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Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer which
finds numerous applications. PTFE is most well known by the DuPont
brand name Teflon.
PTFE shares the properties of fluorocarbons. Therefore, water and
water-containing substances like most foods do not wet PTFE, as
adhesion to PTFE surfaces is inhibited. Due to this property PTFE
is used as a non-stick coating for pans and other cookware. It is
very non-reactive, and so is often used in containers and pipe work
for reactive and corrosive chemicals. Where used as a lubricant,
PTFE reduces friction, wear and energy consumption of machinery.
PTFE is a white solid at room temperature, with a density of about
2.2 g/cm³. Its melting point is 327 °C (620.6 °F),
but its properties degrade above 260 °C (500 °F). PTFE gains
its properties from the aggregate effect of carbon-fluorine bonds,
as do all fluorocarbons.
The coefficient of friction of plastics is usually measured against
polished steel. PTFE's coefficient of friction is 0.03 0.1,
which is the second lowest of any known solid material (Diamond-like
carbon being the first).
PTFE has excellent dielectric properties. This is especially true
at high radio frequencies, making it suitable for use as an insulator
in cables and connector assemblies and as a material for printed
circuit boards used at microwave frequencies. Combined with its
high melting temperature, this makes it the material of choice as
a high-performance substitute for the weaker and lower melting point
polyethylene that is commonly used in low-cost applications. Its
extremely high bulk resistivity makes it an ideal material for fabricating
long life electrets, useful devices that are the electrostatic analogues
of magnets.
Because of its chemical inertness, PTFE cannot be cross-linked
like an elastomer. Therefore it has no "memory," and is
subject to creep (also known as "cold flow" and "compression
set"). This can be both good and bad. A little bit of creep
allows PTFE seals to conform to mating surfaces better than most
other plastic seals. Too much creep, however, and the seal is compromised.
Compounding fillers control unwanted creep and improve wear, friction,
and other properties. Sometimes metal springs apply continuous force
to PTFE seals to give good contact, while permitting some creep.
Due to its low friction, it is used for applications where sliding
action of parts is needed: bearings, bushings, gears, slide plates,
etc. In these applications it performs significantly better than
nylon and acetal; it is comparable to ultra high-molecular weight
polyethylene (UHMWPE), although UHMWPE is more resistant to wear
than Teflon. For these applications, versions of teflon with mineral
oil or molybdenum disulfide embedded as additional lubricants in
its matrix are being manufactured.
Formulations of PTFE include infusions with glass, carbon and bronze
and other fillers, giving it added properties while allowing it
to retain most of its unique characteristics.
A material of the future, PTFE is currently used in over 200 industrial
and consumer applications with more uses being found each year.
Kindly download the following for a more in-depth understanding
of PTFE / Teflon and its properties:
About PTFE | About
TEFLON | PTFE History
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