High density polyethylene (HDPE) is a polyethylene thermoplastic made from petroleum. It takes 1.75 kilograms of petroleum (in terms of energy and raw materials) to make one kilogram of HDPE. HDPE has little branching, giving it stronger intermolecular forces and tensile strength than lower density polyethylene, HDPE is also somewhat harder and more opaque and it can withstand rather higher temperatures (120° Celsius for short periods, 110° Celsius continuously). The lack of branching is ensured by an appropriate choice of catalyst (e.g. Ziegler-Natta catalysts) and reaction conditions.

HDPE is resistant to many different solvents and has a wide variety of applications, including:

• Containers
  • Tupperware
  • Laundry detergent bottles
  • Milk cartons
• Plastic bags
• Containment of certain chemicals
• Chemical-resistant piping systems
• Geothermal heat transfer piping systems