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Sheets of silicone rubber (SiR) were aged under various aging conditions to examine its effects on the mechanical and dielectric properties of SiR. Mainly by analyzing the results obtained by mid-infrared absorption spectroscopy, it has become clear that cross-linked structures with siloxane bonds are formed under all the conditions. This makes SiR hard and then brittle, but it also makes better the dielectric properties apparently. An early stage of degradation in SiR can be detected by EAB and complex electric modulus, which is defined as the reciprocal of complex permittivity. Therefore, EAB and complex electric modulus are useful to monitor the aging status of SiR. [ABSTRACT FROM AUTHOR]

Complex permittivity ( ϵr' and ϵr") and conductivity were measured in a wide temperature range for dicyclopentadiene (DCP) resin and epoxy resin, which show glass transition at a similar temperature around 150 °C. Furthermore, space charge distributions remaining in the two resins that had been polarized in the same wide temperature range were measured at room temperature. As a result, it was found that ϵr ?, ϵ r?, and conductivity are much lower in DCP resin than in epoxy resin at almost all the temperatures and frequencies. A further analysis using complex electric modulus, which is the inverse of the complex permittivity, indicates that charge transport is much more difficult in DCP resin. Furthermore, while similar small amounts of homocharges appear in DCP resin at any polarization temperatures, a significant accumulation of heterocharges, most likely due to ions, is induced in epoxy resin in the vicinity of the cathode/sample interface at polarization temperatures above the glass transition temperature. These results indicate that DCP resin possesses superior stable dielectric behavior, especially at high temperatures. [ABSTRACT FROM PUBLISHER]

Epoxy-based nanocomposites (NCs) were prepared using clay modified by either primary amine or tertiary amine, and the effect of the difference in modifier on the thermal and dielectric properties of the NCs were discussed. The NC with clay fillers modified by the primary amine, 1C, shows a glass transition end temperature (Teg) at a temperature 20 °C lower than the neat epoxy (N). This indicates that the resin of 1C is less crosslinked than that of N. On the other hand, the sample 3C, in which the clay was modified by the tertiary amine, shows a DSC spectrum close to that of N. Namely, 3C has a high crosslinking density similar to N. While the three samples show a relaxation peak in their dielectric loss spectra, the peak appears at high frequencies in 1C compared to N and 3C. Moreover, ionic conduction current flows more at high temperatures in 1C than in N or 3C. These facts are ascribable to the difference in their crosslinking densities. [ABSTRACT FROM AUTHOR]

Effects of the differences in the curing agent and filler dispersion method on the dielectric properties were examined for epoxy/clay nanocomposites. Irrespective of the clay dispersion method, relative permittivity and electrical conductivity are higher in the samples cured with the amine. Moreover, negative heterocharge accumulates in the vicinity of the anode in the amine-cured samples, whereas positive homocharge accumulates in the acid anhydride-cured samples. From the results of UV photon absorption and PL measurement, the bandgap or the energy at which the photon absorption increases drastically is smaller in the amine-cured samples than in the acid anhydride-cured samples. Ion migration can occur easily in the amine-cured samples whose electrical conductivity and relative permittivity are higher than the acid anhydride-cured samples. The curing agent gives the strongest effect, while the existence of clay affects secondly and the filler dispersion method has the weakest effect. [ABSTRACT FROM AUTHOR]

Examines the space discharge distribution around water trees, while analyzing the nature of water trees, electrical insulation and dielectrics. Identification of mechanisms responsible for the formation of space charges; Factors which influence the use of crosslinked polyethylene (XPLE) cables; Methods used to test space charge.

The partial discharge (PD) resistance of three kinds of biodegradable polymers, namely poly-L-lactic acid (PLLA), polybutylene succinate (PBS), and poly e-caprolactone butylene succinate (PCL-BS), was studied in comparison to that of low-density polyethylene (LDPE). The polymers were exposed to PDs under the IEC (b) electrode system, and the PD resistance was judged by the surface erosion depth or the time to breakdown induced by PDs. As a result, the 'practical' PD resistance, which is the resistance to PDs under a constant voltage application, is ranked as LDPE > PLLA ⪢ PBS ≥ PCL-BS, while the 'true' PD resistance, which is the resistance to PDs with a constant charge quantity, is ranked as PLLA ≅ LDPE > PBS ⪢ PCL-BS. [ABSTRACT FROM AUTHOR]

Reports on recent trends and industry developments in Japan. [ABSTRACT FROM PUBLISHER]

The article presents a list of executive members who are elected for the Institute of Electrical Engineers of Japan (IEEJ). Tatsuki Okamoto of the Central Research Institute of Electric Power Industry was elected President of Society A, one of the five societies of IEEJ, which handles fields of dielectrics, electrical insulation, and electrical discharges. Naohiro Hozumi heads the Technical Committee on Dielectrics and Electrical Insulation.

Presents a study on dielectric properties of low-density polyethylene (LDPE)-based nanocomposites by J-Power Systems Corp. Overview of the contributions of J-Power in advancing power cable technologies; Citation of the increasing use of polymer nanocomposites over matrix polymers as insulation material; Development of nanocomposite materials; Dispersion state; Electric volume resistivity; Breakdown strength.

Reports on the activities of several investigational committees addressing dielectrics and electrical insulation in the Institute of Electrical Engineers of Japan (IEEJ). Focus on the activities of the Investigational Committee on Dielectric Materials for Information and Communication Industries; Mobile phone handsets; Satellite communication; Materials used in the space environment.

Focuses on the activities of several investigation committees addressing dielectrics and electrical insulation in the Institute of Electrical Engineers of Japan. Design of electric and electronic devices.

Reports on activities of the Investigation Committee on Environmentally Friendly Materials and Systems for Electrical and Electronic Engineering relating to dielectrics and electrical insulation in the Institute of Electrical Engineers of Japan. Importance of developing measures against environmental problems; Objectives of the committee; Overview of the foundation of the committee.