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Know Your Plastics Series: Low Density Polyethylene

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Low-Density Polyethylene Acronyms and Resin Identification Number. As members of the polyolefin resin family, Low-Density Polyethylene and High-Density Polyethylene are the lightweight, versatile resins used in producing a majority of plastic products in the world. However, LDPE and HDPE differ at one central point – their molecular arrangement. . This difference lies in the structure of the long, chainlike molecules in polyethylene. When these molecules are linear, they form High-Density Polyethylene (HDPE); when branched, they are known as Low-Density Polyethylene (LDPE). Molecular Structure of HDPE and LDPE Low-Density Polyethylene is the result of placing gaseous ethylene with oxide initiators under very high pressures and temperatures. This process creates a structure consisting of both long and short branches that limits the compacting of the polyethylene molecules that should make it crystalline, stiff and hardy. LDPE is the very flexible material used in squeeze bottles, trash

Know Your Plastics Series: Polyvinyl Chloride.

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PVC: Resins, products and recycle code   Following polyethylene and polypropylene, polyvinyl chloride (PVC) is the third most widely used worldwide. In construction, PVC is fast replacing traditional building materials such as rubber, clay, wood, concrete, glass and metal. The first preparation of PVC was in 1935 by a French chemist, Henri Victor Regnault but was patented in 1912 by a German chemist, Freidrich Heinrich August Klatte. The first commercial production was done in 1926 by Waldo Lunsbury Semon while working for the US Company, B. F. Goodrich.   The product of his work is what is known as plasticized PVC today. Polyvinyl chloride is a thermoplastic that is generally white in colour, brittle, solid, odourless and quite popular. Available in pellets and powder form, its versatility cuts across numerous applications such as: Applications of PVC -           water pipes (drinking, waste, irrigation, industrial) -           garden hoses -           roofing and flooring