Polystyrene

Alex Yang

**__Polystyrene__**



__** Properties of polystyrene **__


 * Density || 1.05 g/cm**3** ||
 * Thermal conductivity (k) || 0.08 W/(m·K) ||
 * Melting point || 240 °C ||
 * Molecular weight of repeat unit || 1.04.1 g/mol ||

**__How it was made__**
 * There are 2 main types of polystyrene: pure solid polystyrene, and solid foam polystyrene.
 * Pure solid polystyrene is made from monomer styrene, which is a liquid hydrocarbon that is manufactured from petroleum.
 * Solid foam polystyrene is made by combining ethylene and benzene to make styrene. Other chemicals are then added to styrene which causes the styrene molecules to polymerize. after the reaction has taken place, small beads are created. After cooling and cleaning the beads, the beads are then heated with hot air until their density is 3% of its original. After cooling it once again, the expanded beads are then placed inside a mold. Once inside the mold, they are injected with low-pressure steam, which expands the bead more and fuses them together. After fusion has taken place, the mold has to be cooled again.

__** How it affects us **__ With the 2 main types of polystyrene, there are many uses for it. Pure solid polystyrene is used for producing plastic model assembly kits, plastic cutlery, CD cases,  smoke detector housings, licenses plate frames, petri dishes and many other objects where plastic is needed. Foams are another form of polystyrene, with 2 main branches of foam, expanded polystyrene, there are endless possibilities of where these foams can be used in. Because of the good thermal insulation, expanded polystyrene can provide, it could be used for building insulation. Expanded polystyrene is also used for foam cups, ice coolers, wine shippers, box packaging and many more. Even though polystyrene is a very convenient material, disposing polystyrene has drawbacks.
 * can take up large spaces
 * meat packaging is contaminated with blood, fluids so it can be a health hazard
 * not biodegradable for 500 years

__** Interesting fact **__ Polystyrene was accidentally discovered in 1839 by Eduard Simon when he distilled an oily substance which he named styrol, a monomer. A few days later Simon noticed the substance has hardened and assumed it has oxidized. Six years later, English chemist John Blyth and German chemist August Willhelm von Hoffmann proved the reaction took place with out the oxygen. They called the substance metastyrol. It was later analyzed and shown that it was chemicaly identical to Styroloxyd. It was Marcelin Berthelot that identified the formation of metastyrol from styrol as a polymeriztion process in 1866. It was realized that heating up the styrol created a chain of reaction that produces macromolecules, which was a thesis of German organic chemist Hermann Staudinger. The present name polystyrene was given shortly after.

__** Sources **__
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 * //"//What is expanded polystyrene" //June. 03, 2010. <http://www.wisegeek.com/what-is-expanded-polystyrene.htm>//
 * //"//What Is The Difference Between Styrofoam and Expanded Polystyrene EPS Foam? " //June. 03, 2010. <http://www.youtube.com/watch?v=5qSSchUSbyY>//
 * //"//Invention of Polystyrene and Styrofoam" //June. 03, 2010. <http://inventors.about.com/od/pstartinventions/a/styrofoam.htm>//
 * //"//What are the Different Uses of Polystyrene?//" June. 02, 2010. <What are the Different Uses of Polystyrene?>//
 * //"//File:Polystyrene formation.PNG//" June. 02, 2010. <http://en.wikipedia.org/wiki/File:Polystyrene_formation.PNG>