Monomer radiation-induced cross-linking

In the previous papers, we reported that the radiation-induced cross-linking of polyethylene was accelerated by acetylene (4) and by the mixtures of acetylene and some fluorine-containing monomers (5). 

Radiation-induced cross-linking of LDPE in the presence of various fluorine-containing monomers at a dose of 2.5 Mrad... 

Radiation-Induced Cross-Linking in the Presence of CTFE/Butadiene Mixture. On the basis of the results mentioned in the previous section, it is concluded that in the irradiation of polyethylenes in the presence of CTFE the polyethylenes are mainly cross-linked through the addition reaction of the unsaturated groups contained in the main and the side chains of the polymers to the propagating graft chain radical of CTFE. Therefore, the radiation-induced cross-linking of polyethylene is expected to be accelerated by the presence of the mixture of CTFE and a diene monomer effectively than the presence of pure CTFE. 

Scheme 5. Radiation-induced cross-linking polymerization of monofunctional (O) and multifunctional (U) monomer blends.

The radiation synthesis of polymeric nanocomposites is one of the promising technologies in the production of polymeric nanomaterials (Taleb et al. 2012). Along with the polymerization of monomers in situ (Liu et al. 2001, Meszaros and Czvikovszky 2007), radiation-induced cross-linking leads to the reinforcement of the available polymeric matrix owing to additional bond formation both between polymer chains of the matrix (Glhsel et al. 2003, Sharif et al. 2007) and between the polymer matrix and filler particles (KrkljeS et al. 2007, Planes et al. 2010). It is a very useful technique to improve the thermal stability, stress crack resistance, solvent resistance, and... 

Radiation processing of monomers and polymers by electron beam, such as polymerization and copolymerization of monomers, cross-linking, grafting, and degradation of polymers, is induced by these different chemically reactive species. ... 

Although radical cations are generated in some electron-irradiated monomers (e.g., vinyl ethers or epoxies), efficient cationic polymerization is not observed. Under certain conditions (addition of iodonium, sulfonium, or sulfoxonium salts, cationic polymerization with the use of electron beam irradiation can be induced. Several studies on radiation cross-linking of elastomers support the concept of ionic mechanism. ... 

K. Saito, M. Ito, H. Yamagishi, S. Furusaki, T. Sugo and J. Okamoto, Novel Hollow-Fiber Membrane for the Removal of Metal Ion during Permeation Preparation by Radiation-Induced Cografting of a Cross-Linking Agent with Reactive Monomer, Ind. Eng. Chem. Res., 28 (1989) 1808. 

Other surface modification techniques include the use of free radical-, photochemical-, radiation- redox- and plasma-induced grafting. These are used to covalently attach some useful monomers onto the membrane surface [20]. Gas plasma treatment is also used to induce surface modification water permeabihty is improved by oxygen plasma treatment due to the introduction of hydrophihc carboxylate groups, whereas argon plasma treatment can enhance chlorine resistance by increasing the extent of cross-linking at the nitrogen sites. 

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