• Transactions on Electrical and Electronic Materials
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• 제12권4호
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• pp.160-163
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• 2011

Polymer nanocomposite has been attracting more attention as a new insulation material because homogeneous dispersion of nano-sized inorganic fillers can improve various properties significantly. In this paper, various kinds of epoxy-based nanocomposites were made, and the AC breakdown strengths of Nano filler and micro-$SiO_2$ filler mixtures of epoxy-based composites were analyzed using sphere-to-sphere electrodes. Moreover, nano- and microfiller combinations were investigated as an approach to practical application of nanocomposite insulation materials. Its composition ratio was 100 (resin):82 (hardener):1.5 (accelerator). AC breakdown tests were performed at room temperature ($25^{\circ}C$), $80^{\circ}C$, and $100^{\circ}C$ in the vicinity of $T_g$ ($90^{\circ}C$). Thermal conductivity was measured using TC-30.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.87-87
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• 2010

Epoxy/mica has been used as the material of high-voltage rotator stator winding due to its high insulation performance, mechanical strength, and thermal stability. In recent years, however, it shows frequent changes in the load of generators and frequent automatic stops due to the significant increase in peak loads from the increase in the applied load of power facilities according to the introduction of advanced and high-technology equipments. Thus, it is necessary to develop new materials that highly develop the conventional insulation materials. Nanotechnology introduced in the present time has become an alternative plan that overcomes such technical limitations. In addition, the nano-scaled intercalation composite has been known as the material that represent excellent electrical, mechanical, and thermal characteristics compared to the conventional materials. This study investigated the dielectric dispersion and relaxation characteristics of the nanocomposite, which was fabricated by mixing epoxy matrix with nano-scaled intercalation mica and clay, according to changes in frequencies and temperatures.

• Transactions on Electrical and Electronic Materials
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• 제13권5호
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• pp.252-255
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• 2012

In order to characterize insulation properties of epoxy/micro-silica/nano-silicate composite (EMNC), long-term and short-term AC treeing tests were carried out undr non-uniform electric field generated between needle-plate electrodes. In a long-term test, a 10 kV (60 Hz) electrical field was applied to the specimen positioned between the electrodes with a distance of 2.7 mm in an insulating oil bath at $30^{\circ}C$, and a typical branch type electrical tree was observed in the neat epoxy resin and breakdown took place at 1,042 min after applying the 10 kVelectrical field. Meanwhile, the spherical tree with the tree length of $237{\mu}m$ was seen in EMNC-65-0.3 at 52,380 min (36.4 day) and then the test was stopped because the tree propagation rate was too low. In the short-term test, an electrial field was applied to a 3.5 mm-thick specimen at an increasing voltage rate of 0.5 kV/s until breakdown in insulating oil bath at $30^{\circ}C$ and $130^{\circ}C$, and the data was estimated by Weibull statistical analysis. The electrical insulation breakdown strength for neat epoxy resin was 1,763 kV/mm at $30^{\circ}C$, while that for EMNC-65-0.3 was 2,604 kV/mm, which was a modified value of 47%. As was expected, the breakdown strength decreased at higher test temperatures.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.2071-2072
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• 2011

Withstand voltage characteristics of the nanocomposites, as a material with excellent abrasion resistance and water resistance, low shrinkage upon curing with moisture even in very good adhesion, workability is not lost. In this study, the fusion of nanoparticles and the high functionality epoxy nano-composite material produces the electricity. Degeneration of the unit based on this power structure and breakdown characteristics, efficiency and cross-measurement system as closely related organisms that can be applied to the power plant electrical efficiency of the nano-composite material is designed to develop skills.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1331-1334
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• 2004

The research on electromagnetic shielding has been advanced for military applications as well as for commercial products. Utilizing the reflective properties and absorptive properties of shielding material, the replied signal measured at the rear surface or at the signal source can be minimized. The shielding effect was obtained from materials having special absorptive properties or from structural characteristics such as stacking sequence. Recently researchers studied the electromagnetic properties of nano size particles. In this research {glass fiber}/{epoxy}/{nano particle} composites(GFR-Nano composites), was fabricated using various nano particles, and their properties in electromagnetic shielding were compared. For the visual observation of the nano composite materials, SEM(Scanning Electron Microscope) and TEM(Transmission Electron Microscope) were used. For the measurement of electromagnetic shielding, HP8719ES S-parameter Vector Network Analyser System was used on the frequency range of 8 GHz～12GHz. Among the nano particles, carbon black and Multi-Walled Carbon Nano-Tube (MWCNT) revealed outstanding electromagnetic shielding. Although silver nano particles (flake and powder) were expected to have effective electromagnetic shielding due to their excellent electric conductivities, test showed little shielding effect.

