PEEK
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| PEEK | |
|---|---|
| Density | 1320 kg/m3 |
| Young's modulus (E) | 3700 MPa |
| Tensile strength (σt) | 92 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] | |
PEEK is an organic polymer used in demanding engineering applications. Also referred to as a polyaryletheretherketone, PEEK is a colourless thermoplastic.
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]
Properties
PEEK is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. The Young's modulus is 3.9 GPa and its tensile strength 90 to 100 MPa. PEEK has a glass transition temperatures at around 143 °C 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.
