A polyethylene sheet is a plastic film made from one of the most commonly used plastics. Like all plastics, polyethylene is a petroleum product. It is a very strong plastic that can be found in items ranging from shopping bags to bulletproof vests. When made thin, with a thickness of about 0.01 to 0.4 inches (about 0.3 to 10 millimeters), this material is more properly called polyethylene film. These films are normally translucent, although they can be made opaque with the use of additives.
Thin sheets of polyethylene are sold in rolls and used in many commercial and industrial activities. The material does not rot, and it is resistant to many chemicals. It is not damaged by extreme weather, which makes it a good choice for many kinds of outdoor applications, and the sheets can be reused many times.
Polyethylene is used for many kinds of weatherproofing and can be a permanent weather barrier on exterior walls. It is used in construction and remodeling projects, especially as a vapor barrier in walls. The film is commonly used to temporarily seal off rooms and to cover building materials. Sheets can be used as a painter’s drop cloth or on top of curing concrete to help it retain moisture. Some tarpaulins and tents are made from polyethylene as well.
Sheets also have agricultural uses. They are often used as a weed barrier in landscaping projects, and they can be used as walls and roofs for a temporary greenhouse.
Thicker polyethylene sheets are rigid or semi-rigid. They have a high tensile strength and smooth surface, and are quite resistant to abrasion and environmental stress cracks. Normally, thicker sheets are white, but they can be produced in a variety of colors. Thick polyethylene is sold in panels of standard sizes. Sometimes, larger panels are molded with accordion folds to make them easier to transport, as they are extensively used in the construction industry.
High density polyethylene sheet is used for cutting boards, and it makes a strong, chemical-resistance worktop. This type of sheet is also frequently used for signs. Some is 2 inches (5.08 cm) thick.
Environmentalists have not been particularly fond of products made with polyethylene. The plastic takes centuries to decompose, so it is not considered a biodegradable material. It can be recycled, but most often, it is discarded. Work on finding ways to break it down does continue, however, and in 2008, a Canadian student found that one type of bacteria can degrade about 40% of a set quantity polyethylene plastic bags, as measured by weight, within three months.