Peek, Kel-F (PCTFE) ...
PEEK (Polyether ether ketone) is a semi-crystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. PEEK has a glass transition temperature at around 143°C and melts around 343°C. It is highly resistant ot thermal degradation as well as attack by both organic and aqueous environments. It dissolves completely in concentrated sulfuric acid at room temperature.
Because of its robustness, PEEK is used to fabricate items used in demanding applications, including bearings, piston parts, pumps, HPLC colums, compressor plate valves and cable insulation. It is one of the few plastics compatible with ultra-high vacuum applications. PEEK is considered an advanced biomaterial used in medical implants. It is extensively used in the aerospace, automotive and chemical process industries.
PCTFE (Polychlorotrifluoroethylene) is chemically related to PTFE. PCTFE's most striking property is its capability to operate and maintain its elasticity at extreme low temperatures (-273°C)