Polyethylene (PE) denotes a sizeable family of plastics, including LDPE, MDPE and HDPE. We will confine ourselves here to the properties of HDPE. An important field of application of PE is tape and foil, among other things for packaging purposes and in the agricultural and market gardening sectors. Thanks to its high impact resistance – even at low temperatures – and its resistance to aggressive liquids, PE is frequently used in the production of thick-walled tubes for water, gas and chemicals.
PE has extremely low moisture absorption, i.e. 0.02% when saturated. The melting point is very low, i.e. 130°C: reinforced PE exhibits acceptable cold deformation at temperatures up to 70°C. As a crystalline, non-polar material, PE can excellently withstand chemicals, especially aliphatic hydrocarbons (including petrol, oil and grease), hot water, alkaline substances, alcohol and diluted acids. It is not resistant to oxidising acids, some aromatic and chlorinated hydrocarbons and ketones.
Even at room temperature PE cannot withstand deformation, so the mechanical load must remain low. Reinforced PE has excellent impact resistance, even at temperatures below -40°C. Electrical resistance is extremely high.