Polyethylene

Polyethylene, also known as polythene, is one of the most common types of plastic. There are many different kinds of polyethylene, most of which are identified by the chemical formula (C2H4)n.

Polyethylene is produced from ethylene which is typically obtained from petroleum or natural gas, as well as from less common renewable sources. Polyethylene has a wide range of uses, predominantly as packaging in the form of bags, sacks, films, geomembranes, containers, pipes, and so on.

Polyethylene has high ductility and impact strength as well as low friction and is a good electrical insulator. It also has good resistance to moisture. However, its uses are limited by its relatively low melting point of around 80 °C (176 °F), its low strength, hardness and rigidity.

Polyethylene can pose problems for waste management as it is non-biodegradable and so accumulates in large quantities in landfill sites. If it is incinerated, it can, under some circumstance, produce harmful gaseous emissions.

Its precise properties depend on the variable extent and type of branching, molecular weight and crystal structures. Different classifications are used for different applications; for example, high-density polyethylene is often used for pipes that are corrosion-resistant and leak-free.

In addition to pipes, some of the most common applications of polyethylene in construction include:

• Sheet (film) to provide protection for materials and seal off rooms.
• Damp-proof membranes (DPM).
• A loose lining material for foundations.
• To protect concrete during the curing process.
• A temporary flashing material for doors, windows and so on.

[edit] Related articles on Designing Buildings Wiki

• Acrylic.
• Architectural fabrics.
• Carbon fibre.
• Construction materials.
• Damp proof membrane DPM.
• ETFE.
• EVA film.
• Pipelines.
• Plastic.
• Polymers.
• Polypropylene.
• Polystyrene.
• Polyvinyl chloride PVC.
• PTFE.
• Site storage.