* Properties Polyethylene is a non-polar (low dielectric) material with outstanding hydrophobic and electrical insultating properties. Chemically, polyethylene can be regarded as a high molecular weigth paraffin and rather inert material. PE is unaffected by most of acids (such as concentrated nitric acid), alkalis (such as NaOH solution) and agueous solutions. * Fabrication and Applications PE polymers (HDPE, LLDPE and LDPE) are the most friendly material in fabrication, which can be done by almost all existing processing methods. The polymers can be easily recycled and reused. FDA approves for using PE in food contact. HDPE (strength, stiffness and low permeability) Extrusion grades of high molecular weight HDPE are used mainly for manufactutre of pipe, film and steel-pipe coating. The largest PE pipe diameter available is 1.6 m. Film extrusion process sometime combines with an orientation process by streching PE film in a water both at 90 oC at ratios of 1:7 to 1:10. The orientation improves mechanical strength. Film is used for heavy-duty
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UHMWPE, high molecular weight, Ultra high molecular weight polyethylene, molecular weight HDPE