UHMWPE, along with carbon fiber and aramid, is collectively known as the "world's three major high-tech fibers". Ultra-high molecular weight polyethylene fiber is the strongest and most resilient fiber in the world. Currently, it is the fiber with the highest specific strength and bulletproof performance among industrialized fiber materials. It possesses numerous outstanding properties such as ultra-high strength, ultra-high modulus, low density, wear resistance, low-temperature resistance, UV resistance, shielding resistance, good flexibility, high impact energy absorption, and resistance to strong acids, strong alkalis, and chemical corrosion. In common parlors, it is "as thin as paper and as hard as steel", with a strength 15 times that of steel. In view of its characteristics of light weight, high strength and high specific energy absorption,
Performance characteristics
1. Excellent mechanical properties: Under the same linear density, the tensile strength of ultra-high molecular weight polyethylene fibers is 15 times that of steel wire ropes. It is 40% higher than aramid, which is also one of the "world's three major high-tech fibers", and 10 times higher than high-quality steel fibers and ordinary chemical fibers. Compared with steel, E-glass, nylon, polyenamine, carbon fiber and boron fiber, its strength and modulus are higher than those of these fibers, and it has the highest strength among materials of the same mass.
2. Excellent impact resistance: Ultra-high molecular weight polyethylene fibers have excellent impact resistance. Their ability to absorb energy and resist impact during deformation and shaping is higher than that of aramid fibers and carbon fibers, which are also among the "world's three major high-tech fibers". Compared with polyamide, aromatic polyamide, E-glass fiber, carbon fiber and aramid, ultra-high molecular weight polyethylene fiber has a higher total energy absorption by impact.
3. Excellent wear resistance: When comparing the friction coefficients of ultra-high molecular weight polyethylene fibers with those of carbon fiber and aramid fiber reinforced plastics, the wear resistance and bending fatigue of ultra-high molecular weight polyethylene fibers are far higher than those of carbon fiber and aramid fiber. So its wear resistance is better than that of other high-performance fibers. Also, due to its excellent wear resistance and bending resistance, its processing performance is relatively superior, and it is easy to be made into other composite materials and fabrics.
4. Chemical resistance: The chemical structure of ultra-high molecular weight polyethylene fibers is relatively simple, and their chemical properties are relatively stable. Most chemical substances are not easy to corrode them. Only a few organic solutions can slightly swell them, and the loss of their mechanical properties is less than 10%. The strength retention rates of ultra-high molecular weight polyethylene fibers and aramid fibers in different chemical media were compared. The corrosion resistance of ultra-high molecular weight polyethylene fibers is significantly higher than that of aramid fibers. Its properties and structure are particularly stable in acids, alkalis and salts, but its strength is slightly lost in sodium hypochlorite solution.
5. Excellent optical resistance: Due to the stable chemical structure of ultra-high molecular weight polyethylene fibers, their light resistance is also the most superior among high-tech fibers. Aramid fibers are not resistant to ultraviolet rays and should only be used when direct sunlight is avoided. When comparing ultra-high molecular weight polyethylene fibers with nylon, high modulus and low modulus arylamides, the strength retention rate of ultra-high molecular weight polyethylene fibers is significantly higher than that of other fibers.
6. Other properties: Ultra-high molecular weight polyethylene fibers also have excellent hydrophobic properties, water and moisture resistance, electrical insulation performance, and a relatively long flexural life. It has outstanding water resistance and low-temperature resistance, with a relatively low specific gravity. It is the only high-tech fiber that can float on water and is also a relatively ideal low-temperature material.
Disadvantage: Relatively low melting point. During the processing of it, the temperature must not exceed 130℃; otherwise, due to the weak intermolecular forces between the ultra-high molecular weight polyethylene fibers, creep will occur, shortening its service life. There are no dyeing groups on ultra-high molecular weight polyethylene fibers, which makes their wettability poor. Dyes have difficulty penetrating into the interior of the fibers, resulting in poor dyeability. These drawbacks have affected the scope of their application fields.
