Dupont Teflon resins include one of the most widely recognized compounds throughout the world. Its use is almost endless. Known as PTFE (polytetrafluoroethylene), the compound is most famous for its non stick characteristics.

PTFE is a completely fluorinated polymer manufactured by free radical polymerization of tetrafluoroethylene. With a linear molecular structure of repeating -CF2-CF2- units, PTFE is a crystalline polymer with useful mechanical properties from cryogenic temperatures to 500 degrees Fahrenheit. Higher temperatures can be satisfactorily sustained for shorter exposures.

The key to its non stick is derived from richly electronegative fluorine atoms, which repel one another, but repel other atoms even more.

Impact strength is high, while tensile strength, wear resistance, and creep resistance are significantly enhanced through various resin binders, ceramic, fillers or other structural reinforcement.

PTFE fluoropolymer can be compounded in almost a limitless array of thermoplastic, for increasing load bearing capacity, reduced friction, higher mechanical strengths, improved thermal properties, and greater endurance.

PTFE is highly resistant to oxidation and action of chemicals including strong acids, alkalies, oxidizing agents, nuclear radiation, UV rays, and ozone.

Mechanical properties include, but are not limited to, flexibility at low temperatures, stability at high temperatures, low coefficient of friction, dielectric strength, corrosion resistance, and non stick (release).

There have been many practical non-lubricated mechanical systems developed with coefficient of friction as low as 0.05-0.08. Even at higher dynamic PV (8,000 to 10,000) coefficient of friction around 0.10 is feasible.

Dupont PTFE resins exhibit exceptionally low friction in non-lubricated environments, especially at low surface velocities and pressures higher than 5 pounds per square inch. The coefficient of friction actually increases with sliding speed up to 100 feet per minute, under all pressure conditions. It’s this phenomena that prevents ‘stick-slip’ tendencies. In addition, no ‘squeaking’ or noise occurs, even at the highest speeds. Above 150 feet per minute, sliding velocity has little effect (on friction) at combinations of pressure and velocity below the composition’s PV limit. Static friction decreases with increasing pressure.

PV limits define the maximum combinations of pressure and velocity at which these materials will operate continuously without lubrication. PV limits for PTFE approach zero at temperatures between 550F and 600 F. However, useful PV limits must take into account the composition’s wear characteristics and allowable wear for the application.
When considering Dupont products or PTFE in non stick applications, you must consider creep and cold flow. Generally, a plastic material subjected to continuous load experiences a continued deformation with time called creep or cold flow. Deformation can be significant, even at room temperature or below; hence, the name ‘cold flow’.

Creep is the total deformation under stress after a specified time in a given environment beyond that instantaneous strain which occurs immediately upon loading. Independent variables affecting creep are time under load, temperature, and load or stress level.

As long as the stress level is below the elastic limit of the material, performance is sustainable. And beyond a certain point, creep is small and may be neglected for many applications. In many cases, too, there is compressive recovery from various percentages of strain. Nearly complete where the original strain does not exceed the yield strain.

Again, keep in mind the information presented doesn’t account for other forms of reinforcement available. Today, PTFE dispersions can be integrated with plating, anodizing, thermal spray, and other emerging, wear hardened composites and advanced processing techniques.