Radiation induced chemical reaction

The molecular changes in polymers resulting from radiation-induced chemical reactions may be classified as ... 

For radiation induced chemical reaction, a distinction is often made between single-photon and multiple-photon events. The differentiation is based on the intensity (flux) of the photon source. For single photon events, the maximum energy of mid-IR photons is ca. 2.4kj mole and near-IR photons ca. 48 kj mole [25, 26]. Therefore, single photon mid-IR irradiation is normally considered non-destructive. However, intense irradiation and hence multiple photon absorption in mid-IR is known to promote chemical transformations [27, 28]. As an example of NIR pro-... 

Very primary events in the chemical effect of radiations on matter are excitation and ionization of molecules, which result in the formation of neutral free radicals and radical ions. These reactive species play vital roles in the radiation-induced chemical reactions. As they are paramagnetic with an unpaired electron, electron spin resonance (ESR) spectroscopy has been a useful method for elucidating the mechanism of radiation-induced reactions in solid matter where radical species can be trapped temporarily. Since the early days of the chemical application of ESR, this method has been applied very often to the identification and quantification of free radicals in polymers irradiated by radiation [1]. This is probably because, from the view-point of fundamental research, a variety of free radicals are readily trapped in solid polymers and, from the view-point of applied research, these free radicals have close correlation with radiation-induced crosslinking and degradation of polymers. 

Keene JP. (1960) Kinetics of radiation-induced chemical reactions. Nature 188 843-844. 

The intense primary y radiation due to nuclear fission, the secondary y radiation emitted by the fission and activation products and the radiation from the fission products give rise to radiation-induced chemical reactions. The most important reaction is the radiation decomposition of water in water-cooled reactors, leading to the formation of H2, H2O2 and O2. Many substances dissolved in the water influence the formation of H2 (Fig. 11.18). In most closed coolant systems equipment for... 

Radiation chemistry Radiation-induced chemical reactions, either by nuclear radiation, by X rays or by UV or visible light (photochemistry)... 

Origin of different nature of both kinds of primary products of radiolysis was found in different size of spurs, as the centers of radiation induced chemical reactions were called. The... 

Although the radiation yield of hydrogen from irradiated polymers became no concern from the point of view of safety, it remained the object of interest from the point of view of mechanisms of radiation induced chemical reactions. In analogy to water radiolysis, the yield of hydrogen become of interest if radiations of higher LET values were used for irradiation of polymers [19], These are proton beams and alpha radiation, which can suggest different yields of hydrogen, and they really do. 

Schmidt. K. H., Electrical conductivity techniques for studying the kinetics of radiation induced chemical reactions in aqueous solutions. Int. I. Radiat. Phys. Chem. 4, 439 (1972). 

As mentioned above, the mechanism of degradation of PTFE is unclear, particularly the location of radiation-induced chemical reactions. However, ESR spectroscopy (290-293) has confirmed that the stable free-radical species at low temperatures are the chain-end radicals IX (shown below) and that at higher temperatures the secondary radicals X dominate the spectrum. Hedvig (291) has suggested that chain-end radicals terminate by abstraction to form the more stable secondary radical. These radicals persist for very long times, and this leads some authors (58) to suggest the suitability of PTFE as a radiation dosimeter. 

GAS PHASE RADIATION-INDUCED CHEMICAL REACTION PROCESSES, 645... 

E-Beam (radiation-induced chemical reaction) Ebara D... 

The Ebaia Electron Beam (E-Beam) process utilizes radiation-induced chemical reactions to simultaneously remove both SO2 and NO from a gas stream and produce fertilizer compounds (Frank, 1992). Projected capital costs for power plant applications are 40Q/kW, and projected operating costs are 13 mills/kWh (Hoffinan et al., 1992). With zone irradiation, the capital cost is reported to be halved, and levelized costs are reduced to about 8 to 10 mills/kWh. The process is being tested at five facilities. Hie largest is a 20,000 m /hr flue gas stream from a coal burning plant. It is also being used on a 50,000 m /hr automobile tunnel ventilation system for NO control. (Frank, 1992). Removal efficiencies of 90% and 80% for SO2 and NO,, respectively, have been demonstrated in a 5 MWg pilot plant (Livengood and Markussen, 1992). Removal efficiencies are said to be a function of the electric power input. 

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