Radiation, chemical changes

While almost all the radiation-chemical changes can also be brought about by thermal or photochemical means, there are some advantages of using irradiation since it can be conducted at lower temperatures without contamination by catalysts or initiators (Vereshchinskii, 1972). The radiation is absorbed uniformly over the volume of the reactor, which can be made of metal or glass, and the medium can be transparent or opaque (Wilson, 1972). Further, the G-values of the products are more easily calculated than the quantum yields of corresponding photochemical reactions. 

In principle, a large variety of radiation chemical changes of a semipermanent nature induced in a solution can be utilized for dosimetric purpose. The practical suitability is determined by satisfying as many of the following requirements as possible ... 

Matel, L. 1990. Radiation-chemical changes of benzo-15-crown-5 in chloroform. J. Radioanal. Nucl. Chem. Lett. 146(2) 85-93. 

Bakale, G., Lacmann, K., and Schmidt, W.F., C q and C70 Fullerene ions in nonpolar liquids Mobility and radiation-chemical changes, /. Phys. Chem., 100, 12477, 1996. 

In order to cute, ie, form three-dimensional network stmctures through chemical changes on polymer systems with it radiation, it is necessary to design a reactive functionaUty within the polymer stmcture so that coupling reactions can take place between the polymer chains as shown ia the foUowiag reaction ... 

The ultraviolet absorber could dispose of absorbed energy by radiation, by conversion into heat or by chemical changes leading to stable products. The most important commercial absorbers, such as the o-hydroxybenzophenones, o-hydroxyphenylbenzotriazoles and salicylates, appear to function by conversion of electronic energy into heat. The properties of the main types of ultraviolet absorbers are summarised in Table 7.7. 

Radiation-induced modification or processing of a polymer is a relatively sophisticated method than conventional thermal and chemical processes. The radiation-induced changes in polymer materials such as plastics or elastomers provide some desirable combinations of physical and chemical properties in the end product. Radiation can be applied to various industrial processes involving polymerization, cross-linking, graft copolymerization, curing of paints and coatings, etc. 

UV radiation, certainly not sufficient to disrupt the bonds of common organic molecules. We therefore assume that, essentially, photoinitiation is responsible for a chemical change and MW radiation subsequently affects the course of the reaction. The objective of microwave photochemistry is frequently, but not necessarily, connected to the electrodeless discharge lamp (EDL) which generates UV radiation when placed in the MW field. 

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