Polyether ether ketones

Poly(ether ether ketone) (PEEK) is a highly aromatic semi-crystalline thermoplastic. It is one of the highest performing polymers due to its good properties. This chapter is to provide a review of research on PEEK. Various synthesis of PEEK will be described. Properties including solution, thermal, mechanical, chemical and environmental resistance will also be introduced. In addition, compounding, processing, applications and recent developments of PEEK will be summarized. 

Keywords Poly (ether ether ketone), synthesis, properties, recycling, applications 

Polyether ether ketone (PEEK) is a linear, aromatic, semi-crystalline thermoplastic possessing excellent thermal stability, chemical resistance and mechanical properties under engineering applications. It has the repeating unit structure, 0—Ph—O—Ph—CO Ph—, wherein Ph is the 1,4-phenylene unit. Its true scientific name is poly (oxy-1, 4-phenylene-oxy-l, 4-phenylenecarbonyl-l, 4-phenylene). The polymer is featured in a wide range of applications including transportation, energy, industrial, electronics, semiconductor and medical. 

The history of PEEK can be derived back to the s)mthesis of polyether ketone with the repeating unit stnicturie ofPh 0—Ph-CO-- (PEK) in 1960s. Broadly, polyetherketones can include a vast range of unit structures including ether, ketone and biphenylene units. However, the commercial PEKs consist of simple repeat units 

Sabu Thomas and Visakh P.M. (eds.) Handbook of Engineering and Specialty Thermoplastics, (55-96) Scrivener Publishing LLC 

A study by Yuan and co-workers [26] discusses the influence of molecular weight on the thermal and rheological behaviour of polyarylether ketone. Melt temperature, crystallisation phenomena and rheological properties were compared for polymers with different molecular weights. 

Zhou and co-workers [27] studied the effects of surface treatment on the mechanical and thermal properties of composites comprising calcium carbonate particles with varying proportions of PEEK. Tensile impact and flexural testing were carried out and the effect of particle size, loading and surface treatment on deformation and crystallinity was investigated. 

Calcium carbonate has also been used as a reinforcing agent for a range of polymers, including polyether ether ketone [174], acrylonitrile-butadiene-styrene terephthalate [175], polypropylene, and polydimethyl siloxane. 

The most studied anti-wear material modified by whiskers is PEEK. Wang et al. compared the performances of PEEK before and after modification with potassium titanate whiskers. The friction and wear performances of the latter showed obvious improvement over the former. Under 300 N, the wear resistance of the latter increases 2.64 and 2.11 times than the former, respectively. In addition, calcium carbonate whiskers have an excellent anti-friction effect on PEEK composite material. When the whisker content is less than 15%, the wear rate of the material decreases dramatically. The wear rate of the 

In-vivo investigations of implants showed an unspecific foreign body reaction similar to the reaction found to PE-UHMW. Cylinder specimens made of PEEK were tolerated well after 12 weeks implantation in muscle tissue. Osteosynthesis plates made from short-carbon fiber-reinforced PEEK also showed an unspecific foreign body reaction during in-vivo investigations after 12 weeks of implantation [954]. 

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Polymers used for seat and plug seals and internal static seals include PTFE (polytetrafluoroeth ene) and other fluorocarbons, polyethylene, nylon, polyether-ether-ketone, and acetal. Fluorocarbons are often carbon or glass-filled to improve mechanical properties and heat resistance. Temperature and chemical compatibility with the process fluid are the key selec tion criteria. Polymer-lined bearings and guides are used to decrease fric tion, which lessens dead band and reduces actuator force requirements. See Sec. 28, Materials of Construction, for properties. 

Polyether ether ketone (PEEK) (structure B of Table 21.5). This material was first prepared in the laboratories of ICI in 1977 and test marketed in 1978. The material is now marketed by Victrex as Victrex PEEK. 

Polyether ether ketone ketone (PEEKK), the latest material to be introduced (Hostatec X—Hoechst). 

Polyether ether ketones (PEEK) have been developed using polyethersulphone technology. These materials crystallise, unlike the polysulphones, and have higher maximum service temperatures. They also have better resistance to hydrolysis at elevated temperatures than the polymides. 

