polyethylene [pol″e-eth´ĭ-lēn] polymerized ethylene, (—CH2—CH2—)n, a synthetic plastic material, forms of which have been used in reparative surgery. High-density polyethylene definition, polyethylene consisting mainly of linear, or unbranched, chains with high crystallinity and melting point, and density of 0.96 or more, produced at low pressure and used chiefly for containers and articles made by injection molding. Polyethylene chemical formula is (C 2 H 4) n. LLDPE (Linear-Low Density Polyethylene) is defined by a density range of 0.915 - 0.925 g/cm 3. is a substantially linear polymer, with significant numbers of short branches, commonly made by copolymerization of ethylene with short-chain alpha-olefins (e.g. Based on this mechanism, there are two types of polymerization. Cross-linked polyethylene, commonly abbreviated PEX, XPE or XLPE, is a form of polyethylene with cross-links.It is used predominantly in building services pipework systems, hydronic radiant heating and cooling systems, domestic water piping, and insulation for high tension (high voltage) electrical cables. Manufacture: HDPE is a type of polyethylene, the most common plastic which accounts for over 34% of the global plastic market. Polyethylene is used in applications ranging for films, tubes, plastic parts, laminates, etc. Polyethylene (PE) is an organic polymer made by the polymerization of monomer subunits. in several markets (packaging, automotive, electrical, etc.). Polyethylene is a good example for polyolefin. Physical Chemistry and Mechanical Properties of HDPE High-density polyethylene (HDPE)(0.941