On the origin of the reactive chlorine atoms in polychloroprene

In the light of the results of investigations of crosslinking reactions and of the formation of hydrogen chloride and zinc chloride the authors discuss the origin of a second type of reactive chlorine atom that participates in the crosslinking reactions. This chlorine atom which is present in addition to the allyl chlorine in the 1,2-position is a tertiary or secondary chlorine atom that is formed as a result of the expenditure of double bonds in the 1,4-units during oxidation of the polymer and during interactions of the latter with sulphur, with initiators of free radical reactions and with the products of chlorine separation from polymer (chlorine atoms and polymeric radicals).