Polyetheretherketone is a strong rigid material with outstanding heat resistance.
It withstands long periods at 250°C with little change in mechanical
properties and can be used up to 315°C. This level of heat resistance is the
highest of current commercial melt-processable thermoplastics. The polymer
also has excellent electrical insulation characteristics. Polyetheretherketone is
resistant to all organic solvents although a few can cause environmental
stress-cracking. The material is soluble in concentrated sulphuric acid. Polyetheretherketone
can be injection moulded and extruded on conventional
equipment and can be used to prepare glass-fibre and carbon-fibre composites.
Applications include coatings for high performance wiring used in the
aeronautics and nuclear fields and advanced structural composites.
PEEK can be sulfonated and coated on nanofiltration(NF) membranes which can be used in the fabrication of antifouling based NF membranes. Sulfonated PEEK (up to 50-70 degree of sulfonation(DS)) can be used in the formation of proton exchange membranes(PEMs) for fuel cells based applications.
Polyaryletherketones may be prepared by methods which are analogous to
those used for polysulphones, namely polyetherification and polyacylation.
Polyetherification occurs when fluorinated aromatic ketones react with
phenates, as illustrated by the following reactions:
Polyetheretherketone (CAS 29658-26-2), abbreviated as PEEK, is a polyaromatic semi-crystalline thermoplastic polymer characterised by high resilience and high strength, with a modulus of elasticity of 3.7–4.0 GPa. It is a tooth-coloured material, making it aesthetically appealing. PEEK has been successfully used as a restorative material and in the manufacture of dental implants. However, unmodified PEEK is biologically inert and hydrophobic, allowing neither protein adsorption nor promoting cell adhesion. Bonding and hydrophilicity can be improved through the use of fillers or surface treatments (such as sulphuric acid etching), enabling its widespread application in oral implantology, prosthodontics, orthodontics and the restoration of dental defects. Furthermore, due to its radiopacity, chemical stability and excellent resistance to high-temperature sterilisation, PEEK has been widely used in spinal fusion and craniofacial defect repair, amongst other applications, and can be used in additive manufacturing to produce customised, patient-specific implants. PEEK can also be blended with hydrophilic polymers (such as poly(glycolic acid) and poly(vinyl alcohol)) to produce biodegradable scaffolds for bone tissue engineering [1–3].
Poly(oxy-1,4-phenyleneoxy-1,4-phenylenecarbonyl-1,4-phenylene)(PEEK) is a semi-crystalline polymer with good thermo-mechanical properties and high chemical resistance which can be used as engineering plastics.
PEEK can be injection-molded, compression- molded, or extruded into stock shapes, which are typically machined to final-part dimensions. Most pump components can be injection-molded as long as they do not require tight tolerances. The strict tolerances required for bushings and wear rings require parts to be machined from molded tube stock.
Replacing bronze and steel wear rings with carbon-filled or carbon-reinforced PEEK components, allows manufacturers to increase pump efficiency by achieving tighter clearances. PEEK resins also reduce vibrations caused by fluid flow across wear rings and excess rotor runout. The ductility of plastic pump components helps them outperform metal versions when it comes to reducing vibration, as well as resisting impact.
Polyetheretherketone (PEEK) is generally safe and does not cause chromosomal aberrations. Multiple studies have shown that PEEK materials are neither carcinogenic nor mutagenic. However, there have been reports of a small number of cases of PEEK toxicity, despite PEEK typically having low sensitivity and reactivity. Titanium coatings on PEEK may undergo delamination and wear, and the resulting titanium particulate debris may trigger immune responses and chronic inflammation. Furthermore, certain chemical reagents used for PEEK modification—such as 5,6-epoxyhexyltriethoxysilane (EHTES), used to modify ZnO, and sodium borohydride, used to treat PEEK—are toxic to humans and may irritate the skin, eyes and respiratory system; their use in the manufacture of medical implants should therefore be restricted [1,3].
