• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1990년도 추계학술대회 논문집
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• pp.95-97
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• 1990

This study investigated electrical characteristic of solids and liquid epoxy resins by measuring dielectric breakdown and dielectric loss when epoxy resins were exposed to a mixing cure. It was found that mixing epoxy resins were superior to dielectric breakdown and hardness and has shorter curing time compare with those of pure liquid epoxy resins.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.771-774
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• 2000

Recently, complex insulation method is used in insulation system for underground power delivery devices. Considering the interfaces which affect stability of insulation system, By modeling interface between Epoxy and Rubber, AC interfacial breakdown properties with variation of many conditions to influence on electrical properties were investigated. In this paper, toughened Epoxy and Silicone rubber were used for materials to make interface .

• Korean Chemical Engineering Research
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• 제58권1호
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• pp.64-68
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• 2020

본 연구에서는, 열 전도성 충진제로 충진 된 에폭시복합체를 사용하여 금속 구리판에 이를 코팅한 기판이 제조되었다. 에폭시 복합체의 열전도도를 향상시키기 위해서는 에폭시 매트릭스에 있는 전도성 필러의 최적 분산을 통한 전도성 네트워크를 형성하게 하고, 인접한 필러 입자들 사이에서 열 저항 접합의 수를 감소시키는 것이 중요한 요소이다. 이는 에폭시는 열전도도가 0.2~0.3 W 밖에 안되기 때문에 높은 열전도도를 유지하기 위해선 열전도성 필러가 서로 연결되어 입자간에 갭이 적어야 열저항을 감소시킬수 있기 때문이다. 본 연구의 목적은 에폭시 수지에 Al₂O₃와 Boron Nitride (BN) 충진제를 균일하게 분산시켜 고방열 에폭시 복합체를 개발하는 데 있다. 그 결과, Al₂O₃와 Boron nitride Filler가 에폭시 수지 매트릭스에 서로 연결되어 에폭시 수지와 알루미나/Boron nitride 하이브리드 필러 간에 계면 공극 없이 분산되어 열전도도 특성 향상을 확인 할 수 있었고, 표면 처리한 s-BN 필러가 에폭시 수지의 매트릭스의 계면접착력을 향상시켰으며, 계면 공극을 최소화함에 따라 높은 열전도도 특성을 확보 할 수 있었다.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권5호
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• pp.230-235
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• 2004

In this paper, epoxy elasticity factors were investigated by TMA (Thermomechanical Analysis), DMTA (Dynamic Mechanical Thermal Analysis) and FESEM (Field Emission Scanning Electron Microscope) to improve toughness and reduce brittleness of existing epoxy resin. Dumbbell shaped specimens were made and tested at rates of 0, 20 and 35phr (part per hundred resins). TMA temperatures ranged from -2$0^{\circ}C$ to 20$0^{\circ}C$. Tg (glass transition temperature) of elastic epoxy was measured by thermal analysis. Also investigated were thermal expansion coefficient ($\alpha$), modulus and Tan$\delta$ (loss factor). And we analyzed structure through FESEM, could find elastic-factors of elastic epoxy that is not existing-epoxy. In addition, we measured permittivity and Tan$\delta$ for investigation of the electrical properties of elastic epoxy. Permittivity and Tan$\delta$ depend on elastomer composition. Namely, permittivity and Tan$\delta$ increase according to the elastomer contents. For experimental analysis results, 20phr was considered an excellent specimen.

• 한국수소및신에너지학회논문집
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• 제31권1호
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• pp.49-56
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• 2020

Epoxy/carbon composite was used to prepare a bipolar plate for polymer electrolyte membrane fuel cell (PEMFC). Phenol novolac-type epoxy and diglycidyl ether of bisphenol A (DGEBA)-type epoxy mixture was used as a matrix and graphite powder, carbon fiber (CF) and graphite fiber (GF) were used as carbon materials. In order to improve the mechanical properties of the bipolar plate, surface-modified CF was incorporated into the epoxy/carbon composite. To determine the cure temperature of the epoxy mixture, differential scanning calorimetry (DSC) analysis was performed and the data were introduced to Kissinger equation in order to get reaction activation energy and pre-exponential factor. Tensile and flexural strength was obtained by using universal testing machine (UTM). The surface morphology of the fractured specimen and the interfacial morphology between epoxy matrix and CF or GF were observed by a scanning electron microscopy (SEM).

