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Title: Peek  
Author: World Heritage Encyclopedia
Language: English
Subject: Thermoplastics, List of acronyms: P, Polyethers, Flexible electronics, Biomaterial Surface Modifications
Collection: Organic Polymers, Polyethers, Thermoplastics
Publisher: World Heritage Encyclopedia


Density 1320 kg/m3
Young's modulus (E) 3.6 GPa
Tensile strength (σt) 90-100 MPa
Elongation @ break 50%
notch test 55 kJ/m2
Glass temperature 143 °C
melting point ~343 °C
Thermal Conductivity 0.25 W/m.K
Water absorption, 24 hours (ASTM D 570) - 0.1%

Polyether ether ketone (PEEK) is a colourless thermoplastic polymer in the polyaryletherketone (PAEK) family, used in engineering applications.


  • Synthesis 1
  • Properties 2
  • Applications 3
  • Machining Options 4
  • Shape memory PEEK in biomechanical applications 5
  • References 6
  • External References 7


PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of hydroquinone, which is generated in situ by deprotonation with sodium carbonate. The reaction is conducted around 300 °C in polar aprotic solvents - such as diphenyl sulphone.[2][3]


PEEK is a semicrystalline Bronsted and Lewis acids as well as some halogenated compounds and aliphatic hydrocarbons at high temperatures. It is soluble in concentrated sulfuric acid at room temperature, although dissolution can take a very long time unless the polymer is in a high surface area to volume form such as a fine powder or thin film.


Because of its robustness, PEEK is used to fabricate items used in demanding applications, including bearings, piston parts, pumps, HPLC columns, compressor plate valves, and cable insulation. It is one of the few plastics compatible with ultra-high vacuum applications. PEEK is considered an advanced biomaterial used in medical implants. It is finding increased use in spinal fusion devices and reinforcing rods. It is extensively used in the aerospace, automotive, and chemical process industries.[6] PEEK's mechanical properties at elevated temperatures have led to it being used in at least two varieties of Reprap extruder as thermal insulation. This means the main mechanical structure of the extruder can be made of the same material that is being extruded, provided that the PEEK insulator prevents heat from traveling beyond the intended melt zone.

Machining Options

PEEK melts at a relatively high temperature (343 °C / 649.4 °F) compared to most other thermoplastics. In the range of its melt temperature it can be processed using injection moulding or extrusion methods. Recently a German company demonstrated for the first time the technical possibility of processing granular PEEK into filament form and 3D printing parts from the filament material using Fused deposition modeling – FDM (or Fused Filament Fabrication - FFF) technology.[7][8]

In solid state PEEK can be processed with a Computerized Numerical control (CNC) -machine.

Shape memory PEEK in biomechanical applications

PEEK is not traditionally a shape memory polymer; however, recent advances in processing have allowed shape memory behavior in PEEK with mechanical activation. This technology has expanded to applications in orthopedic surgery.[9]


  1. ^ A.K. van der Vegt & L.E. Govaert, Polymeren, van keten tot kunstof, ISBN 90-407-2388-5
  2. ^ David Parker, Jan Bussink, Hendrik T. van de Grampe, Gary W. Wheatley, Ernst-Ulrich Dorf, Edgar Ostlinning, Klaus Reinking (15 April 2012). "Polymers, High-Temperature".   (subscription required)
  3. ^ David Kemmish "Update on the Technology and Applications of PolyArylEtherKetones" 2010. ISBN 978-1-84735-408-2.
  4. ^ Material Properties Data: Polyetheretherketone (PEEK),
  5. ^ J. Blumm, A. Lindemann, A. Schopper, "Influence of the CNT content on the thermophysical properties of PEEK-CNT composites", Proceedings of The 29th Japan Symposium on Thermophysical Properties, October 8–10, 2008, Tokyo
  6. ^ Lauzon, Michael (May 4, 2012). "Diversified Plastics Inc., PEEK playing role in space probe".  
  7. ^ ", PEEK 3D Printer". July 30, 2015. Retrieved July 30, 2015. 
  8. ^ ", PEEK being 3D-printed". March 21, 2015. Retrieved March 26, 2015. 
  9. ^ Anonymous. "Surgical Technologies; MedShape Solutions, Inc. Announces First FDA-cleared Shape Memory PEEK Device; Closing of $10M Equity Offering". Medical Letter on the CDC & FDA. 

External References

  • Application note on methods of characterizing the crystallinity of PEEK
  • Article about 3D-print revolution
  • [2]
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