As we explained in the introduction of the products produced by Petro Arman Polymer Pars Company, one of the types of materials produced in this industrial complex is polyethylene.
There are different types of polyethylene, but currently two types of linear and injection polyethylene are produced in Pars Petro Arman Polymer Group.
Here we are going to provide explanations about polyethylene and its details and types.
Polyethylene is a type of polymer that is widely used in various industries due to its excellent properties. It is a thermoplastic material made of ethylene monomer units. Polyethylene is known for its excellent durability, flexibility and chemical and impact resistance. It is also lightweight and has a low melting point, which makes it easy to process and mold into various shapes.
Finally, if we want to have a short description of polyethylene, I must say:
Polyethylene, the magical polymer that revolutionized the world of packaging and plastic!
There is no doubt that polyethylene has become a household name.
Lightweight, durable, super versatile. Whether used in grocery bags or milk jugs, polyethylene's beauty lies in its wide range of densities—from low density to high density—which allows manufacturers to create a variety of products for specific purposes, such as Create textured sheets for slip-resistant floors and sturdy pipes for plumbing systems. Polyethylene is also water resistant and performs well in electrical insulation, and it is used to protect electrical cables or as waterproof insulation on roofs during construction projects.
Polyethylene can be easily recycled many times without losing its quality.
The properties of polyethylene can be divided into mechanical, chemical, electrical, optical and thermal properties
We are going to provide detailed explanations about each of the mentioned properties.
Polyethylene has low strength, hardness and stiffness, but it has high plasticity and impact resistance as well as low friction. It exhibits strong creep under continuous force, which can be reduced by adding short fibers. It feels waxy to the touch.
The commercial use of polyethylene is limited by its low melting point compared to other thermoplastics. For common commercial grades of medium and high density polyethylene, the melting point is usually in the range of 120 to 130 °C. The melting point of commercial medium low density polyethylene is typically 105-115°C. These temperatures vary greatly with the type of polyethylene, but the theoretical upper melting point for polyethylene is reported to be 144 to 146 degrees Celsius. Combustion usually occurs at temperatures above 349°C.
Polyethylene consists of non-polar, saturated and high molecular weight hydrocarbons. Therefore, its chemical behavior is similar to paraffin. Individual macromolecules are not covalently linked. Due to their symmetrical molecular structure, they tend to crystallize. Polyethylene is generally partially crystalline. Greater crystallinity increases density and mechanical and chemical stability.
Most grades of LDPE, MDPE and HDPE have excellent chemical resistance, meaning they are not attacked by strong acids or bases and are resistant to mild oxidants and reducing agents. Crystalline samples do not dissolve at room temperature.
Polyethylene can become brittle when exposed to sunlight, carbon black is commonly used as a UV stabilizer.
Polyethylene is a good electrical insulator. Provides good electrical resistance. However, it easily becomes electrically charged (which can be reduced by adding graphite, carbon black, or antistatic agents).
Depending on thermal history and film thickness, polyethylene can vary between nearly transparent (transparent), milky opaque (semitransparent), and opaque. LDPE has the most, LLDPE a little less and HDPE the least transparency. If the crystals are larger than the wavelength of visible light, the transparency will be reduced by the crystals.
Classification :
Polyethylene is classified based on its density and branching. Its mechanical properties depend significantly on variables such as the amount and type of branching, crystal structure and molecular weight. Polyethylene has different types:
It is a polymer that is used in many industries due to its extraordinary advantages. This polymer has a very high molecular weight and due to this characteristic, it has unique physical properties that distinguish it from other polymers.
One of the uses of this polymer is the manufacture of parts that require very high mechanical properties, for example, sliding plates, wear surfaces and collision bodies in industries such as the automotive, aerospace and marine industries.
Also, this polymer is used in the cover of rescue suits and special masks because it has waterproof, anti-wear and anti-scratch properties. Due to the durability and high resistance of this polymer against breakage and corrosion, it can also be used as a suitable replacement for metals in some industrial applications.
or very low molecular weight polyethylene, also known as PE-WAX. This polymer is made from polyethylene with a molecular weight of less than 10,000, which has lower physical properties compared to polyethylene with a higher molecular weight.
The main use of this polymer is in papermaking, chemical plastics and rubber industries. For example, it is used to improve the physical properties of chemicals and plastics, such as softness, flexibility, thermal stability, and increase output speed in the manufacturing process.
Also, ULMWPE is used as a thermal stability and anti-rust factor in the production of thermal and anti-rust coatings for electric cables and automotive industries and in the preparation of cosmetics and health products. Overall, ULMWPE has become one of the vital polymers in various industries due to its unique physical properties.
It is one of the types of polyethylene which, due to its high molecular weight, has very high physical properties, including resistance to wear, corrosion, deformation, impact and heat. This polymer has a high density and is very hard and strong.
HMWPE is used in various industries. For example, in the automotive industry, it is used to make car bodies, interior and exterior coatings, protective equipment, and oil and gas industries to make pipes and parts that require high resistance to corrosion and salt water.
