The Reaction of Sulfur and Sulfur Compounds with Olefinic Substances. IV. The Thermal Decomposition of Organic Polysulfides, and Its Contribution to the Sulfur Olefin-Reaction

At temperatures in the region of 140°, organic polysulfides undergo disproportionation resulting from thermal fission of S—S bonds and recombination of the fission products. In the presence of olefins a considerable proportion of the fission products become attached to ethylenic centers of the olefin, forming mixed mono- and polysulfides. The major part of the monosulfide product is fully saturated, hydrogen capture occurring during, or subsequent to the formation of adducts from the olefin and sulfurated fragments; unsaturation, however, appears in the polysulfide portion. The polysulfides are capable of producing monothio cross-links between the original olefinic molecules only in so far as they are able to yield up elementary sulfur to the olefin, and when the original olefin is a polyisoprene, the tendency towards the formation of a high proportion of intramolecular cyclic sulfide still further reduces the opportunity for formation of intermolecular sulfur-cross-linked products.