Nylon parachute

Nylon Parachutes, synthetic silk, clothing Very tough, withstands hot water... 

Between 1935 and 1939, coverage of chemistry in Science Service s main product - the 40-50 stories sold every week through a syndicated service called Daily Mail Report - increased steadily from approximately 2% of stories during sampled weeks in September 1935 to 7% in March 1936, 11% in December 1938, 11% in May 1939, and 17% in October 1939.23 Attention probably increased because of the achievements of interdisciplinary research with obvious relevance to consumers, such as work on sulfanilamide, plant hormones, fabrics, and insecticides. In 1936, stories discussed rayon and chemical production at Tennessee Valley Authority plants in 1939, they paid attention to liquid helium and nylon parachutes. It was a view of chemistry as integrated smoothly into -and essential contributor to - the scientific whole. 

Leaving aside rayon and artificial silks generally, the first really effective polymeric textile fibre was nylon, discovered by the chemist Wallace Hume Carothers (1896-1937) in the Du Pont research laboratories in America in 1935, and first put into production in 1940, just in time to make parachutes for the wartime forces. This was the first of several major commodity polymer fibres and, together with high-density polyethylene introduced about the same time and Terylene , polyethylene tereph-thalate, introduced in 1941 (the American version is Dacron), transformed the place of polymers in the materials pantheon. 

Nylons have a variety of uses ranging from tire cord to carpet to hosiery. The most important application is cord followed by apparel. Nylon staple and filaments are extensively used in the carpet industry. Nylon fiber is also used for a variety of other articles such as seat belts, monofilament finishes, and knitwear. Because of its high tenacity and elasticity, it is a valuable fiber for ropes, parachutes, and underwear. 

During World War II, nylon became an Allied weapon, along with Carothers Neoprene, Midgley s tetraethyl lead and Freon, and DDT (Chapter 8). The military diverted all available nylon for use in parachutes, airplane tire cords, glider towropes, tents, and the like. Nylon tires enabled bombers and carrier planes fueled with tetraethyl lead to withstand overloading. 

One of the larger uses of nylon fibers is tire cord. In apparel applications, which are another major area, permanent press can be achieved by heat treatment. This crease resistance lasts until abrasion, hear, or pressure wears down the molecule orientation. Since it is strong and lightweight, nylon also is used for rope, parachutes, and some undergarments. 

As women s hemlines rose in the 1930s, silk stockings were in great demand but were very expensive. Nylon changed this, as it could be woven into sheer hosiery. The initial presentation of nylon hose to the public was by Stine at a forum of women s club members in New York City on October 24, 1938. Nearly 800,000 pairs were sold on May 15, 1940 alone—the first day they were on the market. By 1941 nylon hosiery held 30% of the market but by December 1941 nylon was diverted to make parachutes etc. 

Wallace Carothers and coworkers at DuPont synthesized aliphatic polyesters in the 1930s [Furukawa, 1998 Hounshell and Smith, 1988]. These had melting points below 100°C, which made them unsuitable for firber use. Carothers then turned successfully to polyamides, based on the theoretical consideration that amides melt higher than esters. Polyamides were the first synthetic fibers to be produced commercially. The polyester and polyamide research at DuPont had a major impact on all of polymer science. Carothers laid the foundation for much of our understanding of how to synthesize polymeric materials. Out of that work came other discoveries in the late 1930s, including neoprene, an elastomer produced from chloro-prene, and Teflon, produced from tetrafluoroethylene. The initial commercial application for nylon 6/6 was women s hosiery, but this was short-lived with the intrusion of World War II. The entire nylon 6/6 production was allocated to the war effort in applications for parachutes, tire cord, sewing thread, and rope. The civilian applications for nylon products burst forth and expanded rapidly after the war. 

Nylon finally became available to the general public in May 1940. Ten years had passed from initial discovery to full commercialization. It was a tremendous effort, even for a company with the resources of DuPont, and the R D cost was 4.3 million. During World War II, DuPont nylon production went up to 25 million pounds a year, and was used to make parachutes, airplane tire cords, and glider tow ropes. DuPont resumed selling nylon for stockings after the war. 

Approximately 3.9 x 106 t of nylon fiber is produced worldwide nylon-6,6 and nylon-6 account for about 98% of the total production. Nylon fibers are used for carpets, tire cord, cordage, soft-sided luggage, automotive air bags, parachutes, apparel, swimwear, and sheer hosiery. The advantages of nylon fibers over other synthetic fibers are high strength, durability, resilience, ease of dyeability, and low specific gravity. 

When nylon is made in industry, it forms as a solid which is melted and forced through small holes (Figure 15.19). The long filaments cool and solid nylon fibres are produced which are stretched to align the polymer molecules and then dried. The resulting yarn can be woven into fabric to make shirts, ties, sheets and parachutes or turned into ropes or racket strings for tennis and badminton rackets. The annual worldwide production of nylon is expected to reach 6 million tonnes by 2015. 

Like all other synthetic fibers that have become competitively popular, nylon in both the filament and staple form must have certain properties that are superior to natural fibers. It is stronger than any natural fiber and has a wet strength of 80 to 90 percent of its dry strength. Its good flexing tenacity makes it very desirable for women s hosiery, and it has good stretch recovery. Nylon s high tenacity has made it important in parachute fabrics and related nonapparel items. Nylon can be dyed by all acid and dispersed dyes. It has a low affinity for direct cotton, sulfur, and vat dyes. 

Nylon was first synthesized at DuPont by Wallace Carothers in the 1930s. After Japanese control of silk production in the South Pacific made silk unavailable to the United States during World War II, nylon was used to replace silk in the manufacture of parachutes. The synthesis and properties of nylon are discussed in Chapter 22. 

Nylon 6,6, a polymer composed of many amide bonds, was the first synthetic fiber and one of the most iucrative products ever invented at DuPont. Because nyion is strong and durable, and can be spun into a fiber that resembles the silk produced by silkworms, nylon found immediate use in making parachutes, clothing, stockings, and rope. Nylon 6,6 is a polyamide that can be prepared by joining a diacid chloride and a diamine together. In Chapter 22, we learn about amides and other acyl derivatives of carboxylic acids. 

DuPont built the first commercial nylon plant in 1938. Although it was first used by the military to make parachutes, nylon quickly replaced silk in many common clothing articles after World War II. 

Nylon 6,6 is used in many products including parachutes and clothing. 

The discovery of nylon is one example. In 1928, E.l. DuPont de Nemours and Company appointed a young, 32-year-old chemist from Harvard, Wallace Carothers, as the director of its new research center. The goal was to create artificial fibers similar to cellulose and silk. In 1930, Julian Hill, a member of Carothers team, dipped a hot glass rod in a mixture of solutions and unexpectedly pulled out long fibers such as the one shown in Figure 1-14. Carothers pursued the development of these fibers as a synthetic silk that could withstand high temperatures and eventually developed nylon in 1934. Nylon s first use was in a toothbrush with nylon bristles. During World War 11, nylon was used as a replacement for silk in parachutes. Nylon is used extensively today in textiles and some kinds of plastics. 

Nylon, not publicly announced until 1938, was first used for bristles on combs, but made headlines in 1939 when nylon stockings debuted at the World s Fair in New York City. Nylon is known by its chemical name, poly(hexamethylene) adipamide, but more often simply as nylon. The first nylon manufecturing plant went into production at Seaford, Delaware, in 1940. Commercial production of nylon 6 by IG Earben in Germany began in 1941. These two plants would go on to produce millions of pounds of nylon annually. This mass production was essential to the World War II effort, as nylon was used for everything from belts, ropes, and straps to tents and parachutes. 

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