Spandex, also known as Lycra or elastane, is a synthetic fiber that is prized for its exceptional elasticity. It is a polyether-polyurea copolymer that was invented in 1958 by chemist Joseph Shivers at DuPont. Spandex is mainly composed of a polyurea derived from the reaction of a diol and a diisocyanate. Two classes of spandex are defined by the "macrodiols". One class of macrodiols is the oligomer produced from tetrahydrofuran (i.e. polytetrahydrofuran). Another class of diols, the so-called ester diols, are oligomers derived from condensation of adipic acid and glycols. Spandex produced from the ester diols is more resilient photochemically and to chlorinated waters.
Spandex is highly elastic and strong, stretching up to five times its length. It is used in a wide range of garments, especially in skin-tight garments, due to its ability to return to the original shape after stretching and faster drying than ordinary fabrics. For clothing, spandex is usually mixed with cotton or polyester, and accounts for a small percentage of the final fabric, which therefore retains most of the look and feel of the other fibers. An estimated 80% of clothing sold in the United States contained spandex in 2010. Spandex is also used in relatively high percentages in cotton and wool socks, and is highly popular in sportswear, especially in swimwear, bicycling apparel, and types of clothing.
