The crosslinking mechanism in gamma irradiation of polyarylsulfone: Evidence for Y-links

Abstract

Measurements of molecular weights, soluble fractions and examination of NMR spectra of bisphenol-A polysulfone, after gamma irradiation in vacuum at 15O°C were used to elucidate the mechanism of crosslinking. Excellent agreement was obtained between G(S) and G(X) determined from measurements above and below the gel dose when a Y-linking mechanism was assumed, whereas poor agreement was obtained when an H-link mechanism was assumed, which is the mechanism normally believed to be responsible for crosslinking. New resonances were observed in the 13C NMR spectra of the irradiated polymer which were consistent with the formation of Y-links involving phenylene units in the backbone chain. © 1998 John Wiley & Sons, Ltd.