Polytetrafluoroethylene (PTFE) is a special engineering plastic with good physical and chemical properties, and can withstand “aqua regia”, commonly known as “plastic king”. PTFE has a very wide temperature range and can be used continuously for a long time between 180-250 °C. Its coefficient of friction is very low, only 0.04, non-absorbent and non-flammable. However, due to the non-polarity of the PTFE molecular chain, the mechanical properties of PTFE are poor. Taking advantage of the excellent friction and high-temperature performance of PTFE, and using other engineering plastics with higher mechanical strength to blend and modify it, the advantages of each component can be comprehensively blended to achieve complementary advantages and produce engineering plastic friction materials with excellent performance. , PTFE dupont powder, thus broadening the application field of engineering plastics. Commonly used engineering plastics blended with PTFE are as follows:
1 Polyoxymethylene (POM)
POM is a highly crystalline linear thermoplastic polymer with unique mechanical properties, excellent oil resistance, chemical resistance, creep resistance, good thermal and electrical properties, low water absorption, and can be used in a wide temperature range. Maintaining its mechanical, chemical and electrical properties, it is an engineering plastic with excellent comprehensive properties. The modification of POM by PTFE can improve the defects of poor toughness and low notched impact strength of POM, so as to obtain a friction material with excellent performance.
2 Polyetheretherketone (PEEK)
PEEK has excellent comprehensive properties, good heat resistance, long-term use temperature up to 240 ℃, fiber reinforced grade up to 300 ℃, also has high strength, high rigidity, creep resistance and good fatigue resistance, as well as self flame retardant , oil resistance, organic solvent resistance and other characteristics. Since its advent in the 1960s, PEEK and its composite materials have been widely used in aviation, aerospace, electrical and electronic industries. Glass fiber (GF)/carbon fiber (CF) hybrid reinforced PEEK/PTFE composite material is a wear-resistant material with excellent comprehensive properties. It has the advantages of high temperature resistance and wear resistance, and can be used as structural components used in high temperature environments.
3 Polyphenylene Sulfide (PPS)
PPS is a new type of engineering plastic pioneered in 1968 by the Philips Petroleum Company of the United States. Known as the “new plastic for the jet age”, PPS has outstanding thermal stability, good adhesion, electrical insulation, corrosion resistance and self-extinguishing properties. The disadvantage is that the impact resistance is poor, and the forming process is difficult. The inert surface of PTFE makes it difficult to bond with PPS. Domestic scholars use PPS powder and mixture to mix ball milling and then add PTFE powder to make coatings. PTFE/PPS alloy coating solves the problem of high melt flow rate of PPS, which is difficult to directly mold. It can still maintain high mechanical properties above 300 ℃, and is mainly used for corrosion-resistant pumps, gaskets, gaskets, as well as dynamic seals, shaft sleeves, automobile engine valve covers, chromatograph sliding seals and guides, etc.
4 Polyamide (PA)
Adding PTFE to PA mainly improves its sliding properties. When the filling amount of PTFE is more than 10%, the antifriction and wear resistance of PA is also improved, and the friction coefficient and wear amount are greatly reduced.
5 Polyimide (PI)
PI is a general term for polymers containing imide groups on the main chain, and is the representative of the first industrially produced heterocyclic polymer compounds by Dupont Company in the United States. It has outstanding heat resistance, radiation resistance and wear resistance, and products made of thermoplastic polyimide (TPI) and PTFE blended or added with other filler technologies can be used in automotive hood parts, aerospace equipment and office electronics.
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