Irradiation stability of sulfonated styrene resins crosslinked with various divinylbenzene isomers and mixtures thereof

The Co60γ‐irradiation‐induced degradation of sulfonated styrene resins crosslinked with 4 and 8 mole‐% m‐ or p‐divinylbenzene isomers, or mixtures thereof including commercial divinylbenzene have shown a loss in capacity of 5–12.8% at radiation intensities of ca. 290,000 r./hr. and total doses of 0.91–1.90 X 108 rad in the presence of water. The loss is less for the 8% crosslinked resins and is less (2–6%) if irradiated dry. The resins crosslinked with commercial divinylbenzene show a slightly higher loss of capacity (11.2–11.9%) than do others (10.2–10.7%), presumably due to the ethylphenyl contamination. The moisture content also increases on irradiation; 13–16% for the 8% and 2.7–3.0% for the 4% resins at 1.90 X 108 rad. The meta crosslinked resin shows somewhat lower moisture content increase (1.5% for 8%; 0.8% for 4%), indicative of a more stable cross‐linkage. The results are discussed in terms of the reactions involved: desulfonation, hydroxylation, and cleavage of crosslinkages.