SULFONATION OF CROSS-LINKED ASYMMETRIC MEMBRANES BASED ON POLYSTYRENEAND DIVINYLBENZENE

Asymmetric microporous membranes based on polystyrene cross-linked wit h divinyl benzene were prepared. They were sulfonated with sulfonic ac id and washed with solutions of gradually increasing pH to reduce envi ronmental shock. The sulfonation was monitored by infrared spectroscop y, and changes in wettability and sulfur content were also recorded. M orphologies and reverse osmosis performance of sulfonated membranes we re measured, with both water flux and salt rejection increasing after treatment. (C) 1994 John Wiley & Sons, Inc.