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Characteristics and industrial application of ultra high molecular weight polyethylene liner

Aug 20, 2019

Ultra high molecular weight polyethylene sheets are thermoplastic engineering plastics. It combines the superior properties of most plastics, impact resistance, low temperature resistance, wear resistance, chemical resistance, self-lubrication, and absorption of impact energy. These six characteristics are the highest values in plastics. Plastic products are widely used in Europe and the United States, and the demand is increasing. Similarly, the application of ultra-high molecular weight polyethylene products in China is becoming more and more extensive, and it is the promotion project of China's “Ninth Five-Year Plan”, “Guidelines for Priority Development of High-tech Industrialization Key Fields”.

 The ultra-high molecular weight polyethylene plate adopts a Ziegler-type high-efficiency catalyst low-pressure synthesis method, and the molecular weight is controlled at 1.5 to 3 million as needed. Considering the thermal degradation of the molecules in the process, high-density polyethylene having a viscosity average molecular weight of more than 1.7 million can be processed into various products to have superior performance.

 1. High wear resistance: UHMW-PE has the best wear resistance and is the most attractive in all current engineering plastics. The more the molecular weight, the more resistant the material is, even to many metal materials (such as carbon steel, stainless steel, bronze, etc.). For example, UHMW-PE pipe has a service life of 4-6 times that of steel pipe under strong wear conditions, and improves conveying efficiency by 20%. It fully demonstrates the superiority of "energy saving, environmental protection and economy".

 2. Corrosion resistance: It is not corroded in lye. It is stable in 75% concentrated sulfuric acid and 20% nitric acid. It is also stable to seawater and liquid detergent.

 3, very low friction coefficient: static friction coefficient of 0.07, good self-lubricating, is an ideal bearing, bushing, slider, material. UHMW-PE is selected as the friction component of the equipment, in addition to improving the wear life, it can also receive energy-saving effects.

 4, impact resistance: impact resistance is the first in plastics, whether it is strong external impact, or internal pressure fluctuations, it is difficult to crack. Its impact strength is 10 times that of nylon 66, 20 times that of polyvinyl chloride and 8 times that of polytetrafluoroethylene. Especially in low temperature environment, its impact strength reaches the highest value, and its flexibility can provide extremely safe and reliable transportation system. Protection.

 5, anti-aging: stable performance, good aging resistance, ground and underground can be buried, 50 years without aging. According to the ASTM method (load 4.6kg/cm2), the heat distortion temperature is 85 ° C, the use temperature can reach 90 ° C, in special cases, it is allowed to use at higher temperatures. UHMW-PE is an excellent toughness material. It is also excellent in low temperature resistance. It has a certain ductility at -269 ° C and low temperature without signs of brittle fracture. However, the coefficient of linear expansion is large and the thermal conductivity is very poor, so it is necessary to pay sufficient attention when designing the product.

 6. Electrical performance: The volume resistance is large, the breakdown voltage is 50KV/mm, and the dielectric constant is 2.3. It is suitable as a structural material for electrical engineering in a wide range of temperatures and frequencies.

 7. Hygienic and non-toxic: UHMW-PE is tasteless, non-toxic, odorless, non-corrosive, physiologically inert and physiologically adaptable. The Food and Drug Administration (FDA) and the US Department of Agriculture (USDA) allow it to be used in contact with food and medicine. Ultra-high molecular weight polyethylene sheet is the most suitable silo, chute lining material in the storage, transportation process of bulk materials in silos, bins, hoppers or other containers in the chute, funnel, conveying chute and similar equipment In the middle, it is usually blocked due to agglomeration, bridging or knotting of the material, forming a funnel-like flow, a groove-like flow, etc. In severe cases, it forms a blockage of arches and blockage of the bridge, resulting in a pause in production, waste of energy and a series of production involved. The security issues that solve these problems cost a lot of money and valuable production time. It has many years of experience in solving this kind of problem at home and abroad. UHMWPE material is the most suitable form to solve this kind of problem, and it has been widely used and achieved good results.