UHMWPE's very high molecular weight (HDPE's molecular weight is usually only 2 to 300,000) gives it excellent performance, and belongs to the affordable, high-performance thermoplastic engineering plastics, it almost concentrates the advantages of a variety of plastics, with ordinary polyethylene and other engineering plastics incomparable wear resistance, impact resistance, self-lubrication, Corrosion resistance, shock absorption, low temperature resistance, hygienic non-toxic, not easy to adhere to, not easy to absorb water, low density and other comprehensive properties.
In fact, there is no single polymer icing together to have so many excellent properties.
1, wear resistance UHMWPE has the highest wear resistance in plastics and exceeds certain metals, figure 1 shows UHMWPE compared to the wear resistance of other materials. As can be seen from Figure 1, UHMWPE's sand slurry consumption index is only 1/5 of PA66, 1/10 of HEPE and PVC compared to other engineering plastics, and 1/7 of carbon steel and 1/27 of brass compared to metals. Such a high wear resistance, so that the use of general plastic wear test method is difficult to test its wear resistance, so a sand pulp wear test device was specially designed.
UHMWPE's wear resistance is proportional to the molecular weight, and the higher the molecular weight, the better its wear resistance.
2, impact resistance UHMWPE impact strength, among all engineering plastics, Figure 2 is UHMWPE and other engineering plastic impact strength comparison, from Figure 2 can be seen, UHMWPE impact strength is about 2 times the impact-resistant PC, ABS 5 times, POM and PBTP more than 10 times. The impact resistance is so high that it is difficult to break and destroy it using the usual impact test method. Its impact strength increases with the increase of molecular weight, reaches the maximum value at 1.5 million, and then decreases gradually as the molecular weight continues to rise. It is worth noting that it also maintains excellent impact strength in liquid nitrogen (-195 degrees C), a feature that is not available in other plastics.
In addition, it is more the surface of repeated impacts.
3, self-lubricity UHMWPE has a very low friction factor (0.05 to 0.11), so self-lubricity is excellent. Table 1 shows uhMWPE compared with other engineering plastic friction factors. As can be seen from Table 1, UHMWPE's dynamic cause is PA66 and POM under water lubrication conditions, second only to the best self-lubricating polytetrafluoroethylene (PTFE) in plastics under non-lubricated conditions; As a result, UHMWPE is known as the ideal friction material for cost/performance in the field of tribology.
4, chemical resistance
UHMWPE has excellent chemical resistance, in addition to strong oxidizing acid, in a certain temperature and concentration range can withstand a variety of corrosive media (acids, alkalis, salts) and organic media (except for solvents).
It impregnated 30d in 80 organic solvents at 20 degrees C and 80 degrees C, with no abnormality on the exterior and little change in other physical properties.
5, impact absorption
UHMWPE has excellent shock absorption, the highest impact absorption value of all plastics, so the noise damping performance is very good, with excellent sound-cutting effect.
6, low temperature resistance
UHMWPE is highly resistant to low temperatures and is still malleable at liquid helium temperatures (-269 degrees C), making it possible to be used as cryogenic components for the nuclear industry.
7, health non-toxic
UHMWPE is hygienic and non-toxic, fully compliant with japan health association standards, and is recognized by the U.S. Food and Drug Administration and the U.S. Department of Agriculture for access to food and medicines.
UHMWPE surface adsorption capacity is very weak, its anti-stickability is second only to the most non-sticky PTFE in plastics, so the surface of the product and other materials are not easy to viscose.
9, small water absorption
UHMWPE water absorption is very low, generally less than 0.01%, only 1% of PA66, so it is generally not necessary to dry before molding.
10, density Table 2 shows uhMWPE compared with other engineering plastic densities. As can be seen from Table 2, UHMWPE is lower in density than all other engineering plastics, generally 56% lower than PTFE, 33% lower than POM, 30% lower than PBTP, so its products are very lightweight.
11, tensile strength Because UHMWPE has the necessary structural characteristics towards the tensile orientation, so there is an unmatched super-high tensile strength, so through the gel spinning legal system to obtain ultra-high elastic module and strength of fiber, its tensile strength of up to 3 to 3.5GPa, stretch elastic module up to 100 to 125GPa
The fiber ratio strength is the highest of all the commercialized fibers to date, 4 times larger than carbon fiber, 10 times larger than steel wire, and 50% larger than aramid fiber.
12, other performance UHMWPE also has excellent electrical insulation, better environmental stress cracking than HDPE, better fatigue resistance and r-ray resistance than HDPE.