Polytetrafluorethylene, abbreviated to PTFE, is a semi-crystalline fluoropolymer obtained from the polymerisation of the monomer tetrafluoroethylene (TFE). It is a high property material, with an extensive application range. Huge variety of applications are possible only thanks to the characteristics of polytetrafluorethylene , which we will analyse later.
Polytetrafluorethylene was casually discovered in 1938 by Roy Plunkett, but produced only starting from 1945 by the Dupont, which begin to sold it with the most iconic name of PTFE: Teflon.
As written before, Polytetrafluorethylene counts on extremely high technical characteristics and thanks to this factor, it is positioned between the high-performance thermoplastic materials. Great chemical resistance, excellent sliding properties, totally anti-adhesive, good temperature range resistance, these are only few of main polytetrafluorethylene characteristics, which we will see only here above.
Polytetrafluorethylene thermal resistance goes from -260°C to +260°C, with a short range up to 300°C. There are only few materials with such a high thermal resistance. It is anyway important to know that PTFE performance at high temperature depends on load and stress too. Moreover, thermal dilatation is important to be considered during final components design, as a critical factor which could determine application results.
Polytetrafluorethylene suffers no water absorption at all, even after an immersion test period according DIN 53472/8,20.
Another amazing polytetrafluorethylene property is its very low coefficient of friction, the lowest among all solid materials. Moreover, static and dynamic friction coefficient are theoretically the same, this good combination allows a zero stick-slip effect.
There properties are unchanged even under 0°C, only over the 20°C we can begin to notice some lower results.
Sliding properties stands still even with fillings.
The wear resistance of pure polytetrafluorethylene is relatively low. The reason is that polytetrafluorethylene molecules, due to their complete enclosure by fluorine atoms, are capable of developing merely minimal intermolecular interaction.
A significant improvement of wear resistance is achieved thanks to fillers, such as carbon, graphite, glass, carbon fibres, bronze and organic agents.
Polytetrafluorethylene cannot count on excellent mechanical properties, such as other polymers. Anyway, polytetrafluorethylene can be improved by the addition of fillers, such as glass fibres, carbon or bronze.
Polytetrafluorethylene is chemical inert to almost all known acids. Generally, we can affirm:
PTFE has outstanding light, weather and steam resistance. Moreover, we specify that it is not resistant to radiation – a long exposure could deteriorate the material.
Polytetrafluorethylene shows a great fire behaviour. It is tested that fluoropolymers can hardly be burnt. Polytetrafluorethylene is classified according UL94 V0.
As written before, virgin polytetrafluorethylene can be improved by the addition of different fillers. Most common are:
Derived from standard PTFE, modified PTFE (which we call PTFE TFM) is a copolymer of tetrafluoroethylene and a small quantity of a per fluorinated modifier (perfluoro propyl vinyl ether, PPVE). The modifier content is less than 1%.
Modified Polytetrafluorethylene can be considered a second-generation PTFE. While retaining the exceptional properties of polytetrafluorethylene, it offers significantly improved properties:
PTFE is usually known as Teflon, the most famous brand name for this material. Polytetrafluorethylene is available in a wide range of shapes and dimensions. We actually purchase PTFE by the most important Italian producers.
VERGIN PTFE is physiologically inert and it can be certified EU 10/2011 and FDA. And that’s not all, semi-finished materials can be certified USP Class VI too.