PHOTOGRAFTING OF ACRYLAMIDE ON ETHYLENE-VINYL ALCOHOL COPOLYMER FILM

Photografting (lambda > 300 nm) of acrylamide on ethylene-vinyl alcohol copolymer film (vinyl alcohol unit = 56 mol %, film thickness = 20 mum) was investigated at 60-degrees-C in water medium, where photoinitiators were coated on the film earlier. The percent grafting decreased in the order of xanthone > benzophenone > anthraquinone almost-equal-to benzoyl peroxide. The graft efficiencies in each sensitized system were less than 30%, showing a predominant formation of homopolymer. Grafting of acrylamide on the film was also initiated in systems with and without photoirradiation when ceric salt was used as an initiator. Based on electron probe microanalysis of the grafted films, the grafted chains of the sample prepared by photografting were distributed inside the film, while those of the sample prepared by ceric salt-initiated grafting without photoirradiation were located mainly on the film surface. The grafted films prepared by the former system exhibited a higher moisture permeability than those prepared by the latter system.