edited by ROGER R. FESTA Nonheast Missouri State Univwslty Kiksville. Mo. 63501
Neoprene and Nylon Stockings: The Legacy of Wallace Hume Carothers Carol Cummings Warren Township High School Gurnee, lL 60031
What do ruhher tires and nylon stockings have in common? They are both made with synthetic substances developed by the brilliant chemist Wallace Carothers. Neoprene was the first successful synthetic ruhher developed in the United States. It has a wide variety of uses from tires and life rafts to sealants for space vehicles. Nylon revolutionized the textile industry hy ushering in the era of synthetic fibers. In addition to its use as a textile, nylon has many applications as a molded plastic. Today, many well-dressed women would not consider leaving their homes without wearing nylon hose. If Carothers only knew what he had started! allac ace Hum(: Carothers was horn in Burlington, Iowa, on April 27, 1856. His paternal forehrars were Varmers and artisans of Scotch origin. His father, Ira, was horn on a farm in Illinois hut left the farm a t age 19 and taught country school. Later, he entered the field of commercial education and was a teacher and eventually vice president of Capital City Commercial College in Des Moines. His maternal ancestors were farmers of Scotch-Irish stock who loved music. I t may have been the influence of his mother, Mary Evalina McMullin, that led to Carothers' keen interest in and appreciation of music as an adult. Carothers was the oldest of four children. He was especially devoted to his sister, Isohel, who achieved radio fame in the early 1930's as Lu in the trio Clara, Lu, and Em. When she died suddenly in 1936 after a short illness, Carothers was greatly shocked, and he never completely adjusted to her loss. When Carothers was five, his parents moved to Des Moines where he hegan his education in the public schools. He graduated from North High in 1914. During these years, he displayed an overwhelming interest in tools and mechanical things and spent hours experimenting. Carothers was a perfectionist. He carefully finished every task he started. Carothers enrolled in the Capital City Commercial College in the fall of 1914 and graduated in the accountant curriculum in July 1915. In the fall he entered Tarkio College in Missouri, where he pursued a scientific course and also accepted a position as assistant in the commercial department. Carothers excelled in his chemistry courses and, after two years, his superior record in English earned him a teaching assistantship in that department. Then, during World War I, Arthur Pardee, head of the chemistry department, accepted a position a t another institution. Carothers, who had taken all of the chemistrv courses a t Tarkio hv the end of his soohomore vear. " . was appointed to take over thk chemistry instrktion. He had been reiected as a soldier because of a zoiter condition. so he served i s a chemistry teacher duringuhis junior and ienior years while he completed his studies.
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"Profiles in ChemisW' is a biographical feature, highlighting the ~ntrlbutionsof distinauishedchemists in the context of their lives. The column is designed far curriculum enrichment, allowing the secondary school teacher to enhance the vitality of chemistry with the sense of scholarship and adventure shared by chemists throughout history.
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In 1920, Can~therslrft Tarkio College with ii hnchelor of science demee. He heran his rrraduate stt~diesin the chemistrv department of the ~n&ersitiofIllinois. After one year, he had completed the requirements for the master of arts degree hut lacked funds for further study. Carother's former instructor a t Tarkio, now chairman of the chemistry department a t the University of South Dakota, was looking for a young instructor to teach analytical and physical chemistry. Carothers was chosen for the position and went to South Dakota with the idea that he would make enough money to complete his graduate work. The careful preparation of his courses and his concern for the students demonstrated that he could be a very successful chemistry teacher. Carothers started t o develop some independent research projects while he was teaching. His first contribution to the Journal of the American Chemical Society was "The Isosterism of Phenyl Isocyanate and Diazohenzene Imide" in 1923. His second paper, in 1924, was "The Double Bond," in which he presented the first clear aoolication of the electronic theory to brganic chemistry. I t became evident that teaching was not his primary interest, and he spent all of his soare time on researchprojec&. His friends urged him to relax, but it was as if he were driven by an inner desire to investigate. Carothers returned to the University of Illinois in 1922 to complete his studies, and in 1924 he received the PhD in organic chemistry. His thesis research explored the catalytic reduction of aldehydes with platinum-oxide platinum-black, and the effect of promoters and poisons on this catalyst in the reduction of various organic compounds. These studies were completed under the direction of Roger Adams, the legendary Illinois chemist who trained his research students as careful experimentalists and inspired in them an intense interest in chemistry. Adams was strongly oriented toward the chemical industry, and this attitude apparently influenced Carothers. While a t the university, Carothers also studied physical chemistrv and mathematics. He held assistantshios in inorganic and organic chemistry, was promoted to a rrsearch assistant, and a,as later rmnted thv C x r Frllowshil~, . . the hiehest award offered by thechemistry department. After graduation, Carothers was appointed instructor in organic chemistry at the University of Illinois where he taught for two years. In 1926, he was chosen to fill an organic chemistry