• 전기학회논문지
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• 제57권9호
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• pp.1572-1578
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• 2008

The effect of the organoclay_10A nanoparticles on the DSC and Structural and Dielectrics Properties(1Hz-1MHz) for epoxy/Organoclay_10A Nanocomposites has been studied. Dielectric properties of epoxy-Organoclay nanocomposites were investigated at 1, 3, 5, 7, 9 filler concentration by weight. Epoxy nanocomposites samples were prepared with good dispersion of layered silicate using power ultrasonic method in the particles. As structural analysis, the interlayer spacing have decreased with filled nanoparticles contents increase using power ultrasonic dispersion. The maximum increase interlayered spacing was observed to decease for above 5wt% clay loading. The other hand, as decrease with concentration filler of the layered silicate were increased dispersion degree of nanoparticles in the matrix. The interesting dielectric properties for epoxy based nanocomposites systems are attributed to the large volume fraction of interfacesin the bulk of the material and the ensuring interactions between the charged nanoparticle surface and the epoxy chains.

• Carbon letters
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• 제15권1호
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• pp.67-70
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• 2014

In this work, nanocomposites of epoxy resin and chemically reduced graphene oxide (RGO) were prepared by thermal curing process. X-ray diffractions confirmed the microstructural properties of RGO. Differential scanning calorimetry was used to evaluate the curing behaviors of RGO/epoxy nanocomposites with different RGO loading amounts. We investigated the effect of RGO loading amounts on the mechanical properties of the epoxy nanocomposites. It was found that the presence of RGO improved both flexural strength and modulus of the epoxy nanocomposites till the RGO loading reached 0.4 wt%, and then decreased. The optimum loading achieved about 24.5 and 25.7% improvements, respectively, compared to the neat-epoxy composites. The observed mechanical reinforcement might be an enhancement of mechanical interlocking between the epoxy matrix and RGO due to the unique planar structures.

• 한국정밀공학회지
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• 제23권11호
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• pp.103-107
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• 2006

It is well-known that the mechanical properties of MMT(montmorillonite) nanocomposites are better than those of conventional composites. In this study, tensile tests were performed to determine the effect of silane modification of MMT and its weight ratio on the tensile properties of MMT/epoxy nanocomposites. It was found that the tensile strength and the elastic modulus of MMT/epoxy nanocomposites increased with increasing weight ratio of MMT. The elastic modulus of silane-modified MMT/epoxy nanocomposites was higher than that of untreated MMT/epoxy nanocomposites, irrespective of weight ratio.

• Bulletin of the Korean Chemical Society
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• 제30권1호
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• pp.124-128
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• 2009

In this study, the effect of multi-step purification or functionalization on physicochemical properties of multi-walled carbon nanotubes (MWNTs)/epoxy (EP) nanocomposites was investigated. The nanocomposites containing multi-step purified MWNTs showed a stronger influence on $T_g$ and increased in mechanical properties in comparison to nanocomposites containing the same amount of only purified MWNTs. Consequently, the multi-step purification of MWNTs led to an improvement of thermomechanical properties of nanocomposites, resulting from improving the intermolecular interaction of MWNTs in epoxy matrix resins.

• 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.

• 한국전기전자재료학회논문지
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• 제21권6호
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• pp.538-543
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• 2008

Nanostructured materials are attracting increased interest and application. Exciting perspectives may be offered by electrical insulation. Epoxy/Organoclay nanocomposites may find new and upgraded applications in the electrical industry, replacing conventional insulation to provide improved performances in electric power apparatus, e.g, high voltage motor/generator stator winding insulation, dry mold transformer, etc. In the paper work, the electrical and thermal properties of epoxy/organoclay nanocomposites materials were studied. The electrical insulation characteristics were analyzed through the permittivity characteristics. by analyzing the permittivity spectra, it was found that dielectric constant becomes smaller with increase frequency and becomes larger with increase temperature. This indicates restriction of molecular motion and strong bonds at the epoxy/organoclay nanocomposites. The morphology of nanocomposites obtained was examined using TEM and X-ray diffraction. It has been shown that the presence of polar groups leads to an increased gallery distance and partial exfoliation. Nevertheless, full exfoliation of clay platelets has not been achieved.

