1. Wear resistance
The wear resistance of UHMWPE ranks higher than that of plastics, and exceeds that of some metals. The wear resistance of UHMWPE is compared with other materials. It can be seen that compared with other engineering plastics, the mortar abrasion index of UHMWPE is only 1/5 of PA66, 1/10 of HEPE and PVC; compared with metal, it is 1/7 of carbon steel and 1/ of brass. 27. Such a high wear resistance makes it difficult to test its wear resistance by the general plastic wear test method, so a mortar wear test device is specially designed. The abrasion resistance of UHMWPE is proportional to the molecular weight. The higher the molecular weight, the better the abrasion resistance.
2. Self-lubricating
UHMWPE has a very low coefficient of friction (0.05 to 0.11), so it has excellent self-lubricating properties. Table 1 is the comparison of friction factor between UHMWPE and other engineering plastics. As can be seen from Table 1, the dynamic friction factor of UHMWPE is 1/2 of that of PA66 and POM under water lubrication conditions, and it is second only to polytetrafluoroethylene (PTFE) with the best self-lubrication in plastics under non-lubricated conditions. ; When it works in sliding or rotating form, the lubricity is better than that of steel and brass with lubricating oil. Therefore, in the field of tribology, UHMWPE is known as a very ideal friction material in terms of cost/performance.
3. Chemical resistance
UHMWPE has excellent chemical resistance, in addition to strong oxidizing acid, it can resist various corrosive media (acid, alkali, salt) and organic media (except tea solvent) within a certain temperature and concentration range. It has been immersed in 80 kinds of organic solvents at 20 °C and 80 °C for 30 days, and there is no abnormal phenomenon on the surface, and other physical properties are almost unchanged.
4. Impact energy absorption
UHMWPE has excellent impact energy absorption, the impact energy absorption value is the highest among all plastics, so the noise damping performance is very good, and it has excellent sound clipping effect.
5. Low temperature resistance
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.
6. Hygienic and non-toxic
UHMWPE is hygienic and non-toxic, fully complies with the standards of the Japan Hygiene Association, and is approved by the U.S. Food Administration and the U.S. Department of Agriculture for use in contact with food.
7. Not sticky
The surface adsorption capacity of UHMWPE is very weak, and its anti-adhesion ability is second only to PTFE, which is the best non-stick in plastics, so the surface of the product is not easy to stick to other materials.
8. Low water absorption
The water absorption rate of UHMWPE is very low; generally less than 0.01%, only 1% of PA66, so it is generally unnecessary to dry before molding.
9. Density
Table 2 is the density comparison between UHMWPE and other engineering plastics. It can be seen from Table 2 that the density of UHMWPE is lower than that of all other engineering plastics, generally 56% lower than PTFE, 33% lower than POM, and 30% lower than PBTP, so its products are very lightweight.
10. Tensile strength
Because UHMWPE has the necessary structural characteristics towards the tensile orientation, it has unparalleled ultra-high tensile strength, so ultra-high elastic modulus and strength fibers can be obtained by gel spinning method, and its tensile strength is as high as 3 ～3.5GPa, the tensile elastic modulus is as high as 100～125GPa; the specific fiber strength is the highest among all the fibers that have been commercialized so far, 4 times larger than carbon fiber, 10 times larger than steel wire, and 50% larger than aramid fiber.
11. Other properties
UHMWPE also has excellent electrical insulation properties, better resistance to environmental stress cracking than HDPE, better fatigue resistance and r-ray resistance than HDPE.
