Thermally stimulated depolarization currents and dielectric properties of Mg0.95Ca0.05TiO3 filled HDPE composites

Abstract

Mg0.95Ca0.05TiO3 (MCT) filled high density polyethylene (HDPE) composites were prepared by twin-screw extrusion followed by hot pressing technique. The thermally stimulated depolarization current (TSDC) measurement was performed to analyze the contribution of charge distribution and interfacial characteristics to the dielectric loss. TSDC spectra under different polarization conditions show that the introduction of ceramic fillers engenders shallow traps in the vicinity of ceramic-polymer interface, which hinders the injection of space charge from the electrode into the polymer matrix. In the composite materials applied to an external field, charges tend to be captured by these traps. The temperature dependence of relative permittivity and dielectric loss of the composites was measured, and a strong reliance of dielectric loss on temperature was observed. In the heating process, the release of charges accumulating at interfacial region is considered to contribute to the rise in dielectric loss with the increase of temperature.

Thermally stimulated depolarization current characteristic of EVA–conductive PPy composites

“…Detrapping of this large amount of charge results in electrode blocking and decrease in the TSDC current. 17,27 The depolarization kinetic data i.e. activation energy, relaxation times, and charge released of EVA pure and EVA/PPY composite have been calculated by using the initial rise method.…”

“…TSDC technique has proven to be a powerful tool to understand defect properties both qualitatively and quantitatively. [15][16][17] There has been previous study on this three-phase composite (EVA/PPy/CB). 18,19 In this paper, we consider composite containing EVA with different concentrations of PPy loaded with 20% high abrasion furnace (HAF) carbon black, and utilizing TSDC technique as an external stimulus, we try to investigate charge storage phenomena and the effect of stress fields on EVA-PPy composite.…”