Styrene-butadiene

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Styrene-butadiene
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Styrene-butadiene or styrene-butadiene rubber (SBR) describe families of synthetic rubbers derived from styrene and butadiene (the version developed by Goodyear is called Neolite [1] ). These materials have good abrasion resistance and good aging stability when protected by additives. In 2012, more than 5.4 million tonnes of SBR were processed worldwide. [2] About 50% of car tires are made from various types of SBR. The styrene/butadiene ratio influences the properties of the polymer: with high styrene content, the rubbers are harder and less rubbery. [3] SBR is not to be confused with the thermoplastic elastomer, styrene-butadiene block copolymer, although being derived from the same monomers.

Contents

Types

SBR is derived from two monomers, styrene and butadiene. The mixture of these two monomers is polymerized by two processes: from solution (S-SBR) or as an emulsion (E-SBR). [4] E-SBR is more widely used.

Emulsion polymerization

E-SBR produced by emulsion polymerization is initiated by free radicals. Reaction vessels are typically charged with the two monomers, a free radical generator, and a chain transfer agent such as an alkyl mercaptan. Radical initiators include potassium persulfate and hydroperoxides in combination with ferrous salts. Emulsifying agents include various soaps. By "capping" the growing organic radicals, mercaptans (e.g. dodecylthiol), control the molecular weight of the product. Typically, polymerizations are allowed to proceed only to ca. 70%, a method called "short stopping". In this way, various additives can be removed from the polymer. [3]

Solution polymerization

Solution-SBR is produced by an anionic polymerization process. Polymerization is initiated by alkyl lithium compounds. Water and oxygen are strictly excluded. The process is homogeneous (all components are dissolved), which provides greater control over the process, allowing tailoring of the polymer. The organolithium compound adds to one of the monomers , generating a carbanion that then adds to another monomer, and so on. For tire manufacture, S-SBR is increasingly favored because it offers improved wet grip and reduced rolling resistance, which translate to greater safety and better fuel economy, respectively. [5]

Buna S

The material was initially marketed with the brand name Buna S. Its name derives Bu for butadiene and Na for sodium (natrium in several languages including Latin, German, and Dutch), and S for styrene. [6] [7] [5] Buna S is an addition copolymer.

Properties

PropertyS-SBRE-SBR
Tensile strength (MPa)3620
Elongation at tear (%)565635
Mooney viscosity, 100 °C48.051.6
Glass transition temperature (°C)−65−50
Polydispersity 2.14.5

Applications

An SBR chain Styrene-butadiene chain2.png
An SBR chain

Styrene-butadiene is a commodity material which competes with natural rubber. The elastomer is used widely in pneumatic tires. This application mainly calls for E-SBR, although S-SBR is growing in popularity. Other uses include shoe heels and soles, gaskets, and even chewing gum. [3]

Latex (emulsion) SBR is extensively used in coated papers, being one of the cheapest resins to bind pigmented coatings. In 2010, more than half (54%) of all used dry binders consisted of SB-based latexes. [8] This amounted for roughly 1.2 million tonnes.

It is also used in building applications, as a sealing and binding agent behind renders as an alternative to PVA, but is more expensive. In the latter application, it offers better durability, reduced shrinkage and increased flexibility, as well as being resistant to emulsification in damp conditions.

SBR is often used as part of cement based substructural (basement)waterproofing systems where as a liquid it is mixed with water to form the Gauging solution for mixing the powdered Tanking material to a slurry. SBR aids the bond strength, reduces the potential for shrinkage and adds an element of flexibility.

It is also used by speaker driver manufacturers as the material for low damping rubber surrounds.

Additionally, it is used in some rubber cutting boards.

SBR is also used as a binder in lithium-ion battery electrodes, in combination with carboxymethyl cellulose as a water-based alternative for, e.g. polyvinylidene fluoride. [9]

Styrene-butane rubber is also used in gasketed-plate heat exchangers. It is used at moderate temperature up to 85 deg C, (358 K) for aqueous systems. [10]

SBS Filaments [11] also exist for FDM 3D printing

History

SBR is a replacement for natural rubber. It was originally developed prior to World War II in Germany by chemist Walter Bock in 1929. [12] Industrial manufacture began during World War II, and was used extensively by the U.S. Synthetic Rubber Program to produce Government Rubber-Styrene (GR-S); to replace the Southeast Asian supply of natural rubber which, under Japanese occupation, was unavailable to Allied nations. [13] [14]

See also

Related Research Articles

<span class="mw-page-title-main">Petrochemical</span> Chemical product derived from petroleum

Petrochemicals are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane.