The literature proposes a relatively large number of HEX reactors that have been designed and built of different materials such as glass, stainless steel, polyether ether ketone (PEEK), and silicon carbide (SiC). A presentation can be found in Amdoimaz et al. [13]. 

Ti, or PEEK (polyether ether ketone) to allow measurements under very corrosive conditions. The separated phases pass AMX gadgets for on-line detection (radiometric, spectrophotometric, etc.) or phase sampling for external measurements (atomic absorption, spectrometric, etc.), depending on the system studied. The aqueous phase is also provided with cells for pH measurement, redox control (e.g., by reduction cells using platinum black and hydrogen, metal ion determination, etc.) and temperature control (thermocouples). 

In a process environment, the probes must neither corrode nor display catalytic or inhibitory properties. Quinn et al. report that about 30 reactions were run and five different types of metal probes were utilized with a highly corrosive reaction mixture before a custom built PEEK (polyether ether ketone) probe yielded... 

The primary resin of interest is epoxy. Carbon-fiber-epoxy composites represent about 90% of CFRP production. The attractions of epoxy resins are that they polymerize without the generation of condensation products that can cause porosity, they exhibit little volumetric shrinkage during cure which reduces internal stresses, and they are resistant to most chemical environments. Other matrix resins of interest for carbon fibers include the thermosetting phenolics, polyimides, and polybismaleimides, as well as high-temperature thermoplastics such as polyether ether ketone (PEEK), polyethersulfone (PES), and polyphenylene sulfide. 

Matrix materials for commercial composites are mainly liquid thermosetting resins such as polyesters, vinyl esters, epoxy resins, and bismaleimide resins. Thermoplastic composites are made from polyamides, polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polysulfone, polyetherim-ide (PEI), and polyamide-imide (PAI). 

Membrane materials often employed are hydrophobic polysulfone or hydrophilic regenerated cellulose or cellulose acetate other materials are nylon, polytetrafluoro-ethylene (PTFE, Teflon), polyether ether ketone (PEEK) or poly(divinyl fluoride) (PDVF). 

The extraction cell is usually made of stainless steel, PEEK (polyether ether ketone), or any other suitable material that can withstand high pressure (up to 10,000 psi). It is fitted with fingertight frits, which eliminate use of a wrench and reduces the wear and tear that can result from over-tightening. Research indicates that the shape of the cell has little impact on the extraction efficiency [24], Short squat cells are preferred because they are easier to fill than the long thin ones. The extraction cell is placed in an oven that can heat up to 200° C. 

Polyether ether ketone (PEEK) and Polyether sulphone (PES) belong to the most recent developments in the field of technical high-performance polymers. Both possess very good thermal and mechanical properties, which can be further improved by reinforcing fibres. Their application is mainly in aircraft and space vehicles. 

Sulfonation is very useful chemical modification of polymer, as it induces high polarity in the polymer changing its chemical as well as physical properties. Sulfonated polymers are also important precursors for ionomer formation [75]. There are reports of sulfonation of ethylene-propylene diene terpolymer (EPDM) [76, 77], polyarylene-ether-sulfone [78], polyaromatic ether ketone [79], polyether ether ketone (PEEK) [80], styrene-ethylene-butylene-styrene block copolymer, (SEBS) [81]. Poly [bis(3-methyl phenoxy) phosphozene] [82], Sulfonated polymers show a distinct peak at 1176 cm"1 due to stretching vibration of 0=S=0 in the -S03H group. Another peak appears at 881 cm 1 due to stretching vibration of S-OH bond. However, the position of different vibrational bands due to sulfonation depends on the nature of the cations as well as types of solvents [75, 76]. 

In recent years, remarkable progress has been made in the syntheses of aromatic and heterocyclic polymers to search a new type of radiation resistant polymers. Sasuga and his coworkers extensively investigated the radiation deterioration of various aromatic polymers at ambient temperature [55-57] and reported the order of radiation resistivity evaluated from the changes in tensile properties as follows polyimide > polyether ether ketone > polyamide > polyetherimide > polyarylate > polysulfone. 

It was through such research that ICI s PEEK (polyether ether ketone), one of the first high-performance aromatic polymers, was put on sale, as well as Du Pont s aramide fibers Nomex and Kevlar, more resistant than steel in like volume. 

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