Polyethylene (PE) is one of the most widely used thermoplastic polymers in the world, accounting for some 30% of all plastic production. Cheap and simple to produce, it boasts many physical and chemical properties, making it highly popular in all sectors of industry.
Origins and classification
Polyethylene is produced by the polymerisation of ethylene, obtained by breaking down or ‘cracking’ naphtha, a derivative of crude oil. Polyethylene comes in granules.
Right from manufacture, polyethylene can have a variety of different characteristics. High-density Polyethylene (HDPE) is manufactured at low pressure. It is impact-resistant and is a good insulator, even in damp environments, and may be used with food products. Higher pressure produces Low Density Polyethylene (LDPE). This has similar characteristics but is more rigid, stronger (with better temperature resistance) and more transparent.
Very high density PE boasts a better strength-to-mass ratio than Kevlar, enabling it to be used in the design of sports equipment such as skis and surfboards, as well as motorbike gear and bullet-proof vests.
Resistant and waterproof
Polyethylene is impact-resistant, frostproof, corrosion resistant and impermeable, so it was soon used to protect goods (packaging and over-packaging).
Complete chemical inertia
Polyethylene consists solely of carbon and hydrogen molecules, making it completely chemically inert and thus widely used in agri-business and pharmaceuticals, due to it being completely non-toxic.
An extremely affordable material
The production of polyethylene requires very little raw materials and is one of the most accessible, affordable polymers.
Polyethylene is indefinitely recyclable, making it an outstanding contributor to the sustainable development of industry. It does not give off any toxic gases when it combusts, making it an excellent source of energy at the end of its life. Since it is chemically inert, it represents no danger to human health.
Polyethylene can easily be stretched and is thermoplastic, allowing a wide range of models to be developed and reducing thickness. Its characteristics have also allowed stretchable and shrinkable films to be developed - especially useful for automated packaging.
Easy to work, water-repellent and non-abrasive, polyethylene is an excellent protective film for many industrial applications.
Benefits for health applications
Polyethylene is inert, suitable for food contact and can be sterilised by radiation, making it ideal for the healthcare industry.