For the first time using the density functional method in the 6-311++G(2df, 2p) basis set in the M06-2X hybrid functional approximation the nonplanar (dimensional) structure of sulfonyl chloride groups in chlorosulfonated polyethylene has been revealed. It has been shown that their structural features have a direct influence on the concerted mechanism of thermal degradation accompanied by the formation of a carbon-centered macroradical R_n^∙ and a chlorine atom Cl•. The participation of these radicals in the processes of crosslinking macromolecules in the single-step production of thermoplastic vulcanizates has been experimentally verified.