Styrene-butadiene rubber accelerators

The accelerated sulfur vulcanization of general-purpose diene rubbers (e.g., NR, styrene-butadiene rubber [SBR], and butadiene rubber [BR]) by sulfur in the presence of organic accelerators and other rubbers, which are vulcanized by closely related technology (e.g., ethylene-propylene-diene monomer [EPDM] mbber, butyl rubber [HR], halobutyl mbber [XIIR], nitrile rubber [NBR]) comprises more than 90% of all vulcanizations. 

FIGURE 14.7 Comparison of primary accelerators in styrene-butadiene rubber (SBR). (From B.H. To,... 

Comparison of Secondary Accelerators in Styrene-Butadiene Rubber (SBR)... 

Used as a secondary accelerator with antioxidant, antiozonant, and stabilizing function in synthetic rubber and high polymer materials in the plastics and rubber industries. Mainly used in styrene-butadiene rubber (SBR), chloroprene rubber (CR), epichlorohydrin, and chlorosulfonated polyethylene rubber. Promotes heat-resistance of chlorosulfonated polyethylene rubber, EPDM and CSM and sunshine resistance of CR. 

Elastomers include natural rubber (polyisoprene), synthetic polyisoprene, styrene-butadiene rubbers, butyl rubber (isobutylene-isoprene), polybutadiene, ethylene-propylene-diene (EPDM), neoprene (polychloroprene), acrylonitrile-butadiene rubbers, polysulfide rubbers, polyurethane rubbers, crosslinked polyethylene rubber and polynorbomene rubbers. Typically in elastomer mixing the elastomer is mixed with other additives such as carbon black, fillers, oils/plasticizers and accelerators/antioxidants. 

Beiistein Handbook Reference) AI3-08621 BRN 0507434 EINECS 203-674-6 1,3-Dibutylthiourea 1,3-Di-n-butyl-2-thiourea 1,3-Dibutyl-2-thiourea NSC 3735 Pennzone B Pennzone B 0685 Thiate U Thiourea, N,N -dibutyl- Urea, 1,3-dibutyl-2-thio- Urea, 1,3-di-N-butyl-2-thio- USAF EK-2138. Accelerator for mercaptan-modified chlotoprene rubber, an activator for ethylenepropylenediene terpolymers and natural nibber, an antidegradant for natural rubber-latex and thermoplastic styrene-butadiene rubber. Crystals mp = 63-65°. ElfAtochem N. Am. 

The efficacy of polyurethane and styrene butadiene rubber (SBR) as binders for ground rubber prepared from waste tires was compared to a formulation of a compound developed without binder. Without binder, the effect of both sulfur and accelerator content on tensile properties are studied, as well as the effect of ageing on these properties [29]. The suggested uses of the unbound product include rubber blocks, and ballast mats for railway applications. 

Accelerated-sulfur vulcanization is the most widely used method. For many applications, it is the only rapid crossUnking technique that can, in a practical manner, give the delayed action required for processing, shaping, and forming before the formation of the intractable vulcanized network. It is used to vulcanize natural rubber (NR), synthetic isoprene rubber (IR), styrene-butadiene rubber (SBR), nitrile rubber (NBR), butyl rubber (HR), chlorobutyl rubber (ClIR), bromobutyl rubber (BUR), and ethylene-propylene-diene-monomer rubber (EPDM). The reactive moiety for all of these elastomers can be represented by... 

He, S.-J., Wang, Y.-Q., Xi, M.-M., Lin, J., Xue, Y., Zhang, L.-Q. Prevention of oxide aging acceleration by nano-dispersed clay in styrene-butadiene rubber matrix. Polym. Degrad. Stab. 98, 1773-1779 (2013)... 

B. Zhong, Z. Jia, Y. Luo, D. Jia, A method to improve the mechanical performance of styrene-butadiene rubber via vulcanization accelerator modified silica. Composites Science and Technology, ISSN 0266-3538 117 (September 29, 2015) 46-53. http //dx.doi. org/10.1016/j.compscitech.2015.05.012. 

