of these sulfonated membranes. Counter-ion transport numbers and thus permselectivity of these treated membranes were found to be proportional to the concentration of the fixed sulfonic acid groups. Membrane conductance data, along with values of concentration of fixed ionic site in the membrane, were used for the estimation of the tortuosity factor, salt permeability coefficient and frictional coefficient between solute and membrane matrix employing non-equilibrium thermodynamic principles. Furthermore, the transport properties are discussed in relation to the hydrophilic nature and thus the extent of sulfonation of these membranes. (C) 2000 Elsevier Science BN. All rights reserved.