Flora (Flory), Paul John( American chemist, Nobel Prize in Chemistry, 1974)
Comments for Flora (Flory), Paul John
Biography Flora (Flory), Paul John
June 19, 1910, Mr.. - September 8, 1985
American chemist Paul John Flory was born in Stirling, a small town in Illinois, the son of Ezra Flory, a priest-teacher, and Martha (nee Brumbau) Flory, teacher. After secondary education at a local school in Elgin in 1927. Paul enrolled at Manchester College, which at one time studied his mother, located in North Manchester (Indiana), where one of his professors, Karl In. Hall, encouraged his interest in chemistry. After receiving in 1931. Bachelor F. began working at Ohio State University, where he received a master's degree in organic chemistry. Then he switched to physical chemistry, running away from what he called 'chemistry cookbook' (an expression of the novel, Sinclair Lewis 'Erousmit', meaning organic). His thesis was on the photochemical processes in the oxides of nitrogen, had applied nature, as well as oxides of nitrogen are components of smog.
After receiving in 1934. doctoral degree in the same Ohio State University F. transferred to the firm 'Dupont de Nemours' in Wilmington (Delaware), which is part of the leading group of researchers led by Wallace Hume Carothers - the future of the creator of nylon. While the group was engaged Carothers polymer synthesis, molecular sizes were significantly larger than those with what are usually dealt chemists. Polymers obtained with limited variations of smaller components (monomers) joined together in a process called polymerization. Vinyl chloride, for example, polymerized to PVC, and natural rubber - a polymer of hydrocarbon called isoprene. Most of the macromolecules (those that contain more than 100 atoms or so) are true polymers, although many biological macromolecules is not true. For example, hemoglobin - a macromolecule, but not the polymer. Common in the 20's and early 30-ies the idea that many compounds, especially natural substances - cellulose, rubber, and proteins - are macromolecules, was supported by the German chemist Hermann Staudinger. He and his colleagues showed that the polymers - a real molecule, existing in the form of chains of different lengths, and that the polymer properties are determined by its spatial configuration, which in turn is determined by its components. Thus, they finally established the existence of macromolecules. Chemists - specialists in polymers - subsequently focused their efforts on studying the configuration of individual macromolecules. Although the macromolecules are subject to the same laws as the molecule with low molecular weight, their large dimensions require new methods to study their configuration. One of the most successful methods used - a method of statistical mechanics, whose mathematical formalism was developed in XIX century. to evaluate the mechanical properties of gases. The first scientist who used this method for polymers, was a Swiss physicist Werner Kuhn, and was soon used Herman Mark and Eigen Gout in Vienna.
. Although the system program Carothers on the synthesis of polymers has made a firm 'DuPont' leader in the field of organic chemistry of polymers, . Carothers understood, . that the enormous amount of work still to be done on polymers, . using the tools of physical chemistry,
. Knowing the outstanding mathematical abilities AF, Carothers asked him to develop this aspect of the study. In its work, F. became particularly interested in the reaction rate of polymerization. To the surprise of other chemists, he proved that there is no significant difference between the reactivity of the same chemical groups, located in small molecules and polymers, although the polymer may be a thousand times more. In 1936, Mr.. He discovered that the atoms of the terminal groups of a polymer in the process of increasing its mass at some point move to a neighboring molecule, leading to cessation of growth of the polymer chain of the donor.
In 1937, Mr.. Carothers committed suicide, and the next year EFS. leaves the firm 'DuPont' and becomes an associate professor of basic science research laboratory at Tsintsinnatskom University (Ohio). There he developed the theory, which explained the regularity of formation of branches in some polymers, leading to the emergence of cross-linking. Such a mesh structure is typical for flexible polymers. When the outbreak of World War II, America emerged fear of a rubber shortage. In September 1940. F. joined as a senior chemist in the company 'Esso leboratris' in Linden (New Jersey), created under 'Standard Oil Development Company' (now 'Exxon Research for End enzhiniring Company'). To improve the butyl rubber - a new synthetic rubber, derived from the gas after the refining of oil - he began his research in the field of its own long-standing interest - the elasticity of rubber. However, during the war, opportunities for basic research based on 'Standard Oil' were limited. When a firm 'Goodyear Tire Rubber End' invited him to lead a small group to carry out fundamental research, F. seize the opportunity and in October 1943. moved to Akron (Ohio). Within 5 years of work in the 'Goodyear' F. made many fundamental discoveries in the field of polymer chemistry, among them - proof that the strength of rubber to rupture depends on the number of defects in the mesh structure of the polymer.
Jobs 'Goodyear' created F. worldwide fame, and in spring 1948. He was invited by Peter Debye, dean of the chemistry department at Cornell University in Ithaca (New York) to give lectures. His excellent lectures laid the groundwork for a relatively young discipline, which was the chemistry of polymers. This allowed the F. become a chemistry professor at Cornell University.
