polytetrafluoretylen

Polytetrafluoroethylene, commonly abbreviated PTFE, is a fluoropolymer produced by the polymerization of tetrafluoroethylene. Its repeating unit is -(CF2-CF2)-, giving a high molecular weight polymer with the formula (C2F4)n. PTFE is valued for its exceptional chemical inertness, very low friction, and wide temperature range.

Key properties include resistance to almost all chemicals, a high melting point (about 327°C) and a continuous service temperature around 260°C, a low coefficient of friction, and excellent electrical insulation. It is notably non-adhesive and experiences little wear in many environments. PTFE is generally insoluble in common solvents and has a density of about 2.2 g/cm³. It is a semi-crystalline material, with a structure that contributes to its high-temperature stability and low friction but makes melt-processing challenging.

Manufacture and processing typically involve the polymerization of tetrafluoroethylene gas under controlled radical initiation, often via aqueous dispersion or suspension polymerization. PTFE resin is not melt-processable like many plastics due to extremely high melt viscosity; therefore it is processed by methods such as paste extrusion, calendaring, or sintering into finished parts or coatings. In coatings, PTFE is applied as a dispersion and fused to a surface to form a non-stick layer.

Applications are diverse: non-stick cookware coatings are among the most recognizable uses; PTFE also serves as corrosion-resistant linings for pipes and tanks, seals and gaskets, bearings and wear parts, and electrical insulation. Expanded PTFE (ePTFE) finds use in medical devices and vascular grafts, as well as in membranes and gaskets.

History notes: PTFE was discovered in 1938 by Roy J. Plunkett at DuPont. It is also known by the brand name Teflon, though Teflon has become a trademarked term associated with specific products from various producers. Modern production often uses PFOA-free processes.