| Abstract: | On exhaustive drying of sulfonated polystyrene-based ion-exchange resins, it is shown that free-radical centers develop. These have been examined by electron-spin resonance spectroscopy. The formation of the free radicals is largely reversible with respect to desorption and sorption of water which was measured by means of a quartz spiral microbalance. The spin-concentration isotherm as a function of sorbed water concentration is obtained. The presence of free radicals, dependent on water content in the resins, interferes with proton magnetic relaxation studies of hydration of ionized resins by providing a faster electron-spin coupled nuclear magnetic relaxation mechanism. |
