Physicochemical Properties of Profiled Heterogeneous Ion-Exchange Membranes

Optimum values of parameters of hot pressing of heterogeneous ion-exchange membranes MK-40 and MA-40 (temperature, pressure, exposure duration) with the aim of creating geometrical profiles on their surfaces are determined. A method of optical visualization of membrane profiles and a diffusion technique of diagnostics of through pores in the membranes are developed and substantiated. Most important physicochemical and physicomechanical characteristics of profiled membranes are investigated. It is shown that the major obstacle in the production of profiled cation-exchange heterogeneous membranes is encapsulation of grains of the ion-exchange resin by an inert polyethylene film, which leads to an increase in the surface resistance of the membranes and to a decrease in the fraction of their active surface areas. The profiling of heterogeneous anion-exchange membranes is accompanied by an increase in their microscopic porosity and diffusion penetrability.