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Plastics
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Plastics are polymers: long chains of atoms bonded to one another. Common thermoplastics range from 20,000 to 500,000 in molecular weight, while thermosets are assumed to have infinite molecular weight. These chains are made up of many repeating molecular units, known as "repeat units", derived from "monomers"; each polymer chain will have several 1000's of repeat units. The vast majority of plastics are composed of polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur in the backbone. (Some of commercial interest are silicon based.) The backbone is that part of the chain on the main "path" linking a large number of repeat units together. To vary the properties of plastics, both the repeat unit with different molecular groups "hanging" or "pendant" from the backbone, (usually they are "hung" as part of the monomers before linking monomers together to form the polymer chain).
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Plastics that can be disolved in water or the first biodegradable Formula 1 car, are some of the innovations to be presented during the Third International Seminar about biodegradable plastics, in Valencia (Spain) on the 7th March 2008. The seminar is
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Plastics have some disadvantages. When burned, some plastics produce poisonous fumes. Although certain plastics are specifically designed to withstand temperatures as high as 288° C (550° F), in general plastics are not used when high heat resistance is needed. Because of their molecular stability, plastics do not easily break down into simpler components. As a result, disposal of plastics creates a solid waste problem (see Plastics and the Environment below).
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Started in 1986, E & O Tool & Plastics, Inc. has developed into a full-service injection molding company, utilizing 41 presses, ranging in size from 38 to 500 tons. The Minnesota Corporation has plastic molding operations in Elk River Minnesota and Monterrey Mexico, with in house mold building in Elk River .
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Value Plastics® designs and manufactures an extensive line of over 3,100 fittings and connectors for plastic tubing. Major product areas include quick connect fittings (quick disconnect couplings), luer fittings and connectors, tubing fittings and connectors up to 1†(25.4 mm) ID, fittings and connectors joining plastic tubing to threaded ports, blood pressure fittings and connectors, and prototyping (bondable) fittings and connectors.
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Plastics continue to be improved. General Electric introduced Lexan, a high-impact polycarbonate plastic, in the 1970s. Du Pont developed Kevlar®, an extremely strong synthetic fiber that was best known for its use in ballistic rated clothing and combat helmets. Kevlar was so impressive that its manufacturer, DuPont, deemed it necessary to release an official statement denying alien involvement. [5]
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