Polytetrafluoroethylene air filtration membrane, referred to as PTFE air filtration membrane, is a perfluorinated polymer obtained by free radical polymerization of the monomer tetrafluoroethylene.
It was founded in 1938 by the American R. Plunkett invention.
In its molecular structure, the carbon atom is surrounded by 4 fluorine atoms. Since the covalent radius of the fluorine atom (0.064nm) is larger than the radius of the hydrogen atom (0.028nm), the fluorine atoms can be arranged to surround the carbon chain. , and because fluorine atoms repel each other, the entire macromolecular chain does not have a zigzag shape like a hydrocarbon molecular chain, but a helical structure as shown in Figure 1, similar to the human DNA helix. This helical conformation is exactly surrounded by PTFE. Outside the chemically attacked carbon chain skeleton, a tight, completely “fluorinated” protective layer is formed, which protects the PTFE main chain from attack by any external reagents, giving PTFE incomparable solvent resistance and chemical stability that other materials cannot match. and low cohesive energy density.
This helical structure determines the chemical resistance of PTFE.
PTFE air filter membrane is a fluorocarbon chemical with excellent chemical resistance and high and low temperature resistance. It will not deteriorate even when exposed to air, and can be used for a long time in the range of -200~250℃.
Due to the influence of the electron-withdrawing groups of fluorine atoms contained in the molecular structure, the PTFE air filter membrane exhibits a high degree of chemical stability, is almost resistant to the intrusion of all acids and alkalis and other chemical substances, has outstanding non-stickiness, abnormal lubricity and excellent Electrical insulation properties, aging resistance and radiation resistance, minimal water absorption and other characteristics are called the “King of Plastics”.
Widely used in aerospace, petrochemical, machinery, electronics, electrical appliances, construction, textile and many other fields.
It is precisely because of these characteristics that it was secretly used in the military industry as soon as it appeared. It was not applied to static seals until the 1950s. Compared with ordinary spiral seals, it is a good elastic seal. Material.
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