By applying his insights to the synthesis of new high molecular weight substances, including nylon, Wallace Hume Carothers developed the theory of condensation polymers and created a substance that would come to be used every day by millions of people around the world.
Although the Du Pont Corporation’s industrial research laboratory was only one of many, its most famous invention—nylon—became the model for scientifically based industrial research in the chemical industry. Nylon, however, was not the first commercially important polymeric material. From the late nineteenth century, several cellulose derivatives appeared, including celluloid and rayon. In the 1890’s, people began to use the word “plastic” to describe this class of materials. The first important purely synthetic polymer
During World War I, Du Pont tried to diversify; the company was concerned that after the war it would not be able to expand, since explosives had been its primary product. It hired organic chemists and built a research laboratory in the hope of mastering organic chemical reactions and producing synthetic dyestuffs. By 1921, Du Pont had put $20 million into the venture but lacked both the theoretical understanding and knowledge about how to succeed in organic synthesis. Instead, the company bought what it needed to diversify from outside, becoming a producer of rayon, cellophane, and other products.
In this context of dependency on outside inventions, Charles M. A. Stine, Du Pont’s director of chemical research, proposed that Du Pont move into fundamental research by hiring first-rate academic scientists and giving them freedom to work on important problems in organic chemistry. He convinced company executives that a program to explore the fundamental science underlying Du Pont’s technology would ultimately result in discoveries of value to the company. In 1927, Du Pont gave him a new laboratory for research. Stine had given a new role to the industrial research laboratory; it was not to be affiliated with manufacturing departments but was to generate new knowledge. Stine visited universities in search of brilliant young scientists who had not yet established their reputations, and he hired Wallace Hume Carothers.
Stine suggested that Carothers do fundamental research in polymer chemistry, a field that had been a mystery to chemists. Polymeric materials were the result of ingenious laboratory practice, and this practice ran far ahead of theory and understanding. German chemists debated whether polymers were mysterious aggregates of smaller units held together by some unknown special force or genuine molecules held together by ordinary chemical bonds. Chemist Hermann Staudinger,
In April of 1930, Carothers’s group produced two major innovations: neoprene synthetic rubber
Wallace Hume Carothers.
Carothers realized that the reaction also produced water, which was decomposing polyesters back into acid and alcohol. Carothers and his associate Julian Hill
In June, 1930, Du Pont promoted Stine; his replacement as research director was Elmer K. Bolton. Both were organic chemists, but Bolton was a far more traditional industrial chemist. He had opposed Stine’s 1927 fundamental research program; now he was in charge of it. Bolton wanted fundamental research to be more closely controlled, relating it to projects that would pay off and not allowing the research group freedom to pursue purely theoretical questions. Despite their differences, Carothers and Bolton shared an interest in fiber research. Carothers began to work on the synthesis of polyamides from acids and amines, reasoning that since simple amides had higher melting points than simple esters, the same would hold for their polymers. The polyamide research, however, was unsuccessful and by the end of 1933, all fiber work had ceased. In 1934, Bolton pressured Carothers to resume polyamide research. Carothers began trying different approaches to synthesis. On May 24, 1934, his assistant Donald Coffman drew a strong fiber from a new polyamide. This was the first nylon fiber, although not the one commercialized by Du Pont. The nylon fiber was high melting and tough, and it seemed a practical synthetic fiber might be feasible.
By the summer of 1934, the fiber project was the heart of the research group’s activity. It prepared polyamides from many combinations of acids and amines. The one that had the best fiber properties was nylon 5-10 (the numbers referred to the number of carbon atoms in the amine and acid chains). Still, it was the nylon 6-6, prepared on February 28, 1935, that became Du Pont’s nylon. Nylon 5-10 had some advantages, but Bolton realized that its components would be unsuitable for commercial production, whereas those of nylon 6-6 could be obtained from chemicals in coal. Bolton pursued nylon’s practical development, a process that lasted nearly four years. In April, 1937, Du Pont filed a patent for synthetic fibers, which included a statement by Carothers that there was no previous work on polyamides, and that this was a major breakthrough. After Carothers’s death on April 29, 1937, the patent was issued posthumously and assigned to Du Pont.
Carothers was responsible for the discovery of the laboratory process for nylon, but Bolton was responsible for the commercial process. Du Pont wisely decided not to pursue the full range of possibilities, confining its efforts to the silk hosiery market. The company knew that about $70 million was spent on silk hosiery each year. By focusing on this use of nylon, Du Pont would find it easier to overcome the considerable obstacles involved in commercializing the fiber. The practical development was as exceptional as the laboratory discovery, and it took several years for Du Pont’s skilled and ingenious chemists and engineers to bring nylon into the marketplace. The first test of a yarn knitted into stockings came in February, 1937. It was not satisfactory, and it took until the end of 1937 to obtain high-quality nylon hosiery. Du Pont made the first public announcement of nylon on October 27, 1938.
Nylon, a generic term for polyamides, became an important component of several commercial products. In addition to nylon 6-6, other kinds of nylons found widespread use as both a fiber and as a moldable plastic. Since it resisted abrasion and crushing, was nonabsorbent, stronger than steel on a weight-for-weight basis, and almost nonflammable, it embraced an astonishing range of uses: laces, screens, surgical sutures, paint, toothbrushes, violin strings, coatings for electrical wires, lingerie, evening gowns, leotards, athletic equipment and clothing, outdoor furniture, shower curtains, handbags, sails, luggage, fish nets, carpets, slip covers, subway and bus seats, and in space as the safety nets on the space shuttle.
