Nylon

Nylon is a group of synthetic polymers defined by amide bonds that usually link aliphatic or semi-aromatic groups. These materials are generally brownish, can feel soft, and some types look silky. Because they are thermoplastics, nylons can be melted and shaped into fibers, films, and various forms. Their properties are often adjusted by mixing in additives.

There are several kinds of nylon. One type, called nylon-XY, comes from diamines and dicarboxylic acids, where X and Y are the carbon chain lengths of those components. Nylon-6,6 is a well-known example. Another type, nylon-Z, is made from aminocarboxylic acids with a carbon chain length Z, such as nylon-6. Nylons are used widely in textiles and fibers—for clothing, flooring, and rubber reinforcement—as well as in molded parts for cars and electronics, and in films, mostly for food packaging.

**History**

DuPont’s work on nylon grew out of its earlier development of cellulose-based fibers, especially rayon. The project began in 1927, when Charles Stine proposed a new structure at DuPont: small research teams focused on “pioneering research” that might lead to practical uses. Wallace Hume Carothers, a Harvard instructor, was hired to lead the polymer group. Initially, he concentrated on pure research, testing the theories of German chemist Hermann Staudinger. His work greatly advanced the understanding of polymers.

Nylon was the first synthetic thermoplastic polymer to succeed commercially. Carothers and his team had already created two new polymers by spring 1930: neoprene, a synthetic rubber later used heavily in World War II, and an elastic paste that hardened into a strong material—this would become nylon. After these discoveries, the team shifted from pure research to a practical goal: finding a chemical combination suitable for industry.

In early 1935, a polymer called “polymer 6-6” was finally made. Carothers’ colleague Julian W. Hill had used a cold-drawing method on a polyester in 1930, and Carothers applied that method in 1935 to fully develop nylon. The first nylon, nylon 6,6, was synthesized on February 28, 1935, at DuPont’s Experimental Station. It had the desired elasticity and strength but required a complex manufacturing process. DuPont patented the polymer in September 1938 and quickly gained a monopoly on the fiber. Carothers died 16 months before nylon was announced, never seeing its success. The name “Nylon” came from altering “norun” (no run) into a unique, marketable name, though it was never trademarked.

Nylon first appeared commercially in a toothbrush with nylon bristles in 1938. It became famous in women’s stockings, shown at the 1939 New York World’s Fair and first sold in 1940; 64 million pairs were sold in the first year. During World War II, nearly all nylon production went to the military for parachutes and cord. Wartime use of nylon and other plastics expanded the market.

Producing nylon required collaboration among three DuPont departments: Chemical Research, the Ammonia Department, and the Rayon Department. Some key ingredients needed high-pressure chemistry, the Ammonia Department’s specialty. Nylon was a “godsend” to that department, which had been struggling financially; the reactants soon made up half its sales, creating jobs and revenue during the Great Depression. The nylon project showed the importance of chemical engineering, created 1,800 jobs, and used advanced technologies that still serve as a model. The first nylon plant began commercial production on December 15, 1939, in Seaford, Delaware. On October 26, 1995, the American Chemical Society designated it a National Historic Chemical Landmark.