Polychlorotrifluoroethylene (PCTFE or PTFCE) is a thermoplastic chlorofluoropolymer with the molecular formula (CF2CClF)n, where n is the number of monomer units in the polymer molecule. It is similar to polytetrafluoroethene (PTFE), except that it is a homopolymer of the monomer chlorotrifluoroethylene (CTFE) instead of tetrafluoroethene. It has the lowest water vapor transmission rate of any plastic.
PCTFE has high tensile strength and good thermal characteristics. It is nonflammable[ 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 fluoro, 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 fluoro content. However, it swells slightly in halocarbon compounds, ethers, esters and aromatic compounds.[2] 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.