• Structural Engineering and Mechanics
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• 제73권6호
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• pp.715-724
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• 2020

The influence on flexural strength of Glass/Epoxy laminated composite curved panels of different geometries (cylindrical, spherical, elliptical, hyperboloid and flat) due to inclusion of nano cenosphere filler examined in this research article. The deflection responses of the hybrid structure are evaluated numerically using the isoparametric finite element technique and modelled mathematically via higher-order displacement structural kinematics. To predict the deflection values, a customised in-house computer code in MATLAB environment is prepared using the higher-order isoparametric formulation. Subsequently, the numerical model validity has been established by comparing with those of available benchmark solution including the convergence characteristics of the finite element solution. Further, a few cenosphere filled hybrid composite are prepared for different volume fractions for the experimental purpose, to review the propose model accuracy. The experimental deflection values are compared with the finite element solutions, where the experimental elastic properties are adopted for the computation. Finally, the effect of different variable design dependent parameter and the percentages of nano cenosphere including the geometrical shapes obtained via a set of numerical experimentation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.92-92
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• 2010

In this paper, the test is performed on MgO, which is used as a filler in epoxy additives, respectively (0, 1.0, 3.0, 5.0, 7.0, 10 [wt%]) for HVDC(high voltage direct current) submarine cable insulating material to improve electrical properties of epoxy resin in high temperature. The breakdown strength due to increasing amount of filler increased to 5.0 [wt%] by the effects of the Coulomb blockade. However, it is confirmed that strength of dielectric breakdown decreased because the filler functioned as impurities and affected the breakdown when filler additive exceeded by 5.0 [wt%] or more. We have found that the highest dielectric breakdown strength of specimen added 5.0 wt% at $25^{\circ}C$, and is more increased approximately 13.7 [%] than virgin specimen.

• Advances in nano research
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• 제16권4호
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• pp.353-363
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• 2024

The incorporation of nanoplatelets in composite and polymeric materials represents a recent and innovative approach, holding substantial promise for diverse property enhancements. This study focuses on the application of nanocomposites in the production of sports equipment, particularly soccer balls, aiming to bridge the gap between theoretical advancements and practical implications. Addressing the longstanding challenge of suboptimal interaction between carbon nanofillers and epoxy resin in epoxy composites, this research pioneers inventive solutions. Furthermore, the investigation extends into unexplored territory, examining the integration of glass fiber/epoxy composites with nanoparticles. The incorporation of nanomaterials, specifically expanded graphite and graphene, at a concentration of 25.0% by weight in both the epoxy structure and the composite with glass fibers demonstrates a marked increase in impact resistance compared to their nanomaterial-free counterparts. The research transcends laboratory experiments to explore the practical applications of nanocomposites in the design and production of sports equipment, with a particular emphasis on soccer balls. Analytical techniques such as infrared spectroscopy and scanning electron microscopy are employed to scrutinize the surface chemical structure and morphology of the epoxy nanocomposites. Additionally, an in-depth examination of the thermal, mechanical, viscoelastic, and conductive properties of these materials is conducted. Noteworthy findings include the efficacy of surface modification of carbon nanotubes in preventing accumulation and enhancing their distribution within the epoxy matrix. This optimization results in improved interfacial interactions, heightened thermal stability, superior mechanical properties, and enhanced electrical conductivity in the nanocomposite.

• 한국분말재료학회지
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• 제22권4호
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• pp.234-239
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• 2015

Electronic products are a major part of evolving industry and human life style; however most of them are known to emit electromagnetic waves that have severe health hazards. Therefore, different materials and fabrication techniques are understudy to control or limit transfer of such waves to human body. In this study, nanocomposite powder is dispersed into epoxy resin and shielding effects such as absorption, reflection, penetration and multiple reflections are investigated. In addition, nano size powder (Ni, $Fe_2O_3$, Fe-85Ni, C-Ni) is fabricated by pulsed wire evaporation method and dispersed manually into epoxy. Characterization techniques such as X-ray diffraction, Scanning electron microscopy and Transmission electron microscopy are used to investigate the phase analysis, size and shape as well as dispersion trend of a nano powder on epoxy matrix. Shielding effect is measured by standard test method to investigate the electromagnetic shielding effectiveness of planar materials, ASTM D4935. At lower frequency, sample consisting nano-powder of Fe-85%Wt Ni shows better electromagnetic shielding effect compared to only epoxy, only Ni, $Fe_2O_3$ and C-Ni samples.

• 마이크로전자및패키징학회지
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• 제28권2호
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• pp.51-57
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• 2021

이 연구에서는 에폭시 수지에 포함된 나노 실리카 입자의 농도가 재료의 열/기계적 물성에 미치는 영향에 대해 알아보았다. 약 12 nm 크기의 나노 입자를 에폭시 수지에 다섯가지 무게비로 섞은 나노복합소재를 제작하였다. DMA와 TMA 방법을 이용하여 유리전이온도, 응력이완, 열팽창 거동을 측정하였다. 이를 통해 나노입자가 재료의 점탄성 거동에 어떠한 영향을 미치는지 보였다. 실리카 입자의 함량이 증가할수록 순수 에폭시 재료 대비 탄성 물성은 증가하였고, 유리전이온도는 감소하였다. FTIR 결과는 분자구조의 관점에서 충진제 함량에 따른 물성변화의 원인을 찾고 나노입자가 에폭시 분자 구조에 어떠한 영향을 미치는지를 규명하는데 중요한 역할을 하였다.