Exploring the Properties and Applications of PEEK (Polyether ether ketone)

PEEK is a polymer that revolutionized the world of materials science. PEEK is known for its versatility and ability to be processed through various manufacturing techniques. It is widely used in multiple industries, including aerospace, automotive, oil and gas, and medical. 

What is PEEK?

PEEK which is an abbreviation for polyetheretherketone  is a type of high-performance thermoplastic polymer or sometimes referred to as an engineering plastic, that is classified as a member of the polyaryletherketone family.   It is known for its excellent mechanical properties, chemical resistance, and thermal stability.

PEEK Chemical Structure and Properties

PEEK has a linear and symmetrical molecular structure consisting of repeating units of 4,4'-difluorobenzophenone and biphenyl-4,4'-diol. This gives it a high degree of crystallinity, making it semi-crystalline. Strong intermolecular forces such as hydrogen bonding, van der Waals forces, and pi-pi interactions hold the polymer chains together. These strong bonds contribute to its excellent mechanical and thermal properties.

PEEK has a high melting temperature (Tm) of around 343°C, which allows it to maintain its mechanical properties at high temperatures. It also has a high glass transition temperature (Tg) of approximately 143°C, which means it has good dimensional stability and stiffness at elevated temperatures. PEEK is also highly resistant to chemicals such as acids, bases, hydrocarbons, and radiation, making it suitable for harsh environments. Additionally, it has low water absorption and excellent wear resistance.

PEEK Advantages Over Other Thermoplastics

PEEK vs. PPS (Polyphenylene sulfide)

  • PEEK has higher strength, stiffness, and toughness than PPS
  • PEEK has better thermal stability and can withstand higher temperatures than PPS

PEEK vs. PTFE (Polytetrafluoroethylene)

  • PEEK has better mechanical properties than PTFE, including higher strength and stiffness
  • PEEK is easier to process and can be machined, molded or extruded, while PTFE can only be machined

PEEK vs. PEI (Polyetherimide)

  • PEEK has higher strength and stiffness than PEI
  • PEEK has better chemical resistance than PEI

Manufacturing Methods

Depending on the application requirements and desired properties, PEEK can be processed through various manufacturing methods. Each technique has advantages and limitations, and selecting the appropriate method depends on cost, lead time, complexity, and accuracy.

Injection Molding Machine Internal-1

Molding - PEEK can be processed through injection molding, compression molding, or transfer molding. Injection molding is the most commonly used method, which involves melting the PEEK pellets and injecting them into a mold cavity under high pressure. Compression molding consists in placing the PEEK material into a preheated mold and applying heat and pressure to mold the material into shape. Transfer molding involves melting the PEEK material in a separate chamber and then transferring it to the mold cavity under pressure.

Machining - PEEK can be machined using conventional techniques such as turning, milling, drilling, and grinding. However, due to its high crystallinity and strength, PEEK is a complex material to machine, and special tooling and cutting conditions are required to avoid material deformation, chipping, or cracking.

Additive Manufacturing - PEEK can be processed through various additive manufacturing techniques such as fused deposition modeling (FDM), selective laser sintering (SLS), and stereolithography (SLA). These techniques involve building up the material layer-by-layer using a computer-controlled process. Additive manufacturing of PEEK parts can provide benefits such as complex geometry, reduced lead time, and reduced waste. However, the cost of PEEK powder and equipment for additive manufacturing can be high.

PEEK Grades

We at CDI Products are committed to providing our clients with the highest technical support, engineering expertise, and advanced manufacturing capabilities worldwide. From design and prototyping to mass production, we can help you optimize your product design and supply chain to ensure high-quality, cost-effective, and timely delivery. Our expert team has extensive experience working with PEEK, and we can offer custom solutions to meet your specific application requirements. Whether you need PEEK components for the aerospace, automotive, medical, or oil and gas industry, we are your one-stop global solutions provider. Let us be your trusted partner in harnessing the full potential of PEEK in your application.