Effect of Reactive Diluents on the AC Electrical Treeing in Epoxy/Nanosilicate Systems

박재준 한국전기전자재료학회 2014 Transactions on Electrical and Electronic Material Vol.15 No.2

The effect of reactive diluents on the ac electrical treeing in epoxy/nanosilicate systems was studied, in a needle-plateelectrode geometry. Diglycidyl ether of bisphenol A (DGEBA) type epoxy was used as a base resin, and layered silicatewas used as a nano-sized filler. Polyglycol (PG) or 1,4-butanediol diglycidyl ether (BDGE) was introduced as a reactivediluent to the DGEBA/nanosilicate system, in order to decrease the viscosity of the nanocomposite system. PG actedas a flexibilizer, and BDGE acted as a chain extender, after the curing reaction. To measure the treeing propagationrate, a constant alternating current (ac) of 10 kV/4.2 mm (60 Hz) was applied to the specimen, in a needle-plateelectrode arrangement, at 30℃ of insulating oil bath. When 10 kV/4.2 mm (60 Hz) was applied, the treeing propagaterate in the DGEBA system was 1.10×10-3 mm/min, and that in the DGEBA/PG system was 1.05×10-3 mm/min. As 1.5wt% of nanosilicate was added to the DGEGA/PG system, the propagation rate was 0.33×10-3 mm/min. This meantthat the nano-sized layered silicates would act as good barriers to treeing propagation. The effect of chlorine contentwas also studied, and it was found that chlorine had a bad effect on the electrical insulation property of the epoxysystem.

Effect of Organically Modified Layered Silicate on Thermal, Mechanical, and Electrical Properties of Epoxy-Based Nanocomposites

박재준,Soon-Seok Kwon,이재영 한국전기전자재료학회 2011 Transactions on Electrical and Electronic Material Vol.12 No.4

In an effort to develop new electrical insulation materials, four different kinds of organically modified layered silicate were incorporated into an epoxy matrix to prepare nanocomposites for electrical insulation. Five wt% of organically modified layered silicates were processed in a planetary centrifugal mixer in an epoxy matrix, and the thermal,mechanical, and electrical properties of the cured epoxy/layered silicate were investigated. The morphology of the nanoscale silicate dispersed in the epoxy matrix was observed using transmission electron microscopy, and the interlayer distance was measured by wide-angle X-ray scattering diffraction analysis.

Effect of Electric Field Frequency on the AC Electrical Treeing Phenomena in an Epoxy/Layered Silicate Nanocomposite

박재준 한국전기전자재료학회 2013 Transactions on Electrical and Electronic Material Vol.14 No.5

The effects of electric field frequency on the AC electrical treeing phenomena in an epoxy/layered silicate (1.5wt%) were investigated in a needle-plate electrode arrangement. A layered silicate was exfoliated in an epoxy-base resin with AC electric field apparatus. To measure the treeing initiation and propagation- and the breakdown rate,a constant alternating current (AC) of 10 kV with three different electric field frequencies (60, 500, and 1,000 Hz)was applied to the specimen in the needle-plate electrode specimen in an insulating oil bath at130℃. At 60 Hz, the treeing initiation time was 12 min, the propagation rate was 0.24 × 10-3 mm/min, and the morphology was a dense branch type. As the electric field frequency increased, the treeing initiation time decreased and the propagation rate increased. At 1,000 Hz, the treeing initiation time was 5 min, the propagation rate was 0.30 × 10-3 mm/min, and the morphology was a dense bush type.

AC Electrical Treeing Phenomena in an Epoxy System with Low-chlorine BDGE at Various Electric Field Frequencies

박재준 한국전기전자재료학회 2013 Transactions on Electrical and Electronic Material Vol.14 No.6

An alternating current (AC) electrical treeing phenomena in an epoxy system with low chlorine BDGE (1,4-butanediol diglycidyl ether) was studied in a needle-plate electrode arrangement. To measure the treeing propagation rate and breakdown time, a constant AC of 10 kV with three different electric field frequencies (60, 500, and 1,000 Hz)was applied to the needle-plate electrode specimen at 130℃ in aninsulating oil bath. The treeing propagation rate of the DGEBA/high-chlorine BDGE system was higher than that of the DGEBA/low-chlorine BDGE system and the breakdown time of the system with high-chlorine BDGE was lower than that of the system with low-chlorine BDGE. These results implied that chlorine had a negative effect on the electrical insulation property of the epoxy system. As the electric field frequency increased, the treeing propagation rate increased and the breakdown time decreased.

Effect of Electric Frequency on the Partial Discharge Resistance of Epoxy Systems with Two Diluents

박재준 한국전기전자재료학회 2013 Transactions on Electrical and Electronic Material Vol.14 No.6

Partial discharge resistance for the epoxy systems with two diluents was investigated in the rod-plane electrodes arrangement, and the effect of electric frequency on the partial discharge resistance was also studied. Diglycidyl ether of bisphenol A (DGEBA) type epoxy was used as a base resin, and 1,4-butanediol diglycidyl ether (BDGE) or polyglycol (PG) as a reactive diluent was introduced to the DGEBA system, in order to decrease the viscosity of the DGEBA epoxy system. BDGE wasacted as a chain extender, and PG acted as a flexibilizer, after the curing reaction. To measure the partial discharge resistance, 5 kV alternating current (ac) with three different frequencies (60, 500and 1,000 Hz) was applied to the specimen in a rod-plane electrode arrangement, at 30℃. PG had a good effect,while BDGE had a bad effect on the partial discharge resistance of the DGEBA system, regardless of the electric frequency.

