Radiation induced grafting

The various methods of radiation induced grafting are briefly reviewed. Special attention is focused on the 'direct' (mutual irradiation) method and the peroxidation method. The most significant parameters of the corresponding reactions are discussed. Examples of grafting systems are taken from recent work in these laboratories. The grafting of vinylidene chloride onto nylon filaments leads to a product which no longer melts on burning but chars, leaving a carbonaceous residue. Various hydrophilic monomers were grafted into Teflon films to produce permselective membranes. The specific problems encountered with monomers such as acrylic acid, 4-vinylpyridine and N-vinylpyrrolidone are described. Homogeneous acido-basic membranes were prepared by grafting in two successive steps acrylic acid and vinylpyridine. Finally the preparation of mosaic membranes can be achieved by localized grafting using an absorbing shield in which a proper pattern is cut out. (author)