Some Applications of High-Frequency Electric Currents to the Latex Industry
Abstract The “radiocoagulation” of latex has been developed in the laboratories of L'Office National des Recherches et Inventions by Dufour and Leduc, who conceived the idea of applying the effect of electric fields of high frequency to rubber latex. When latex is exposed to the action of an electric field of high frequency, the entire body of liquid is heated uniformly, provided that the electric field itself is uniform. The causes of this heating effect are difficult to ascertain because various phenomena are involved simultaneously, e. g., a dielectric loss in the rubber and a loss by the Joule effect in the serum. Each of these effects is, according to conditions, the predominant one, e. g., by increasing the conductivity of the serum, electrolytes such as sodium sulfate or ammonium sulfate increase the Joule loss, U2/R, whereas an increase in the concentration of latex tends to increase the dielectric loss. Finally, since rubber particles are not electrically neutral, they are subject to alternating forces of the electric field, which is a specific effect of the high frequency, and these forces impart to the rubber particles movements throughout the liquid. Now latex can be rendered sensitive to mechanical forces, i. e., some mixtures can be coagulated by slight agitation. Accordingly it is conceivable that a high-frequency electric field, by setting the rubber particles in motion throughout the emulsion, is capable of coagulating a mass of latex exposed to the field.