J.+Todd+reaction+wiki

=Polyethylene=

Polyethylene is the world's most popular plastic. It is used in such items as shampoo bottles, bullet proof vests, toys, and so many more everyday items. It has one of the most simplest structures, it is just a bunch of carbon atoms with hydrogen atoms coming off of them (as you can see in this photograph). It can be more difficult then this shows it to be, but most of the time it will look like this. It was discovered in 1933 by Renigald Gibson and Eric Fawcett in an Imperial Chemistry Industrie in Britain. One day, they were applying high pressure to a mixture of ethylene and benzaldehyde, and they got a white waxy material, later found as, polyethylene. This material eventually separated into two different forms, low density polyethylene (LDPE) and high density polyethylene (HDPE). The low density is material such as plastic bags, high density is material such as containers. This reaction is used to make the plastic that is used in everyday life, every single da people pack lunch, or anything else into plastic bags or containers. As you can imagine alot of people by these things, so major industries that make plastic materials have to buy polyethylene all the time. They buy this to make sure there customers are getting there materials to help them live their everyday lives.

Briefcases are just one example of a material made of polyethylene used in everyday life.

Now i will get more into the three main types of polyethylenes.

First there is LDPE. These initials stand for Low Density Polyethylene. This type of material has good corrosion resistance and low moisture permeability. It is used where stiffness, high temperatures, and structural strength are not important. It is highly flexible product and is also frequently used in comsumer packaging, bags, bottles, and liners.

Next there is HDPE. These initials stand for High Density Polyethylene. It is the largest portion of the polyethylene materials. HDPE has excellent impact resistance, light weight, and low moisture absorption. This material is non-toxic and non-staining and meets FDA and USDA's rules for food processing.

The final one i will talk about is UHMW PE. This stands for Ultra High Molecular Weight Polyethylene. UHMW PE is the very best material for many parts in machinery and equipment such as storage containers. It is self-lubricating, shatter resistant, long-wearing, abrasion and corrosion resistant.

Linear polyethylenes are more complicated then normal polyethylenes. This occurs when the carbons do not not attach to hydrogens but instead to long branches of polyethylenes. When this happens it is known as LDPE (explained above). Non linear polethylenes, are known as HDPE(explained above), and this why HDPEs are known as the most common type of polyethylene.

Good Looks Doc

http://pslc.ws/macrog/pe.htm
 * Sources

http://www.packagingtoday.com/introplasticexplosion.htm

http://www.3dchem.com/molecules.asp?ID=332**