PTFE, better known by its DuPont tradename of Teflon, is a popular choice for polymer bearings and bushings especially for applications involving high speeds and high temperatures. In this blog post, we will look at seven reasons why this is so.
PTFE Can Withstand High Temperatures
Virgin PTFE can continuously operate in temperatures up to 500°F, however, when operating at its maximum service tempature a loss of mechanical properties will occur. Proper design is necessary to avoid the negative impact in a specific application. The addition of additives (which will be discussed in a moment) can increase this to up to 550°F.
PTFE Can Perform in High PV Applications
There are high PV grades of PTFE that excel when used as bushings in applications with high speeds and higher loadings, including surface speeds up to 30 m/s.
PTFE is Not Chemically Reactive
This is another reason why PTFE is often the material of choice for high-performance bushings. High
temperatures often mean aggressive chemicals, especially in industries like oil and gas. PTFE is the least chemically reactive polymer there is, and its kryptonite seems to be alkali metals like elemental sodium.
PTFE Has Extremely Low Friction
PTFE has the lowest coefficient of friction of any solid material in existence today with virgin PTFEs
coefficient of friction estimated to be between 0.05 and 0.10, making it an excellent choice for high
performance bushing application. Low friction also means less buildup of heat, which in turn means less wear even under high speed and high temperature conditions. In addition, additives can be added to reduce friction even further.
PTFE Can Operate in Dry Running Conditions
PTFE bushings can do their job with no lubrication because PTFE is a self-lubricating polymer. This is a definite bonus for situations where lubrication either isnt possible or isnt recommended. It also offers extremely low breakout friction and stiction.
PTFE is Compatible with a Variety of Additives
There are a variety of additives for PTFE, including glass, carbon, and graphite fibers, as well as MoS 2. When added to PTFE bushings, they materials increase strength, stiffness, and durability, and some additives like MoS 2 can reduce friction even further.
PTFE is USDA and FDA Compliant
Certain grades of PTFE are both USDA and FDA compliant (which is why Teflon is a popular coating for cookware). When combined with its ability to withstand high temperatures, its low chemical reactivity, and almost no moisture absorption, it performs well in industries where aggressive cleaning is involved (i.e., it is certainly wash-down resistant). PTFE bushings are commonly used in both the food, medical, and pharmaceutical industries.
Conclusion
PTFE bushings are an excellent choice for performance applications involving high speeds and high
temperatures. Factors such as its high temperature and high speed capabilities, low friction, dry running lack of chemical reactivity, and available additives make it a strong contender when choosing a polymer material for a bushing. Dont forget to add PTFE to your list the next time you are selecting a polymer bushing.
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