Polyethylene is a versatile thermoplastic polymer belonging to the polyolefin family.
It is composed of repeating units of ethylene (–CH₂–CH₂–) and is produced from petroleum or natural gas feedstocks.
Because of its favourable balance of properties, polyethylene is widely used in many applications including containers, piping, and industrial components.
Polyethylene exists in several forms, each with slightly different characteristics:
| Type | Description & Features |
|---|---|
| High-Density Polyethylene (HDPE) | Rigid and strong plastic with good chemical resistance and impact strength. Commonly used for drums, containers, piping, and structural parts. |
| Low-Density Polyethylene (LDPE) | More flexible and less dense. Used in films, bags, squeeze bottles, and insulation. |
| Linear Low-Density Polyethylene (LLDPE) | A variant of LDPE with a more linear structure combining flexibility of LDPE and improved strength and puncture resistance. |
However, like all materials, it has limits. Some strong solvents or extreme conditions may degrade polyethylene.
For example, many OilSafe containers use HDPE for their cans and lids because it offers a good barrier against moisture and durability in industrial settings.
Polyethylene is typically manufactured by polymerising ethylene monomers under controlled conditions (pressure, temperature, catalysts).
Different polymerisation methods or catalysts yield different structures (e.g. branching) and thus different grades (HDPE, LDPE, LLDPE).
Polyethylene is among the more recyclable plastics. HDPE and LDPE are commonly accepted by recycling programmes.
Its durability and resistance to degradation also make it a concern when disposed of improperly—polyethylene products may contribute to plastic pollution if not recycled.
Efforts are ongoing to improve recyclability, reduce plastic waste, and develop biodegradable or alternative materials.