Also, in the food industry, HMWPE is used to produce food packaging and sheets that come into contact with food. Since this polymer is resistant to grease, oil and acid, packages made from HMWPE are suitable for food packaging.
Also, HMWPE is used in the medical industry to make joint prostheses, dental implants and surgical instruments.
High-density polyethylene (HDPE) is a type of polymer plastic that is used to produce plastic glasses, car parts, industrial and irrigation pipes, candy bottles, chocolate boxes, and food packaging. This type of plastic has high density, hardness and high compressive strength and is resistant to corrosion, heat, temperature changes and chemicals.
HDPE is obtained from polymer material that has a high density due to having many hydrogen atoms in its molecule. The polyethylene molecules in HDPE are connected in a continuous chain without side branches, which makes it have a high density.
Due to its features such as high resistance to temperature changes, resistance to corrosion and chemicals, lightness and flexibility, HDPE is used in various industries such as automotive, construction, packaging and many other industries.
High-density cross-linked polyethylene (HDXLPE) is a type of synthetic polymer that is created by refining and molecularly cutting high-density polyethylene. In this process, high density polyethylene molecules are converted into a denser structure of higher density following purification.
In HDXLPE, due to the presence of polymers with long molecules, it has hardness, resistance to pressure and fatigue, resistance to corrosion, resistance to heat and temperature changes, as well as resistance to harmful radiations, including UV rays and X-rays. In addition, this type of plastic is highly resistant to the adverse effects of gamma rays and other radioactive rays in dealing with waterproof coatings and other chemical substances.
Due to its unique properties, HDXLPE is used in many industries such as medical, automotive, refinery, energy, electrical tools, sports and other consumer industries.
Cross-linked polyethylene, or PEX (also known as XLPE), is a type of plastic with very diverse properties that is created by molecular refining and strengthening of polyethylene. In the cross-linking process, polyethylene molecules are cross-linked using different isomers of chemicals, which leads to increased heat, pressure, abrasion, fracture and chemical resistance.
PEX has properties such as high flexibility, corrosion resistance, electrical insulation, disinfection, scratch resistance and corrosion resistance. Also, due to the cross-linked molecules, PEX has a very high resistance to heat, pressure, gas penetration, and corrosive and chemical agents.
PEX is used in the construction industry, including water, gas, heating and sewage pipes, automotive uses, electrical and electronic industries, and oil and gas industries as transportation pipes. In addition, due to its high thermal properties, it is also used in heating and cooling systems, cable covers, automotive industries and electronic industries.
Medium density polyethylene or MDPE is a type of polymer that is widely used in the plastic industry. MDPE is a type of polyethylene with a density between high-density polyethylene (HDPE) and low-density polyethylene (LDPE).
MDPE has very good physical properties that make it suitable for various industrial applications. In general, this polymer has a high resistance to impact, bending and cracking, and is also suitable for resistance to various chemicals, heat and UV.
Common uses of MDPE include gas pipes, water pipes, sewer pipes, chemical storage containers, plastic bags, irrigation containers, moisture protection, thermal coatings, and agricultural industries.
Linear low density polyethylene or LLDPE is a type of polymer that is widely used in the plastics industry. In LLDPE, linear polymer chains with a semi-open structure have been used, which creates low density and unique physical properties in this polymer.
LLDPE has very good physical properties that make it suitable for various industrial applications. This polymer has very good resistance to breaking, wear and tear, and also has high flexibility and tensile strength. In addition, LLDPE is resistant to UV rays, heat and various chemicals.
Common uses of LLDPE include water pipes, gas pipes, food packaging, plastic bags, polymer coatings and agricultural industries. Due to its unique properties, LLDPE is recognized as one of the most important types of polymers used in the plastic and packaging industries worldwide.
Chips pipe (LDPE) is a type of thermal polymer made from ethylene monomer. This polymer is highly insulating and resistant to chemicals and water, so it is commonly used in the packaging industry, plastic bags, water and sewer pipes, stationery and other plastic products. Due to its high softness and flexibility, LDPE is also used to produce coated packaging for electronic and pharmaceutical products, the clothing industry, and recycled products.
Very low density polyethylene (VLDPE) is a thermoplastic polymer that is widely used in various industries such as packaging, piping, automotive industries, etc. VLDPE is well suited for some special applications due to its low density, high flexibility, high resistance to impact and corrosion, and no water absorption. This type of polymer is usually formed from ethylene and butene monomers and is created in the polymerization process.
Chlorinated polymer (CPE) is a type of thermoplastic polymer produced by adding chlorine to polyethylene. Due to its good properties, this polymer is widely used in various industries such as automobiles, plumbing, flooring, packaging, etc. The characteristics of CPE include high resistance to impact, corrosion, good bonding with other materials, and having better heat processing and shaping capabilities than polyethylene. Also, chlorinated polymer, like polyethylene, can be recycled, which is considered one of its advantages.