175kV Electron beam irradiation of poly(vinyl butyral)

Poly(vinyl butyral) (PVB) was exposed to a 175Kv electron beam under a nitrogen atmosphere. Infrared spectrometric studies revealed the formation and growth of a carbonyl band attributed to decomposition of the poly(vinyl alcohol) group, and cleavage of the cyclic acetal structure. GPC analysis indicated an increase in the polydispersity of the polymer as a function of absorbed dose. An overall G value of 0.25 was obtained, with a G value for scission G(S) = 0.60 and the G value for crosslinking G(x) = 0.35; the dose required for gel formation is 68 Mrad. Engineering stress-strain measurements of thin films indicate decreasing tensile strength and ductility as a function of absorbed dose.