Page 43 - Carrahers_Polymer_Chemistry,_Eighth_Edition

6 Carraher’s Polymer Chemistry

Over a century ago, Graham coined the term colloid for aggregates with dimensions in the range
−9
−7
of 10 – 10 m. Unfortunately, the size of many macromolecules is in this range, but it is important
to remember that unlike colloids, whose connective forces are ionic and/or secondary forces, poly-
mers are individual molecules whose size cannot be reduced without breaking the covalent bonds
that hold the atoms together. In 1860, an oligomer, a small polymer, was prepared from ethylene
glycol and its structure was correctly given as HO–(–OCH CH –) –OH. But when poly(methacrylic
2 2 n
acid) was made by Fittig and Engelhorn in 1880 it was incorrectly assigned a cyclic structure.
Polymers were thought of as being colloids or cyclic compounds like cyclohexane. By use of the
Raoult and van’t Hoff concepts, several scientists obtained high molecular weight values for these
materials and for a number of other polymeric materials. But since the idea of large molecules was
not yet accepted they concluded that these techniques were not applicable to these molecules rather
than accepting the presence of giant molecules.
The initial “tire-track in the sand” with respect to tires was the discovery of vulcanization
of rubber by Charles Goodyear in 1844. The first rubber tires appear in the mid-1880s. These

tires were solid rubber, with the rubber itself absorbing the bumps and potholes. John Dunlop

invented the first practical pneumatic or inflatable tire with his patent granted in 1888. Andre
Michelin was the first person to use the pneumatic tire for automobiles. The Michelin broth-

ers, Andre and Edouard, equipped a racing car with pneumatic tires and drove it in the 1895

Paris–Bordeaux road race. They did not win, but it was sufficient advertising to begin interest
in pneumatic tires for automobiles. Further, because they did not cause as much damage to the
roads, pneumatic tires were favored by legislation. It is interesting to see that the names of these
three pioneers still figure prominently in the tire industry. Even so, another inventor had actu-

ally been given the first patent for a vulcanized rubber pneumatic tire in 1845 but it did not take
off. Thompson was a prolifi c inventor, also having patented a fountain pen in 1849 and a steam
traction engine in 1867.
A number of the giant tire companies started at the turn of the century. In America, many of
these companies centered around Akron, the capital of the rubber tire. In 1898, the Goodyear Tire
and Rubber Company started. The Firestone Tire and Rubber Company was started by Harvey
Firestone in 1900. Other tire companies followed shortly.
Hermann Staudinger studied the polymerization of isoprene as early as 1910. Intrigued by the
difference between this synthetic material and natural rubber, he began to focus more of his studies
on such materials. His turn toward these questionable materials, of interest to industry but surely not
academically important, was viewed unkindly by his fellow academics. He was told by one of his
fellow scientists, “Dear Colleague, Leave the concept of large molecules well alone . . . There can be
no such thing as a macromolecule.”
Staudinger systematically synthesized a variety of polymers. In the paper “Uber Polymerization”

in 1920, he summarized his findings and correctly proposed linear structures for such important
polymers as polyoxymethylene and polystyrene. X-ray studies of many natural and synthetic mate-
rials were used as structural proof that polymers existed. Foremost in these efforts were Herman
Mark and Linus Pauling. Both of these giants contributed to other important areas of science.
Pauling contributed to the fundamental understanding of bonding and the importance of vitamins.
Mark helped found the academic and communication (journals, short courses, workshops) basis
that would allow polymers to grow from its very diverse roots.

Probably the first effort aimed at basic or fundamental research in the chemical sciences was by

DuPont. Their initial venture in artifi cial fibers was in 1920 when they purchased a 60% interest in

Comptoir des Testiles Artificels, a French rayon company. The combined company was named the
DuPont Fiber Company. DuPont spent considerable effort and money on expanding the properties
of rayon. In 1926, Charles M. A. Stine, director of the chemical department, circulated a memo to
DuPont’s executive committee suggesting that the company move from investing in already exist-
ing materials to investigating new materials. This was a radical idea that a company supposedly
focused on profit spends some of its effort on basic research. The executive approved much of Stine’s

9/14/2010 3:35:51 PM
K10478.indb 6 9/14/2010 3:35:51 PM
K10478.indb 6