Table of Contents
What is Polyethylene?
Polyethylene – Detailed Explanation: Polyethylene is a polymer of ethylene, a hydrocarbon gas. It is the most common plastic, and is used in everything from water pipes to food packaging. The major polyethylene compounds are high-density polyethylene (HDPE), medium-density polyethylene (MDPE), and low-density polyethylene (LDPE). Polyethylene is non-toxic and recyclable.
Chemical Composition and Molecular Structure of Benzene
- Benzene is an organic compound with the chemical formula C6H6. It is a colorless, flammable liquid with a sweet odor. Benzene is mainly used as a precursor to polymers and as an additive in gasoline.
- Benzene has a molecular formula of C6H6 and a molecular weight of 78.11 g/mol. It is a colorless, flammable liquid with a sweet odor. Benzene is mainly used as a precursor to polymers and as an additive in gasoline.
- Benzene is composed of six carbon atoms bonded together in a ring, with one hydrogen atom bonded to each carbon atom. The carbon atoms are sp3 hybridized, meaning that they each have one unpaired electron in their outer orbitals. This electron is delocalized over the entire ring, giving benzene its characteristic stability.
Low Density Polyethylene
Low Density Polyethylene (LDPE) is a thermoplastic polymer made from the monomer ethylene. LDPE is the most common type of polyethylene. It is characterized by its low density, flexibility and toughness. It is used in manufacturing products such as bags, films, bottles and containers.
Linear Low Density Polyethylene
Linear low-density polyethylene (LLDPE) is a polyethylene thermoplastic made from ethylene monomers. It is characterized by its low density and linear chain structure. LLDPE is less dense than traditional polyethylene resins and has higher impact strength. These properties make it an ideal material for packaging and other applications that require toughness and impact resistance.
High Density Polyethylene (HDPE)
HDPE is a high-density polyethylene. It has high tensile strength and impact resistance. It is also resistant to most chemicals. HDPE is widely used in the manufacture of plastic bottles and containers.
Ultra High-Molecular-Weight Polyethylene
- Ultra high-molecular-weight polyethylene (UHMWPE) is a polyethylene formed with very long chains, usually of at least 3 million repeating units. UHMWPE is sometimes called high-molecular-weight polyethylene, ultra-high-molecular-weight polyethylene, or long-chain polyethylene.
- UHMWPE is a translucent white plastic with a density of 0.93 to 0.96 g/cm³. It has a Young’s modulus of between 6 and 9 GPa, a tensile strength of between 550 and 750 MPa, and a flexural strength of between 850 and 950 MPa.
- UHMWPE is highly resistant to abrasion, with a coefficient of friction of 0.2, and is resistant to creep deformation. It has a low coefficient of thermal expansion and a low thermal conductivity. It is also resistant to chemical attack, with a pH range of 2 to 13.
- UHMWPE was first commercially produced in the 1950s by ICI, using a technique called high-pressure molding. Today, UHMWPE is produced by two main processes: mechanical extrusion and chemical vapor deposition.
- UHMWPE is used in a wide range of applications, including medical implants, artificial joints, and replacement body parts. It is also used in the automotive, aerospace, and engineering industries.
Ethylene Copolymers
- Polyethylene is a polymer consisting of repeating units of ethylene, CH2=CH2. Polyethylene can be made from a variety of monomers, including ethylene, propylene, 1-butene, and 1-hexene. The different monomers used to make polyethylene produce polyethylenes with different properties. For example, polyethylene made from propylene is harder and more brittle than polyethylene made from ethylene.
- Copolymers are polymers made from more than one monomer. Copolymers of ethylene and propylene are called ethylene-propylene copolymers, or EPDM. EPDM is a tough, rubbery polymer that is resistant to oils, ozone, and weathering. It is used in the manufacture of hoses, belts, and seals.
