Electron irradiation of polyacrylates

Abstract

Abstract The crosslinking and degradation of seven polyacrylates by 1000 kvp. electrons has been investigated. Gel content‐radiation dose analysis reveals the energy dissipation per main‐chain fracture, E d , to be the same (530 ± 100 electron volts) for methyl, n ‐butyl, sec ‐butyl, isobutyl, and tert ‐butyl acrylate polymers. The energy dissipation per crosslinked unit formation, E c , is 80–90 e.v. for methyl, n ‐butyl, isobutyl and neopentyl acrylate polymers. E c may be slightly higher for poly‐ sec ‐butyl acrylate. Poly‐ tert ‐butyl acrylate possesses a uniquely high E c of 300 e.v. The presence of hydrogen atoms alpha to the alcoholic oxygen of the ester group is believed to contribute strongly to the crosslinking reactions of polyacrylates under ionizing radiations. Poly‐1,1‐dihydroperfluorobutyl acrylate exhibits an initial E c of ∼45 e.v. and an E d of ∼450 e.v. Beyond 15 megareps the ration of main‐chain fracture to crosslink formation increases.