CASTING ULTRAFILTRATION MEMBRANES PREPARED FROM ACRYLONITRILE COPOLYMERS - A KINETIC-STUDY

The kinetics of phase separation in solutions of acrylonitrile copolym ers containing various precipitants was studied using high-speed filmi ng. The apparent diffussion coefficients for the diffusion of the prec ipitant into casting solutions were calculated; the structure and filt ration characteristics of the prepared membranes were examined. It was demonstrated that at close degrees of saturation of casting solutions , the transport properties of the membranes were sharply enhanced when precipitants with higher precipitant ratios were used. The morphology of cleavage surfaces was equally controlled by the power of the preci pitant and the rate of phase separation.