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=**Polyethylene**= = = <<This shows the chain of CH2 that is Polyethylene.

Polyethylene is a common Polymer made up of chains of repeating CH2. It's monomer, and what it is created from, is ethylene. Polyethylene can have many different properties depending on the conditions it is created under, generally it forms two main types of polyethylene, HDPE (High Density Polyethylene which is linear) or LDPE (Low Density Polyethylene which is branched). HDPE is hard and has a large molar mass, it's used to make hard plastic containers, toys, drums, crates and other hard plastics. LDPE is soft with a lower molar mass and is used in making plastic bags, plastic rings holding cans of soda together, computer hardware, plastic containers such as those used in labs and other thin, flexible plastic objects. From those two types of polyethylene different strengths were formed including, Very Low Density Polyethylene, Linear low density Polyethylene, Ultra high Molecular weight Polyethylene, Ultra Low molecular Weight Polyethylene, High molecular weight Polyethylene, High Density cross-linked polyethylene, Cross linked Polyethylene and Medium density polyethylene, all having different strengths and uses. Polyethylene is an important part of modern culture and unknown to most is a huge part of our everyday life.

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Polyethylene was discovered accidentally in 1932 when scientists were looking for new reactions under high pressure. In one of the failed experiments Polyethylene was formed on the walls of the container the reaction was to happen in. when they tried to repeat the experiment without adding a chemical they believed had no part in the formation of this new substance, that only the ethylene created it, the sealed vessel containing the ethylene leaked allowing air to get in, but the polyethylene still formed. When they tried again, making sure the container would not leak, no Polyethylene was formed so they learned that Oxygen must be present for the polyethylene to form. Since it was discovered during World War II the first application for polyethylene was for warfare, mainly as radar insulator. After the war however it quickly found many commercial uses. This early Polyethylene is what we know of now as LDPE, it was not as useful as HDPE is now because of it's low melting point. In 1953 Karl Ziegler solved this problem and was able to create HDPE which could handle boiling liquids without melting. unfortunately this had it's own problems, mainly cracking, and most of this Polyethylene went to making the popular toy, the Hula-Hoop. Alterations were made until the Polyethylene was the desired strength.

<<Hula hoops were some of the first toys made of Polyethylene (HDPE).

The only waste left from the formation of polyethylene is excess plastic which can be recycled back into other plastic materials.

Current problems in Polyethylene production is the rising cost. Higher energy costs in general impact the price and production of ethylene used to make polyethylene, this increased price is having an affect but producers are optimistic that this rise in price will not affect production.

Bibliography: [|http://www.personal.rdg.ac.uk/~spsolley/pe.html] http://pslc.ws/macrog/pe.htm http://news.dow.com/dow_news/prodbus/2006pricing/20060801d.htm http://www.spipipe.com/PDF/PEprices01-04.pdf