PTFE thread seal tape

PTFE seal tape.

Polytetrafluoroethylene or PTFE or Teflon is a synthetic fluoropolymer of tetrafluoroethylene, well known for its chemical inertness and very low coefficient of friction.



PTFE is extremely resistant to chemical attacks, being only affected by molten alkali and strong fluorinating agents such as cobalt(III) fluoride and xenon difluoride. Teflon strips can burn in air, but it's most likely that the pyrolysis products are the one that catch fire.


PTFE is a white solid at room temperature, with a melting point of 327 °C. Its density is 2.2 g/cm3. PTFE maintains mechanical properties down to temperatures of 5 K (−268.15 °C), and has good flexibility at temperatures above −79 °C. Teflon materials however are susceptible to creep. When melted, PTFE has the consistency of paste, so items can only be cast via injection.


PTFE is cheaply available as thread seal tapes. Many lab items, such as stoppers, gaskets, sleeves, magnetic stirrers are made of it and can be easily procured online. However, items made of PTFE are expensive, as PTFE cannot be molded like the more common type of plastics.


PTFE is made via polymerization of tetrafluoroethylene. This process is difficult and expensive for the amateur chemist.




PTFE, being chemically inert, is non-toxic. Its pyrolysis is detectable at 200 °C, giving off fluorocarbon gases, that in large quantities can be dangerous for humans and are very toxic to wildlife, such as birds.


No special storage is required.


Being chemically inert, PTFE poses hazard to the environment, as it cannot be digested by wildlife.


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