Excellent performance of UHMWPE and detection method

UHMWPE performance:
UHMWPE has the advantages of low friction coefficient, low abrasion, excellent chemical resistance, impact resistance, pressure resistance, frost resistance, heat preservation, self-lubricating, anti-scaling, stress cracking resistance, reproducibility, etc. Among them, wear resistance, low temperature resistance, corrosion resistance, self-lubrication, and impact resistance are the highest among all plastics.

1. Low density and good flexibility: UHMWPE has a density that is 56% lower than PTFE, 33% lower than POM, 30% lower than PBTP, and has a lower density than other engineering plastics. And the density of UHMWPE pipes is low, only 1/8 of that of steel pipes. It is easy to use, can be bent and laid, has good flexibility, and can be used simply and quickly.
2. Abrasion resistance: The abrasion resistance can be matched with polytetrafluoroethylene (PTFE) as a super wear-resistant thermoplastic resin. Compared with other engineering plastics, the mortar abrasion index of UHMWPE is only 1/5 of PA66, and 1/10 of HEPE and PVC. The wear resistance of UHMWPE is directly proportional to the molecular weight. The higher the molecular weight, the better the wear resistance. The wear resistance of UHMWPE pipes is 4-7 times higher than steel pipes and stainless steel pipes when conveying various slurries, and about 10 times higher than PVC pipes and polyethylene pipes, which greatly increases the service life of the pipelines. .
3. Self-lubricating: UHMWPE has a very low friction factor (0.05～0.11), so it has excellent self-lubricating. Compared with the friction factor of other engineering plastics, the dynamic friction factor of UHMWPE is 1/2 of PA66 and POM under water lubrication conditions, which is second only to the best self-lubricating polytetrafluoroethylene (PTFE) in plastics under non-lubrication conditions. Therefore, UHMWPE in the field of tribology is known as a friction material with very ideal cost/performance.
4. Impact resistance: Comparing the impact strength of other engineering plastics, the impact strength of UHMWPE is about 2 times that of impact-resistant PC, 5 times that of ABS, more than 10 times that of POM and PBTP, 10 times that of nylon 66, and 20 times that of polyvinyl chloride. Times, 4 times that of polyethylene. The impact resistance is so high that it is difficult to break it using the usual impact test method. Its impact strength increases with the increase of molecular weight, reaching the maximum when the molecular weight is 1.5 million, and then gradually decreases as the molecular weight continues to increase. It can also maintain excellent impact strength in liquid nitrogen (-195°C), which is not available in other plastics. UHMWPE has excellent impact energy absorption, and the impact energy absorption value is the highest among all plastics, so it has good noise damping performance and excellent noise reduction effect.
5. Chemical resistance: UHMWPE is a saturated molecular group structure with extremely high chemical stability. In addition to strong oxidizing acid, it can withstand various corrosive media (acids) within a certain temperature and concentration range. , Alkali, salt and organic medium (except tea solvent). When immersed in 80 kinds of organic solvents at 20°C and 80°C for 30 days, there is no abnormal appearance and almost no change in other physical properties.
6. Tensile strength: Because UHMWPE has the necessary structural characteristics toward tensile orientation, it has unmatched ultra-high tensile strength. Therefore, fibers with ultra-high elastic modulus and strength can be produced by the gel spinning method. Its tensile strength is as high as 3～3.5GPa, and its tensile modulus is as high as 100～125GPa; the specific strength of fiber is the highest among all commercialized fibers so far, 4 times larger than carbon fiber, 10 times larger than steel wire, and higher than aramid fiber. The fiber is 50% larger.
7. Weather resistance and aging resistance: On the one hand, because there are few unsaturated molecular chains in the molecular chain of ultra-high pipelines, the molecular weight is large; on the other hand, the addition of anti-aging agents makes the service life of ultra-high molecular weight polyethylene pipelines greatly exceed Ordinary polyethylene pipes. The low temperature embrittlement temperature of UHMWPE pipe is extremely low, and it can be used safely within -60℃～40℃. Special protective measures are not required during winter construction, and pipe embrittlement will not occur. UHMWPE has excellent low-temperature resistance, and is still ductile at liquid helium temperature (-269°C), so it can be used as a low-temperature resistant component in the nuclear industry.
8. Low water absorption: UHMWPE has a very low water absorption rate; generally less than 0.01%, only 1% of PA66, so it is generally not necessary to dry it before molding.
9. Non-stickiness: UHMWPE has a very weak surface adsorption capacity, and its anti-adhesion ability is second only to the non-sticky PTFE in plastics, so the surface of the product is not easy to stick to other materials. Ultra-high molecular weight polyethylene has self-lubricating and non-adhesive properties, non-scaling, low friction coefficient, anti-corrosion, anti-wear, so the flow resistance is small, and the flow rate and flow can be maintained for a long time.
10. Flame retardancy: It is used in special industries for fire protection environment. It is modified by adding flame retardant and manufactured by special processing technology. It overcomes the flammability of UHMWPE itself and has flame retardant properties.
11. Hygiene and non-toxic: UHMWPE is hygienic and non-toxic, fully in line with the standards of the Japanese Health Association, and approved by the US Food and Drug Administration and the US Department of Agriculture, and can be used in contact with food and drugs.
    The above content is the introduction to UHMWPE. UHMWPE has good electrical insulation properties, especially the dielectric loss is lower than the tangent value. It can be used to make electroplating tanks, rollers, and insulators and insulation that work in high frequency and ultra high frequency ranges. Trailers, cable ducts, circuit breakers, cable terminals and other electrical devices.

Identification method for UHMWPE detection

UHMWPE is a kind of high molecular compound, which is difficult to process. It has excellent wear resistance, self-lubricity, high strength, chemical stability and strong aging resistance. Therefore, when distinguishing real and fake high molecular polyethylene, attention must be paid to these characteristics. The specific identification method is as follows:

1. Weighing rules: The ratio of real UHMWPE products is between 0.93-0.95, the density is very small, and it can float on the surface. If it is not a pure polyethylene material, it will sink to the bottom.
2. Temperature measurement: UHMWPE products will not melt or deform at 200 degrees Celsius, but will become soft. If it is not a pure polyethylene material, it will deform at 200 degrees Celsius.
3. Visual method: The surface of the real UHMWPE base is flat, uniform, smooth, black and bright, the density of the cut surface is very uniform, if it is not pure polyethylene material, the color is dim and the density is uneven.
4. Edge test method: The end face of the pure UHMWPE flange is round and even and smooth. If it is not pure polyethylene material, the flange end has cracks, and the slag phenomenon will appear after the flange is raised.