Spandex in the context of "Copolymer"

Polyurethane (/ˌpɒliˈjʊərəˌθeɪn, -jʊəˈrɛθeɪn/; often abbreviated as PUR and PU) is a class of polymers composed of organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane refers to a group of polymers. Unlike polyethylene and polystyrene, polyurethanes can be produced from a wide range of starting materials, resulting in various polymers within the same group. This chemical variety produces polyurethanes with different chemical structures leading to many different applications. These include rigid and flexible foams, and coatings, adhesives, electrical potting compounds, and fibers such as spandex and polyurethane laminate (PUL). Foams are the largest application accounting for 67% of all polyurethane produced in 2016.

A polyurethane is typically produced by reacting a polymeric isocyanate with a polyol. Since a polyurethane contains two types of monomers, which polymerize one after the other, they are classed as alternating copolymers. Both the isocyanates and polyols used to make a polyurethane contain two or more functional groups per molecule.

A wetsuit is a garment worn to provide thermal protection while wet. It is usually made of foamed neoprene, and is worn by surfers, divers, windsurfers, canoeists, and others engaged in water sports and other activities in or on the water. Its purpose is to provide thermal insulation and protection from abrasion, ultraviolet exposure, and stings from marine organisms. It also contributes extra buoyancy. The insulation properties of neoprene foam depend mainly on bubbles of gas enclosed within the material, which reduce its ability to conduct heat. The bubbles also give the wetsuit a low density, providing buoyancy in water.

Hugh Bradner, a University of California, Berkeley, physicist, invented the modern wetsuit in 1952. Wetsuits became available in the mid-1950s and evolved as the relatively fragile foamed neoprene was first backed, and later sandwiched, with thin sheets of tougher material such as nylon or later spandex (also known as lycra). Improvements in the way joints in the wetsuit were made by gluing, taping and blind-stitching, helped the suit to remain waterproof and reduce flushing, the replacement of water trapped between suit and body by cold water from the outside. Further improvements in the seals at the neck, wrists, ankles, and zippers produced a suit known as a "semi-dry".

Slim-fit pants or skinny jeans (when made of denim) are tight trousers that have a snug fit through the legs and end in a small leg opening that can be anywhere from 9" to 20" in circumference, depending on size. Other names for this style include drainpipes, stovepipes, tight pants, cigarette pants, pencil pants, skinny pants, gas pipes, skinnies, and tight jeans.

Skinny pants taper completely at the bottom of the leg, whereas drainpipes are skinny but then the lower leg is straight instead of tapering and so they are often slightly baggier at the bottom of the leg than skinny jeans. In some very skinny styles, zippers are needed at the bottom of the leg to facilitate pulling them over the feet because the leg opening is so small. Stretch denim, with anywhere from 2% to 4% spandex, may be used to allow jeans to have a "super-slim fit". Skinny jeans come in a variety of colors and styles.

A bodysuit is a one-piece form-fitting or skin-tight garment that covers the torso and the crotch. The design of a basic bodysuit is similar to a one-piece swimsuit and a leotard, though the materials may vary. Thong or T-front thong bodysuits usually have the crotch opening moved up to the front to underbelly area to increase the wearer's comfort. A bodysuit may have sleeves and varying shoulder strap and collar. Bodysuits can be made from a number of fabrics, including cotton, lace, nylon, etc. In general, textile bodysuits include expandable fiber such as spandex for a better fit to the shape of the body.

A bodysuit is normally worn with trousers or a skirt. The top, torso part may act as a top for the smooth line it gives or because it cannot become untucked from trousers or skirt. They may also be worn generally by women as underwear, activewear, or foundation garments. Unlike a leotard, a bodysuit is not usually considered a form of athletic wear.