PEEK is naturally abrasion resistant when it is virgin (unfilled). In comparison to basic PEEK, glass-filled PEEK has improved mechanical and thermal properties. It also offers superior resistance to corrosive chemicals and electrical insulation.

PEEK grades can operate at greater temperatures while providing chemical and water resistance akin to PPS (PolyPhenylene Sulfide). PEEK may be continuously utilized in hot water or steam up to 480°F (250°C) without permanently losing its physical qualities. PEEK is a high strength alternative to fluoropolymers for adverse settings. When exposed to flame, PEEK has a V-0 flammability rating and emits very little smoke and harmful gasses. Glass fibers are included in glass filled PEEK, which greatly slows the material’s rate of expansion and raises its flexural modulus. Particularly at temperatures above 300°F (150°C), this grade is appropriate for structural applications that call for enhanced strength, stiffness, or stability. PEEK with glass filling is tan or light brown in hue.

The highest elongation and hardness of all PEEK grades are found in the general purpose grade, which is unreinforced. Glass fibers greatly lower the expansion rate of PEEK and raise its flexural modulus. In particular at temperatures over 300°F (150°C), this grade is perfect for structural applications requiring increased strength, stiffness, or stability. PEEK with glass inside is tan or light brown in hue.

For a variety of applications, there are additional formulations (such as mineral-filled, carbon-filled, bearing, and medical grades) and variations within these grades (FDA compliance, static dissipative, high temperature).