In polymer chemistry, emulsion polymerization is a type of radical polymerization that usually starts with an emulsion incorporating water, monomers, and surfactants. The most common type of emulsion polymerization is an oil-in-water emulsion, in which droplets of monomer are emulsified in a continuous phase of water. Water-soluble polymers, such as certain polyvinyl alcohols or hydroxyethyl celluloses, can also be used to act as emulsifiers/stabilizers. The name "emulsion polymerization" is a misnomer that arises from a historical misconception. Rather than occurring in emulsion droplets, polymerization takes place in the latex/colloid particles that form spontaneously in the first few minutes of the process. These latex particles are typically 100 nm in size, and are made of many individual polymer chains. The particles are prevented from coagulating with each other because each particle is surrounded by the surfactant ('soap'); the charge on the surfactant repels other particles electrostatically. When water-soluble polymers are used as stabilizers instead of soap, the repulsion between particles arises because these water-soluble polymers form a 'hairy layer' around a particle that repels other particles, because pushing particles together would involve compressing these chains.

<span class="mw-page-title-main">Butadiene</span> Chemical compound

1,3-Butadiene is the organic compound with the formula CH2=CH-CH=CH2. It is a colorless gas that is easily condensed to a liquid. It is important industrially as a precursor to synthetic rubber. The molecule can be viewed as the union of two vinyl groups. It is the simplest conjugated diene.

<span class="mw-page-title-main">Copolymer</span> Polymer derived from more than one species of monomer

In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained from the copolymerization of two monomer species are sometimes called bipolymers. Those obtained from three and four monomers are called terpolymers and quaterpolymers, respectively. Copolymers can be characterized by a variety of techniques such as NMR spectroscopy and size-exclusion chromatography to determine the molecular size, weight, properties, and composition of the material.

<span class="mw-page-title-main">Elastomer</span> Polymer with rubber-like elastic properties

An elastomer is a polymer with viscoelasticity and with weak intermolecular forces, generally low Young's modulus (E) and high failure strain compared with other materials. The term, a portmanteau of elastic polymer, is often used interchangeably with rubber, although the latter is preferred when referring to vulcanisates. Each of the monomers which link to form the polymer is usually a compound of several elements among carbon, hydrogen, oxygen and silicon. Elastomers are amorphous polymers maintained above their glass transition temperature, so that considerable molecular reconformation is feasible without breaking of covalent bonds. At ambient temperatures, such rubbers are thus relatively compliant and deformable.

<span class="mw-page-title-main">EPDM rubber</span> Type of synthetic rubber

EPDM rubber is a type of synthetic rubber that is used in many applications.

A synthetic rubber is an artificial elastomer. They are polymers synthesized from petroleum byproducts. About 32 million metric tons of rubbers are produced annually in the United States, and of that amount two thirds are synthetic. Synthetic rubber, just like natural rubber, has many uses in the automotive industry for tires, door and window profiles, seals such as O-rings and gaskets, hoses, belts, matting, and flooring. They offer a different range of physical and chemical properties which can improve the reliability of a given product or application. Synthetic rubbers are superior to natural rubbers in two major respects: thermal stability, and resistance to oils and related compounds. They are more resistant to oxidizing agents, such as oxygen and ozone which can reduce the life of products like tires.

<span class="mw-page-title-main">Polybutadiene</span> Type of synthetic rubber formed from the polymerization of butadiene

Polybutadiene [butadiene rubber, BR] is a synthetic rubber. It offers high elasticity, high resistance to wear, good strength even without fillers, and excellent abrasion resistance when filled and vulcanized. "Polybutadiene" is a collective name for homopolymers formed from the polymerization of the monomer 1,3-butadiene. The IUPAC refers to polybutadiene as "poly(buta-1,3-diene)". Historically, an early generation of synthetic polybutadiene rubber produced in Germany by Bayer using sodium as a catalyst was known as "Buna rubber". Polybutadiene is typically crosslinked with sulphur, however, it has also been shown that it can be UV cured when bis-benzophenone additives are incorporated into the formulation.

Nitrile rubber, also known as nitrile butadiene rubber, NBR, Buna-N, and acrylonitrile butadiene rubber, is a synthetic rubber derived from acrylonitrile (ACN) and butadiene. Trade names include Perbunan, Nipol, Krynac and Europrene. This rubber is unusual in being resistant to oil, fuel, and other chemicals.

Kraton is the trade name given to a number of high-performance elastomers manufactured by Kraton Polymers, and used as synthetic replacements for rubber. Kraton polymers offer many of the properties of natural rubber, such as flexibility, high traction, and sealing abilities, but with increased resistance to heat, weathering, and chemicals.

<span class="mw-page-title-main">Acrylate polymer</span> Group of polymers prepared from acrylate monomers

An acrylate polymer is any of a group of polymers prepared from acrylate monomers. These plastics are noted for their transparency, resistance to breakage, and elasticity.

