Dielectric absorption in low loss materials

In 1949 a paper was presented before this Conference on Electrical Insulation giving the results of measurements of volume and surface conductivities made on Polystyrene, Polymethylmethacrylate and Polyvinylbutyral under standard room conditions. The use of a vibrating reed electrometer in place of a more sluggish quadrant electrometer has permitted a more detailed study of the current flow through dielectric specimens having very low conductivities, Dr. Paul Ehrlich has recently published a paper(1) on results obtained with the vibrating reed electrometer in which the change of volume conductivity with time was followed from a few seconds up to 10₄ seconds, for Polystyrene and Polymethylmethacrylate. In the work now being described measurements were made of both volume and surface conductivities at various relative humidities. The materials on which measurements were made are Diallyl Phthalate, Polymethyl Methacrylate, Polystyrene and Teflon.