PTFE is linear polymer fluoride, it is a kind of highly symmetric nonpolar polymer compound, its structure is linear macromolecule structure, spiral and molecular chain conformation. According to the apparent color different, PTFE fiber can be divided into the brown and white fiber two kinds. Brown PTFE fiber carrier usually in spinning, the fabric is very soft, and low friction factor, widely used in machinery industry, oil free, dynamic and static anti-wear areas. White PTFE fiber is generally by membrane crack cutting method, the fiber filter material can improve filtering section, so as to improve the accuracy of filtering.
The performance of PTFE fiber
Chemical resistance
The key of “C – F” in PTFE molecules has a very high bonding energy, molecular chain appear conformation which is spiral, nonpolar and crystal structure, This makes the PTFE has very excellent chemical resistance. In addition to the strong element fluoride and fluoride medium (such as trifluoride chloride), molten alkali metals and 300 ℃ of sodium hydroxide, corrosion of PTFE almost without any chemical reagent, all of the strong acid, strong alkali, strong oxidizing agents, salt for PTFE are no effect, even in aqua regia boil, its quality and performance are also don’t have any change. For organic compounds, in addition to aromatic hydrocarbons and halide amine on the slight swelling, other organic solvent has no effect on PTFE, so is known as “plastics king”.
Thermal properties
PTFE has very excellent high and low temperature resistance, can be used in – 190 ~ 260 ℃ temperature for long time. It can not only bear the instant high temperature of up to 290 ℃, but is not brittle below -260 ℃, still can keep a deflection. So in some poor conditions, PTFE products are often used.
Mechanical properties
Because PTFE is nonpolar molecular chain, the mutual attraction between macromolecules is very small; Combined with the molecular chain is not branched chain of high rigidity, entanglement is very small, leading to poor mechanical properties of PTFE. Under long-term load, PTFE will have large creep, prone to cold flow phenomenon. But its fatigue resistance is excellent, general won’t appear permanent fatigue damage.
In addition to the above excellent performance, PTFE also has a good flame retardant performance, excellent lubricity, water repellency and electrical insulating properties, resist ultraviolet ageing resistance, etc.
The research progress of PTFE fiber preparation technology.pdf