Radiation-initiated graft

Wellons, J. D., A. Schindler, and V. Stannett Molecular weight distributions of the side chains of radiation initiated graft copolymers. Polymer 5, 499... 

This preliminary study has shown that radiation initiated graft polymerization and co-polymerizatlon on a polyolefin film surface can be achieved using the above described process with electron initiation. This process can be employed with a wide range of monomers. ... 

Ellinghorst, G., Niembller, A., and Vierkotten, D. 1983. Radiation initiated grafting of polymer films -an alternative technique to prepare membranes for various separation problems. Radiat Phys Chem. 22 635-642. 

Kostov, G.K. and Atanassov, A.N., 1993. Radiation initiated grafting of acryhc acid onto tetrafluoroethylene-ethylene copolymers. J Appl Polym Sci. Al 361-366. 

Kostov, G.K. and Turmanova, S.C. 1997. Radiation-initiated graft copolymerization of 4-vinylpyridine onto polyethylene and polytetrafluoroethylene films and anion-exchange membranes therefrom. J Appl Polym Sci. 64 1469-1475. 

B. Jansen and G. Ellinghorst, Radiation initiated grafting of hydrophilic and reactive monomers on polyetherurethane for biomedical application, Radiat. Phys. Chem. 18 1195 (1981). 

The quantitative effect of diffusion control on the rate of radiation-initiated graft polymerization has been studied theoretically for systems in which the diffusion-free reaction may show various dependences of rate on the concentration of monomer other than the usual first-order dependence. The study is very general and could be applied to systems involving a variety of modes of initiation and termination. 

The effects of diffusion control on the rate of radiation-initiated graft polymerization of cellulose have been studied theoretically. The effects of such variables as the initiator concentration, temperature, and monomer polymer ratio on the graft copolymerization of acrylamide and 0-methylcellulose have been investigated. The thermal properties and behaviour of graft copolymers of formaldehyde-cross-linked 0-cyanoethylcellulose and acrylates have been studied. Copolymerization of periodate-oxidized cellulose (aldehydocellulose) with glycidyl methacrylate in the presence of an enzyme e. peroxidase) afforded a means of immobilizing the enzyme without loss of activity. ... 

The theory of radiation-induced grafting has received extensive treatment [21,131,132]. The typical steps involved in free-radical polymerization are also applicable to graft polymerization including initiation, propagation, and chain transfer [133]. However, the complicating role of diffusion prevents any simple correlation of individual rate constants to the overall reaction rates. Changes in temperamre, for example, increase the rate of monomer diffusion and monomer... 

Polymer radicals can also be produced by the irradiation of a polymer-monomer mixture with ionizing radiation. Thus, the interaction of ionizing radiation with polyethylene-styrene produces radical centers on polyethylene, and these initiate graft polymerization of styrene to produce poly(ethylene-gra/i-styrene) [Rabie and Odian, 1977]. 

Xerogels Ag, Au Two steps (1) gamma radiation initiation of metal-particle growth in a solution containing metal ions and multifunctional silanes (2) xerogels with metal clusters grafted on an oxide network prepared via hydrolysis and condensation 76... 

Trradiation provides a powerful method for modifying polymers, and radiation-initiated processes such as crosslinking and graft coply-merization have attracted considerable interest in past years. Although only a few irradiation processes are currently used in industry, it seems most likely that this field will grow and expand actively in the not-too-distant future. 

Grafting of Vinyl Monomer on Radiation-Peroxidized Polymer. The polymer is irradiated in the presence of air or oxygen and then immersed in monomer. The peroxides in the irradiated polymer are decomposed by heat or catalysts to form free radicals, capable of initiating graft polymerization. 

Okamura, S., T. Iwasaki, Y. Kobayashi, and K. Hayashi Gamma-ray initiated graft copolymerization on the surface of nylon fibers and in the inner layers of cellulosic fibers. Large Radiation Sources in Ind., Proc. Conf., Warsaw, 1959, 1, 459. 

Usually, free-radical initiators such as azo compounds or peroxides are used to initiate the polymerization of acrylic monomers. Photochemical and radiation-initiated polymerizations are also well known. Methods of radical polymerization include bulk, solution, emulsion, suspension, graft copolymerization, radiation-induced, and ionic with emulsion being the most important. 

The butadiene and butadiene-acrylic monomer systems polymerize when irradiated on PVC or vinyl chloride copolymer latex. The structure of the polymer obtained may be grafted if it can be proved that the copolymer properties are different from the blend properties. To elucidate the structure we studied a copolymer obtained by polymerizing butadiene-acrylonitrile on a PVC homopolymer lattice. Owing to practical reasons and to exclude the secondary effect of catalytic residues we used y radiation. However, we shall observe in a particular case the properties of peroxide-initiated graft copolymer. 

The modification of the properties of cotton cellulosic textile products, through free radical-initiated graft copolymerization reactions with vinyl monomers, has been investigated at the Southern Laboratory for a number of years (6, 9). In this chapter, we summarize the basic mechanisms and principles involved in free radical reactions of cellulose, initiated by high energy radiation, ceric ion in acidic solution, and aqueous solutions of ferrous ion and hydrogen peroxide. Some of the properties of fibrous cotton cellulose graft copolymers are also presented. 

Two important factors in initiating graft copolymerization reactions of vinyl monomers with activated cellulose are (1) the lifetime of the free radical sites and (2) the accessibility of the free radical sites to the monomers. For ceric ion initiation or hydroxyl radical initiation the lifetimes of the free radicals on the cellulose molecule were short (5, 19) therefore, the monomer should be present when the free radicals were formed. For ionizing radiation both short lived and long lived (trapped) free radicals were formed (22, 26, 44). Consequently, the activation reaction and the copolymerization reaction could either be conducted... 

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