Polyetherketone

Polyetherketone (PEK) is a partially crystalline high-performance aromatic ketone-based thermoplastic that is heat stable and readily processed. As a member of the ketone family it shares with PEEK such properties as good chemical resistance exceptional toughness. 

Super PEKs designed for advanced composites have a continuous-service temperature rating of 260 C (500°F), a glass-transition temperature (Tg) of 200°C (400 F), and a slow crystallization rate that suits them for processes with slow rates of cooling from the melt. 

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Newer resins include polysulfone, polyethersulfone, polyetherimide, and polyetherketone. Some of these newer materials are high temperature thermoplastic, not thermoset, resins. They are being promoted for the design of injection-molded printed circuit boards in three-dimensional shapes for functional appHcations as an alternative to standard flat printed circuit boards. Only semiadditive or fully additive processing can be used with these devices. 

The chemistry and technology of this class of polymer may be considered as an extension to those of the polysulphones, particularly insofar as there are strong parallels in preparative methods. The two polymer classes also have strong structural similarities with polysulphones containing the structure (I) and the polyetherketones the structure (II) of Figure 21.6. 

Polyarylates can be blended with a wide range of commercially available thermoplastics, including polyamides, polycarbonates, polyetherketones, polyesters, and poly(phenylene sulfide), thus broadening their application domain. 

Figure 76 Fire-resistant carborane-containing polyetherketones [133,134 and 135 (meta-derivatives) and 136, 137 and 138 (orf/w-derivatives)]. (Adapted from ref. 155.)...

Figure 77 The trifluromethanesulfonic acid-promoted polycondensation reaction between diarylcarborane dicarboxylic acid (139) and diaryl carborane diether monomer acid (140) to yield the polyetherketone acid, 141. (Adapted from ref. 156.)...

This report contains unpublished results on the spinning of cellulose II, polyetherketone (POK), PpPTA, DABT and PIPD (or M5) fibres from the Akzo Nobel Research Laboratories Arnhem in The Netherlands. 

Fig. 9 The end points of the tensile curves of the various polyetherketone (POK) yarns spun by B.J. Lommerts [27-29]. The dashed curve has been calculated with Eqs. 9,23 and 24 using rb=0.25 GPa...

Figure 28 shows the observed relations between strength and modulus for polyetherketone or POK yarns. The experimental data have been obtained from... 

Figure 8.4. Effect of humidity on the dielectric constant of polyetherketones 3-7.

Connectors, switches, electric distributors, fuse boxes and other electric fittings need a subtle balance of electrical and mechanical properties, durability, cost and aesthetics. This broad field creates fierce competition not only between engineering thermoplastics and SMC/BMC for the main applications but also with polypropylene and polyethylene or PVC for the lower performance parts and, at the opposite end of the scale, with high-tech plastics such as polyetherketone, polyetherimide, liquid crystal polymers. .. For example, without claiming to be exhaustive ... 

Figure 4.105 displays two examples of tensile strength retention versus temperature for a neat and a carbon fibre reinforced polyetherketone, showing the rather fast decay up to 180°C followed by a stabilization. 

Table 4.82 Polyetherketones examples of chemical behaviour at room temperature...

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