Plastics

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A. Extraction Plastics encompass most disposable items that American use daily, such as plastic water bottles, food containers, and trash bags. Plastics are cheap, lightweight, strong, tough, and corrosion resistant and have high thermal and electrical insulation properties (Thompson et al, 2009). 3-4% of world oil and gas usage is used to manufacture plastics and 4% is used as a component of plastics. Plastics are mostly derived from petrochemicals produced from fossil oil and gas (Thompson et al, 2009). The most commonly used plastic is polypropylene, which is used to make food carriers, such as yogurt cups and Ziploc bags (Andrady, 2009). Oil and natural gas are the primary raw materials of plastics. The process begins by treating components of oil or natural gas in the cracking process. This process results in the formation of hydrocarbon monomers (ethylene, propylene). These monomers are further processed into more monomers (stryene, ethylene glycol). These monomers are then bonded together by polymerization to form a polymer backbone, a reaction carried out by addition or condensation reactions (American Chemistry Council Inc, 2005) B. Produced Plastics are never used alone, usually additives are used to strengthen, thermal stabilizers, colorers, UV stabilizers, and fire retardants (Andrady, 2009). These additives are blended with plastics to improve their basic attributes. Plasticizers a specific type of additive is used to increase flexibility, and is sued in film wraps and flexible tubing. There are four main methods of processing plastics, extrusion, injection molding, blow molding, and rotational molding (American Chemistry Council, Inc, 2005). In extrusion plastic pellets are heated and then forced out through a ... ... middle of paper ... ...ttles) and HDPE milk bottles, these bottles can be recovered, sanitized and reused to make new PET and HDPE bottles. HDPE bottles can also be downgraded into plastic crates and bins or the production of the creation of plastic lumber. Feedstock 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 takes large amounts of energy to reverse the reactions that created the plastic (Hopewell et al, 2009). Source reduction is also an important resource conservation scheme that involves the use of less raw materials to create the same products. This accomplished by using less packaging of materials by redesigning products, using packaging that reduces the amount of waste, and reusing packaging.

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