Thermoplastic elastomers (TPE), sometimes referred to as thermoplastic rubbers (TPR), are a class of copolymers or a physical mix of polymers that consist of materials with both thermoplastic and elastomeric properties.

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Solution polymerization is a method of industrial polymerization. In this procedure, a monomer is dissolved in a non-reactive solvent that contains a catalyst or initiator.

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<span class="mw-page-title-main">2-Vinylpyridine</span> Chemical compound

2-Vinylpyridine is an organic compound with the formula CH2CHC5H4N. It is a derivative of pyridine with a vinyl group in the 2-position, next to the nitrogen. It is a colorless liquid, although samples are often brown. It is used industrially as a precursor to specialty polymers and as an intermediate in the chemical, pharmaceutical, dye, and photo industries. Vinylpyridine is sensitive to polymerization. It may be stabilized with a polymerisation inhibitor such as tert-butylcatechol. Owing to its tendency to polymerize, samples are typically refrigerated.

<span class="mw-page-title-main">Charles Goodyear Medal</span> Award

The Charles Goodyear Medal is the highest honor conferred by the American Chemical Society, Rubber Division. Established in 1941, the award is named after Charles Goodyear, the discoverer of vulcanization, and consists of a gold medal, a framed certificate and prize money. The medal honors individuals for "outstanding invention, innovation, or development which has resulted in a significant change or contribution to the nature of the rubber industry". Awardees give a lecture at an ACS Rubber Division meeting, and publish a review of their work in the society's scientific journal Rubber Chemistry and Technology.

<span class="mw-page-title-main">Kumho Petrochemical</span> South Korean multinational chemical company

Kumho Petrochemical Co., Ltd. is a multinational chemical company based in South Korea, with headquarters in Seoul. It was founded in 1970 when Kumho Group struggled to secure raw materials for its bus and tire businesses. Kumho Petrochemical has a global market leadership in the manufacturing of synthetic rubbers with the world's largest production capacity based on SBR and BR by IISRP 2012. It focuses on synthetic rubbers, synthetic resins, specialty chemicals, electronic chemicals, energy, building materials and advanced materials as its core business.

Walter Bock was a German chemist who developed styrene-butadiene copolymer by emulsion polymerization as a synthetic rubber (SBR).

References

  1. Steven Di Pilla (2 June 2004), Slip and Fall Prevention: A Practical Handbook, CRC, p. 82, ISBN   978-0-203-49672-5
  2. Market Study Synthetic Rubber "Marktstudie Synthetische Elastomere von Ceresana". Archived from the original on 2015-03-18. Retrieved 2013-08-23., published by Ceresana, June 2013
  3. 1 2 3 Werner Obrecht; Jean-Pierre Lambert; Michael Happ; Christiane Oppenheimer-Stix; John Dunn; Ralf Krüger (2012). "Rubber, 4. Emulsion Rubber". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.o23_o01. ISBN   978-3527306732.
  4. International Institute of Synthetic rubber Producers, Inc. (IISRP) article on S-SBR (retrieved 2011-12-02)
  5. 1 2 H.-D.Brandt et al. "Rubber, 5. Solution Rubbers" in Ullmann's Encyclopedia of Industrial Chemistry, 2012, Wiley-VCH, Weinheim. doi : 10.1002/14356007.o23_o02
  6. Mark Michalovic (2000) "The Story of Rubber. Germany: The Birth of Buna" from The Polymer Learning Center and Chemical Heritage Foundation
  7. Evonik Industries Invention and Production of Buna
  8. Holik, Herbert (2013). Holik, Herbert (ed.). Handbook of Paper and Board. Wiley-VCH Verlag GmbH & Co. p. 250. doi:10.1002/9783527652495. ISBN   9783527331840.
  9. "Water based anode binder | JSR Micro NV". Archived from the original on 2016-03-25.
  10. K., Sinnott, R. (2009). Chemical engineering design. Towler, Gavin. (5th ed., SI ed.). Oxford: Butterworth-Heinemamn. ISBN   978-0-7506-8551-1. OCLC   774295558.{{cite book}}: CS1 maint: multiple names: authors list (link)
  11. "SBS PLUS - SA FILAMENT".
  12. Malcolm Tatum What is syrene-butadiene rubber from Wisegeek
  13. Wendt, Paul (1947). "The Control of Rubber in World War II". Southern Economic Journal. 13 (3). Southern Economic Association: 203–227. doi:10.2307/1053336. JSTOR   1053336.
  14. "Rubber Matters: Solving the World War II Rubber Problem & Collaboration". Chemical Heritage Foundation. Archived from the original on December 5, 2014. Retrieved 24 June 2013.