PEEK

For other uses, see PEEK (disambiguation).

PEEK
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%
source:[1]

Polyether ether ketone (PEEK) is a colourless organic polymer thermoplastic used in engineering applications.

Synthesis

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 diphenylsulphone.^[2][3]

Properties

PEEK is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. The Young's modulus is 3.6 GPa and its tensile strength 90 to 100 MPa.^[4] PEEK has a glass transition temperature at around 143 °C (289 °F) and melts around 343 °C (662 °F). It is highly resistant to thermal degradation as well as attack by both organic and aqueous environments. It is attacked by halogens and strong Bronsted and Lewis acids as well as some halogenated compounds and aromatic hydrocarbons at high temperatures.

Applications

Because of its robustness, PEEK is used to fabricate items used in demanding applications, including bearings, piston parts, pumps, 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 extensively used in the aerospace, automotive, teletronic, and chemical process industries.

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.^[5]

References

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 "Polymers, High-Temperature" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002.
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. ^ 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.