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Low-density polyethylene is produced by the high-pressure process by radical polymerization, thereby numerous short chain branches as well as long chain branches are formed. Short chain branches are formed by intramolecular chain transfer reactions, they are always butyl or ethyl chain branches because the reaction proceeds after the following ...
Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene. It was the first grade of polyethylene, produced in 1933 by John C. Swallow and M.W Perrin who were working for Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. [1] Its manufacture employs the same method today.
HDPE is known for its high strength-to-density ratio. [4] The density of HDPE ranges from 930 to 970 kg/m 3. [5] Although the density of HDPE is only marginally higher than that of low-density polyethylene, HDPE has little branching, giving it stronger intermolecular forces and tensile strength (38 MPa versus 21 MPa) than LDPE. [6]
High-density polyethylene (HDPE or PE-HD) Polyvinyl chloride (PVC or V) Low-density polyethylene (LDPE or PE-LD), Polypropylene (PP) Polystyrene (PS) Polyurethanes (PUR) and PP&A fibers [18] are often also included as major commodity classes, although they usually lack RICs, as they are chemically quite diverse groups.
Polyethylene – The most common plastic film is made of one of the varieties of polyethylene: low-density polyethylene, medium-density polyethylene, high-density polyethylene, or linear low-density polyethylene. Polypropylene – Polypropylene can be made a cast film, biaxially oriented film (BOPP), or as a uniaxially oriented film.
Linear low-density polyethylene differs structurally from conventional low-density polyethylene (LDPE) because of the absence of long chain branching. The linearity of LLDPE results from the different manufacturing processes of LLDPE and LDPE. In general, LLDPE is produced at lower temperatures and pressures by copolymerization of ethylene and ...
The degradation of polyethylene occurs by random scission—a random breakage of the bonds that hold the atoms of the polymer together. When heated above 450 °C, polyethylene degrades to form a mixture of hydrocarbons. In the case of chain-end scission, monomers are released and this process is referred to as unzipping or depolymerization ...
The ethene molecule (known almost universally by its common name ethylene) C 2 H 4 is CH 2 =CH 2, Two CH 2 groups connected by a double bond, thus: Polyethylene is created through polymerization of ethene. It can be produced through radical polymerization, anionic addition polymerization, ion coordination polymerization or cationic addition ...