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  • Essay / Plastics - 917

    A. ExtractionPlastics encompasses most of the disposable items that Americans use every day, such as plastic water bottles, food containers and trash bags. Plastics are cheap, lightweight, strong, corrosion resistant and have high thermal and electrical insulation properties (Thompson et al, 2009). 3-4% of global oil and gas consumption is used to make plastics and 4% is used as components of plastics. Plastics mainly come from petrochemicals produced from fossil oil and gas (Thompson et al, 2009). The most commonly used plastic is polypropylene, which is used in the manufacture of food carriers, such as yogurt pots and Ziploc bags (Andrady, 2009). Oil and natural gas are the main raw materials for plastics. The process begins by processing the components of the oil or natural gas during the cracking process. This process results in the formation of hydrocarbon monomers (ethylene, propylene). These monomers are then transformed into more monomers (stryene, ethylene glycol). These monomers are then linked together by polymerization to form a polymer backbone, a reaction carried out by addition or condensation reactions (American Chemistry Council Inc, 2005)B. The plastics produced are never used alone, additives are generally used to reinforce, thermal stabilizers, dyes, UV stabilizers and flame retardants (Andrady, 2009). These additives are mixed into plastics to improve their basic attributes. Plasticizers, a specific type of additive is used to increase flexibility and is used in packaging films and flexible tubes. There are four main methods of processing plastics: extrusion, injection molding, blow molding, and rotational molding (American Chemistry Council, Inc, 2005). During extrusion, plastic pellets are heated and then expelled through a medium of paper (bottles) and HDPE milk bottles, these bottles can be collected, disinfected and reused to make new bottles in PET and HDPE. . HDPE bottles can also be downgraded into plastic crates and bins or into the production of plastic lumber. Raw material recycling can recover the raw materials (oil and natural gas) used to create the plastic. These recovered raw materials can be used to make new plastics or other synthetic materials. This process is sometimes uneconomical because it requires large amounts of energy to reverse the reactions that created the plastic (Hopewell et al, 2009). Source reduction is also an important resource conservation program that involves using fewer raw materials to create the same products. This is accomplished by using less packaging materials by redesigning products, using packaging that reduces the amount of waste, and reusing packaging..