Polyethylene or polyethylene is one of the simplest and cheapest polymers. Polyethylene is a waxy and inactive solid. It is obtained by polymerization of ethylene and is abbreviated as PE.

Types of polyethylene:
Polyethylenes are classified based on their density, which is involved in the amount of density, the size of the polymer chain and the type and number of branches in the chain.
HDPE (High Density Polyethylene)
This polyethylene has a higher tensile strength than other polyethylenes.
LDPE (Low Density Polyethylene)
This polyethylene has low tensile strength. Other properties of this polymer are flexibility and the possibility of degradation by microorganisms.
LLDPE (Low Density Linear Polyethylene)
This polyethylene is a linear polymer with a number of short branches and is usually formed by the copolymerization of ethylene with long chain alkenes.
MDPE
Medium density polyethylene.
Uses:

Polyethylene is widely used in the production of various plastic appliances used in the kitchen and food industries. LDPE is used in the production of lightweight plastic containers as well as plastic bags. HDPE is used in the production of milk and liquid containers and all kinds of plastic kitchen utensils. MDPE is commonly used in the production of pipes and piping fittings.
Due to its high degree of flexibility, LLDPE is used in the production of a variety of flexible plastic devices such as bendable tubes. Recently, many researches have been done in the production of polyethylenes with long chains and short branches. These polyethylenes are originally HDPE with a number of side branches. These polyethylenes have a combination of HDPE strength and LDPE flexibility.