Space charge distributions in glass fibre/epoxy resin composites under dc 10 kV mm⁻¹electric field

Abstract

In this paper, the authors discuss one- and three-dimensional space charge distributions in glass fibre/epoxy resin composites. By the conventional pulsed electroacoustic (PEA) method, only a one-dimensional distribution of the average charge over a whole area parallel to the two electrodes can be observed. Therefore, the authors have developed a new PEA system capable of measuring a three-dimensional space charge distribution. Using this system, they measured the charge distribution in glass fibre/epoxy resin composites made of lattice-woven glass fibre and epoxy resin. It has become clear that spatial variation in signal intensity observed depends on the internal structure of the composite. There appear repetitious positions where a high charge density is observed on the same lateral cross section along the vertical direction in the composite. Such positions are consistent with the intersections of the glass fibres. Accumulation of mobile charge carriers or appearance of polarization charge due to mismatch of the ratio of the conductivity and permittivity between the glass fibre and the epoxy resin is thought to be responsible for the PEA signals.

High-k Materials with Low Dielectric Loss Based on Two Superposed Gradient Carbon Nanotube/Cyanate Ester Composites

“…Simultaneously, there is a positive charge density peak (with a maximum density of 9.5 C/m 3 ) at a distance of 600 μm away from the cathode, demonstrating that there exists a place where the trap energy is so high that the space charges cannot go through. 35 Considering the equal distance between the cathode and anode as well as the structure of the [g-MWCNT0.5/CE] 2 material, the place is believed to be the interface between the two composites. As the conductor fault appears in the interface, where positive and negative charges aggregate, leading to a significantly improved dielectric constant.…”

Effect of water absorption temperature on space charge profiles in paper/phenol‐resin composites for printed circuit boards

“…Figures 4 to 7 show the space charge distribution and electric field distribution immediately after application of a DC electric field (3 kV/mm) in the samples treated at room temperature (24 °C) and at 40, 65, and 85 °C. The diagrams indicate a periodic pattern of positive and negative space charge distribution, which can be explained by the charge induced due to a nonuniform permittivity to conductivity ratio in the laminated paper/phenol-resin structure [10]. However, we did not correct for this effect in the space measurement.…”

Study on the properties of space charge and breakdown for epoxy–paper composites

“…Much work has been done on the properties of breakdown and space charge in epoxy resins and micro/nanofiller epoxy composites . Being a layered structure rather than an even mixture, the mechanism of epoxy/paper composite is totally different from that of micro/nanofiller epoxy composites . The property of space charge in such epoxy/paper composite insulation materials, which have a layered structure, has not been thoroughly discussed earlier.…”