by Polyether ether ketone or PEEK is a semi-crystalline thermoplastic belonging to a class of polymers called polyaryletherketones (PAEK). It was first introduced in 1978 by Victrex. PEEK possesses outstanding mechanical, chemical, thermal and electrical resistance properties, making it one of the most versatile specialty engineering plastics used across various sectors.
Chemical Structure and Properties of PEEK
Polyether Ether Ketone (PEEK) is synthesized by nucleophilic substitution of bisphenolate ester with diphenyl sulfone. Its chemical structure consists of aromatic ketone and ether groups connected by carbon atoms in the polymer backbone. The presence of bulky and rigid phenyl rings in the backbone confer high dimensional and thermal stability to PEEK up to 260°C. It has a glass transition temperature of around 145°C and melts between 330-340°C. The semi-crystalline nature of PEEK results in a good balance of strength, stiffness and toughness. It has excellent fatigue and creep resistance even at high temperatures. PEEK is also self-extinguishing with high flame retardancy.
Mechanical Properties and Applications
PEEK exhibits outstanding mechanical properties with a tensile strength of 90-100 MPa, flexural modulus of 3.6 GPa and compressive strength of 170 MPa. It has very low moisture absorption ranging from 0.1-0.2% and is highly resistant to a wide variety of solvents and chemicals. Due to its superior mechanical and chemical resistance properties, PEEK finds widespread use as an engineering plastic. Some key application areas of PEEK include aerospace, automotive, medical implants, semiconductor processing equipment and oil & gas extraction systems.
Aerospace Applications
In the aerospace industry, PEEK is used to manufacture structural aircraft components, guide vanes, engine components and ducting systems. It replaces traditional metal alloys in applications requiring reduced weight, corrosion resistance and durability at high temperatures. PEEK components are found in civil and military aircraft from Boeing, Airbus, Dassault, Lockheed Martin, Gulfstream and Bombardier. Owing to its light weight, PEEK helps improve fuel efficiency and reduce noise levels in aircraft.
Automotive Applications
The automotive sector is another major end-use industry for PEEK. It is used to manufacture gears, bearings, valve guides, fuel system components and electrical connectors. PEEK provides safety, reliability and longevity even under harsh engine bay conditions involving oils, fuels, heat and vibrations. Premium car brands like BMW, Mercedes, Audi, Volkswagen and Tesla employ PEEK for its high temperature resistance up to 250°C. PEEK components are also becoming popular in electric vehicles (EVs) due to their strength, lightweighting abilities and sustainability.
Medical Implant Applications
In the medical industry, PEEK has emerged as an ideal biomaterial for fabricating orthopedic, dental and spinal implants and prostheses. It has similar flexural properties to cortical bone, making PEEK biocompatible for load-bearing implant applications. Some distinctive benefits of PEEK implants include X-ray compatibility for post-surgery scans, fatigue and wear resistance for long-term functionality. Leading implant manufacturers like Depuy Synthes, Zimmer Biomet and Smith & Nephew have commercialized various PEEK-based joint replacements, screws, plates and cages. Most significantly, PEEK implants eliminate concerns around metal ion leaching seen with titanium and cobalt-based implants.
Electrical and Electronics Applications
The non-conductive and radiolucent properties of PEEK have popularised its usage in the electrical and electronics industries. Electronic components, PCB laminates and connectors relying on precise dimensions can be efficiently produced from PEEK. It offers high dielectric strength for insulating applications. PEEK components provide dimensional stability without degradation at high frequencies and temperatures encountered in these industries. Semiconductor manufacturing equipment extensively use PEEK for its vacuum compatibility and chemical resistance against hazardous etching agents. In power applications, PEEK replaces metals in bushings, switches and plugs & sockets for durability in corrosive environments.
Other Niche Application Areas
Additionally, PEEK finds various niche applications leveraging its unique set of engineering properties. In oil and gas industries, it is used in pipeline fittings, valves, wellheads and down-hole tools to withstand hydrocarbon fluids at pressures up to 207 MPa and temperatures up to 250°C. PEEK plays a key role in 3D printing for producing high performance prototypes and end-use parts in industries from medical to aerospace. In the chemical process industry, it is employed in pumps, seals and linings dealing with highly corrosive chemicals across pH ranges. Other emerging application areas of PEEK include photonics, solar energy and water treatment systems.
Polyether Ether Ketone has revolutionized materials selection across diverse industrial sectors over the past few decades. Its versatile mechanical, thermal and chemical resistance characteristics have enabled widespread substitution of metals and other engineering plastics. Continuous R&D has further optimized PEEK properties and processing techniques for new generation products. PEEK is undoubtedly one of the most significant high performance thermoplastics developed to date with a very promising future of applications ahead.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
