Abstract:The vulcanization of ENBH (C9H14), a model for vulcanization of EPDM containing ENB, was studied (140°, 1 h) using four different vulcanization systems (conventional, sulfur free, low-sulfur and high-sulfur). The influence of the system on the total yield of crosslinked products (C9H13—Sn—C9H13) is considerable, low-sulfur giving the lowest and high-sulfur giving the highest yield. The influence of the system on the composition of the crosslinked products as determined by HPLC is surprisingly small. By using 1… Show more
“…Therefore, the chemistry of vulcanization has been worked out largely by using lowmolecular mass analogues of the rubber structure (model alkenes) and extrapolating the results to the polymeric system. These studies have considerably increased the general knowledge about organic polysulfanes 133,367,[376][377][378] but the exact mechanism of the rubber vulcanization by sulfur or sulfur-donors is still far from being completely understood. For an excellent review on the model-compound vulcanization studies, see Nieuwenhuizen et al 379 The quantitative determination of mono-, di-, and polysulfanes during the curing process has first been attempted by the application of a variety of chemical probes such as triphenylphosphane for cross-link shortening, di-n-butyl phosphite for cleaving di-and polysulfane cross-links, and a thiol-amine reagent which cleaves only polysulfanes.…”
Section: B Vulcanization Of Rubber By Sulfurmentioning
confidence: 99%
“…Therefore, the chemistry of vulcanization has been worked out largely by using low-molecular mass analogues of the rubber structure (model alkenes) and extrapolating the results to the polymeric system. These studies have considerably increased the general knowledge about organic polysulfanes ,,− but the exact mechanism of the rubber vulcanization by sulfur or sulfur-donors is still far from being completely understood. For an excellent review on the model-compound vulcanization studies, see Nieuwenhuizen et al 7 Schematic representations of rubber after vulcanization by sulfur, resulting in pendant groups (−S y −X) as well as in mono-, di-, and polysulfane bridges.…”
Section: B Vulcanization Of Rubber By Sulfurmentioning
“…Therefore, the chemistry of vulcanization has been worked out largely by using lowmolecular mass analogues of the rubber structure (model alkenes) and extrapolating the results to the polymeric system. These studies have considerably increased the general knowledge about organic polysulfanes 133,367,[376][377][378] but the exact mechanism of the rubber vulcanization by sulfur or sulfur-donors is still far from being completely understood. For an excellent review on the model-compound vulcanization studies, see Nieuwenhuizen et al 379 The quantitative determination of mono-, di-, and polysulfanes during the curing process has first been attempted by the application of a variety of chemical probes such as triphenylphosphane for cross-link shortening, di-n-butyl phosphite for cleaving di-and polysulfane cross-links, and a thiol-amine reagent which cleaves only polysulfanes.…”
Section: B Vulcanization Of Rubber By Sulfurmentioning
confidence: 99%
“…Therefore, the chemistry of vulcanization has been worked out largely by using low-molecular mass analogues of the rubber structure (model alkenes) and extrapolating the results to the polymeric system. These studies have considerably increased the general knowledge about organic polysulfanes ,,− but the exact mechanism of the rubber vulcanization by sulfur or sulfur-donors is still far from being completely understood. For an excellent review on the model-compound vulcanization studies, see Nieuwenhuizen et al 7 Schematic representations of rubber after vulcanization by sulfur, resulting in pendant groups (−S y −X) as well as in mono-, di-, and polysulfane bridges.…”
Section: B Vulcanization Of Rubber By Sulfurmentioning
Organic polysulfanes are compounds of the type RS
n
R with n > 2. They may be chain‐like or cyclic. The organic residues (alkyl or aryl) are linked to the sulfur atoms via carbon atoms. In the literature these compounds are often termed as organic polysulfides, but the IUPAC recommended nomenclature is polysulfanes. Sulfur‐rich organic polysulfanes can be viewed as intermediates between organic and inorganic compounds. On one hand, they are characterized by organic substituents R, which terminate the sulfur chain or close this chain to form a ring. On the other hand, compounds with sulfur chains of three or more sulfur atoms are ‘inorganic’ enough to attract the interest of inorganic chemists who have contributed much to this area. Organic polysulfanes with up to 16 sulfur atoms in the molecules have so far been obtained as pure substances, but species with up to 35 sulfur atoms in a chain or ring have been prepared in mixtures. Organic polysulfanes play an important role not only in basic research and industry, they are also found as natural products in organisms and occur in the inanimate nature. The main importance of organic polysulfanes comes, however, from their role in the large scale industrial vulcanization of natural and synthetic rubber. In this article, the preparation, structure, modern analysis, basic reactions, natural occurrence, biological activity, and practical importance of organic polysulfanes with three or more neighboring sulfur atoms in a chain or ring have been presented.
The chemistry of organic polysulfanes (or polysulfides) is thoroughly and critically reviewed. The synthesis of chain‐like and cyclic polysulfanes with alkyl and aryl substituents as well as their analysis, molecular structures, reactions with nucleophiles, natural occurrence and potential applications are described.
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