Ultra high molecular weight polyethylene fiber: excellent performance makes it so "useful"

Ultra high molecular weight polyethylene fibers have excellent mechanical properties unmatched by other fibers. At present, the industrialized ultra-high molecular weight polyethylene fiber has a strength of more than 40 cN/dtex, and its modulus is extremely high, second only to special carbon fiber , and the elongation at break of the fiber is equivalent to that of other high-performance fibers, and the fracture work is large.

Compared with other high performance fibers, ultra high molecular weight polyethylene fibers have the following advantages: First, the density is small. With a density of 0.97g/cm3, it is the smallest of all types of high-performance fibers and can float on water, making it an excellent advantage in rope applications for offshore engineering. Second, the specific strength and specific modulus are high. The single structural unit of the fiber has a relatively tight molecular chain arrangement, high crystallinity and large degree of orientation, which determines its high ultimate strength and modulus. Due to its low density, its specific strength is the highest in the world today, which is 15 times higher than that of high-quality steel wire and nearly 10 times higher than that of ordinary chemical fiber. Third, chemical and weather resistant. Since the fiber has an extremely stable molecular structure and no chemically active group, it has excellent chemical corrosion resistance. The fiber also has good weather resistance and UV resistance. After 1500 hours of sun exposure, the fiber strength retention rate is still above 80%. Fourth, wear resistance and bending resistance are good. The fiber has a smooth surface and a low coefficient of friction, so it has superior wear resistance. And its good resistance to bending deformation enables ultra-high molecular weight polyethylene fibers to have good textile processing properties. Fifth, the impact resistance is good. Since the ultrahigh molecular weight polyethylene fiber is a flexible chain macromolecular polymer and has a very high modulus and sonic orientation, it has excellent impact resistance and its energy absorption performance is superior to that of aramid. Sixth, low temperature resistance. Due to the low melting point of polyethylene and the extremely low glass transition temperature, the fiber is suitable for use in low temperature environments, especially in extremely low temperature (can be as low as -150 ° C), and its fiber strength remains good while The softness does not change much. Seventh, low conductivity. The ultrahigh molecular weight polyethylene fiber has a low dielectric constant and a small loss tangent, and is particularly suitable for use under high frequency electric waves, and is used as a radome to exhibit good radio wave transmittance.

Due to the above-mentioned excellent properties of ultra-high molecular weight polyethylene fibers, it has important application value in many high-end technology fields.

In the field of bulletproof and protection, ultra high molecular weight polyethylene fiber has good impact toughness and has gradually replaced aramid in the field of bulletproof. It is widely used in the manufacture of flexible body armor, hard bulletproof board, bulletproof helmet, and can also be used in Armored shields for helicopters, tanks and ships, radar protective enclosures, and missile covers. In addition, it can also be used for helmets for miners, racers and mountaineers, a variety of bulletproof and impact resistant panels, as well as cut-resistant gloves, stab-resistant garments, shields, etc. Because of its light weight, the weight of the body armor can be reduced by about 40% on the basis of the same anti-ballistic performance, which is of great significance for the weight reduction of military equipment.

In the aerospace industry, the fiber composite material is suitable for the wing tip structure, spacecraft structure and buoy aircraft of various aircraft due to its light weight, high strength and good impact resistance. The fiber can also be used as a speeding parachute for space shuttle landings and as a rope for hanging heavy objects on the aircraft, replacing traditional steel and synthetic fiber ropes.

In the field of marine engineering, ropes, cables, sails and fishing gear made of this fiber are particularly suitable for marine engineering, and are commonly used in negative ropes, heavy-duty ropes, salvage ropes, tow ropes, sailing ropes and fishing lines. . The rope made of the fiber has a breaking length of 8 times that of the steel rope and 2 times that of the aramid fiber under its own weight. The rope is used for fixed anchor ropes of supertankers, marine operating platforms, lighthouses, etc., which solves the corrosion and meshing of the ropes encountered in the past, and the corrosion, hydrolysis and ultraviolet degradation of nylon and polyester cables. , the problem of frequent replacement.

In the field of sports equipment, the fiber has been made into helmets, skis, sail boards, fishing rods, rackets and bicycles, glides, ultra-lightweight aircraft parts, etc., which is superior to traditional materials.

In medicine, the fiber reinforced composite material is used in the fields of tray materials, medical implants and plastic sutures, and has good biocompatibility and durability, high stability, and no allergies. Has been used clinically.

In other industrial applications, the fiber and its composite materials can be used as pressure-resistant containers, conveyor belts, filter materials, automobile buffer boards, etc.; construction can be used as wall, partition structure, etc., which can be used as reinforced cement composite materials. Improve the toughness of cement and improve its impact resistance. Due to its excellent wear resistance and impact resistance, the fiber is also widely used in the mechanical manufacturing industry to produce a variety of gears, cams, impellers, rollers, pulleys, bearings, bushings, bushings, gaskets, gaskets. Mechanical parts such as flexible couplings. (Professor Hu Zuming of Donghua University)