Applications of Ultraviolet Spectrography. A Study of the Transformations Which Tetramethylthiuram Disulfide Undergoes during the Vulcanization Process

Abstract

Abstract Various experiments make it clear that the method of spectrographic determination can be applied to a complicated case where the product to be determined does not remain intact in a mixture but is transformed into some other compound. Furthermore the results obtained, which were confirmed by chemical tests, are definite and precise enough to make it possible to determine the type of transformation which takes place in rubber when tetramethylthiuram disulfide is used as a vulcanizing agent. The liberation of sulfur is only an accessory reaction, in fact there is probably not even any such reaction. More probably there is a dehydrogenation of the rubber, without liberation of hydrogen sulfide, a dehydrogenation which involves perhaps certain restricted parts of the molecule, e.g., the extremities of the chains, as has been suggested by Boggs and Blake. It is possible to conceive various schemes whereby this dehydrogenation may take place and which would make it possible to explain at the same time the formation of zinc dimethyldithiocarbamate, the decrease in unsaturation found by Hauser and Brown, and the fixation of a certain amount of sulfur on the rubber.