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Polyethylene wax can be made by direct polymerization of ethylene under special conditions that control molecular weight and chain branching of the final polymer. Another method involves thermal and/or mechanical decomposition of high molecular weight polyethylene resin to create lower molecular weight fractions.
The main use of polyethylene and polypropylene waxes is in the formulation of colourants for plastics. Waxes confer matting effects (i.e., to confer non-glossy finishes) and wear resistance to paints. Polyethylene waxes are incorporated into inks in the form of dispersions to decrease friction.
Polyethylene was first synthesized by the German chemist Hans von Pechmann, who prepared it by accident in 1898 while investigating diazomethane. [12] [a] [13] [b] When his colleagues Eugen Bamberger and Friedrich Tschirner characterized the white, waxy substance that he had created, they recognized that it contained long −CH 2 − chains and termed it polymethylene.
A natural wax is chemically defined as an ester with a very long hydrocarbon chain that also includes a long chain alcohol. [2] Examples are: Stearic acid (E570) Beeswax (E901) Candelilla wax (E902) Carnauba wax (E903) Shellac (E904) Microcrystalline wax (E905c), Crystalline wax (E907) Lanolin (E913) Oxidized polyethylene wax (E914) Esters of ...
Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW) is a subset of the thermoplastic polyethylene. Also known as high-modulus polyethylene ( HMPE ), it has extremely long chains, with a molecular mass usually between 3.5 and 7.5 million amu . [ 1 ]
Polypropylene is commonly used in car bumpers, interior trims, and other components [19] where TiO₂ is added to improve the UV stability of the plastic, ensuring that parts do not degrade or lose color when exposed to sunlight over time. [20] Polyethylene films are widely used in agriculture for greenhouses, mulching, and silage wraps. [21]
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]
It has some of the properties of a low-density polyethylene but increased gloss (useful for film), softness and flexibility. The material is generally considered non-toxic. The EVA copolymer which is based on a medium proportion of VA (approximately 4 to 30%) is referred to as thermoplastic ethylene-vinyl acetate copolymer and is a ...