polytetrafluorethyleen

Polytetrafluorethyleen, commonly abbreviated PTFE, is a synthetic fluoropolymer produced by polymerizing tetrafluoroethylene. Its repeating unit is [-CF2-CF2-]n. The strong carbon–fluorine bonds give PTFE exceptional chemical inertness, a very low surface energy, and the ability to withstand high temperatures. The material is highly non-reactive and exhibits a very low coefficient of friction, along with excellent electrical insulation properties.

Production and forms: PTFE is formed by free-radical polymerization of tetrafluoroethylene in water, typically via emulsion or suspension polymerization. The resulting resin is processed into powders, pellets, films, or dispersions. Because PTFE does not melt and flow before decomposition, shaping is accomplished by sintering of powders, paste extrusion, or applying dispersions followed by heat treatment. Expanded PTFE (ePTFE) is a porous form used for membranes and some medical implants.

Properties: PTFE remains stable over a wide temperature range and resists most chemicals, acids, and bases. It has a very high melting point (approximately 327°C) and excellent dielectric properties, along with an extremely low coefficient of friction. It is chemically inert and bioinert in many contexts, but it is not easily bonded to other materials and requires special processing for coatings or composites. At high temperatures, decomposition can release toxic fumes, so caution is advised during heating.

Applications: The material is widely used for non-stick coatings on cookware, linings and seals in chemically resistant equipment, bearings and gaskets, and electrical insulation. Expanded PTFE membranes are used in filtration and medical devices, including vascular grafts.

History: PTFE was discovered in 1938 by Roy J. Plunkett while working for DuPont and was later commercialized under the trade name Teflon. It remains a benchmark fluoropolymer in research and industry.

Safety and environment: PTFE is generally inert, but fumes from heated material can be hazardous. Modern manufacturing aims to minimize associated processing aids and environmental impact; PTFE is not readily biodegradable and requires appropriate end-of-life handling.