Styrene-butadiene
749071
225880010
2008-07-15T20:53:47Z
Biscuittin
3955768
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'''Styrene-Butadiene''' ('''SBR''') is an [[elastomer]]ic [[copolymer]] consisting of [[styrene]] and [[butadiene]]. It has good [[Wear#Abrasive_wear|abrasion]] resistance and good ageing stability when protected by additives, and is widely used in car [[tires]] where it is blended with [[natural rubber]]. It was originally developed in the USA during World War II to replace natural rubber supplies from the far east that were captured by the Japanese.
[[Image:SBR.png|right|243px|thumb|Styrene-Butadiene Monomer]]
SBR can be produced from solution or as emulsion. In both instances, the reaction is via free radical polymerization. Pressure reaction vessels are required and usually charged with the two monomers, a free radical acid and a chain transfer agent such as an alkyl mercaptan. The latter prevents high molecular weight and high viscosity product from forming. High styrene-content rubbers are hard, since the Tg (glass transition temperature)of butadiene is extremely low.
==Properties==
*[[Glass transition temperature]] approx. -55 °C [1] but varies with styrene content
*Possible temperature range of use: approx. -40 to +100 °C (-40 to +212 °F)
*Chemical Type: styrene-butadiene ([[copolymer]])
*Trade names (common): '''GRS''', [[Buna S]] (SBR)
*Elongation (%): 450-500
*Useful temperature range: -60 to 120 degrees Celsius (-75 to 250 degrees Fahrenheit)
*Major application characteristics: good physical properties; excellent abrasion resistance; but sensitive to oil, and [[ozone]]; electrical properties good, but not outstanding
==Applications==
The [[elastomer]] is used widely in pneumatic [[tire]]s, shoe heels and soles and [[gasket]]s. It is a commodity material which competes with [[natural rubber]]. Latex (emulsion) SBR is extensively used in coated papers, being one of the most cost-effective resins to bind pigmented coatings.
==See also==
*[[elastomer]]
*[[ozone cracking]]
*[[tyre]]
== References ==
[1] Gent, A. N.; Campion, R. P.; American Chemical Society.Division of Rubber Engineering With Rubber : How to Design Rubber Components; Munich : Hanser Publishers: 1992.
[[Category:Copolymers]]
[[Category:Elastomers]]
[[Category:polymers]]
[[de:Styrol-Butadien-Kautschuk]]
[[es:Caucho estireno-butadieno]]
[[it:Gomma SBR]]
[[ja:スチレン・ブタジエンゴム]]
[[fi:Buna]]
[[vi:Cao su styren-butađien]]