Thermally stimulated currents in polyethylene/ionomer blend. I. Effect of poling temperature, time and voltage

In a recent paper [1] the use of measurements of thermally stimulated currents (TSC) to study the annealing of a polyethylene/ionomer blend was reported. TSC's for this blend changed considerably in several days of combined thermal and voltage aging at 70°C and +48 kV/cm. No change in the TSC's were observed in pure polyethylene. Further characterization of the blends was done using thermal analysis and microscopy. The thermal and mechanical characteristics of the blends were observed to change for up to two weeks of annealing. After two weeks, further annealing produced only minor changes. Two distinct melting endotherms developed in the annealing and correspondingly morphological changes were observed microscopically in the cryofracture surfaces. This may indicate that the ionic component is one of the controlling factors in the TSC characteristics of this blend, because the ionomer, one component of the blend, has the ionic phases which exist as ionic multiplets and/or clusters [2] and the ionic phases may modify the internal field profile upon poling at high electric field. Therefore, for understanding the aging characteristies of the polyethylene/ionomer blend, the study of the charge storage mechanisms of these blends is needed.