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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]
Black plastic bags were introduced in 1950 as star sealed bags. The first bags in the United States were green and black, rather than the now-common white and clear. Flat-sealed bags first appeared in 1959. In the 1960s, the white bin bags were introduced. Two-ply (Heavy Duty) bags were introduced in 1974, with 3 ply bags following in 1980.
A plastic bag, poly bag, or pouch is a type of container made of thin, flexible, plastic film, nonwoven fabric, or plastic textile.Plastic bags are used for containing and transporting goods such as foods, produce, powders, ice, magazines, chemicals, and waste.
Plastic films are typically formed into rolls by roll slitting. Often additional coating or printing operations are also used. Films can be modified by physical vapor deposition to make metallised films. Films can be subjected to corona treatment or plasma processing; films can have release agents applied as needed.
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]
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.
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