Polyethylene(abbreviated PE) or polythene is the world’s most commonly used plastic. Polyethylenes are long polymers of ethylene subunits. They have a central chain, from which they can branch out. From the varing degree of branching, we get different types of polyethylenes.


Low-Density Polyethylene (LDPE)
Low density polyethylene plastic (LDPE) was discovered in 1933 by accident during an experiment conducted by Reginald Gibson and Eric Fawcett. Once discoverd, the two scientists began to process the polymer material, giving it the name “Polythene.”
LDPE contains many branches of high molecular weight, with a less compact molecular structure, making LDPE less dense. LDPE has much better flexibility, impact toughness, and resistance to environmental stress cracking than HDPE.
LDPE is often used to make plastic films and plastic bags. It is also used to make bottles and tubings, food storage containers, trays, laboratory storage containers, extrusion coatings, and cable insulation.


High-Density Polyethylene (HDPE)
In 1953, German chemists Karl Ziegler and Erhard Holzkamp invented high density polyethylene plastic (HDPE). For his successful invention of HDPE, Ziegler won the Nobel Prize for Chemistry in 1963.
HDPE is unbranched, so the polymers can be packed together much more tightly, making HDPE denser than LDPE. As a result, HDPE is stronger, more resistant to chemicals and less permeable than LDPE.
HDPE is often used to make containers for household and industrial chemicals. It is used to make bottles for milk and other drinks, food storage containers, toys, automotive supplies, folding chairs and tables, and various kinds of pipelines, etc.


Ultra-High Molecular Weight Polyethylene (UHMWPE)
UHMWPE is first commercially polymerized in 1955 by Ruhrchemie AG, Oberhausen, Germany. In that same year, the material was first introduced at the K55 Plastics Trade Show.
UHMW-PE is made up of extremely long chains, with molecular weight measured in the millions. The material has the highest impact strength among the polyethylenes. It has high abrasion resistance, low coefficient of friction, and excellent chemical resistance.
UHMWPE is often used to make wear strips, edge protection on ice rinks, gears, pistons, etc. UHMWPE is widely used as bearing material in total joint replacements.
Besides, there are many other grades in the PE family, such as Linear Low-Density Polyethylene(LLDPE), Medium Density Polyethylene (MDPE), etc. Our plastic crushers can crush PE materials into granules, which can be recycled for reproduction of plastic products.