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What is PTFE or polytetrafluoroethylene? A complete guide 

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Accidentally discovered by US chemist Roy J. Plunkett at the end of the 1930s, polytetrafluoroethylene (PTFE) is a fluoropolymer renowned for its exceptional physical and chemical properties. Used in a wide range of industrial sectors, PTFE has revolutionised the way we face challenges linked to corrosion, temperature and chemical resistance.

Composition and molecular structure of PTFE

Teflon® PTFE belongs to the family of fluoropolymers, characterised by the replacement of hydrogen atoms with fluorine atoms.  Like Teflon® PFA (also belonging to the family of thermoplastic polymer coatings) PTFE, too, is commonly found in the form of a fine, crystalline powder. Its molecular structure is composed of polymer repeating units in which carbon atoms are completely replaced by fluorine atoms.  Synthesis of polytetrafluoroethylene through chain polymerization occurs via a free-radical process, with the presence of an appropriate initiator, often oxidising substances such as hydrogen peroxide, Peroxydisulfate or organic peroxides. The temperature and pressure conditions required depend on the type of catalyst used.  Widely used in mechanical, pneumatic and chemical spheres and for pharmaceutical applications, PTFE is combined with stabilizing and fluidifying agents to broaden the scope of application, or mixed with silica, carbon, bronze, stainless-steel or barium-sulphate content to increase performance. It is also the material with the lowest known coefficient of friction: the kinetic friction value for PTFE and steel is 0.04, while the static friction value is 0.07–0.14.

Physical properties of PTFE

Teflon® PTFE coating is applied by spraying after mechanical and/or chemical pretreatment and followed by a final heat treatment.  The physical properties of PTFE make it an extremely versatile and reliable material for a wide range of industrial applications. In fact, it offers excellent performance in all of the areas listed below.

  • Chemical resistance: PTFE coating is known for its extraordinary chemical resistance, which makes it immune to the majority of corrosive chemicals. This resistance means it is ideal for applications where reliable corrosion protection is required.
  • Heat resistance: Teflon® PTFE coatings can withstand extreme temperatures without physical and chemical properties being compromised. The polymer can be used safely at sustained temperatures of up to 260°C and intermittent temperatures up to 310°C.
  • Non-stick properties: the surface of PTFE has excellent non-stick properties and is ideal for application where low levels of material adherence is required. This feature makes it particularly useful in sectors such as the food industry and manufacturing of seals and membranes, as well as applications involving high levels of mechanical stress. These are use cases requiring non-stick properties and a low coefficient of friction, such as pins, bushings, drive systems, gears, etc.
  • Sliding: Teflon® PTFE is specially designed to provide effective lubrication and is used in TempCoat® coatings on components that need to guarantee high levels of sliding. These applications include hoppers, sliding rails, welding rods, mixers, and cutting blades for the food industry.

Applications of PFTE polymer

Thanks to the properties listed, PTFE is used in a wide range of industrial sectors, including:

  • Chemicals industry: PTFE is used for protective coatings in contact with aggressive chemicals, guaranteeing reliable corrosion protection.
  • Material engineering: the polymer is used for the production of seals, membranes and components in high-temperature and extremely corrosive environments.
  • Food industry: thanks to its non-stick surface and chemical inertness, PTFE is used in the production of kitchen utensils and in the food industry to guarantee hygiene and easy cleaning.