• 동력기계공학회지
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• 제14권4호
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• pp.68-75
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• 2010

The effect of dispersion agent, the content and size of nanoparticle on the mechanical and thermal properties has been investigated in $TiO_2$ nanoparticle/epoxy resin composites(nanocomposites). The weight fraction of fabricated nanocomposites were 0, 1, 3, 5%, respectively. The glass transition temperature was lower than pure epoxy resin and decreased with the increasing of nanopaticle content. This is considered that the cross link of epoxy resin during solidification was hindered by the presence of nanoparticles. Nanocomposites of 3wt% content with dispersion agent showed the best tensile strength. The tensile strength of 20㎚ $TiO_2$ nanocomposites were higher than one of 200nm $TiO_2$ nanocomposites.

• 한국전기전자재료학회논문지
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• 제21권2호
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• pp.188-193
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• 2008

Epoxy/Organically Modified Layered Silicate Nanocomposites were prepared by dispersing synthetic layered silicate modified with alkyl ammonium ions. In the dispersing process, the organically modified layered silicate were mixed in epoxy resin with shearing, and aggregation of the silicate were removed by centrifugal separation after mixing epoxy resin and silicates. Micrographs taken by transmission electron microscopy(TEM) indicate that the nanocomposites have a mixed morphology including both parallel silicate layers and exfoliated silicate layers area, As the thermal properties, the glass transition temperature of the nanocomposites was shifted to a higher temperature($+6^{\circ}C$)than pure epoxy. Furthermore, dispersion of OMLS will prevented relative permittivity from increasing at a high temperature above the glass transition temperature.

• 한국염색가공학회지
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• 제30권2호
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• pp.98-106
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• 2018

In this study, graphene oxide(GO) was synthesized by using Hummer's method. Then, GO was used as a additive for epoxy resin nanocomposites that were prepared by mixing Tetraglycidyl diamino diphenyl methane(TGDDM) and hardner(MDEA+M-MIPA). Thermal and mechanical properties of epoxy resin nanocomposites were confirmed by analytical methods such as TG-DTA, DMA, fracture toughness, tensile strength, and flexural strength. The fracture surfaces of epoxy resin nanocomposites with different content of the GO were observed by a Scanning Electron Microscope(SEM). The mechanism for mechanical properties of epoxy resin nanocomposites was analyzed by modeling of nanocomposites with different GO weight. Due to the GO, both the heat resistance and the glass transition temperature of the epoxy resin nanocomposites were improved. Interestingly, when 0.1wt.% of GO was added to the epoxy resin/hardner mixture, the properties of mechanical increased compared with the neat epoxy resin. This results were caused by an aggregation between the GO.

• Advances in materials Research
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• 제1권1호
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• pp.93-107
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• 2012

Epoxy resin is widely used in high voltage apparatus as insulation. Fillers are often added to epoxy resin to enhance its mechanical, thermal and chemical properties. The addition of fillers can deteriorate electrical performance. With the new development in nanotechnology, it has been widely anticipated that the combination of nanoparticles with traditional resin systems may create nanocomposite materials with enhanced electrical, thermal and mechanical properties. In the present paper we have carried out a comparative study on dielectric properties, space charge and dielectric breakdown behavior of epoxy resin/nanocomposites with nano-fillers of $SiO_2$ and $Al_2O_3$. The epoxy resin (LY556), commonly used in power apparatus was used to investigate the dielectric behavior of epoxy resin/nanocomposites with different filler concentrations. The epoxy resin/nanocomposite thin film samples were prepared and tests were carried out to measure their dielectric permittivity and tan delta value in a frequency range of 1 Hz - 1 MHz. The space charge behaviors were also observed by using the pulse electroacoustic (PEA) technique. In addition, traditional epoxy resin/microcomposites were also prepared and tested and the test results were compared with those obtained from epoxy resin/nanocomposites.