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Marvelous, mysterious macromolecules
When Wallace H. Carothers joined the research staff of E.I. du Pont de Nemours and Company (now DuPont) in early 1928,
polymer science was still in its infancy -- poorly understood and full of uncertainties.
By the early 20th century, chemists had learned that many materials were polymeric -- including such natural substances as
proteins, cellulose, and rubber. Other polymers had been synthesized in the laboratory from smaller molecules like styrene,
vinyl chloride, and acrylic acid. At least one synthetic polymer, Bakelite, a hard resin produced from phenol and formaldehyde
by Leo H. Baekeland {link to Bakelite} about 1907, was a big commercial success. Chemists knew, too, that polymers were molecules
of high molecular weight (for example 40,000 or more) made up of huge numbers of smaller chemical units. But how these units were
arranged and held together was not clear. Many eminent chemists believed that polymers were aggregates, perhaps colloids,
consisting of relatively small molecules held together by some intermolecular force of uncertain nature.
In the early 1920s, the German organic chemist (and 1953 Nobel laureate) Hermann Staudinger {link to Staudinger} postulated
that polymers consisted of units linked together by the same covalent bonds found in smaller organic molecules. Throughout the
1920s, Staudinger supported his view with new experimental evidence, and other chemists, among them Karl Freudenberg, Michael
Polanyi, Kurt Meyer, and Herman Mark {link to PRI}, came up with additional evidence backing Staudinger. The subject, nevertheless,
remained controversial well into the 1930s.
Carothers had no direct contact with these chemists, but his ideas were generally in line with those of Staudinger. His research
approach, on the other hand, was quite different. Whereas Staudinger focused his study on the analysis of natural polymers, Carothers
built up polymers by reacting small organic molecules by means of well-known reactions -- for example, by combining dicarboxylic
acids with diols or diamines -- to form long, macromolecular chains.
In addition to the many experimental studies, Carothers believed that mathematics could be applied to understand the formation
and properties of polymers. To this end, Paul J. Flory was hired in 1934 and introduced to polymers by Carothers. The seminal ideas
they advanced provided the foundation of many of the theoretical methods for studying polymers used to this day. Flory's accomplishments
were recognized with the 1974 Nobel Prize in chemistry.
The research accomplishments of Staudinger and Carothers, along with that of their colleagues, during the 1920s and 1930s laid the
foundations of modern polymer science and today's plastics, synthetic fiber, and rubber industries. Today, approximately half of the
industrial chemists in the United States work in some area of polymer chemistry.
Marvelous, mysterious macromolecules |
Wallace Carothers |
A new synthetic rubber |
The "superpolymers" | Copyright
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The development of nylon |
Going public |
An extraordinary but brief career |
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