CHARACTERISTICS OF CROSS-LINKED POLYMER AS REACTION ARENA .5. INFLUENCE OF POLYMER SWELLING ON CROSS-LINKED POLYMER SULFONATION

As part of a series of studies on the characteristics of crosslinked polymers as a reaction arena in sulfonation, the crosslinked polymer was pre-swelled by exposure to tetrachloroethylene for 0 approximately 120 min and then subjected to sulfonation by chlorosulfonic acid at various temperatures and reaction times. The distribution of the sulfonic group in the polymer was found to vary markedly with the pre-swelling conditions, and was limited to a thin-shell surface layer when pre-swelling for 20 min at 25-degrees-C and sulfonation at 0-degrees-C were employed. Swelling and reaction rate analyses indicate that the spatial progress of sulfonation in a crosslinked polymer can be be specifically controlled by utilization of the slow interaction between the rigid polymer network and the swelling agent. This control can be employed effectively for further elucidation of the crosslinked polymer as a reaction arena.