Perfluoropolyether (PFPE for short) are synthetic polymer liquids at room temperature. Lubricants have been used for aerospace and mechanical components for decades. Its physical, chemical, and tribological properties have been known.
The molecular structure of PFPE lubricants is similar to that of hydrocarbon lubricants. Still, in molecules, fluorine atoms replace hydrogen atoms, thereby replacing the c—H bonds in hydrocarbons with more robust c—F bonds. And the presence of c—o and c—c strong covalent bonds, as well as the neutral characteristics of PFPE molecules, make Perfluoropolyether have high thermal stability, oxidation stability, and good chemical inertness and insulating properties. Perfluoropolyether with immense molecular weight also has low volatility, a more comprehensive liquid temperature range, and excellent viscosity-temperature characteristics. In addition, the main physical and chemical properties of PFPE polymers include detection stability, biological inertness, low surface energy, good lubricity, and compatibility with plastics, metals, and artificial rubber.
The main perfluoropolyether chain comprises -CF2-O-CF 2 – an ether chain that differs from the perfluoroolefin chain of -CF2CF2CF2-has flexibility, low glass transition temperature, and a co-liquid temperature range (freezing point to boiling point) extensive. On the other hand, due to the substantial electron-withdrawing effect of fluorine, the polymer does not show the properties of ether, so it has good heat resistance, chemical stability, oxidation stability, and complete non-combustibility.
However, this substance lacks hygroscopicity and is insoluble in organic solvents, having miscibility only in perfluorinated oil or Freon 113 (trifluorotrifluoroethane). This property has little harmful effect on plastics and rubbers.
Perfluoropolyether has an enormous specific gravity but low surface tension and refractive index. It has the characteristics of perfluorinated compounds and is an oily substance with high transparency. The LD56 value of the oral acute toxicity test on mice is very high, and it has no accumulation in the organism, so it is almost non-toxic. On decomposition, however, highly toxic substances are produced. When used in an environment where corruption expects to occur, ventilation equipment must install, and this fluorine oil must take lightly because of its specific stability.