position a t Harvard University. During his first year at Harvard he taught experimental organic chemistry and an advanced course in structural chemistry. I t was here that Carothers hegan his studies on polymerization. Then in 1928, Du Pont hegan a new program of fundamental research a t the Experimental Station at Wilmington, Delaware. Carothers was asked to head the organic chemistry program, and it was at this time that he permanently left education. From the time Carothers ioined Du Pont until his death. his accompliil~mentswere pk.ntiful and of great \.slue. Ihring the nine-vear period that he was with Du Punt. Carothers not only made nukerous contributions to the theory of organic chemistry hut also provided inspiration and guidance to the chemists under his direction. His work laid the foundation for several new developments of commercial importance. The first area which he studied extensively was acetylene polymers and their derivatives. Julius A. Nieuwland, a priest a t the University of Notre Dame, had completed the basic research on the synthesis of vinylacetylene and divinylacetylene. When a chemist from Du Pont heard Nieuwland's Volume 61
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presentation a t an American Chemical Society Organic Chemistry Symposium in 1925, he realized that Nieuwland's knowledge could be valuable to Du Pont, and an association was formed. Now that vinylacetylene and divinylacetyleue were available to Carothers, he completed a detailed study of these substances. Further, he found a way to add hydrogen chloride to monovinylacetylene to form chloroprene. This substance is structurally analogous to isoprene, hut polymerizes several hundreds of times faster to produce polychloroprene. The first polychloroprene was named duprene; however, Carothers changed the name to neoprene. Neoprene resemhles rubber and is used as an additive to natural rubber to improve its properties. The first large-scale application of neoprene was for the production of gasoline hose which could withstand attack by gasoline and hydrocarbons. Today, Du Pont produces about 175,000 tons of neoprene a year, which results in sales of about $400 million annually. While investigating the chemistry of polymerization, Carothers also synthesized some cyclic polymers which possessed a musklike aroma. Du Pont marketed these substances under the trade name Astrotone synthetic musk for the perfume industry. Carothers' most outstanding scientific accomplishment was his work on linear polymers. He wrote a series of 31 papers in the field of polymerization and held 50 patents. In these papers, he proposed a theory of condensation-polymerization and a terminology suitable for this field. During the 1930's Carothers devoted his attention to the preparation of polymers which were structurally analogous to cellulose and silk. Many compounds were studied; however, the results were disappointing. Du Pont was on the verge of abandoning the project when in 1935, success was attained when nylon was developed. Nylon is a macromolecule obtained as a condensation product from adipic acid and hexamethylene-diamine, with a molecular weight of over 10,000. Nylon has become a fiber particularly suited for textiles. Carothers' advice was sought by chemists throughout the world. At the age of 33, he was elected associate editor of the Journal of the American Chemical Society. The following year, he became the editor of Organic Syntheses. In 1935, he
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spoke before the Faraday Society in London on "Polymers and the Theory of Polymerization." He was the first industrial oreanic chemist to he elected to the National Academv of Sciences. Apparently Carothers never regretted his decision of research over teaching; he turned down several academic positions during his years a t Du Pont. On Fehruarv. 21.. 1936. Crothers married Helen Everett Sweetman ot' ~ i l r n i n ~ r o Delnwnrr. n, She bad received her bachelor's decree in rhrmistrv at the Universitv of Delaware and was emproyed in Du ~ o n $ schemical patent division. Carothers was an avid reader and especially enjoyed poetry. He also liked to sing, and he found i t very relaxing to listen to his manv recordincs - of -ereat comvosers such as Bach, Beethoven, and Brahms. Carothers w& shy and sensitive, &d he avoided ~ a r t i e and s crowds. His close friends described him as deepG emotional, generous, and modest. In very small aroups, . . he was a brilliant conversationalist. Carothers suffered from a nervous condition, revealed in his later sears, in his poor health. He was plagued by periods of depression which became more and more prono&ed. On April 29,1937, at the age of 41, he checked into a Philadelphia hotel and committed suicide by drinking cyanide. He never saw his daughter, Jane, who was horn seven months later. Despite the brevity of his career, Carothers'contrihutions to organic chemistry are recognized as outstanding, and he is acknowledged as a pioneer in the field.
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References Adams. Roger, "Nationel Academy of Sciences d the USA, Biwrsphicsl Memoin," Wsshington, 1939. p. 20. Farber, Ed (Editor), '"GreatChemists? Inteneimee, New York. 1961. Findlay, Alexander, "A Hundred Years of Chemistry," Humanities, NJ, 1965. Hsssler, William W.. "Hov Nylon Was Diseovered,"Ame~iconHialory, 5.32 (1970). Ihde, Aaron. "The Development of Modern Chemistry," Harper and Raw. New York, 19M .....
Loehemann. Ge0.Z. "The Story of Chemistry," Philoaophicsl Library, Philadelphia, 1959. Miin, Wyndhsm D. (Editor). "American Chemist. and Chemical Engineera," American Chemical Society. Washington, 1976. "NeopreneCelebrat~8aHalf-CenturynfCommercialSucceaa"ChemicolondEngineering N01us.59.44(1981). Tarbell, D. S.,Tarbell, A. T., and Joyce,R.M.. Isis,71,620 (1980). "The Father of Neoprene? Nofre Damp New& 10,1(1961).
