Thesis (Ph. D.)--Ohio State University, 1922. / Vita.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1936. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Inaug.-Diss.--Bonn. / "Nachweis der benutzten Literatur": p. [145]-146.

Thesis (Ph. D.)--Columbia University, 1929. / Vita. Description based on print version record.

Thesis (Ph. D.)--University of Wisconsin, 1965. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis--Wisconsin. / Includes bibliographical references (leaf 126).

The thermal conductivity of natural and butyl rubber-sulphur compounds has been investigated at temperatures from - 150° C. to + 30° C. and extensions of 0% to 100%. Readings obtained are plotted on graphs in the order in which they were obtained to show a likely time effect. Results of previous experiments are included in the tables. The results show a very definite change in conductivity due to the addition of sulphur. They do not definitely prove the existence of a completely reproducible hysteris curve. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The dielectric properties of natural and butyl rubber-sulphur compounds have been investigated at temperatures of 20°C and 60°C and extensions of 0% and 200%, in a frequency range extending from 100 cycles to 20 megacycles. This investigation has shown that the dielectric constant of butyl rubber is less than that of natural rubber and that the dielectric constants of both types of rubber decrease with increasing temperature and increasing extension. The investigation has also shown that the dielectric behaviour of these rubbers may be explained by the Gevers' extension of the Debye dipole theory. If free sulphur is present in the rubbers, the behaviour must be explained by a combination of the dipole theory and the inhomogeneity theory. The Kirkwood-Fuoss theory for polar polymers, has been applied to natural rubber with 2% sulphur. The dipole moment per monomer unit obtained from the Kirkwood-Fuoss plot for this sample was 0.41 Debye units. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

This paper deals with the problem of measuring the dielectric properties of rubber under various conditions of stress and temperature over a broad range of frequencies. A discussion of the more modern theory of dielectrica is given and a survey made on the mechanical and electrical properties of natural and synthetic rubbers. Values of dielectric constant and dissipation factor are presented for natural rubber gum stock (2% sulphur) unstretched and stretched 300% at 25°C and unstretched and stretched 300% at 68°C over the range of frequencies 10² to 10⁷ c.p.s. The dielectric constant decreases and the loss peak shifts to higher frequencies when the temperature is raised. Stretching the rubber at 25°C lowers the dielectric constant and increases the losses. The changes upon stretching may be due to orientation and crystallization of the molecular dipole components of the rubber. Heating the stretched rubber to 68°C seems to increase the dielectric constant and to lower the loss peak. This may be explained by the assumption that the higher temperature lowers the degree of orientation and melts the crystallites. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Thesis (M.Eng.)--University of Louisville, 2007. / Title and description from thesis home page (viewed December 14, 2007). Department of Chemical Engineering. Vita. "August 2007." Includes bibliographical references (p. 70-71).