Electrical Insulation and Mechanical Properties of Epoxy/Micro‑silica (MS)/Micro‑alumina (MA) Composites

박재준 한국전기전자재료학회 2019 Transactions on Electrical and Electronic Material Vol.20 No.1

Effect of mixture ratio of micro-silica (MS) and micro-alumina (MA) on the electrical insulation and mechanical properties of epoxy composites was investigated in order to develop a new insulation material for high voltage gas insulated switchgears. The mixing ratio of inorganic filler to epoxy resin was fixed to 70 wt%, and the mixture ratio of MS and MA in inorganic filler was 10:0, 9:1, 7:3, 5:5, 3:7, 1:9, and 0:10, respectively. Insulation breakdown strength increased with increasing MS content, however it did not follow the mixture rule of composite showing synergy effect. Those values for neat epoxy, epoxy/MS (70 wt%), and epoxy/MA (70 wt%) were 44.5, 53.4 and 47.1 kV/2 mm, respectively. Tensile strength and flexural strength were measured using a universal testing machine at a crosshead speed of 10 mm/min, and they also increased with increasing MS content, while they did not follow the mixture rule of composite.

Thermal and Mechanical Properties of Epoxy/Micro- and Nano- Mixed Silica Composites for Insulation Materials of Heavy Electric Equipment

박재준,윤기근,이재영 한국전기전자재료학회 2011 Transactions on Electrical and Electronic Material Vol.12 No.3

A 10 nm nano-silica was introduced to a conventional 3 μm micro-silica composite to develop an eco-friendly new electric insulation material for heavy electric equipment. Thermal and mechanical properties, such as glass transition temperature (Tg), dynamic mechanical analysis, tensile and flexural strength, were studied. The mechanical results were estimated by comparing scale and shape parameters in Weibull statistical analysis. The thermal and mechanical properties of conventional epoxy/micro-silica composite were improved by the addition of nano-silica. This was due to the increment of the compaction via the even dispersion of the nano-silica among the micro-silica particles.

Preparation of Epoxy/Organoclay Nanocomposites for Electrical Insulating Material Using an Ultrasonicator

박재준,Young-Bum Park,이재영 한국전기전자재료학회 2011 Transactions on Electrical and Electronic Material Vol.12 No.3

In this paper, we discuss design considerations for an n-channel metal-oxide-semiconductor field-effect transistor (MOSFET) with a lateral asymmetric channel (LAC) doping profile. We employed a 0.35 μm standard complementary MOSFET process for fabrication of the devices. The gates to the LAC doping overlap lengths were 0.5, 1.0, and 1.5μm. The drain current (I_(ON)), transconductance (g_(m)), substrate current (I_(SUB)), drain to source leakage current (I_(OFF)), and channel-hot-electron (CHE) reliability characteristics were taken into account for optimum device design. The LAC devices with shorter overlap lengths demonstrated improved I_(ON) and g_m characteristics. On the other hand, the LAC devices with longer overlap lengths demonstrated improved CHE degradation and I_(OFF) characteristics.

Effect of Particle Size on the Mechanical and Electrical Properties of Epoxy/Spherical Silica Composites

박재준 한국전기전자재료학회 2013 Transactions on Electrical and Electronic Material Vol.14 No.1

The effects of particle size on the mechanical and electrical properties of epoxy/spherical silica composites were studied. The silica particle sizes were varied from 5 to 30 μm and the filler content was fixed to 60 wt%. Tensile and flexural tests were carried out and the interfacial morphology was observed by scanning electron microscopy (SEM). The electrical insulation breakdown strength was estimated using sphere-sphere electrodes with different insulation thicknesses of 1, 2 and 3 mm. The tensile strength and flexural strength increased with decreasing particle size, while electrical insulation breakdown strength increased with increasing particle size.

EMNC_60과 EMNC_65에 대한 열적, 기계적, 전기적 특성 연구

박재준,Park, Jae-Jun 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.11

In order to application for high voltage heavy electric equipments, epoxy/microsilica 60 wt%/nano layered silicate composites (EMNC_60) and epoxy/microsilica 65 wt%/nano layered silicate composites (EMNC_65) respectively was synthesized by our electric field dispersion method and the result was obtained completely dispersion state. Thermal properties such as glass transition temperature (Tg) and thermal expansion coefficient, and DMA characteristics were studied, and mechanical properties such as tensile and flexural tests were performed. AC electrical insulation strength was also tested. The study on thermal property, EMNC_65 was better than EMNC_60 and mechanical, electrical properties much improved EMNC_60 compared with EMNC_65.