Minoru Ezoe

Soluble and high molecular weight polyaniline

Low temperature polymerization of aniline using ammonium peroxodisulphate results in a soluble, high molecular weight polyaniline which forms a very strong free-standing film.

Effects of ionic impurity on space charge distribution in solid dielectrics

We are interested in the interfacial phenomena concerning breakdown mechanism in solid dielectrics. We have been researching the effect of ionic impurity on space charge distribution and electric properties in filled epoxy resin and polyimide resin containing carbon. We have studied on the factors for hetero space charge accumulated near the electrodes by means of comparing the result of ionic analysis with the result of space charge behavior in high polymer this time. And we have guessed that hetero charge (positive charge) accumulated near the cathode are proton (H/sup +/) separated from organic acid, and negative charge accumulated near the anode are various -COO/sup -/ ions separated from organic acid.

Three-dimensional space charge measurements of polymers using the pulsed electroacoustic method

We have observed three dimensional space charge profiles of an epoxy resin sheet with internal wires and of a polyimide flexible printed circuit board. Experimental results suggest that the three-dimensional pulsed electroacoustic (3D-PEA) space charge measurement system can be applied evaluate the printed circuit board and to investigate its breakdown phenomena.

A study on the antistatic agent behavior by space charge observation

We have searched for antistatic agent behavior by surface resistivity and space charge measurement. In a structure of three layer (PET/PE/EVA) that EVA layer is mixed with an antistatic agent, we measured the humidity characteristic of the surface resistivity (/spl rho/s) in order to observe the influence of a PE layer against the behavior of antistatic agent. As a result, we confirmed that EVA surface resistivity were influenced by character of PE layer. Next, we searched for the diffusion speed of the antistatic agent by measuring the change in the surface resistivity (/spl rho/s) of the PE layer when we laminated two films of EVA film and PE film together at 403 K (130 /spl deg/C). As a result, we confirmed that diffusion speed of antistatic agent varied with PE layer. Finally we tried to observe diffusion of antistatic agent from EVA to PE using pulse electroacoustic method. We could observe the mobility of a space charge in PE layer.

Space charge formation in polyimide/carbon compound film for electronics devices

With the specimens disperse carbon black of same volume in polyimide film, we investigated dispersion state of carbon black, electrical conductivity and space charge distribution. The result was confirmed that electrical conductivity of polyimide films was indeterminable only volume of carbon black. About space charge distribution, in all specimens of polyimide films the plus hetero charge occurred much, in each different specimens of electrical conductivity the occurrence volume was different. The distribution state of carbon black was not different in the result of SEM observation. We guessed the electron from polymer structure had influence on the electrical conductivity. We confirmed the occurrence of space electric charge at an applied voltage pulse of 10-500 ms intervals.

Relevance with resistance distribution and accumulated charge by three-dimensional space charge observation in a PI film with carbon

We examine the toner transcription mechanism by the observation of space charge movement in intermediate transfer belt on the applied voltage. And it was observed about the relevance with the resistivity distribution and image defect by the measurement such as three-dimensional space charge distribution and electrical conductivity. Therefore, it became possible that an image defect was predicted by measuring the space charge distribution in a intermediate transfer belt. In the future, we intend to investigate about the electrical conductivity mechanism of a intermediate transfer belt.

Visualization of Diffusion Process of an Antistatic Agent in Insulating Polymer Using Space Charge Measurement and Its Numerical Calculation

Antistatic agent is often used for avoiding electrification of polymer films. In some cases, the film has a double-layer structure to improve its adhesive property. As an example, an ethylene-vinylacetate copolymer (EVA) film, in which an antistatistic agent is mixed, is laminated with a low-density polyethylene (LDPE) film. In such a case, there is a possibility that the antistatic property of the EVA may be lost because of the diffusion of the antistatic agent into the LDPE side. A space charge study on the LDPE/EVA laminate was carried out using the pulsed electroacoustic method under DC voltage. The space charge once formed at EVA/LDPE interface decreased with time, and propagated into LDPE. A space charge profile at EVA/LDPE interface was also calculated with difference of conductivities between LDPE and EVA. The space charge profile at EVA/LDPE interface was qualitatively corresponded to that from space charge measurement. As a result, it was suggested that diffusion of the antistatic agent led to this space charge behavior. It was considered that measurements of space charge profiles would enable the assessment of diffusion of antistatic agent in multi-layer