Manchester College Archives and Brethren Historical Collection
Manchester College Collection
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Title: Paul Flory Collection
Number: MC2001/2
Size/Location: 1 file/Large Box 172
Citation: Paul Flory Collection, MC2001/2, Archives and Brethren Historical Collection, Funderburg Library, Manchester College, North Manchester, Indiana.
Access and Reproduction/Copyright: Unrestricted access and reproduction.
Provenance: Emily Flory
Date of Accession:
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Biographical/Historical Note:
Paul Flory '31 won the 1974 Nobel prize in chemistry.
Please note: Paul Flory's papers were given to the Chemical Heritage Foundation by his wife, Emily, shortly after his death in 1985 (Mangravite, Andrew. "Flory Papers Processed!" Chemical Heritage v.19:4 (Winter 2001/2): 16-17.).
Paul Flory was considered one of the most significant scientists of the 20th century and a 1931 graduate of Manchester College. At commencement on May 29, 1950 the College conferred upon him the honorary Doctor of Science degree. See his groundbreaking textbook published in 1953, "Principles of Polymer Chemistry." He was awarded the Nobel Prize for Chemistry in 1974 and The American Chemical Society's most prestigious honor, the Priestly Medal, also in 1974.
An autobiographical sketch is available at Nobel e-Museum. The following Press Release is taken from that source:
THE CHEMISTRY OF PLASTICS
This year's Nobel Laureate in Chemistry, Paul J. Flory, has done epoch making
research in the field of the physical chemistry of macromolecules. Among the
substance which are made up of macromolecules we find our most common plastics -
polymers - but also a great number of very important biological compounds, e.g.
proteins, nucleic acids, cellulose and rubber. Flory's early research concerned
polymers of the nylon type, polystyrene. Their molecules are built up of long
chains of atoms and can be compared to strings of beads where the atoms are
represented by the beads. These strings can be very long and contain thousands
of atoms - beads - in the chain. These chains are also very flexible and can
assume the most varying shapes. Stretched molecules - chains - are found in
fibres such as nylon. In solid plastics the molecules are rolled into balls. In
solvents the molecules assume more or less ballshaped structures.
It was very difficult to find a satisfactory theory of how these molecules
behaved. On the one hand, the statistical treatment of the shape of chains is
very complicated and, on the other hand, it is difficult theoretically to define
quantities so that the properties of polymer chains can be compared with
different chemical properties.
The Flory temperature
Flory has solved both these problems. He has introduced a new concept, theta
temperature and theta point properties. A simplified description is as follows:
If a polymer molecule is dissolved in a good solvent agent then the chain is
somewhat stretched out as the attraction forces between the chain and the
solvent molecules are stronger than those between the different links in the
chain. If the temperature is lowered, the solvent agent deteriorates and the
attractive forces between the molecules of the solvent agent and the chain
become weaker whereas the attraction forces between the links of the chain
strengthen. Consequently, the molecules of the chain draw closer together and it
decreases in size. It becomes increasingly compact and finally becomes
insoluble. There must then exist a certain intermediate temperature - theta
temperature - where both these different attraction forces balance each other.
At this temperature, now called the Flory temperature, the polymer molecule
assumes a kind of ideal state. The Flory temperature varies for different types
of polymers and for different solvent agents, but by using their respective
Flory temperatures it is possible to make useful comparisons.
Flory has also succeeded in working out quantitative terms describing the
extension of polymer chains when the temperature is raised above the Flory
temperature. He has demonstrated that the chain in solid polymers has the same
extension as it has in polymers in solution at the Flory temperature. This has
been of vital importance for the development of polymer chemistry.
Universal constant
Flory has also demonstrated how quantities used in the theory can be determined
experimentally by measurements of viscosity, light dispersion, ultra
centrifugation and diffusion. By skilful analysis Flory has shown that it is
possible to find a universal constant which quantitatively summarizes all the
properties of polymer solutions. This constant is now known as Flory's Universal
Constant. It can be said to be analogous to the universal gas constant.
Flory has done pioneer research in elucidating the formation of polymer
molecules. This takes place by the addition or condensation of small molecules
which then link up into long chains. Flory was the first scientist to
demonstrate the theoretical connection between the lengths of formed chain
molecules and reaction conditions. He also discoverer a very important, entirely
new type of reaction, the so-called chain transmission. A growing chain can
transmit its growing power to another molecule and itself stop growing.
Has remained in the lead
In recent years Flory has increasingly turned his attention to polymers of
biological origin, both in solutions and in gells. He has carried out important
studies - both experimental and theoretical - in this field.
During the nearly 40 years Flory has been active as a research scientist the
chemistry of macromolecules has developed from what was, theoretically speaking,
a primitive discipline, to the highly advanced science of today. This progress
has been made thanks to the great achievements of various groups of research
scientists at universities and research laboratories. All this time, Flory has
remained the leading researcher in this field and this demonstrates his
exceptional standing as a scientist. This is largely due to his ability to find
essentially simple solutions to fundamental problems. At the same time he has an
outstanding ability to extract the necessary experimental findings from
well-planned, but often simple experiments, which he carries out with a
comparatively small research team.
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Scope and Content Note:
Correspondence, general info
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Description prepared 28 August 2002 by Sara L. Smith and updated 28 November by Jeanine Wine.