Spontaneous formation of free radicals in cryochemical reactions of halogenation of hydrocarbons and nanomaterials
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A range of issues related to free-radical processes in polymer-monomer systems is considered. Spectral (EPR, IRS) and other physicochemical methods (calorimetry, chromatography, viscometry) are used to demonstrate that the low-temperature treatment of polymers and monomers with halogens (fluorine, chlorine) is accompanied by the spontaneous formation of free radicals. At F2 and Cl2 pressures below 100 Torr, the concentration of radicals reaches 1017–1019 spin/g, which can be reproduced in the case of radiolysis only by using doses of several hundred (or thousand) kGy. The formation of radicals through the cleavage of chemical bonds (without external energy impact on the system) is discussed in the framework of the model of low-temperature reactions in polymolecular complexes, involving the simultaneous occurrence of endothermic and exothermic steps in one elementary event with an overall exothermic effect. It is shown that the radicals formed can be used to initiate the polymerization of vinyl and acetylene monomers.
Keywordshalogens polymers cryochemical reactions free radicals
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