PTFE and compounds of PTFE

PTFE is a unique material in that it is very versatile and covers a wide range of applications, this is due to it being virtually chemically inert, with only a few strong acids and alkali being able to effect its performance.

Also it as a very low coefficient of friction, one of the lowest of all man made materials.

And lastly it as a very wide operating temperature range, it remains effective in liquid nitrogen at -196 deg C and does not become brittle even in liquid helium at -269 deg C.

At the other end of the scale it as a continuous working temperature of 260 deg C with a short term usage of up to 300 deg C.

PTFE in its unfilled state is quite a soft material, but the mechanical properties of PTFE can be improved with the addition of fillers.

For instance the addition of glass fibre gives the material a much better wear resistance, allowing a longer life span, in such applications as ball valve seats.

Whilst the addition of Carbon fibre greatly improves its creep resistance especially at raised temperature, also giving a better expansion resistance making it a good bearing material.

Below is a chart showing some generic mechanical properties of PTFE and a few compounds.