Polyethylene (PE) is an organic polymer made by the polymerization of monomer subunits. The chemical formula of polyethylene is (C2H4)n. Polyethylene is a combination of similar polymers of ethylene with different values of n. A typical polyethylene molecule can contain more than 500 ethylene subunits.

Polyethylene has shown good mechanical, thermal, chemical, electrical and optical properties. It is cheap, flexible, and electrically and chemically resistant.

Polyethylene is the most widely used plastic in the world. It can be processed into any shape for flexible or hard and strong products. It is used for lining tubes and tanks, and to wrap pipes to protect against corrosive materials.

Polyethylene is classified according to its density and branching. The three main types are:

1. High-density polyethylene (HDPE). HDPE has a low degree of branching. It is the sturdiest and most inflexible type. It has high tensile strength and is used to produce milk jugs, detergent bottles, butter tubs, garbage containers and water pipes.
2. Low-density polyethylene (LDPE). LDPE has a high degree of short- and long-chain branching, which give it a lower tensile strength and increased ductility. This gives molten LDPE unique and desirable flow properties. It is used for both rigid containers and plastic film applications, such as plastic bags and film wrap