Nitrile polymers are vulcanized in essentially the same manner as styrene butadiene rubber (SBR) and natural rubber. The same ingredients are used, although not necessarily in the same amounts. Sulfur is less soluble in nitrile rubber than in SBR or natural rubber, and smaller amounts are used. A corresponding increase in accelerator is required. Sulfur/accelerator, sulfur donor, and peroxide cures are chosen depending on the ultimate processing methods and applications. 

Synonyms N,N -dibutyl-thiourea N,N-dibutylthiourea N,N -di-n-butylthiourea i,3-dibutyl-2-thiourea 1,3-dibutylthiourea Uses accelerator for mercaptan-modified chloroprene rubber activator for ethylene-propylene-diene terpolymers and natural rubber antidegradant for natural rubber latex and thermoplastic styrene-butadiene rubber A... 

Rudewicz and Munson [45] used this technique for the direct determination of additives in PP. The technique has also been used to determine oligomers in polyacrylates, PEG, siloxanes and polycarbonates [87], polyglycols [88] and adhesion promoters, primers and additives in the surface of PET film [89], volatile antioxidants in styrene-butadiene rubbers [34, 50], mercaptobenzothiazole sulfenamide accelerator in rubber vulcanisates [90] and divinyl benzene in styrene-divinyl benzene copolymer [91]. 

Altenau and co-workers [26,27] used MS to identify quantitatively volatile antioxidants in 0.02-0.03 inch thick samples of synthetic styrene-butadiene rubbers and rubber-type vulcanisates. They extracted the polymer with acetone in a Soxhlet apparatus, removed excess solvent, and dissolved the residue in benzene. Substances identified and determined by this procedure include N-phenyl-P-napthylamine, 6-dodecyl-2,2,4-trimethyl-l,2-dihydroquinolines, trisnonylphenylphosphate, isobutylene-bisphenol, 2-mercaptobenzothiazole sulfenamide (accelerator), N-cyclohexyl-2-benzothiazole... 

Several strategies have been reported to improve the compatibility of NR/ EPDM blends, including the addition of a third component with low molar mass or a third polymer, sueh as polybutadiene (BR), styrene butadiene rubber (SBR), chlorinated rubber, chlorosulfonated PE or polyvinylchloride (PVQ, the incorporation of an accelerator moiety in the less unsaturated phase, and the functionalization of EPDM with maleic anhydride. ... 

Falco AD, Matzocca AJ, Corcuera MA, Eceiza A, Mondragrai I, Rubiolo H, Goyanes S (2009) Accelerator adsorption onto carbon nanotubes surface affects the vulcanization process of styrene-butadiene rubber composites. J Appl Polym Sci 113 2851-2857... 

One of the most widely used examples of polymerization in a CSTR train is that of synthetic rubber. Styrene-butadiene rubber (SBR) and neoprene are free radical polymerized, most often in an emulsion polymerization system. These rubbers are highly susceptible to branching. Excessive branching will cause the rubber to be unusable. Branching is accelerated by a high ratio of polymer to monomer. For this reason, the monomer is often polymerized to 50-70% conversion, then the polymerization is stopped and the monomer is steam-stripped from the product and recycled. In this case, very high conversion is not necessary and a train of 5-15 CSTRs is often used. This number of CSTRs in... 

More important and with better properties are the cold-setting, two-component acrylate adhesives, which contain methacrylates or acrylates, sometimes mixed with styrene and methacrylic acid as monomer and, in addition, various polymers. The polymers used are primarily synthetic rubbers, such as polychloroprene, styrene-butadiene rubber, butyl rubber, polystyrene, polymethacrylates, and acrylate graft polymers of these polymers. Amines are used as accelerators, and benzoyl peroxide in the form of plasticizer pastes or a powder mixture with fillers is preferred as hardener [43]. 

Dyed natural rubber (NR) and styrene butadiene rubber (SBR), designed for outdoor applications, were exposed to an accelerated artificial aging in xenon light. The aging results in the deterioration of the exposed surface material properties. The ability of dyed polymers to withstand prolonged sunlight... 

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