Dielectric properties of an epoxy resin

The dielectric properties of an unmodified epoxy resin with a wide range of hardener content were investigated over the frequency range 5 cycles/sec. to 50 Mcycles/sec and over the temperature range 12–95°C. In the frequency region below 1 Kcycle/sec., the loss is predominently high both in the pure resin and the pure hardener and, interestingly, is very much reduced when the two are mixed to obtain a plasticized product; the loss is at a minimum when the percentage of epoxy is about 10 and increases appreciable on both sides of the figure. At frequencies above 1 Kcycle/sec., a relaxation type loss is obtained in the hardener and the plasticized samples; pure resin again shows a predominently high loss, the maximum for it at room temperature being above 100 Mcycles/sec.