Wallace Hume Carothers, one of the founders of the modern synthetic materials industry, was born in Burlington, Iowa, on April 27, 1896. At first, his
education was directed not toward chemistry, but toward accounting. In 1915 he graduated from the Capital City Commercial College in Des Moines, Iowa, where his father was an instructor. He then attended Tarkio College in Missouri, where he taught accounting while studying for a bachelor's degree in science. For a brief time during World War I, he was actually the head of the chemistry department there. Carothers graduated in 1920 and went on to receive a master's degree at the University of Illinois at Urbana in 1921. After teaching for a year at the University of South Dakota, where he began serious work on organic chemistry, he returned to his studies at the University of Iowa, where he earned his doctorate in chemistry in 1924. Carothers taught for several years at Iowa and was then recruited by Harvard University. He found that he liked research better than teaching, however, and when the E. I. du Pont de Nemours & Co. asked him to direct its research in organic chemistry, he accepted the post in 1928. His principal area of interest was in polymers (long-chain molecules), particularly high molecular weight compounds, both their fundamental properties and their suitability for commercial exploitation.
Carothers's early research at Du Pont focused on products related to acetylene, whose molecules were known to form long chains. With Arnold Collins, in 1931, he produced polychlorobutadiene, better known by its commercial name Neoprene, the first wholly synthetic rubber to be manufactured commercially (beginning in 1933).
Du Pont was particularly interested in developing synthetic fibers. Because of political and trade problems resulting from Japan's war in China, the United States's main source of silk was restricted, so work was directed toward producing an artificial substitute. Carothers believed that polycondensation, in which polymers are formed by condensation and the elimination of small molecules such as water, would yield interesting new materials. His work with dibasic acids (acids with two hydrogen atoms, such as sulfuric acid [H 2 SO 4 ]) and dihydroxy compounds (compounds with two OH-ions, such as tartaric acid [2,3-dihydrobutanedioic acid] produced different kinds of polyesters, but because they had low melting points and were either water-soluble or dissolved in dry cleaning fluids, they were not commercially viable. Part of the problem with polyesters was that they were chemically related to fats and oils, and were not particularly stable.
Carothers turned to another group of chemicals, collectively known as polyamides. Silk, produced by the silkworm, is the best-known natural polyamide fiber. Synthetic polyamides were made by mixing dibasic acids with diamines . (Amines are compounds that replace one or more of the hydrogen atoms in ammonia with organic groups. Diamines contain two amino [-NH 2 ] groups, and are found in many important organic molecules such as glutamine [C 5 H 10 N 2 O 3 ].) The products of these reactions were synthetic proteins and tended to be very stable molecules. A number of different materials with good qualities were produced, but because of the cost of their base materials, were not manufactured commercially. Then Carothers and his team attempted to use adipic acid and hexamethylenediamine (1,6-diaminohexane), which could be made from benzene, a widely available material. This produced long fibers of 6,6′-polyamide, later named Nylon 66. Patented in 1937, nylon went into commercial production in 1939 and was an immediate success. To promote the new fiber, Du Pont showed nylon stockings at the New York World's Fair that same year, advertising it as a material made from coal, air, and water. During World War II nylon production was shifted to meet wartime needs, especially for parachutes. When the war ended and Du Pont resumed commercial production, there was such a high demand for nylon stockings that fights actually broke out in stores for the limited supplies.
Carothers published over sixty scientific papers and held numerous patents, and was the first organic chemist elected to the National Academy of Sciences. Nylon was and continues to be an important product, but Carothers did not live to see its success. Throughout his life, he had suffered from bouts of severe depression. Early in 1937 his sister died suddenly and he subsequently went into a deep depression. On April 29, 1937, Carothers committed suicide, prematurely ending one of the most productive careers in chemistry.
Morris, Peter J. T. (1989). Polymer Pioneers. Philadelphia: Beckman Center for the History of Chemistry.
Taylor, Graham D., and Sudnik, Patricia E. (1984). Du Pont and the International Chemical Industry. Boston, MA: Twayne.
"Chemical Achievers: Wallace Hume Carothers." Chemical Heritage Foundation. Available from http://www.chemheritage.org/educationalservices/chemach/pop/whc.html .
"Polymers: Molecular Giants: Wallace Carothers." Chemical Heritage Foundation. Available from http://www.chemheritage.org/explore/poly-carothers.html .