Viton
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2008-07-15T20:46:04Z
Biscuittin
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[[Image:Genuineviton.jpg|thumb|right|100px|Genuine Viton]]
'''Viton''' is a brand of [[synthetic rubber]] and [[fluoropolymer]] [[elastomer]] commonly used in [[O-ring]]s and other [[Molding (process)|moulded]] or [[Plastics extrusion|extruded]] goods. The name is a registered trademark of [http://www.dupontelastomers.com DuPont Performance Elastomers L.L.C.].
Viton fluoroelastomers are categorized under the [[ASTM]] D1418 & [[International Organization for Standardization|ISO]] 1629 designation of [[FKM]]. This class of [[elastomer]]s is a family comprising copolymers of [[hexafluoropropylene]] (HFP) and vinylidene fluoride (VDF or VF2), terpolymers of [[tetrafluoroethylene]] (TFE), vinylidene fluoride (VDF) and hexafluoropropylene (HFP) as well as perfluoromethylvinylether (PMVE) containing specialties. The [[fluorine]] content of the most common Viton grades varies between 66 and 70%.
==== Four families of polymers ====
<blockquote style="background: white; border: 1px solid black; padding: 1em;">
* A(Dipolymers of VF2/HFP): General purpose sealing. Automotive, Aerospace fuels & lubricants
* B(Terpolymers of VF2/HFP/TFE): Chemical Process plant, Power Utility Seals & Gaskets
* F(Terpolymers of VF2/HFP/TFE): Oxygenated Automotive fuels. Concentrated aqueous inorganic acids, water, steam
* Viton Extreme(Copolymers of TFE/Propylene and Ethylene/TFE/PMVE): Automotive, Oil Exploration, Special Sealing, Ultra Harsh Environments
</blockquote>
The performance of fluoroelastomers in aggressive chemicals depends on the nature of the base polymer and the compounding ingredients used for moulding the final products (e.g. O-rings). This performance can vary significantly when end-users purchase Viton polymer containing rubber goods from different sources. Viton is generally compatible with [[hydrocarbon]]s (an advantage over [[Buna-N]], which is the most common O-ring material), but incompatible with [[ketone]]s such as [[acetone]] and [[organic acid]]s such as [[acetic acid]]. O-rings made of Viton are typically color coded as black.
Viton O-rings have been used safely for some time in the [[SCUBA diving]] world for divers who dive with gas blends referred to as [[Nitrox]]. Viton is used because it has a lower probability of catching fire, even with the increased percentages of oxygen found in Nitrox. It is also less susceptible to decay under increased oxygen conditions.
== External links ==
* [http://www.dupontelastomers.com/viton?id=wikiviton DuPont Performance Elastomers L.L.C.]
* [http://www.zrunek.at/download/ZruElast%20FPM%20UK.pdf Designing with Fluoroelastomers]
[[Category:DuPont]]
[[Category:Elastomers]]
[[Category:Fluoropolymers]]
[[Category:Thermoplastics]]
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