Chloroprene compounds

Chlorinated polyethylene (CPE) has excellent o2one, oil, and heat resistance. In addition chlorinated polyethylene has replaced chloroprene elastomers. CPE has a lower specific gravity than chloroprene compounds and produces compounds that are similar to CR in properties but with lower costs. In addition, due to high levels of chlorine in the polymer, the flame resistance of the compounds of CPE are high. 

Khachatryan, E.A. (1972b) The role of chloroprene compounds in the process of skin neoplasm formation. Gig. Tr. prof. Zabol., 16, 54-55 (in Russian)... 

Another study that concerned the use of an activated rubber crumb was also performed by Adov and co-workers [43]. They introduced a finely ground activated polychloroprene powder into a virgin chloroprene compound and made a quantitative assessment of the Payne effect in the vulcanisate. They produced data that showed the dependence of the real and imaginary parts of the dynamic shear modulus, and the dependence of the mechanical loss tangent on the logarithm of the strain amplitude for vulcanisates containing different contents of activated powder. Their results indicated that the introduction of the activated chloroprene powder into the vulcanisate promoted an improvement in the interaction of the rubber with the filler present in the compound, which should lead to an increase in the level of service properties for the products and open up a route for the effective re-use of the rubber waste. 

Cuprous salts catalyze the oligomerization of acetylene to vinylacetylene and divinylacetylene (38). The former compound is the raw material for the production of chloroprene monomer and polymers derived from it. Nickel catalysts with the appropriate ligands smoothly convert acetylene to benzene (39) or 1,3,5,7-cyclooctatetraene (40—42). Polymer formation accompanies these transition-metal catalyzed syntheses. 

Rubbers. Plasticizers have been used in mbber processing and formulations for many years (8), although phthaHc and adipic esters have found Htde use since cheaper alternatives, eg, heavy petroleum oils, coal tars, and other predominandy hydrocarbon products, are available for many types of mbber. Esters, eg, DOA, DOP, and DOS, can be used with latex mbber to produce large reductions in T. It has been noted (9) that the more polar elastomers such as nitrile mbber and chloroprene are insufficiendy compatible with hydrocarbons and requite a more specialized type of plasticizer, eg, a phthalate or adipate ester. Approximately 50% of nitrile mbber used in Western Europe is plasticized at 10—15 phr (a total of 5000—6000 t/yr), and 25% of chloroprene at ca 10 phr (ca 2000 t/yr) is plasticized. Usage in other elastomers is very low although may increase due to toxicological concerns over polynuclear aromatic compounds (9). 

By-products from EDC pyrolysis typically include acetjiene, ethylene, methyl chloride, ethyl chloride, 1,3-butadiene, vinylacetylene, benzene, chloroprene, vinyUdene chloride, 1,1-dichloroethane, chloroform, carbon tetrachloride, 1,1,1-trichloroethane [71-55-6] and other chlorinated hydrocarbons (78). Most of these impurities remain with the unconverted EDC, and are subsequendy removed in EDC purification as light and heavy ends. The lightest compounds, ethylene and acetylene, are taken off with the HCl and end up in the oxychlorination reactor feed. The acetylene can be selectively hydrogenated to ethylene. The compounds that have boiling points near that of vinyl chloride, ie, methyl chloride and 1,3-butadiene, will codistiU with the vinyl chloride product. Chlorine or carbon tetrachloride addition to the pyrolysis reactor feed has been used to suppress methyl chloride formation, whereas 1,3-butadiene, which interferes with PVC polymerization, can be removed by treatment with chlorine or HCl, or by selective hydrogenation. 

If flammabiHty is an issue, Hquid chloroprene polymers (eg, Du Pont PB or Denki LCR-H-050) can be used. They cocure and, for that reason, are nonvolatile and nonextractable. They are particularly useful in hard compounds where they do not detract from physical properties as much as nonreactive plastici2ers (132,133). Methacrylate esters have been used as reactive plastici2ers (qv). Por example, hexa(oxypropylene)glycolmonomethacrylate can be used as a reactive plastici2er to enhance flex life without increasing hardness (134). 

C. W. Stewart, Sr., R. L. Dawson, and P. R. Johnson, Effect of Compounding Variables on the Rate of Heat and Smoke Release from Poly chloroprene Foam, Du Pont elastomer bulletin C-NL-550.871, 1974. 

Butadiene is not only the most important monomer for synthetic ruh-her production, hut also a chemical intermediate with a high potential for producing useful compounds such as sulfolane hy reaction with SO2, 1,4-hutanediol hy acetoxylation-hydrogenation, and chloroprene hy chlori-nation-dehydrochlorination. 

Butadiene produces chloroprene through a high temperature chlorination to a mixture of dichlorohutenes, which is isomerized to 3,4-dichloro-1-hutene. This compound is then dehydrochlorinated to chloroprene ... 

C2EI2, a colourless poisonous flammable gas the starting material for many organic compounds, e.g., chloroprene. See Neoprene. 

The double bonds in isoprene and chloroprene allow these compounds to be vulcanized. In vulcanization, sulfur attaches to the doubly bonded carbon to produce cross-linked chains ... 

Another chlorinated compound which, like vinyl chloride, is used only in its polymeric form, is chloroprene (2-chloro-l,3-butadiene), which is polymerized to make neoprene, first produced in 1940. As far as is known (17) y the monomer is made commercially only from acetylene via addition of hydrochloric acid to monovinylacetylene in the presence of cuprous chloride, but syntheses from butylenes or butadiene have been described. The production of chloroprene exceeded 100,000,000 pounds per year at the wartime peak and has been somewhat lower since then, but in view of the many valuable properties of the neoprene rubber it will continue to be important. 

Kawata, K., Uemura, T. Kifune, 1. (1982) Determination of organic compounds in waste gas from a chloroprene plant. Niigata-ken Kogai Kenkyusho Kenkyu Hokoku, 6. 81-85 (in Japanese) [Chem. Abstr.. 91, 168021]... 

Power Cables. The materials mosdy used to produce power cables are ethylene copolymers loaded with conductive carbon black for semiconductive shielding layers, polyethylene or ethylene—propylene mbber-based compounds as insulations, and either thermoplastic materials (eg, polyethylene, PVC) or thermosetting (based on chlorinated polyethylene (CPE), chlorosulfonated polyethylene (CSPE), chloroprene, etc) for jackets. 

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