During my time at Cornell University F. found that if the configuration of small molecules in solution can be accurately described by a probabilistic-statistical method, then the large size of polymer molecules, this approach becomes unreliable. The situation changes completely when the solution temperature is lowered to a certain value, which varies depending on the type of polymer. At such temperatures the solution is the 'ideal' solution (similar to the proposed P. Boyle 'ideal' gas - a concept introduced to study the properties of gases). F. called the temperature at which the solution is ideal, theta-point. Currently known as the Flory temperature, it is a fundamental parameter in determining the shape of macromolecules.
F. also discovered the possibility of determining the constants, sums up all the properties of the polymer solution. In 1930. Staudinger suggested that there is a linear relationship between the viscosity of the polymer solution and the average molecular weight of the polymer. His model was too simplified, and 1949. many chemists, including Debye, came to the conclusion that there are considerable difficulties for the interpretation of viscosity in such a way. Taking this direction, F. showed that the viscosity is a reliable indicator of the length of the polymer, as well as increasing the viscosity of the polymer solution is proportional to the radius of the molecule in the third degree. This constant is common to all solutions of polymers. On the basis of F. could use a large amount of existing data to study the configuration of polymer chains. He also investigated the configuration of proteins and polypeptides - macromolecules, which play an important role in metabolism.
Liquid crystals are well known today for use in hand-held watches and calculators, were almost unknown when V. in 1956. published his first work on the theory of liquid crystals. It took 12 years to the moment when the first liquid crystals were synthesized. F. interest in this field of chemistry to the end of his life.
In 1956, Mr.. F. became deputy director for science in Mellonskom Applied Research Institute in Pittsburgh (Pennsylvania). There, he moved the center of gravity of the institute of applied research work under the control of manufacturers, sponsors, to the more fundamental problems. However, the administration seemed to V. boring, and when it became clear that the government institution does not wish to sever ties with industry, he in 1961. moved to a professorship at Stanford University in California.
In 1974. F. was awarded the Nobel Prize in Chemistry 'for fundamental advances in theory and practice of physical chemistry of macromolecules'. In his Nobel lecture F. noted that one of the components of explosives, developed by Alfred Nobel - nitrocellulose - is a macromolecule. He added: 'The acquisition of knowledge about this subject (macromolecule) must be regarded as necessary for understanding the relationship between chemical structure and the properties, . which makes the polymer-active in regard to living organisms and the necessary people '.,
. Even after retirement from Stanford University in 1975
. F. remained an active researcher. While still in 1968. consultant 'International Business meshins' (IBM), he, after 1977. spent two days a week in the department of polymer science and technology of this firm in San Jose (California). The new technique of neutron scattering has provided direct evidence in terms of FA, developed in previous years and lies in the fact that the configuration of polymers in disordered amorphous state. In collaboration with other researchers from the San Jose F. played an important role in the development of this new field of polymer science. He always paid great attention to work with solutions of polymers and liquid crystals, and even somewhat expanded the scope of research to include the problems of elasticity (the study of fibrous proteins such as muscle).
. While almost unknown outside the circle of academic specialists on Polymers, F
. used the glory of the Nobel laureate to promote the two ideas, which he specifically supported: human rights and education in the field of polymers. He was trying to help persecuted scientists, especially scientists from socialist countries, such as Andrei Sakharov, and supported the moratorium on scientific cooperation with the Soviet Union. He even offered himself as hostage to the Soviet government, in order to Elena Bonner, Sakharov's wife, were allowed to travel to the West for treatment. Although his proposal was not adopted, Bonner later received permission to travel for treatment in the hospitals of Rome and the United States of America.
F. believed that the science of polymers unjustly neglected in American universities, especially in courses. He reminded that this economically important subject is completely excluded from the school curriculum in chemistry in the U.S., while in Japan and Europe, he paid much more attention.
In 1936, Mr.. F. married Emily Catherine Tabor. They had two daughters and a son. Tall, slender man, F. engaged in swimming and golf, and remained physically active until the end of his life. September 8, 1985, Mr.. He died of a heart attack while working at his country house in the Big Su, California.
In addition to the Nobel Prize, F. Nichols was awarded the Medal of the American Chemical Society (1962), . New Year's bonus, Charles (1968), . Peter Debye Award in Physical Chemistry (1969), . Willard Gibbs Medal (1973) and the Priestley Medal (1974), . and Charles Frederick Chandler Medal, Columbia University (1970) and John Kirkwood Medal, Yale University (1971),
. He was a member of various scientific societies, . among which the American National Academy of Sciences, . American Academy of Arts and Sciences, . American Chemical Society, . and member of the boards of the American Physical Society and the American Association of Basic Sciences,
. He was awarded honorary degrees to several universities, including Manchester College (Indiana), Ohio State University and University of Milan (Italy).