Dependence on Temperature of the Electrical Resistivity of Thermosetting Polymers

Abstract

TO-DAY'S great usage of thermosetting polymers has served to emphasize the lack of fundamental data on the electrical and physical properties of these materials. With the exception of the data published by us^1,2, there is almost none available on the dependence on temperature of the electrical volume resistivity and on the activation energy for the electrical conduction process, E _c, in cross-linked polymers. Data of this type are of great importance not only in technological applications but also in the study of the physics and chemistry of these polymers. For example, it has recently been shown^1,2 that the dependence on temperature of the resistivity is a convenient index of the extent of polymerization. Also, recent work has shown that electrical resistivity measurements can be successfully employed in the study of the reactions and the determination of the extent of polymerization of composite solid propellants³. These experimental techniques can likewise be used to investigate the properties of organic semiconductors. It is the purpose of this communication to indicate briefly how these measurements can be accurately and rapidly made and to present typical results.