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Pyeongtaek, South Korea

Park J.-J.,Joongbu University | Yoon C.-Y.,Joongbu University | Lee J.-Y.,Woosuk University | Cheong J.-H.,Dongwoo Electrical Co. | Kang G.-B.,Dongwoo Electrical Co.
Transactions on Electrical and Electronic Materials | Year: 2016

The effect of microsilica content modified with silicone-modified epoxy on electrical and mechanical properties of cycloaliphatic epoxy/microsilica system was investigated. The cycloaliphatic epoxy resin was diglycidyl 1,2-cyclohexanedicarboxylate and curing agent was an anhydride. Surface of microsilica was modified with silicone-modified epoxy. Electrical breakdown strength, the most important property for electrical insulation materials was tested. Tensile and flexural tests were also performed using universal testing machine (UTM). The microcomposite with 60 wt% microsilica shows maximum values in electrical breakdown strength. © 2016 KIEEME. All rights reserved. Source


Park J.-J.,Joongbu University | Kim J.-S.,Joongbu University | Yoon C.-Y.,Joongbu University | Shin S.-S.,Joongbu University | And 4 more authors.
Transactions on Electrical and Electronic Materials | Year: 2015

Mechanical and electrical properties of epoxy/silica microcomposites were investigated. The cycloaliphatic- type epoxy resin was diglycidyl 1,2-cyclohexanedicarboxylate and the curing agent was of an anhydride type. To measure the glass transition temperature (Tg), dynamic differential scanning calorimetry (DSC) analysis was carried out, and tensile and flexural tests were performed using a universal testing machine (UTM). Electrical breakdown strength, the most important property for electrical insulation materials, and insulation breakdown strength were also tested. The microcomposite with 60 wt% microsilica showed maximum values in mechanical and electrical properties. © 2015 KIEEME. All rights reserved. Source


Lee J.-Y.,Woosuk University | Park J.-J.,Joongbu University | Kim J.-S.,Joongbu University | Shin S.-S.,Joongbu University | And 4 more authors.
Transactions on Electrical and Electronic Materials | Year: 2015

The cure kinetics of a neat epoxy system and epoxy/silica composite were investigated by DSC analysis. A cycloaliphatic type epoxy resin was diglycidyl 1,2-cyclohexanedicarboxylate and curing agent was anhydride type. To estimate kinetic parameters, the Kissinger equation was used. The activation energy of the neat epoxy system was 88.9 kJ/mol and pre-exponential factor was 2.64×1012 min-1, while the activation energy and pre-exponential factor for epoxy/silica composite were 97.4 kJ/mol and 9.21×1012 min-1, respectively. These values showed that the silica particles have effects on the cure kinetics of the neat epoxy matrix. © 2015 KIEEME. All rights reserved. Source


Kim Y.-M.,Cheongju University | Kwon J.-H.,Cheongju University | Kang S.-H.,Cheongju University | Jung J.-H.,Dongwoo Electrical Co. | And 2 more authors.
Journal of Ceramic Processing Research | Year: 2012

This paper presents the manufacture and testing of nano/micro epoxy resins and their properties. In order to prepare the specimens, a main resin, a hardener, an accelerator and a nano/micro filler were used. Varying amounts of CuO and Ag nano fillers were added to the epoxy mixture along with a fixed amount of micro silica. The thermomechanical and electrical properties of these mixtures were then determined by DC breakdown (DCBD) test and TMA analysis. The DCBD strength value of the composites can be described by a Weibull distribution. Totally, the epoxy resin exclusively filled with the nano particles had better electrical properties than micro composite in which there isn't nano filler. However, according to the quantities and type of filler, the properties of the epoxy composites were not found to be linear or proportional. There were optimal combinations and ratios. This results can be explained by Nordheim's rule. And it was confirmed that thermal expansion coefficients (TEC) of nano-epoxy composites have similar value with Al or Cu. Source

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