Perfluoropolyether

Perfluoropolyether (PFPE) is a type of synthetic liquid lubricant that has been used in the aerospace industry for over 30 years.[2] The main properties of PFPE are being temperature resistant between −58 °C (215 K) and 257 °C (530 K) (depending on specific composites), having very low outgassing compared to other fluids (vapour pressure of 6×10−8 Torr) and having a dielectric strength of around 15.7 MV/m.[3]

Perfluoropolyether
Names
Other names
PFPE
Identifiers
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Perfluoropolyether consists of a polymer chain in which monomers consisting of perfluoro-alkyl groups are joined by ether linkages. The bonds between carbon and oxygen or fluorine are strong.[4] Perfluoropolyethers are a type of PFAS.[5]

The thermal and chemical stability of PFPE along with a vapor–liquid equilibrium of 230 °C when mixed with the right composites make it a suitable candidate for vapor phase soldering technologies.[6]

History

Perfluoropolyether was developed in the early 1960s for the USAF, who needed a lubricant that would not react with liquid or gaseous oxygen (O2).[7]

Manufacture

Perfluoropolyether can be synthesized from tetrafluoroethylene or hexafluoropropylene.[4]

Properties

PFPE is chemically inert to many acids and oxidants (like fuming sulfuric acid (oleum, SO3), chlorine gas, oxygen) and solvents, etc..

PFPE is non-toxic under normal conditions, nonflammable, and exhibit unusually high load carry capabilities.[7][1]: 275  PFPE can withstand gamma ray degradation.[7]

Electrical resistivity is 1014 ohm/cm (20 °C (68 °F))[7]

Applications

Generally PFPE may be used as lubricant in all sorts of bearing, plug valves, gaskets, chains, and joint bearing applications, where oxygen inertness of a material is a requirement.[7][1] Examples include aircraft fuel systems, mechanical components of devices used in airspace, deep space or high vacuum and at cryogenic temperatures.[7]

PFPE may be used in mold release agent for plastic injection molding.[7]

As top coating lubricant on computer disc drives and Scanning Electron Microscope[7][1]: 275 

As anti-galling compounds.[7]

As fluid medium in ferrofluidic seals.[7]

Semiconductor industry

In the semiconductor industry, PFPE may be used as a vacuum grease or in plasma etching equipment, or for robots used in semiconductor wafer handling, clean rooms, and other commercial environments.[7]

See also
  • Krytox, a PFPE-based lubricant

References
  1. Ash, Michael (2004). Handbook of green chemicals. Irene Ash (2 ed.). Endicott, NY: Synapse Information Resources. ISBN 978-1-934764-29-9. OCLC 747426845.
  2. Bradley Shogrin (August 1995). "Spontaneous Dewetting of a Perfluoropolyether" (PDF). National Aeronautics and Space Administration. Retrieved November 29, 2017.
  3. "Fomblin® PFPE Lubricants".
  4. Fluorochemie. "Brief Introduction of PFPE Synthesis Methods". Fuzhou Topda New Material Co., Ltd. Retrieved June 27, 2022.
  5. Kwiatkowski, Carol F.; Andrews, David Q.; Birnbaum, Linda S.; Bruton, Thomas A.; DeWitt, Jamie C.; Knappe, Detlef R. U.; Maffini, Maricel V.; Miller, Mark F.; Pelch, Katherine E.; Reade, Anna; Soehl, Anna; Trier, Xenia; Venier, Marta; Wagner, Charlotte C.; Wang, Zhanyun; Blum, Arlene (11 August 2020). "Scientific Basis for Managing PFAS as a Chemical Class". Environmental Science & Technology Letters. 7 (8): 532–543. doi:10.1021/acs.estlett.0c00255.
  6. "Archived copy" (PDF). Archived from the original (PDF) on 2021-02-27. Retrieved 2020-08-23.{{cite web}}: CS1 maint: archived copy as title (link)
  7. "HUSKEY Specialty lubricants" (PDF). HUSK-ITT Corporation.
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