Manufacture and Composition
Traditional plastic bags are usually made from polyethylene, which consists of long chains of ethylene monomers. Ethylene is derived from natural gas and petroleum. The polyethylene used in most plastic shopping bags is either low-density (resin identification code 4) or, more often, high-density (resin identification code 2). Color concentrates and other additives are often used to add tint to the plastic. Plastic shopping bags are commonly manufactured by blown film extrusion.
Read more about this topic: Plastic Shopping Bag
Famous quotes containing the words manufacture and, manufacture and/or composition:
“I believe that the miseries consequent on the manufacture and sale of intoxicating liquors are so great as imperiously to command the attention of all dedicated lives; and that while the abolition of American slavery was numerically first, the abolition of the liquor traffic is not morally second.”
—Elizabeth Stuart Phelps (1844–1911)
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“Give a scientist a problem and he will probably provide a solution; historians and sociologists, by contrast, can offer only opinions. Ask a dozen chemists the composition of an organic compound such as methane, and within a short time all twelve will have come up with the same solution of CH4. Ask, however, a dozen economists or sociologists to provide policies to reduce unemployment or the level of crime and twelve widely differing opinions are likely to be offered.”
—Derek Gjertsen, British scientist, author. Science and Philosophy: Past and Present, ch. 3, Penguin (1989)