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=**Polyethylene**= Polyethylene is the most commonly used type of plastic, by consumers, or for that matter anyone in the world. It is used for artificial flowers, straws, PBC pipes, cords, keyboards, or really many things. Polyethylene is resistant to water, acids, alkalis, and most solvents. It is the simplest form of a commercial polymer, because it is a chain of carbon atoms with two hydrogen atoms coming off of each (in the picture below). Polyethylene is produced by the polymerization of ethylene. It can be produced through five different types of polymerization, radical polymerization, anionic addition polymerization, ion coordination polymerization or cationic addition polymerization. Ziegler took a big part in the advancement in polyethylene. He received dozens of licenses, that earned him millions of dollars. At times though, polyethylene is more complicated. Instead of hydrogen atoms attached to the carbon, they will have long chains of polyethylene attached to them, this is called branched. When there is no branching, it is called linear polyethylene, which is stronger, but more difficult and expensive to make. Although, there are ten types of polyethylene, which are, ultra high molecular weight polyethylene, ultra low molecular weight polyethylene, high molecular weigh polyethylene, high density polyethylene, high density cross linked polyethylene, cross linked polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene and very low density polyethylene. For common commercial grades of medium-density and high-density polyethylene, the melting point is typically in the range 120 to 130 °C. The melting point for average commercial low-density polyethylene is typically 105 to 115 °C. The people who discovered this long chain of carbon were Karl Ziegler, Heinz Martin, Erhard Holzkamp, and Heinz Breil. Polyethylene, was first discovered in 1898 by Hans von Pechmann, by accident and the first practical use of it was discovered by Reginald Gibson and Eric Fawcett in 1933 in Britain. It evolved in two forms, as i mentioned before, low density polyethylene (branched), and high density polyethylene (linear). Low density polyethylene, is used more for films, grocery bags and packaging things, while high density polyethylene is used more for piping, car fittings, and containers. Polyethylene eventually led to the discovery of polypropylene.



Polyethylene Pipe
http://www.britannica.com/eb/article-260910/Karl-Ziegler http://www.3dchem.com/molecules.asp?ID=332 http://www.packagingtoday.com/introplasticexplosion.htm http://pslc.ws/macrog/pe.htm