Biodegradable Plastic Essay

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ABSTRACT Creating components with complex internal structures is a difficult business. Not only do you have to be able to define the necessary geometry, using a material that can withstand the conditions required for producing the component, but you’ve also got to be able to get rid of any unwanted material at the end of the process. The key to success is finding a suitable sacrificial material. In the ancient lost wax technique for producing cast metal components, wax was used, as the name implies. Now, the lost-wax technique is being updated for injection moulding with a new sacrificial material - an environmentally benign, water-soluble, biodegradable polymer known as ‘polyvinyl alcohol’. Polyvinyl alcohol is soluble in warm water but offers a range of mechanical properties that make it extremely useful in a number of applications. The properties of the basic material can be tailored to suit the application, for which it is being developed, and this is one of the key differences between ‘polyvinyl alcohol’ and earlier biodegradable plastics - it has user-controllable solubility in water. Depending on the formulation used, materials can be designed that dissolve at present temperature ranges centering on, for example, 20°C, 55°C or 80°C. After about two to twenty minute’s immersion at the designated temperature, the ‘polyvinyl alcohol’ polymer dissolves in water leaving a harmless, non-toxic aqueous solution of polyvinyl alcohol with a small amount of glycerol. Once this comes into contact with micro-organisms such as those found in water treatment plants, biodegradation to carbon dioxide and water takes place within about 30 days. These impressive properties open up a wide range of potential applications for the materials. The sacrificial nature of the materials is crucial in their current areas of use and should prove extremely attractive to product and

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