PCTFE (Kel-F®)

PCTFE was designed to work mainly in the cryogenics field of applications, this is due to its mechanical properties being retained at extremely low temperatures down to -240°C. With excellent chemical resistance, radiation resistance and flammability properties this makes it an ideal choice for cryogenic valves and when dimensional stability is essential.

PCTFE has high tensile strength and good thermal characteristics. It is non-flammable and the heat resistance is up to 175°C. It has a low coefficient of thermal expansion. The glass transition temperature (Tg) is around 45°C.

PCTFE has one of the highest limiting oxygen index (LOI). It has good chemical resistance. It also exhibits properties like zero moisture absorption and non wetting.

It does not absorb visible light. When subjected to high-energy radiation, it undergoes, like PTFE, degradation. It can be used as a transparent film.

The presence of a chlorine atom, having greater atomic radius than that of fluorine, hinders the close packing possible in PTFE. This results in having a relatively lower melting point among fluoropolymers, around 210–215°C.

PCTFE is resistant to the attack by most chemicals and oxidizing agents, a property exhibited due to the presence of high fluorine content. However, it swells slightly in halocarbon compounds, ethers, esters and aromatic compounds. PCTFE is resistant to oxidation because it does not have any hydrogen atoms.

PCTFE exhibits a permanent dipole moment due to the asymmetry of its repeating unit. This dipole moment is perpendicular to the carbon-chain axis.