Answer: Polyethylene (PE), one of the most widely used plastics, is produced through the polymerization of ethylene, a hydrocarbon derived from natural gas or petroleum. The process varies depending on the type of polyethylene—high-density (HDPE), low-density (LDPE), or linear low-density (LLDPE)—but follows a general framework.
First, ethylene is obtained via steam cracking, where hydrocarbons like ethane or naphtha are heated to 750–900°C, breaking them into smaller molecules, including ethylene gas. This gas is purified and compressed. Polymerization then occurs in one of two primary methods: high-pressure or low-pressure processes.