The day after Du Pont’s announcement in 1938, The New York Times ran articles on nylon, headlining one “New Hosiery Strong as Steel.” Another article focused on nylon’s indestructibility, stressing that it was made from simple substances in coal, air, and water. A well-orchestrated publicity campaign kept the public aware of nylon until May, 1940, when the first nationwide sales took place. During the eighteen-month period between Du Pont’s announcement and nylon’s sale, sample nylon stockings became available, and rave notices appeared. Du Pont called its exhibit at the New York World’s Fair “The Wonder World of Chemistry,” and the display celebrated its acetate, cellophane, and neoprene products and, above all, nylon. Visitors to the exhibit also saw a machine that rolled out sheer nylon stockings.
Newspapers reported that four million pairs of nylon hosiery were sold, and the supply was exhausted in one day. Before year’s end, 60 million pairs had been sold. Nylon heralded a future of synthetic polymers that would become standard in clothing, building materials, and furnishings. The American military began to use nylon when the United States entered World War II, and Du Pont tripled its production during the war. Nylon served as a replacement for the silk of parachutes, as mosquito screens in tropical hospitals, as rope for towing gliders and mooring ships, and as surgical sutures and filters for blood plasma. In its moldable plastic form, nylon was made into gears, valves, bearings, and propellers for outboard motors. On the home front, nylon became a black-market item in great demand.
After the war, it took more than two years to retool manufacturing processes so that nylon stockings could be made. When the hosiery reappeared, demand again outstripped supply, and there were near riots in some stores. Nylon became the biggest moneymaker in Du Pont’s history, and its striking success led the company to create new uses for the material and to create new forms of nylon hosiery. By the mid-1950’s, Du Pont had produced more new textile fibers, notably Orlon, a polyacrylic, and Dacron, a polyester. These new materials and nylon’s spectacular growth helped Du Pont effect a revolution in manufacturing that propelled its earnings.
The invention of nylon stimulated notable advances in the chemistry and technology of polymers. Some historians of technology have even dubbed the postwar period the “age of plastics” in recognition of the importance of the giant molecules made by ingenious chemists and engineers. The increasing use of synthetics has also been regarded as a measure of a country’s prosperity, although such success comes at a cost. Several environmental problems have been found to be related to synthetic materials: Some plastics are not biodegradable, and sustainability has been threatened by the utilization of valuable, vanishing natural resources such as petroleum, which contains the essential chemicals needed to make polymers.
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Adams, Roger. “Wallace Hume Carothers.” Biographical Memoirs of the National Academy of Sciences 20 (1939): 291-309. This official biography of the National Academy of Sciences was written by Carothers’s doctorate professor. It includes a bibliography of his articles and a listing of his patents. -
Brun, Roger. “Of Miracles and Molecules.” American History Illustrated 23 (December, 1988): 24-29, 48. This is an outstanding and well-written article on the social impact of nylon, from its introduction as hosiery to its many uses over five decades to its association with both glamor and toughness. -
Dickerson, Kitty G. Textiles and Apparel in the International Economy. New York: Macmillan, 1991. An excellent overview of the global textile industry. -
Fenichell, Stephen. Plastic: The Making of a Synthetic Century. New York: Collins, 1996. Traces the history of plastics and discusses their sociological importance as they revolutionized many fields, from fashion to medicine. -
Garrett, Alfred. The Flash of Genius. Princeton, N.J.: D. Van Nostrand, 1963. Chapter 13 provides a narrative of the discovery of nylon. The use of nontechnical language enables those not trained as chemical scientists to appreciate the discovery and to become acquainted with Carothers’s work. -
Hounshell, David A., and John Kenly Smith, Jr. “The Nylon Drama.” American Heritage of Invention and Technology 4 (Fall, 1988): 40-55. Two American historians explore how Du Pont took Carothers’s discoveries on synthetic fibers and translated them into a commercial textile fiber. This is the best account available on the difficult technological development that made nylon possible. -
Joseph, Marjory L., Peyton B. Hudson, Anne Calvert Clapp, and Darlene Kness. Joseph’s Introductory Textile Science. 6th ed. Fort Worth, Tex.: Harcourt Brace Jovanovich, 1992. The authors relate fiber properties to end-use performance. The section on the modification of nylon is easy to understand. -
Kadolph, Sara J., Anna Langford, Norma Hollen, and Jane Saddler. Textiles. 7th ed. New York: Macmillan, 1993. Chapter 8 offers a basic understanding of how nylon is made. Properties and end uses of nylon are provided in an easy-to-read manner. Chapters 6 and 7 provide excellent background material on synthetic fibers. -
Marvel, Carl S. “The Development of Polymer Chemistry in America: The Early Days.” Journal of Chemical Education 58 (July, 1981): 535-539. A good description by a leading American organic chemist of Carothers’s contribution and the contributions of his contemporaries to the theory and practice of polymerization. -
Mossman, Susan, ed. Early Plastics: Perspectives 1850-1950. New York: Continuum, 2000. A collection of essays by historians of art and technology on all aspects of the social history of the first century of plastic. Includes twenty color plates. -
Smith, John K., and David A. Hounshell. “Wallace H. Carothers and Fundamental Research at Du Pont.” Science 229 (August 2, 1985): 436-442. The authors contribute an excellent article on Carothers and his work at Du Pont. They provide a coherent narrative as well as insight into his brilliance as a theoretical chemist who could also lead a research group into unchartered territory and make important laboratory discoveries. -
Tortora, Phyllis. Understanding Textiles. 4th ed. New York: Macmillan, 1992. The types of nylon, along with consumer considerations, are discussed.
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