PFA (perfluoroalkoxy) is a copolymer of tetrafluoroethylene and perfluoroethers. These fluoropolymers have properties similar to PTFE. It differs from the PTFE resins in that it is melt-processable using conventional injection molding and screw extrusion techniques.
PFA was invented by DuPont and is sold under the brand name Teflon® PFA. Other brand names for granules are Neoflon® PFA from Daikin or Hyflon® PFA from Solvay Solexis.
On a molecular level, PFA has a smaller chain length and higher chain entanglement than other fluoropolymers. It also contains an oxygen atom at the branches. This results in a material that is more translucent and has improved flow, creep resistance and thermal stability, close to or exceeding PTFE. PFA shares PTFE’s useful properties of low coefficient of friction and non-reactivity, but PFA is softer than PTFE and melts at 305 °C.
PFA is commonly used as material for piping and fittings for aggressive chemicals, as well as corrosion-resistant lining of vessels in the chemical-processing industry. Typical applications are in the construction of gas scrubbers, reactors, containment vessels and piping. PFA is often used when clarity, flexibility and a higher continuous operating temperature are required.
Key properties
- Low coefficient of friction and non-reactivity
- Low dielectric constant
- Easily formable
- Maximal continuous operating temperature 260 °C: (lower/softer than PTFE)
- No ageing
- Transparent
- Excellent flame resistance
- Low permeability to liquids, gases, moisture and organic vapors
- Anti-stick properties
- Not hygroscopic
Applications
- Valve seats
- Piping and fittings for aggressive chemicals
- Gas scrubbers, reactors, containment vessels and piping
- Lining for heat exchangers
- Aircraft wire
- Tubing
- Inert bags for medical applications