Electric field‐assisted grafting of 4‐vinylpyridine on an activated cation exchange membrane

Abstract

SynopsisThe influence of forced diffusion by a d.c. electric field on the graft polymerization of ionic 4vinylpyridine onto a host membrane was determined. The host was a commercial cation exchange membrane. Initiation was by a redox couple of titanious ions at the exchange sites of the membrane and t-butylhydroperoxide in the bulk solution along with the monomer. Undesirable effects of electrode reactions were avoided by isolation of the electrode compartments with permselective membranes. Measurements were a t monomer concentrations of 0.05, 0.1, and 0.2M and d.c. current densit.ies of 0.08 and 0.16 mA/cm2. Applying the field accelerated the graft rate and provided greater control of the amount and distribution of the polymer than when free diffusion alone directed the reaction. This suggests possible value of forced diffusion by an electric field to tailormake membranes to special properties such as in the case of ampholytic mosaic membranes.