Inventing Polymer Science: Staudinger, Carothers, and the Emergence of Macromolecular Chemistry. Yasu Furukawa. 416 pp. University of Pennsylvania Press, 1998. $49.95.
Today we take for granted the existence of enormously long polymer molecules, which can be many millions of times larger than water, carbon dioxide and other so-called ordinary molecules. Yet as recently as the 1920s, the chemical community regarded with derision the idea that a single molecule could be so huge. This resistance to polymers had always been an enigma to me—until I read Yasu Furukawa's meticulously researched historiography.
Emil Fischer, the great organic chemist and 1902 Nobelist in chemistry, said around 1913 that organic compounds having a molecular weight greater than 5,000 grams per mole might not exist. Such was his influence that this dictum was almost unquestioningly and universally accepted by chemists. Adherents of the nascent discipline of physical chemistry, notably Wolfgang Ostwald, further muddied the waters by postulating that polymers we now know to be long-chain molecules (starch, cellulose, silk, rubber) were merely physical aggregates of smaller molecules united by vague "partial valences," not true giant molecules held together by chemical bonds. X-ray crystallography of polymer fibers revealed unit cells no bigger than those of ordinary molecules. This was taken as evidence supporting the aggregate theory. By the late 1910s, this theory was firmly entrenched in the academy.
Onto this scene burst—there can be no other word—Hermann Staudinger, the German chemist who in 1917 first proposed the idea that polymers were giant molecules whose small-molecule constituents were linked together in long chains by chemical bonds no different from chemical bonds in ordinary organic compounds. His idea, postulated not as much from empirical evidence as from a deep belief in August Kekulé's organic-structural view of chemistry, met with immediate scorn from the scientific community. Staudinger, "not exactly a gentle and compromising protagonist of his work," as one of his contemporaries put it, promptly embarked on a campaign to refute the aggregate theory while vigorously and vociferously promoting his macromolecular theory—entirely on his own. In 1926, Fritz Haber helped arrange what was later to be viewed as a landmark symposium on polymers, held in Düsseldorf. Besides his Nobel Prize-winning synthesis of ammonia, Haber had also played an important role in Germany's development of poison gas during World War I, a role that Staudinger, a staunch pacifist, had criticized quite openly. Haber never forgot the insult, and took his revenge at the 1926 symposium by packing the roster with several leading advocates of the aggregate theory, pitting them against Staudinger as the lone voice for the macromolecular view.
Haber's plans backfired somewhat, as Staudinger's vehement defense of his theory convinced conference chairman Richard Willstätter, who nevertheless said he found "the concept that a molecule can have a molecular weight of 100,000 [grams per mole] . . . somewhat terrifying." Another chemist is said to have remarked, "We are shocked like zoologists would be if they were told that somewhere in Africa an elephant was found who was 1,500 feet long and 300 feet high." Staudinger, however, had held his own at the meeting, and the tide of scientific opinion was soon to turn in his favor.
X-ray crystallography now appeared to be the last remaining refuge of the aggregate theorists, who were still convinced that the small size of polymer unit cells, unequivocally established some years earlier, necessarily implied the small size of polymer molecules. This incorrect assumption was addressed in the years following the Düsseldorf conference by several physicists working in the field, who concluded that small unit-cell sizes corresponding to the size of the monomers were perfectly compatible with long chain polymers and that the molecular size of polymeric substances could not be inferred from x-ray diffraction results.
Just as Staudinger was beginning to win over his opponents, Wallace Carothers, a continent away in America, nailed the coffin's lid on the aggregate theory with his brilliant synthesis in the late 1920s of a series of polymers through organic condensation reactions using bifunctional starting compounds. By the 1930s, the existence of long-chain giant molecules was no longer seriously in doubt, and, in 1953, Staudinger was awarded the Nobel prize in chemistry "for his discoveries in the field of macromolecular chemistry," becoming the first polymer scientist in history to receive this honor.
In Inventing Polymer Science, Furukawa sets out to provide an analysis of the formative period of macromolecular chemistry in its intellectual and social setting. He succeeds in doing so and highlights the industrial setting of the emergence of this discipline as well.
The two scientists, Staudinger and Carothers, on whose work and lives this book is primarily focused, may rightly be viewed as the founders of polymer chemistry. Furukawa examines their few similarities and contrasts their different scientific objectives, work environments, personalities and cultures, shedding light on a great many details of the development of polymer chemistry from the concept of a macromolecule in 1917 to the mature multifaceted discipline it is today. Some of these details are already widely known, such as that Carothers took his own life, yet the author handles these well-known facts adroitly. In Furukawa's account, Carothers's suicide comes on the reader like a thunderclap, as shattering now as it was then. Other details are in turn illuminating and inspiring, such as the accounts of Staudinger's lone defense of his macromolecular theory and his prodigious research efforts during the height of Nazi oppression. (More than half of his papers were published between 1933 and 1945, while he was a victim of Nazi antipathy, Gestapo investigations and professional back-stabbing.) Nevertheless, the picture painted of these giants shows their all too human side as well—for instance, depicting unflinchingly Staudinger's abandonment of his family and pacifist principles to obtain a job at Freiburg in 1926. The author treats the maturing of polymer chemistry beyond the 1940s rather sketchily, sticking with the book's title and stated focus.
Inventing Polymer Science suffers from a few shortcomings, notably a somewhat cumbersome reference system consisting of separate "Notes" and "Bibliography" sections that could have been combined. Notwithstanding these venial flaws, this book will doubtless serve as a useful reference that provides a sound historical examination of the early years of polymer chemistry.