Unit_8_-_Plastic_Packaging

Unit_8_-_Plastic_Packaging - Unit 8 Plastic Packaging In...

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8. 1 Unit 8 Plastic Packaging In this unit we will learn about plastics used for packaging. This includes a brief history of plastics, packaging plastics and their identifiers and properties, and how plastic packages are produced. 8.1 Brief History of Plastics The first synthetic plastic, a form of cellulose nitrate called Parkesine, was invented in 1838 by A. Parker and was presented at the Great International Exhibition in London. Parkesine was developed to replace some natural materials, particularly ivory used for billiard balls. During the late 1860s, J. Wesley Hyatt developed celluloid from a homogeneous colloidal dispersion of cellulose nitrate and camphor, and in 1907, L. Baekeland developed another synthetic plastic material, phenol formaldehyde, commonly known as Bakelite. A natural polymer of significance was Gutta-percha, made from the sap of rubber trees. It could be molded into shapes which would harden. This early form of "plastic" was used for tool handles, and similar applications around the mid-1800s. The exact nature of plastics, rubber, and similar natural materials was not known until 1920 when H. Staundinger proposed that all plastics, rubber, and materials such as cellulose were macromolecules or "polymers". This explanation permitted the rational interpretation of experiments and gave industrial chemists a firm guide for their work, consequently becoming the spark for the development of many new polymer materials. Since 1930, the growth in the number of polymers has been rapid. Low density polyethylene (LDPE), polystyrene (PS), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polymethyl methacrylate, polyvinylacetate (PVA) and Nylon 66, were all developed during the 1930s. During the 1940s, polytetrafluoroethylene, unsaturated polyesters, polyethylene (PE), butyl rubber, Nylon 6, fluoropolymers, silicones, polyethylene terephthalate (PET), epoxies and ABS resins were developed. Polypropylene (PP), polycarbonate (PC), ionomers, polyamides, moldable elastomers, ethylene vinyl alcohol (EVOH), methalocene polymers and polyethylene naphthalate have all been invented since the 1950s. Applications were slow at first. One of the most significant early applications was the use of polyethylene to waterproof wires and other components in RADAR, SONAR, and similar equipment that was first used during WWII. Polyethylene insulation was more effective than earlier rubber based materials and greatly improved the reliability of the equipment. Since that time, applications of plastic have exploded onto the commercial landscape. In packaging, plastic containers have replaced many of the metal, glass, paper, or wood packages that were formerly used for many products. Many new products have been introduced that are made of plastic and/or have plastic packaging. Many of these products would have been impossible to develop without plastic. Today, more than 100 million tons of plastics are made each year, and thousands of
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This note was uploaded on 10/17/2011 for the course PKG 101 taught by Professor Haroldhughes during the Spring '08 term at Michigan State University.

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Unit_8_-_Plastic_Packaging - Unit 8 Plastic Packaging In...

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