|
【】 PTFE Gasket 【】
| |
Polytetrafluoroethylene (PTFE) gasket is a synthetic fluoropolymer of tetrafluoroethylene that finds numerous applications. PTFE
is most well known by the DuPont brand name Teflon. PTFE is a fluorocarbon
solid, as it is a high-molecular-weight compound consisting wholly of carbon
and fluorine. PTFE is hydrophobic: neither water nor water-containing
substances wet PTFE, as fluorocarbons demonstrate mitigated London
dispersion forces due to the high electronegativity of fluorine.
PTFE gasket has one of the lowest coefficients of friction
against any solid. PTFE is used as a non-stick coating for pans and other
cookware. It is very non-reactive, partly because of the strength of
carbon–fluorine bonds, and so it is often used in containers and pipework
for reactive and corrosive chemicals. Where used as a lubricant, PTFE
reduces friction, wear, and energy consumption of machinery. It is commonly
believed that teflon, like velcro, is a spin-off product from the NASA space
projects. However, that is not so, even though both products have been used
by NASA.
The pyrolysis of PTFE is detectable at 200 °C (392
°F), and it evolves several fluorocarbon gases and a sublimate. Animal
studies indicate that it is unlikely that these products would be generated
in amounts significant to health at temperatures below 250 °C (482 °F),
although birds are proven to be much more sensitive to these decomposition
products.While PTFE is stable and nontoxic, it begins to deteriorate after
the temperature of cookware reaches about 260 °C (500 °F), and decomposes
above 350 °C (662 °F). These degradation by-products can be lethal to birds,
and can cause flu-like symptoms in humans. Meat is usually fried between 200
and 230 °C (392 and 446 °F), and most oils will start to smoke before a
temperature of 260 °C is reached, but there are at least two cooking oils
(refined safflower oil and avocado oil) that have a higher smoke point than
260 °C. Empty cookware can also exceed this temperature upon heating.
Teflon® has been a familiar name for decades.
Invented at DuPont's Jackson Laboratory in 1938, Teflon® is actually a
substance called polytetrafluoroethylene (PTFE), which is considered to be
the most slippery substance that exists. Its nonstick properties have
transcended the kitchen, and is widely used in other areas including
aerospace, communications, electronics, industrial processes, and
architecture. Teflon® changed the plastics industry forever, and DuPont has
received numerous awards and recognitions for its contribution to the field
of man-made polymers.
|
【】 PTFE Gasket 【】
