PEEK – The Heavy Hitter of Plastics
When you enter the fascinating world of plastics, you start by being either frightened or amused by the names of different types of them. For example, try to say "perfluoroalkoxy alkane" or "polybenzimidazole" five times in a row correctly after a pub round!
Polyetheretherketone, between friends known as PEEK, is one of the hardcore plastics. Or to say it in proper language, it is a high-performance specialty polymer. PEEK is most commonly known for its unique thermal properties and its continuous use temperature, roughly 260 °C, is one of the highest among thermoplastics. In addition, the mechanical strength as well as chemical resistance of PEEK are extremely good. Therefore, it is not surprising that PEEK is mostly used in very demanding applications (read: it is expensive).
The history of PEEK originates in the 1980s. One of the first applications of PEEK was tennis racquet strings made with a melt spinning technique. Gradually, the number of applications has increased. Even though PEEK is an expensive plastic, the pros easily beat the cons. For example, in airplanes PEEK can be used to replace metals to lower the lifetime costs by reducing weight and thus the fuel consumption. The additional bonus are the fast manufacturing cycle times. Not to mention the fact that in aerospace, the material must withstand the low temperatures and atmospheric particles – something that PEEK can romp through easily.
PEEK has very good gamma radiation resistance and therefore seals made of it are used in nuclear power plants to prevent coolant leaks. You could assume that if it can withstand nuclear power plants, it can withstand everything. Well, maybe not, but if you ever happen to break your skull, a new one can be made of PEEK. The material is flexible, durable and strong. Due to its biocompatibility, PEEK has been utilized also in other applications in the medical sector. Its heat resistance makes it an excellent material for example in cleaning medical equipment where high temperatures are required.
Lately, we have expanded the use of PEEK to dielectric materials with tunable dielectric constants. Compared to standard PREPERM® grades, the unloaded short-term maximum use temperature increases roughly 100 °C, fire resistance improves to V0, chemical resistance improves, and mechanical strength and stiffness jump to a new level. The downside is that you pay with decreased RF performance. Unfortunately, the molecular structures often found in high temperature plastics (e.g. ether, imide, sulfide, sulfone) cause an increase in the dielectric losses. Among high-temperature plastics, PEEK has very competitive dielectric properties and these can even be further improved with Premix proprietary filler technology.
So, to sum it all up, PEEK’s characteristics make it an excellent choice for different kind of break-throughs. We can think of a few applications where it could fit like a glove: military applications, ceramic replacement, radars, electrical components, filters, screws and phantom materials. And of course, that new skull when you mistreat your existing one.
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