Electrostatic Properties of Rubber and GR‐S

摘要

A new ``electrostatic modulator'' for measuring the electrostatic charges on various materials is described in this paper. In this apparatus the electrostatic lines of force established between the charged specimen and the grid of an audiofrequency amplifier are cut or modulated at audiofrequency by a motor‐driven fan. The resultant alternating current voltage is amplified and measured on a meter in the output circuit. This device, in conjunction with a mirror surfaced metal plunger system for contacting the sample, has been used to measure the contact potential of various rubber and GR‐S compounds. Data are shown on both rubber and GR‐S compounds, and they bear out the formulation of an ``electrostatic contact potential theory of reinforcement'' in which reinforcement is explained on the basis of contact potentials and resultant electrostatic forces set up between the rubber and the reinforcing agents. By the application of this theory, organic materials, which have a highly positive charge, such as polymerized Trimethyldihydroquinoline and Flectol H, have been found to increase the tensile of GR‐S pure gum type compounds as much as fivefold and to nearly double the tensile of high zinc oxide GR‐S compounds.