CAROTHERS, WALLACE HUME

(b. Burlington, Iowa, 27 April 1896;

d. Philadelphia, Pennsylvania, 29 April 1937), chemistry, organic chemistry, polymer chemistry. For the original article on Carothers see DSB, vol. 3.

Since the mid-1980s, a number of in-depth studies on Carothers, based on a large quantity of manuscripts, letters, and documents, have revealed some important aspects of his scientific career and work, such as his early encounter with chemistry, the origins of his polymer research, the process of his invention of nylon, and the industrial context in which Carothers worked on polymers.

Early Years . When Carothers was a high school student in Des Moines, Iowa, his early interest in chemistry began with his reading of Robert K. Duncan’s popular books, The New Knowledge: A Popular Account of the New Physics and the New Chemistry in Their Relation to the New Theory of Matter (1905), an exposition of recent theories of matter, and The Chemistry of Commerce: A Simple Interpretation of Some New Chemistry in Its Relation to Modern Industry (1907), which stressed the importance of pure science for industry. While at Tarkio College in Missouri, Carothers decided on chemistry as his life’s work, largely at the encouragement of his chemistry teacher, Arthur M. Pardee. The synthetic-chemical approach and industrial orientation of Roger Adams at the University of Illinois also exerted a profound influence on Carothers’s style in chemistry and his career.

Before moving to the DuPont Company, Carothers had neither published nor performed any experiment in the field of polymers. In the spring of 1927, when DuPont approached Carothers to offer him a position in its newly established fundamental research program in Wilmington, Delaware, the company promised to leave the selection of research subject entirely to him. Carothers chose polymers and polymerization as his new research subject because of the need for theoretical exploration as well as the vast commercial implications of polymers. Had it not been for the DuPont job offer, it is unlikely that the young Harvard instructor would have set out on a journey into the frontier of polymer research.

Carothers had been reading recent German articles on the structure of polymers by Hermann Staudinger and his opponents. Since the early 1920s, Staudinger had proposed the theory that polymers, such as rubber, cellulose, resins, and proteins, were made up of very large molecules, what he called “macromolecules.” His theory was severely criticized by many chemists, who claimed that polymers were the aggregates of relatively small molecules. The unsettled German debate over the existence of macromolecules appealed to Carothers’s theoretical interest.

Research on Macromolecules . By the time he joined DuPont in early 1928, Carothers had already developed his ideas into a coherent program for the synthesis of macromolecules by the use of established condensation reactions such as esterification. He did not intend to produce a synthetic fiber when he started working at DuPont; what he intended was simply to make molecules as large as he could in order to examine the properties of the products. If the products exhibited properties (such as elasticity and fibrousness) similar to natural polymers, then Staudinger’s claim that polymers were composed of macromolecules would be supported.

Overcoming technical difficulties, his group was able to synthesize what he called “superpolymers,” polymers with molecular weights of ten thousand or more. This success was soon followed by the discovery of the “cold-drawing” phenomenon peculiar to these materials. In April 1930, his co-worker Julian Hill observed that a superpolyester could be mechanically drawn out from a melt or dry-spun from a solution into fibers or threads. This led Carothers to foresee the possibility of making artificial fibers from linear-condensation superpolymers.

Realizing its practical implication, DuPont management delayed publication of Carothers’s paper on super-polymers and recommended that the result should be thoroughly protected by a well-planned patent program. This restriction appeared to abridge the academic freedom assured him at the inception of the fundamental research program. From this time on, Carothers’s basic research group was obliged to shift its aim to a more practical goal, that is, to the search for polymers that could be drawn into fibers for commercial use.

During the period from 1930 to 1933, Carothers and his group systematically investigated various types of linear condensation superpolymers, including polyesters, polyanhydrides, polyacetals, polyamides, and polyester-polyamide mixtures, which were synthesized by his coworkers from hundreds of possible combinations of starting materials. After careful consideration, the company selected a superpolyamide for manufacture, first synthesized by a co-worker, Gerard Jean Berchet, in February 1935. The fiber was named “nylon” in 1938, after examining some four hundred names submitted by DuPont employees (the naming committee decided on “nylon” by arbitrarily modifying the finalist “no-run”). Nylon would become the most successful commercial product in DuPont’s research and development history. A year and half before DuPont announced nylon, however, Carothers committed suicide by taking cyanide in a hotel in Philadelphia. He neither lived to hear the name nylon nor to see its enormous commercial production and subsequent impact on culture.

The nylon venture, which would become a prototype for the science-based polymer industry, also turned out to be a large-scale test of the validity of the macromolecular theory. As an industrial researcher, Carothers did not train students in polymer chemistry. Yet he introduced a number of able research chemists at DuPont to the world of polymers. From June 1928 to his death in April 1937, he had a total of twenty-five co-workers, most of them only slightly younger than the group leader, including twenty chemists with PhD degrees. The “Wilmington School” bequeathed a research tradition on polymers not only within the company, but also to American academe. Under Carothers’s influence, a new generation of polymer chemists emerged in American universities. Paul J. Flory, Elmer O. Kraemer, and Carl S. Marvel were among the influential scholars who inherited Carothers’s legacy.

American polymer chemistry, which first emerged from a basic research program in industry, gradually spread as an academic discipline by the late 1940s. DuPont’s venture into fundamental research was rewarded by discoveries that not only had great industrial value, but also sparked original theoretical innovations. Even beyond the perspective of a single company, industrial research turned out to play a seminal role in the birth of a new science in America.

SUPPLEMENTARY BIBLIOGRAPHY

Papers of Wallace Hume Carothers and DuPont Company documents are stored at the Hagley Museum and Library, Wilmington, Delaware. Correspondence between Carothers and Roger Adams is in the Roger Adams Papers at the University of Illinois Archives, Urbana-Champaign, Illinois.

OTHER SOURCES

Furukawa, Yasu. Inventing Polymer Science: Staudinger, Carothers, and the Emergence of Macromolecular Chemistry. Philadelphia: University of Pennsylvania Press and Chemical Heritage Foundation, 1998.

Hermes, Matthew E. Enough for One Lifetime: Wallace Carothers, Inventor of Nylon. Washington, DC: American Chemical Society and Chemical Heritage Foundation, 1996.

Hounshell, David A., and John K. Smith. Science and Corporate Strategy: Du Pont R&D, 1902–1980. New York: Cambridge University Press, 1988.

Morawetz, Herbert. Polymers: The Origins and Growth of a Science. 1985. New York: Dover, 1995.

Yasu Furukawa