CHARACTERIZATION OF CROSS-LINKED POLYMERS FOR THE REACTION ARENA .4. INFLUENCE OF POLYMER NETWORK 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 spherical crosslinked polymer was sulfonated at various temperatures after through swelling by an effective swelling agent. The rate-determining step was found to be local reaction at low temperatures, and sulfonating agent diffusion at temperatures of 40-degrees-C or higher. The sulfonation proceeded from the particle surface region so that the sulfonic groups occupied a spherical shell having a thickness determined by reaction time and temperature. The results thus indicate that the rate of the sulfonating agent diffusion is decreased by collisions or other interactions between its molecules and the molecular chains of the crosslinked polymer network.