PTFE O-Rings are popular for use in axial static faces or flange applications which require a chemically resistant and non-compressible material.
PTFE is the most chemically inert of the O-ring materials. It is resistant to most chemicals including acids, bases, oils, steam and other chemicals. It is also very tough and abrasion resistant. However the material is not easily compressed, and therefore may not seal as easily as some of the other polymers.
Its outstanding tear resistance and abrasion resistance result in its slippery surface properties that make it advantageous for use in seals in moving systems such as mass spectrometer probes and valves.