Polytetrafluoroethylene fiber, also known as Teflon, is a kind of fiber made from polytetrafluoroethylene as raw material, which is directly spun or made into polytetrafluoroethylene (PTFE) film and then cut with a knife and then fibrillated. synthetic fiber. PTFE is a chemically stable and self-lubricating polymer material. Polytetrafluoroethylene (PTFE) has excellent physical properties such as high melting point, corrosion resistance, high temperature resistance and low friction, and is widely used in electronics, machinery and chemical industries.
1. Molecular structure
The molecular structural unit formula of polytetrafluoroethylene is (CF2-CF2), and the molecular chain of polytetrafluoroethylene is formed by covalent bonding of two elements, fluorocarbon. And because of the high bond energy of molecular bonds, the molecular structure is very stable.
Due to the extremely high bond energy of the “fluorine” bond, it is not easy to be disassembled, and the packing density of PTFE molecules is relatively large, which makes it difficult for various reagents to penetrate into the middle of the molecular chain. The substitution of fluorine atoms makes PTFE form a helical structure and form an inert shell around the C chain. This inert helical perfluoro “shell” plus the non-polar and crystalline structure of the PTFE molecule gives PTFE excellent chemical resistance, ad9100 PTFE dipersion.
In high temperature or chemically flammable environments, the flame spread is very, “appropriately, and better flame retardant materials are needed for protection, and polyoxyethylene red dimensional star thorns are the earliest developed varieties of high temperature muscle burning fibers.
Lubricity and non-stick
The molecular chain of polytetrafluoroethylene presents a rigid helical structure, and the mutual attraction between macromolecules is small, which makes the molecular chain of polytetrafluoroethylene easy to be relatively weak, and its surface is also less attractive to other molecules. This makes the friction coefficient of PTFE material very small, between 0.008 – -0.05, which is the smallest among existing synthetic fibers.
The raw materials for the production of tetrafluoroethylene are fluorine ore (CaF) (used to produce various hydroperacetic acids) and trichloromethane (CHCI).
Anhydrous oxyfluoric acid reacts with chloroform to obtain difluoromonochloromethane (the gas boils at -41°C), which is decomposed at a high temperature of 600°C to 800°C to obtain tetrafluoroethylene. Its chemical reaction equation is as follows: CHCl3+2HF=CHClF2+2HCl
Polytetrafluoroethylene is polymerized from tetrafluoroethylene monomer under the action of high temperature and high pressure and initiator. The polymerization methods include bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization (also known as dispersion polymerization), etc. Suspension polymerization and emulsion polymerization are mainly used in industrial production. The polymerization is generally carried out under the conditions of 40 ~ 80 ℃, 3 ~ 26 kgf / square centimeter, using inorganic persulfates and organic peroxides as initiators.
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