Excellent Properties Of UHMWPE Fiber

The unique structure of UHMWPE gives it excellent physical and chemical properties, but the flexible linear macromolecular backbone structure of UHMWPE and its extremely high molecular weight (long molecular backbone) also restrict the molding process of this material. Due to its long molecular chain, UHMWPE macromolecular chain still maintains a high degree of mutual curling and winding state after melting, resulting in its high viscosity in the molten state, which cannot form a viscous flow state but a high elastic state, and the melting index is almost 0. Therefore, extrusion and spinning processing and molding methods commonly used in polyethylene cannot be achieved through hot melting. At the same time, the critical shear rate of UHMWPE in the high elastic state is low, and the viscosity of the melt is very large, so it is easy to make the surface of the product uneven, kinking, rough, melt cracking and other problems in the extrusion or injection molding process, which is also a factor that makes the material difficult to process. Compared with conventional fibers, UHMWPE fibers are most concerned about their high tensile strength and tensile modulus, low density, and high impact resistance based on flexible chain structure. In addition, UHMWPE fiber has excellent insulation, low temperature resistance, chemical stability and hydrophobicity.
1 Ultra-high molecular weight polyethylene fiber excellent mechanical properties
UHMWPE fiber has excellent mechanical properties. Under the same linear density, the tensile strength of UHMWPE fiber is 15 times that of steel wire rope, 40% higher than that of aramid fiber, and 10 times that of high-quality steel fiber and ordinary composite fiber. Compared with steel, E-laminated glass, nylon, polyenamine, it has higher strength and modulus, and has the highest strength in raw materials of the same quality.
2 Ultra-high molecular weight polyethylene fiber excellent density and specific strength
The density of UHMWPE fiber is about 0.95g/cm3 ~ 0.98g/cm3, which has a lower density than carbon fiber and aramid fiber, and the density is less than the density of water, similar to polypropylene, is a special high-performance fiber with a density less than water.
UHMWPE fiber is a kind of lightweight high-strength fiber, the specific strength is much better than carbon fiber, aramid and other special polymer fiber.
The tensile strength of UHMWPE fiber is about 2.8 ~ 4N/tex (density calculated at 0.98g/cm3, the tensile strength is about 2744MPa ~ 3920MPa). The tensile modulus is about 91 ~ 140N/tex (density calculated at 0.98g/cm3, then the tensile modulus is about 90GPa ~ 137GPa). Although the tensile strength of UHMWPE fiber is similar to that of special fibers such as carbon fiber and aramid, the specific tensile strength of UHMWPE is about 50% higher than that of aramid and carbon fiber, which is basically the highest specific tensile strength of polymer special fiber at present.
3 Ultra-high molecular weight polyethylene fiber excellent wear resistance
In general, the greater the modulus of the raw material, the lower the wear resistance, but for UHMWPE fiber, the opposite is true. Because the friction coefficient of UHMWPE fiber is low, the higher the modulus, the higher the wear resistance. Therefore, its wear resistance is superior to other excellent chemical fibers. Due to its wear resistance and bending resistance, it has excellent production and processing characteristics and is easy to manufacture other polymer materials and textiles.
4 UHMWPE fiber is resistant to chemical corrosion
The chemical structure of UHMWPE fiber is relatively simple, the physical properties are relatively stable, and it has the tendency of high crystal structure. Therefore, the active gene in the strong acid and base is not easy to attack, and only a few other organic chemical aqueous solutions can make it slightly swell, and its mechanical properties damage is less than 10%. Ultra-high content polyethylene fibers and aramid fibers have very high compressive strength retention rates in different chemicals. The corrosion resistance of ultra-high content polyethylene fiber is significantly higher than that of aramid fiber. Its structure is very stable in acids, bases and salts, and its strength is broken only in sodium hypochlorite solution.
5 UHMWPE fiber has good light resistance
The chemical structure of UHMWPE fiber is stable, so its light resistance is also the best among the new chemical fibers. The strength retention rate of UHMWPE fiber is obviously higher than that of nylon, and the strength retention rate of high and low modulus aramid fiber is improved.
6 Other properties of ultra-high molecular weight polyethylene fiber
UHMWPE fiber has excellent hydrophobicity, moisture resistance, insulation and service life. Its moisture resistance and cold resistance are excellent, and the specific gravity is small. It is the only new chemical fiber that can float on water, and it is ideal for low temperature fiber. However, it also has a disadvantage, namely a low melting point. In the production process, the temperature should not exceed 130 ° C, otherwise, due to the weak interaction between the molecular structure chain of UHMWPE fiber, it will cause stress relaxation and shorten the service life. UHMWPE fibers do not have dye groups, which makes them poorly permeable, and dyes cannot penetrate into the fibers, resulting in poor dye. This defect affects the range of its primary uses.