Polyethylene is a typical thermoplastic, is odorless, tasteless, non-toxic flammable white powder. Polyethylene resin with molded by extrusion granulation are waxy pellets, milky white appearance.
    10,000 molecular weight polyethylene to 100 million between molecular weight of more than 1 million for ultra-high molecular weight polyethylene. The higher molecular weight, the better their physical and mechanical properties, but with the higher molecular weight, processing performance. Therefore, according to the use to select the appropriate molecular weight and processing conditions. Processing of high molecular weight polyethylene is a load of structural materials and materials, and to molecular weight polyethylene is only suitable for coating, polishes, lubricants and softener.
    Mechanical properties of polyethylene compounds depends largely on the molecular weight, degree of branching and crystallinity. Tensile strength of high-density polyethylene is 20 ~ 25MPa, tensile strength and low density polyethylene is only 10 ~ 12MPa. Elongation of polyethylene depends on the density, density, high crystallinity, the spread of the more backward.
    Polyethylene electrical insulation performance. Because it is non-insulating material, its dielectric constant and dielectric loss to teach almost temperature independent of frequency; good high frequency performance, suitable for manufacture of various high-frequency cables and submarine cable insulation.
The density range of low-density polyethylene 0.910 ~ 0.925g/cm ³. Molecular structure of the main chain with long and short of the different branched-chain branched-chain molecules. In the main chain carbon atoms per 1000, about 50 below with ethyl, butyl or longer branched chain. With high density and medium density polyethylene, it has a lower crystallinity (55% ~ 65%), low softening point (108oC ~ 126oC) and wide melt index (0.2 ~ 80g/10min) .
    As the low-density polyethylene and paraffin hydrocarbon chemical structure similar to non-polar groups, it has good chemical stability, acid, alkali and salt solution resistant to corrosion. Its electrical properties and good, with low conductivity, low dielectric constant, low dielectric loss and high dielectric strength characteristics. However, poor heat resistance of low density polyethylene, also intolerant of oxygen and light aging. Therefore, in order to improve its anti-aging properties, usually in the resin by adding antioxidant and ultraviolet absorber.
    Low-density polyethylene has good flexibility, scalability and transparency, but the mechanical strength lower than the high-density polyethylene and linear low density polyethylene.
    Mainly for the manufacture of low-density polyethylene film. Density polyethylene film products to products accounting for more than half of total output for agricultural films and a variety of food, textiles and industrial packaging. Low-density polyethylene excellent electrical insulation properties, commonly used for wire and cable coating materials. Injection molding products have a variety of toys, covered boxes, containers and so on. After mixing with high-density polyethylene by injection molding and blow molding system of pipes and containers available.
    Density, high temperature, greater hardness and mechanical power, good chemical resistance.
    Specific uses include: manufacturing of blow molding bottles, cans and all kinds of industrial tank, barrels and other containers; injection molding manufacturing all kinds of pots, barrels, blue, basket, baskets and other household Synthesizer, household goods and furniture ; extrusion manufacturing all kinds of pipe, strapping, and fiber, a single wire. In addition, can be used to manufacture wire and cable coating materials and synthetic paper; after adding a large number of inorganic salts, calcium plastic box and can also manufacture furniture, doors and windows. Recently, high-density polyethylene for the manufacture of high-intensity ultra-thin film, do the food, agricultural products and textiles, packaging materials has developed rapidly.
    Density of 0.926 ~ 0.940g/cm ³, the number of branched-chain molecular structure between the high-density polyethylene and linear low density ethylene polymer between. Crystallinity of 70% to 75%, softening temperature of 110oC ~ 115oC, in addition to both high and low density polyethylene performance, but also has excellent resistance to stress cracking resistance, rigidity and heat resistance.
    Best suited to high-speed blow molding manufacturing bottles, wrapped with high-speed automatic and a variety of film products, injection molding and rotation molding products, such as drums, cans and so on. Can be used for wire and cable coating.
The density of linear low density polyethylene 0.910 ~ 0.925g/cm ³.
    As linear low density polyethylene side chains of short branched-chain molecules, the molecular structure between the linear high density polyethylene and with a long-chain branching between the high pressure low density polyethylene, so its physical and mechanical properties superior to ordinary low density polyethylene.
In mechanical properties, tensile strength of linear low density polyethylene and ethylene than the average density by 50% to 70%, 50% elongation, impact strength, low temperature impact strength and puncture resistance than low density polyethylene is good.
    In physical performance, in the case of the same density, linear low density polyethylene low density polyethylene melting point than high, wide temperature range, allows the use of high temperature than low-density polyethylene 10oC ~ 15oC.
    Linear low density polyethylene can be replaced by low-density polyethylene film, pipe, injection molding products, blow molding containers, rotational molding products and wire and cable coating materials. Obtained the mechanical properties better than the low-density polyethylene. Therefore, the strength of manufacturing the same products, the linear low density polyethylene products can be thinned.