Effect of Temperature and Frequency on the Dielectric Constant, Power Factor, and Conductivity of Compounds of Purified Rubber and Sulfur

The electrical measurements given in this paper differ from those previously reported by the authors and by other investigators in that they were made on specimens prepared from purified rubber. The purification, which involved the removal of proteins, resins, and water-soluble salts, affected all the electrical properties to some extent, but did not alter the general character of the variation in electrical properties with composition, temperature, or frequency. The results of the present investigation afford comprehensive data on the electrical properties of rubber-sulfur compounds, and may form a basis for designing rubber compounds for specific electrical uses. They also demonstrate the inadequacy of the simple numerical coefficients that are sometimes employed to evaluate the changes in the electrical properties with temperature and frequency. A discussion of the results from the standpoint of modern dielectric theory is not included in the present paper, but is contemplated for a separate paper.