Perfluoropolyethers (PFPEs) are a class of organofluorine compound. Some types are synthetic liquid lubricants that have been used in the aerospace industry for over 30 years. [1] 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. [2]
Perfluoropolyethers 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. [3] Perfluoropolyethers are a type of PFAS. [4]
The thermal and chemical stability of PFPEs 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. [5]
Perfluoropolyethers were developed in the early 1960s for the USAF, who needed a lubricant that would not react with liquid or gaseous oxygen (O2). [6]
Each type of perfluoropolyether is synthesized differently: PFPE-K is obtained from HFPO by anionic polymerization. For PFPE-Y and PFBE-Z, photooxidation of hexafluoropropylene and tetrafluoroethylene, respectively, is applied. PFPE-D is synthesized by anionic ring-opening polymerization of 2,2,3,3-tetrafluorooxetane. PFPE-A is obtained by an initial esterification of polyethylene glycol with a perfluoroacyl fluoride. Then, it is converted into a fully fluorined polymer using direct fluorination. [3] [7]
PFPEs are chemically inert to many acids and oxidants (like fuming sulfuric acid (oleum, SO3), chlorine gas, oxygen) and solvents, etc.
PFPEs are non-toxic under normal conditions, nonflammable, and exhibit unusually high load carry capabilities. [6] [8]: 275 PFPEs can withstand gamma ray degradation. [6]
Electrical resistivity is 1014 ohm/cm (20 °C (68 °F)) [6]
Generally, PFPEs 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. [6] [8] Examples include aircraft fuel systems, mechanical components of devices used in airspace, deep space or high vacuum and at cryogenic temperatures. [6]
PFPEs may be used in mold release agent for plastic injection molding. [6]
As top coating lubricant on computer disc drives and Scanning Electron Microscope [6] [8]: 275
As anti-galling compounds. [6]
As fluid medium in ferrofluidic seals. [6]
In the semiconductor industry, PFPEs 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. [6]
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cite web}}
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Perfluoropolyethers (PFPEs) are a class of organofluorine compound. Some types are synthetic liquid lubricants that have been used in the aerospace industry for over 30 years. [1] 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. [2]
Perfluoropolyethers 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. [3] Perfluoropolyethers are a type of PFAS. [4]
The thermal and chemical stability of PFPEs 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. [5]
Perfluoropolyethers were developed in the early 1960s for the USAF, who needed a lubricant that would not react with liquid or gaseous oxygen (O2). [6]
Each type of perfluoropolyether is synthesized differently: PFPE-K is obtained from HFPO by anionic polymerization. For PFPE-Y and PFBE-Z, photooxidation of hexafluoropropylene and tetrafluoroethylene, respectively, is applied. PFPE-D is synthesized by anionic ring-opening polymerization of 2,2,3,3-tetrafluorooxetane. PFPE-A is obtained by an initial esterification of polyethylene glycol with a perfluoroacyl fluoride. Then, it is converted into a fully fluorined polymer using direct fluorination. [3] [7]
PFPEs are chemically inert to many acids and oxidants (like fuming sulfuric acid (oleum, SO3), chlorine gas, oxygen) and solvents, etc.
PFPEs are non-toxic under normal conditions, nonflammable, and exhibit unusually high load carry capabilities. [6] [8]: 275 PFPEs can withstand gamma ray degradation. [6]
Electrical resistivity is 1014 ohm/cm (20 °C (68 °F)) [6]
Generally, PFPEs 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. [6] [8] Examples include aircraft fuel systems, mechanical components of devices used in airspace, deep space or high vacuum and at cryogenic temperatures. [6]
PFPEs may be used in mold release agent for plastic injection molding. [6]
As top coating lubricant on computer disc drives and Scanning Electron Microscope [6] [8]: 275
As anti-galling compounds. [6]
As fluid medium in ferrofluidic seals. [6]
In the semiconductor industry, PFPEs 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. [6]
{{
cite web}}
: CS1 maint: archived copy as title (
link)