Application field
1. Defense field: Due to the excellent impact resistance and high specific energy absorption of this fiber, it can be made into protective clothing materials, helmets, bulletproof materials in the military, such as armor plates for helicopters, tanks and ships, protective outer covers for radars, missile covers, bulletproof vests, anti-puncture vests, shields, etc. Among them, the application of bulletproof vests is the most remarkable. Taking advantage of its low dielectric constant, low dielectric loss and high sonar transmittance, it is applied in antenna fairings, missile covers, radar protective housing covers and other aspects. It has the advantage of being lightweight and its bulletproof effect is better than that of aramid. It has now become the main fiber occupying the bulletproof vest market in the United States. In addition, the specific impact load value U/p of ultra-high molecular weight polyethylene fiber composites is ten times that of steel and more than twice that of glass fiber and aramid. Bulletproof and riot helmets made of this fiber-reinforced resin composite material abroad have become substitutes for steel helmets and aramid reinforced composite material helmets. From an international perspective, 70% of UHMWPE fibers are used in military fields such as bulletproof vests, bulletproof helmets, bulletproof armor for military facilities and equipment, and aerospace. However, at present, the proportion of UHMWPE fibers used in military applications in China is still very low. In the future, the application of high-end military UHMWPE fibers is expected to grow rapidly.
2. Aviation field: In aerospace engineering, due to the light weight, high strength and good impact resistance of this fiber composite material, it is suitable for the wingtip structures of various aircraft, spacecraft structures and buoy aircraft, etc. This fiber can also be used as a deceleration parachute for the landing of space shuttles and a rope for suspending heavy objects on aircraft, replacing traditional steel cables and synthetic fiber ropes. Its development speed is extremely rapid.
3. Industrial field: In industry, this fiber and its composite materials can be used as pressure-resistant containers, conveyor belts, filter materials, automotive buffer plates, etc. In terms of construction, it can be used as a wall, partition structure, etc. When used as a reinforcing cement composite material, it can improve the toughness of cement and enhance its impact resistance. Due to its excellent wear resistance and impact resistance, it is widely used in the mechanical manufacturing industry and can be used to make various mechanical parts such as gears, cams, impellers, rollers, pulleys, bearings, bearing shells, shaft sleeves, machined shafts, gaskets, sealing gaskets, elastic couplings, and screws.
Ultra-high molecular weight polyethylene can be used to make the linings of buckets, silos and chutes for storing coal, lime, cement, mineral powder, salt, grains and other powdered materials. This is because it has excellent self-lubricating and non-stick properties, which can prevent the above-mentioned powdered materials from adhering to storage and transportation facilities, ensuring stability and reliability.
Ultra-high molecular weight polyethylene is used for liquid sponsorship pipes such as quicksand. Compared with other pipes, its outstanding performance is as follows: compared with bamboo pipes, its service life is increased by 18 times and the interest rate is reduced to 1/25; compared with nylon pipes, its service life is increased by 3 times and the interest rate is reduced to 1/8. When underwriting, the barrier inside the pipe is 25% smaller than that of non-metallic pipes, which greatly increases the underwriting frequency.
In areas such as chutes, buckets and the inner linings of ore compartments, when cold and damp weather occurs, items will thaw on non-metallic surfaces, but this will never happen with the use of high-molecular polyethylene plates, thus significantly reducing unloading costs. After lining a layer of high-molecular polyethylene sheet on the dump drain of bulk trucks and ships, the uniform unloading time was reduced from the original 16 to 20 hours to 8 hours.
4. Civilian field
Applications in ropes and cables: Ropes, cables, sails and fishing gear made from this fiber are suitable for Marine engineering, which was the initial use of this fiber. It is widely used in load-bearing ropes, heavy-duty ropes, salvage ropes, towing ropes, sailboat ropes and fishing lines, etc. The rope made of this fiber has a breaking length under its own weight that is eight times that of steel rope and twice that of aramid. This rope is used as a fixed anchor rope for super oil tankers, offshore operation platforms, lighthouses, etc. It solves the problems of rust encountered in the previous use of steel cables and corrosion, hydrolysis, ultraviolet degradation, etc. in nylon and polyester cables, which cause the reduction of cable strength and breakage, and require frequent replacement.
Sports equipment and supplies: In sports goods, products such as football backboards, safety helmets, skis, sailboards, fishing rods, rackets, bicycles, gliders, and ultra-lightweight aircraft parts have been made, and their performance is better than that of traditional materials.
As a biomaterials: This fiber-reinforced composite material is used in dental trays, medical grafts, and plastic sutures, etc. It has good biocompatibility and durability, and is highly stable without causing allergies. It has been applied in clinical practice. It is also used in medical gloves and other medical measures, etc.
