It has high resistance to biodegradation. It is soluble in concentrated sulfuric acid at room temperature, although dissolution can take a very long time unless the polymer is in a form with a high surface-area-to-volume ratio, such as a fine powder or thin film. It is attacked by halogens and strong Brønsted and Lewis acids, as well as some halogenated compounds and aliphatic hydrocarbons at high temperatures. It is highly resistant to thermal degradation, as well as to attack by both organic and aqueous environments. The thermal conductivity increases nearly linearly with temperature between room temperature and solidus temperature. Some grades have a useful operating temperature of up to 250 ☌ (482 ☏). PEEK has a glass transition temperature of around 143 ☌ (289 ☏) and melts around 343 ☌ (662 ☏). Its Young's modulus is 3.6 GPa and its tensile strength is 90 to 100 MPa.

The processing conditions used to mould PEEK can influence the crystallinity and hence the mechanical properties. PEEK is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. The reaction is conducted around 300 ☌ in polar aprotic solvents - such as diphenyl sulfone. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of hydroquinone, which is generated in situ by deprotonation with sodium carbonate. PEEK polymers are obtained by step-growth polymerization by the di alkylation of bis phenolate salts. 5 Shape-memory PEEK in biomechanical applications.

Peek plastic