PEEK
252277
218633127
2008-06-11T14:26:20Z
Mani1
86923
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{| border="0" cellpadding="2" cellspacing="0" align="right" style="margin-left:1em"
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! colspan="2" bgcolor="#cccccc" | PEEK
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| [[Density]]
| 1300 [[kilogram per cubic metre|kg/m<sup>3</sup>]]
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| [[Young's modulus]] (''E'') || 3700 [[Mega|M]][[Pascal (unit)|Pa]]
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| [[Tensile strength]] (''σ<sub>t</sub>)''
| 90 [[Mega|M]][[Pascal (unit)|Pa]]
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| Elongation @ break || 50%
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| notch test
| 55 [[kilo|k]][[joule|J]]/[[Metre|m]]<sup>2</sup>
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| [[Glass transition temperature|Glass temperature]]
| 130-150 °[[Degree Celsius|C]] and 260-290 º[[Degree Celsius|C]]
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| [[melting point]] || ~350 °[[Degree Celsius|C]]
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| Vicat B{{Fact|date=February 2007}} || -
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| heat transfer coefficient (λ) || 0.25 W/[[Metre|m]].[[Kelvin|K]]
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| [[Coefficient of thermal expansion|linear expansion coefficient (α)]]
| 1.7 10<sup>-5</sup> /[[Kelvin|K]]
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| [[Specific heat capacity|Specific heat]] (c)
| - [[kilo|k]][[joules|J]]/[[kilogram|kg]].[[Kelvin|K]]
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| Water absorption, 24 hours (ASTM D 570) || - 0.1%
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| Price || 40-90 €/[[kilogram|kg]]
<!-- Dead note "<vic>": Deformation temperature at 10kN needle load <small> -->
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! colspan="2" align="left" | <small>source: <ref>A.K. van der Vegt & L.E. Govaert, Polymeren, van keten tot kunstof, ISBN 90-407-2388-5</ref><small>
|}
{{otheruses}}
'''Polyetheretherketone''' ('''PEEK'''), also referred to as '''[[polyketone]]s''', is obtained from aromatic dihalides and bisphenolate salts by [[nucleophilic substitution]]. The bisphenolate salt is formed ''in situ'' from bisphenol and either added sodium or added alkali metal carbonate or hydroxide, by the [[Williamson ether synthesis]].
[[Image:peek.png]]
The aromatic dihalides are obtained from the [[4,4’-Dihydroxybenzophenone]].
PEEK is a semicrystalline [[thermoplastic]] with extraordinary mechanical properties. The [[Young's modulus]] is 3.6 GPa and its tensile strength 90 MPa. PEEK exhibits two [[glass transition temperature]]s at around 140°C (284°F) and around 275ºC (527°F), depending on cure cycle and precise formulation. PEEK melts at around 350°C (662°F) and is highly resistant to thermal degradation. The material is also resistant to both organic and aqueous environments, and is used in bearings, piston parts, pumps, compressor plate valves, and cable insulation applications. It is one of the few plastics compatible with [[ultra-high vacuum]] applications.
PEEK is considered an advanced biomaterial used in medical implants, often in reinforced format using biocompatible fibre fillers such as carbon. Also in carbon fibre reinforced form, PEEK has come under consideration as an aerospace structural material due to its high strength-to-weight ratio. Electronic circuitry also has a high demand for PEEK's large temperature range.
== Chemical resistance ==
PEEK also exhibits good chemical resistance in many environments, including [[alkali]]s (i.e. sodium, potassium and ammonium hydroxides), aromatic hydrocarbons, alcohols (i.e. ethanol, propanol), greases, oils and halogenated hydrocarbons.
However, its performance in acids is very dependent on the type of acid - PEEK shows poor resistance in concentrated [[sulfuric acid|sulfuric]], [[nitric acid|nitric]], [[hydrochloric acid|hydrochloric]], [[hydrobromic acid|hydrobromic]] and other mineral acids (though performance may be adequate for short term use with these acids in very dilute form). Its resistance to [[hydrofluoric acid]] and [[oleum]] is very poor. PEEK shows good resistance to [[phosphoric acid]] and organic acids (acetic, citric, oxalic, tartaric etc.), but varying resistance in the presence of halogens. PEEK is resistant to dissolution by some aldehydes and ketones such as acetone, but not (at higher temperature) methylethyl ketone.
==References==
<references/>
[[Category:Polyethers]]
[[Category:Organic polymers]]
[[Category:Thermoplastics]]
[[ar:بولي إيثير إيثير كيتون]]
[[de:Polyetherketone]]
[[fa:پلیاتراترکتون]]
[[fr:PolyEthylEtherKetone]]