How to Choose the Right Grade of Polyether Ether Ketone (PEEK)

Polyether ether ketone (PEEK) is a high-temperature polymer renowned for its outstanding mechanical, thermal, and chemical properties. It is widely used in aerospace, automotive, medical, and electronics industries.

But what sets PEEK apart from other high-performance plastics? Why do engineers choose PEEK over alternatives?

In this guide, we’ll explain how PEEK is manufactured and its molecular structure, and help you select the ideal PEEK grade for your applications.

What Is PEEK Plastic?

PEEK belongs to the polyaryletherketone (PAEK) family, which includes PEK, PEEK, PEEKK, PEKK, and PEKEKK. Among these, PEEK is the most widely used and produced on a large scale.

The abbreviation PEEK reveals its chemical backbone:

• Poly: many repeating units (polymer)
• Ether: an oxygen linkage in the chain
• Ether: another oxygen linkage
• Ketone: a carbonyl group (C=O) linkage

This specific arrangement gives PEEK its exceptional properties. Since commercialization in the early 1980s by Imperial Chemical Industries (ICI, now part of Victrex PLC), PEEK has been fully recyclable.

Performance Comparison with Other High-Temperature Polymers

Physical Properties

• Semi-crystalline, high-performance engineering thermoplastic
• Excellent resistance to liquids and fatigue
• Insoluble in common solvents and hydrolysis-resistant
• Can withstand steam or high-pressure water for 1,000 hours without degradation
• High dimensional stability, inherent purity, and biocompatibility

Mechanical Properties

• Excellent tensile strength, toughness, and creep resistance
• Balanced flexural and tensile properties for high-load, high-temperature applications
• Retains flexural modulus at very high temperatures
• Lightweight components suitable for harsh environments