For centuries, inventors tried to create a “synthetic silk.” In the early 1880’s, Sir Joseph Swan
experimented with forming threads by dissolving the inner bark of mulberry trees. Although Swan did realize that fabric could be woven from this material, he never pursued this application as he was mainly interested in finding a filament for Thomas Edison’s light bulbs. It was not until 1889 that the French chemist Count Hilaire de Chardonnet developed rayon or “artificial silk,” which he introduced at the Paris Exhibition. He is known as the “father of the rayon industry.”

 

On February 28, 1935 the American chemist Wallace Carothers, working at DuPont created the “miracle fiber,” nylon 6/6. The number is derived from its chemical formula. In Germany, by 1938, Paul Schlack of I.G. Farben Company had polymerized caprolactam, a different kind of polymer now known as nylon 6. Nylon started a revolution in the fiber industry. While previous attempts at “synthetic silk” had involved plant cellulose, nylon was completely made from petrochemicals. DuPont began to make nylon commercially in 1939. It was made into parachute fabrics, tooth brushes and women’s stockings. At the San Francisco Expostition in February 1939, nylon stockings were first introduced and were an immediate sensation.

The start of WWII in December of 1941 ended, at least temporarily, the use of nylon in stockings. All production of nylon was allocated to the war effort. Nylon replaced Asian silk in parachutes as well as tires, tents, ropes, ponchos and even the high-grade paper used in the production of U.S. currency. By the end of the war, the use of cotton fiber still predominated at 75% but synthetic fibers had risen to 15%. After the war, nylon stockings became all the rage once again. Stockings are still made of this material. Perhaps one of the most famous uses of nylon was when Neil Armstrong took his walk on the moon. His lunar space suit was made of multi-layers of nylon and aramid fabrics and the flag he planted was made of nylon. To this day, nylon is used in a wide-variety of clothing including outdoor gear and sports uniforms.

Nylon is a strong, synthetic fiber that resists abrasion and will not shrink or stretch when washed. However, it is degraded by ultraviolet light unless UV additives are used and is flammable without the addition of flame retardants.  It also has a higher water absorption rate than many other polymers. Nylon is a thermoplastic made of repeating units linked by peptide bonds and are a type of polyamide. Nylon 6/6 has a melting point of 509°F (265°C) while the melting point of nylon 6 is 428°F (220°C). Nylon is made via a condensation polymerization reaction and is formed by reacting di-functional monomers containing equal parts of amine and carboxylic acid. The amides form at both ends of the monomer in a process analogous to polypeptide biopolymers. The monomers for nylon 6/6 are adipic acid and hexamethylene diamine while nylon 6 requires a lactam or an amino acid. In each case the two molecules combine to make nylon with water as a byproduct. The water must then be removed or it inhibits the polymerization process. The name nylon 6 or nylon 6/6 is used based on how many carbon atoms there are between the two acid groups and the two amine groups.

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