Polyethylene :: Polymer Plastic

German Chemist Hans von Pechmann first synthesized Polyethylene by accident in 1898 by heating diazomethane. His colleagues characterized the waxy substance polyethylene due to the fact that they recognized that it consisted of long ethene chains. It was then first industrially synthesized by accident in 1933 by applying extremely high pressure to ethylene and benzaldehyde. Over the years, development of polyethylene has increased due to the additions of catalyst. This makes ethylene polymerization possible at lower temperatures and pressures.1 Polyethylene is a polymer that is made of a long chain of CH2 monomers bonded together. It is one of the most commonly used polymers in everyday items. Grocery bags, soap bottles, children’s toys, and even bullet proof vests are all made from polyethylene.2 This polymer is very versatile and can be used in many materials but this all depends on the way that the polymer is chemically made or enhanced. There are many different types of polyethylene classified by density and branching. 2 Higher density polyethylene is very linear and has no branching. Lower density polyethylene is a result of some of the carbon atoms bonding with other polyethylene chains instead of hydrogen atoms. Cross-linking is another way in which the polymer can be made stronger. This involves ultraviolet radiation that bombards the polymer with electrons and formulates bonds between the molecular chains of the polymers. This is like linear polyethylene but different in that it is more impact resistant, and it has a much higher density. This allows it to be stored or be used with different chemicals that would normally cause the polymer to desolve.3 This can start to become a problem because as the polymer continues to become chemically enhanced. So the ways of dissolving and recycling the polymer become more difficult. Other alterations such as dying the polymer are less cost efficient to recycle and can be more difficult as well. There are certain types of HDPE (high density polyethylene) that are blown into shapes such as bottles. Different chemicals are used in this process and therefore have to be separated into their own category when recycling. The reason people have moved away from landfill dumping and moved towards recycling is due to the fact that it is much more cost effective to recycle compared to paying engineers and environmentalist to designing landfills.4 The HDPE can also be mechanically recycled through curb side pick ups.