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polyester fiber[′päl·ē‚es·tər ′fī·bər]
a synthetic fiber formed from a polyethylene terephthalate melt. Polyester fibers surpass most natural and chemical fibers in thermostability, as they retain 50 percent of their strength at 180°C. They do not catch fire easily and go out once the source of ignition is removed; no charring occurs upon contact with a spark or electric arc. The fibers also are relatively weather-resistant. They are soluble in phenols and partly soluble (with decomposition) in concentrated sulfuric and nitric acids, but they decompose completely when boiled in concentrated alkalies. Steam processing at 100°C reduces fiber strength (0.12 percent after 1 hr) owing to partial hydrolysis of the polymer. Polyester fibers are resistant to acetone, carbon tetrachloride, dichloroethane, and other solvents. They also resist deterioration from microorganisms, moths, molds, and carpet beetles. The resistance of polyester fibers to abrasion and multiple flexure is lower than that of polyamide fibers, whereas the impact strength is higher. The fibers display higher tensile strength than other types of chemical fibers.
Polyester fibers have the following deficiencies: they are difficult to dye by the usual methods, they have strong electrostatic properties and a tendency to peel, and the fabrics are stiff. These weaknesses are eliminated in many cases by introducing a chemical modification of polyethylene terephthalate, for example, dimethyl isophthalate or dimethyl adipinate. (These compounds are added to the reaction mixture during the synthesis of polyethylene terephthalate.)
Commercial polyester fibers are used in the manufacture of conveyer belts, transmission belts, ropes, cables, sails, fishing nets and trawls, gasoline-resistant and oilproof hoses, electrical insulating materials, filtering materials, and tire cord. They have also been used successfully in medicine (synthetic arterial grafts, surgical thread). The monofilament is used in the manufacture of netting for paper-making machines, brushes for cotton-harvesting machines, and strings for sports rackets. Commercial fibers are used in the manufacture of knitwear, tafetta-like fabrics, and crepes. Bulky yarn, such as Crimplene and Melane, is obtained by false twisting. Polyester staples are blended with wool, cotton, or linen for the manufacture of fabrics for suits, coats, shirts, dresses, and tulle curtains. Polyester fibers in pure or mixed form are used to make synthetic furs and carpets. Felt made from polyester fibers surpasses felt made from natural wool in basic properties.
Polyester fibers are manufactured under the following trade names: Lavsan (USSR), Terylene (Great Britain), Dacron (United States), Tetoron (Japan), Elana (Poland), Tergal (France), and Tesil (Czechoslovakia). World production of polyester fibers totaled approximately 3.4 million tons in 1975.