• 동력기계공학회지
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• 제21권1호
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• pp.11-17
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• 2017

This study is about the mechanical properties of epoxy composite reinforced with nano $TiO_2$ particle. Tensile strength, fracture toughness, vicker's hardness and Izod Impact test were carried out to investigate the effect of particle size and content of $TiO_2$ on the mechanical properties of $TiO_2$/epoxy composites. The results showed that the strength of the $TiO_2$/epoxy composites were higher than that of the pure epoxy. The best improvement of tensile strength was achieved in case of the particle size was 21 nanometer and the content was 3 weight percent. However, the Izod Impact value and the Vicker's hardness of $TiO_2$/epoxy composites showed no clear tendency.

• Corrosion Science and Technology
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• 제13권5호
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• pp.163-169
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• 2014

The corrosion resistance of epoxy-coated carbon steel was evaluated. The carbon steel surface was subjected to different treatment methods such as steel grit blasting and power tool treatment as well as contamination of water soluble salt. To study the effect of the surface treatments and contamination, the topology of the treated surface was observed by confocal microscopy and a pull-off adhesion test was conducted. The corrosion resistance of the epoxy-coated carbon steel was further examined by electrochemical impedance spectroscopy (EIS) combined with immersion test of 3.5 wt% of NaCl solution. Consequently, the surface contamination by sodium chloride with $16mg/m^2$, $48mg/m^2$ and $96mg/m^2$ didn't affect the adhesion strength for current epoxy coated carbon steel and blister and rust were not observed on the surface of epoxy coating contaminated by various concentration of sodium chloride after 20 weeks of immersion in 3.5 wt% NaCl aqueous solutions. In addition, the results of EIS test showed that the epoxy-coated carbon steel treated with steel grit blasting and power tool showed similar corrosion protection performance and surface cleanness such as Sa 3 and Sa 2.5 didn't affect the corrosion protectiveness of epoxy coated carbon steel.

• 한국응용과학기술학회지
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• 제28권1호
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• pp.109-117
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• 2011

In this study, we experimented that how influence chain extension to waterborne urethane-epoxy hybrid resin for leather garment coatings. First of all, We had analyzed datas by FT-IR, SEM and machanical properties. By instruments analysis measurement we confirmed that synthesis of epoxy and hybrid resin. In this experiment we knew that polyurethane-epoxy hybrid resin have 5 grades of solvent resistance. Tensile strength measured in the polyurethane-epoxy resin(EDA 5.37g, 2.386 $kg_f/mm^2$) had the most strong strength.. Also polyurethane-epoxy hybrid resin had better result(EDA 5.37g. 37.4 mg. loss) than other hybrid resins. As hight proportion of EDA in hybid resin, we obtained low elongation and low flexibility. In this result, chain extension of waterborne polyurethane-epoxy hybrid resin showed that how effect in leather coating by ratio of EDA.

• 전기학회논문지
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• 제65권9호
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• pp.1511-1517
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• 2016

The aim of this study is to improve of properties for electrical AC insulation breakdown strength using epoxy/micro-nano alumina composites with adding glycerol diglycidyl ether (GDE:1,3,5g). This paper deals with the effects of GDE addition for epoxy/micro alumina contents (40,50,60wt%)+surface modified nano alumina(1_phr) composites. 14 kinds specimen were prepared with containing epoxy resins, epoxy micro composites and epoxy nano-micro alumina mixture composites. Average particle size of nano and micro alumina used were 30nm and $1{\sim}2{\mu}m$, respectively. The micro alumina used were alpha phase with Heterogeneous and nano alumina were gamma phase particles of spherical shape. The electrical AC insulation breakdown strength was evaluated by sphere to sphere electrode system and raising velocity 1kV/s. The AC breakdown strength decreased insulation properties of multi-composites according to increasing micro alumina and GDE addition contents.

• 한국응용과학기술학회지
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• 제24권3호
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• pp.264-271
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• 2007

Effect of dispersion methods for Vapor Grown Carbon Fibers (VGCF) in epoxy caused the change in mechanical properties of VGCF/epoxy nanocomposites, such as tensile modulus and tensile strength. The influence of VGCF types - atmospheric plasma treated (APT) VGCF and raw VGCF - and their contents was discussed in detail. Treating VGCF with atmospheric plasma enhanced the surface energy, therefore improved the bonding strength with epoxy matrix. Two different methods used to disperse VGCF were ultrasonic and mechanical homogenizer methods. When using dispersion solutions, the VGCF demonstrated good dispersion in ethanol in both homogenizer and ultrasonic method. The uniform dispersion of VGCF was investigated by scanning electron microscopy (SEM) which showed well-dispersion of VGCF in epoxy matrix. The tensile modulus of raw VGCF/epoxy nanocomposites obtained by ultrasonic method was higher than that of one obtained by homogenizer method. APT VGCF/epoxy nanocomposites showed higher tensile strength than that of raw VGCF/epoxy nanocomposites.