2024 Author: Beatrice Philips | [email protected]. Last modified: 2023-12-16 05:33
High molecular weight polyethylene (PE-500) is a plastic polymer. It possesses a number of unique physical and chemical properties, due to which it can be used in extreme conditions. In this article, we will consider everything about high molecular weight polyethylene.
What it is?
This material belongs to one of the types of plastic polymerized ethylene. Its feature is elongated linear molecular bonds oriented in the same direction. Such circuits are distinguished by better perception and transfer of loads.
In appearance, high molecular weight polyethylene resembles plastic . It is solid, odorless, and contains no toxic substances. The material is produced by the synthesis of ethylene and metallocene catalysts in low-pressure plants. At the production stage, a color is added to the raw materials to give the polymerized ethylene color.
Manufacturers also produce an ultra-high molecular weight (ultra-high molecular weight) polymer with a molecular weight of more than 10,000,000 units. (PE-1000) . In terms of strength characteristics, it is several times superior to some grades of carbon and stainless steels.
Advantages and disadvantages
The material has a number of significant advantages. The main advantages are as follows:
- excellent resistance to wear and mechanical abrasion; high density polymer has high impact resistance;
- resistance to cracks, chips and other types of deformation;
- resistance to temperature fluctuations, due to which the material is allowed to operate both at excessively high and at minimum temperature indicators;
- resistance to moisture and aggressive substances (except for oxidants); this feature is achieved due to the absence of amides, esters or hydroxyl groups in the material, which are susceptible to chemically aggressive substances;
- resistance to solar radiation;
- high hygienic properties - the material is not susceptible to attacks by pathogenic microorganisms; fungus and mold do not form on it;
- good electrical insulating and dielectric ability;
- PE-500 polyethylene has excellent weldability;
- radiation resistance.
The disadvantages of the material include its low melting point (not more than + 150 ° C), which is why it is recommended to operate the polymer at a temperature not exceeding +100 degrees.
High molecular weight polyethylene is relatively new . It is produced by 2 domestic enterprises (Tomskneftekhim and Kazanorgsintez). Manufacturing technology is complex and costly, which affects the cost of the finished product.
Material properties and characteristics
High-strength polyethylene has long molecular chains that are almost parallel to each other. This structural feature provides high strength indicators. However, weak bonds arise between some molecules, which is why the material cannot be called heat-resistant. Its operating temperatures are up to + 100 ° С. With an increase in temperature indicators to +140 degrees, the polymer melts and turns into a viscous mass.
Polymer PE-1000 has the following technical characteristics:
- water absorption - 0.01-0.05%;
- specific gravity - 0, 93-0, 94 g / cm³;
- flexural modulus - no more than 1 GPa;
- coefficient of friction - about 0, 1;
- impact strength coefficient - 160-170 kJ / m²;
- bending elongation - 8-10%;
- surface resistance - 1014 ohms.
The material is classified as normally flammable. During operation, it does not emit harmful substances into the environment.
Processing methods
High molecular weight polyethylene is manufactured according to standards corresponding to GOST 16338-85. The production uses the method of ethylene synthesis under the influence of metallocene catalysts. At the moment, there are several known methods of polymer processing.
Sintering and hot pressing
Thanks to these methods, large-format monolithic polyethylene, plates and cylinders are obtained. In the process of further machining, planed strips and various mechanisms for equipment are obtained from them. The production technology implies cold pressing of the polymer powder into blanks and their subsequent sintering at a temperature of +200 degrees . As a result of heat treatment, semi-finished products are obtained - monoliths, plates and blocks.
Plunger extrusion
The production process consists in melting the feedstock at high temperatures to a homogeneous rubbery mass. From it, using special units with nozzles, rods, pipes or tapes of various lengths are squeezed out.
Gel spinning
The manufacturing technology includes several stages: dissolving the feedstock in paraffin oil and forcing the resulting mass through thin holes into water. As a result, yarns are obtained, which are subsequently fired in furnace equipment with simultaneous drawing of fibers and removal of solvent substances. When processed by gel spinning, a super-strong fiber is obtained.
The latter processing method is more popular.
Applications
Due to its unique properties, high molecular weight polyethylene is used in various fields. It is often used as an analogue, replacing various non-ferrous metals, high-alloy steels and other materials.
In medicine
Ultra-strong polymer has been used for the manufacture of implants since 1962. Today, it is used to make prostheses for hip joints in surgery and dental implants in dentistry. The material is used to create various orthopedic products.
In the chemical, food and light industries
The material is used for the manufacture of equipment and components for food production, containers for storage and transportation of chemically aggressive substances, bottles for cosmetics, barrels, tanks.
In the military industry
Strong polymer fibers are used for the manufacture of personal protective equipment for security personnel. In particular, bulletproof vests and helmets are made of them. The resulting armor is lightweight, but at the same time it reliably protects against bullet wounds . And also with the help of this polymer, special equipment is armored.
In mechanical engineering
High-strength polyethylene is used for the manufacture of spare parts that operate in hydraulic or oil environments. It is used to produce bearings, bushings, bushings, gears - parts subject to a high degree of mechanical abrasion. Spare parts for pneumatic installations with increased working pressure are made of heavy-duty polymer PE-1000.
Sports goods and equipment
The material is used in the manufacture of fencing suits, mountaineering uniforms, skis, snowboards.
Numerous consumer goods are made from high-strength polymer . These include floriculture and bathroom furnishings, household items and garden tools. It is used for the production of furniture, children's toys, mobile toilets, and equipment for arranging children's playgrounds.
Recommended:
Density Of Crushed Stone: Bulk And True Density Of Crushed Stone 5-20 Mm, 40-70 Mm And Other Fractions, Table And GOST, Average Density Of Black And Other Crushed Stone
Crushed stone density: bulk and true. The density of crushed stone is 5-20 mm, 40-70 mm and other fractions, table and GOST, average density of black and other crushed stone
Density Of Expanded Clay: Bulk And True, Density Of Expanded Clay With A Fraction Of 5-10 And 20 Kg Per M3, Expanded Clay With A Density Of 400-600, Other Options
During construction work with expanded clay, you need to know its density. The main types of density are bulk and true. So what does it depend on and how to determine the density of expanded clay with a fraction of 5-10 and 20 kg per m3?
Linear Polyethylene: What Is It? Features LLDPE (Low Density) And High Density Polyethylene
In the modern world, polymers have replaced metal, glass, wood, ceramics in many spheres of life, and linear polyethylene is one of such materials. What is it, features of lldpe, properties of low density and high pressure polyethylene
Polyethylene Sheet: Low And High Pressure Polyethylene Sheets, Characteristics Of High Molecular Weight Polyethylene 10 Mm And Other Sizes
What is polyethylene sheet? What properties does it have? Types of this material: sheets of low, high pressure polyethylene and others. What are the characteristics of high molecular weight polyethylene 10 mm and other sizes? Where is it used?
Sand Density: Kg Per M3, True Density Table And Test, Average Density Of Dry And Wet Sand
What is the density of sand in kg per m3? True density table. Laboratory Test: Cutting Ring Method. What factors influence the density index? What methods can be used to determine the required parameter? How is the formula calculated?
