Effect of Gamma-Irradiation on Cation Exchange Resin

Several forms of cation exchange resins with different crosslinkages have bsen subjected to 60 Co γ-radiation, in wet or dry state and the effects of such variables as adsorbed ionic species, crosslinkage of the resin, and the water content in the resin on radiation damage to organic resin have been examined in their relation to γ-radiation dose. The result showed that radiation caused marked changes in the chemical and physical properties of the resin, and phenomena such as de-crosslinking, loss of strong-acid capacity, formation of a functional group composed of a weak-acid exchange group were observed. The degree of such degradation phenomena was not affected by adsorbed ions when their valency states were kept unchanged during irradiation, but when the adsorbed ions were reduced during exposure, the extent of degradation was found inhibited to a significant extent. It may be concluded from the results that the decomposition of the cation exchange resin is mainly initiated by reaction with the resin produced by radiation-formed reducing species, i.e., H atoms. A mechanism of resin degradation is also proposed.