• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 추계학술대회 논문집
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• pp.75-79
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• 1993

The Thermally Stimulated Current(TSC) method has been allied to study the influence of the structural change and interface on the electrical properties of epoxy composites. Three DGBA- MeTHPA matrix model samples mixed different ratios arts silica(SiO$_2$) filled sample and silaln treating-filled sample have been studied. Above room temperature, the relaxation mode ${\alpha}$ peak associated with T$\_$g/ has been located at 110$^{\circ}C$. Below glass transition temperature(T$\_$g/), three relaxation modes are observed in all samples : a ${\beta}$ mode situated at 10$^{\circ}C$, a ${\gamma}$ mode located at -40$^{\circ}C$ and a $\delta$mode appeared in -120$^{\circ}C$, which may be due to segmental motion, side chains, substitution and terminal groups. The analysis of its fine structure indicates that constitution of elementary processes is characterized by the activation energy and relaxation time. Also the change of the molecular structure and their thermal motion are compared with the relaxation mode and conduction mechanism in TSC spectra through the dielectric properties and FTIR measurements.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.1162-1164
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• 1993

The Thermally Stimulated Current(TSC) spectroscopy has been applied to study the influence of the structual cahange and interface on the electrical properties of epoxy composites. Three DGEBA-MeTHPA matrix model samples mixed different ratios and silica($SiO_2$) filled sample and silaln treating-filled sample has been studied. Above room temperature, the relaxation mode $\alpha$ peak associated with Tg has been located at $110^{\circ}C$. Below glass transition temperature(Tg), three relaxation modes are observed in all samples: a $\beta$ mode situated at $10^{\circ}C$, a $\gamma$ mode located at $-40^{\circ}C$ and a $\delta$ mode appeared in $-120^{\circ}C$. The analysis of its fine structure indicates that constitution of elementary processes is characterized by the activation energy and relaxation time. Also the dielectric relaxation properties have been investigated to compare the the change of the molecular structure and motion to the relaxation properties and conduction mechanism in TSC spectra.

• 접착 및 계면
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• 제23권4호
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• pp.108-115
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• 2022

본 연구에서는 표면처리된 Cu 리드프레임과 에폭시 컴포지트의 접착강도를 향상시키기 위하여 신규 고분자 접착증진제인 poly(itaconic acid-co-acrylamide) (IAcAAM)를 합성하였다. 이타콘산과 아크릴아마이드를 포함하는 IAcAAM은 라디칼 수성 중합을 통해 제조되었다. IAcAAM의 구조 및 물성은 FT-IR, ¹H-NMR, GPC 및 DSC로 분석하였다. Cu 리드프레임의 표면은 고온, 알칼리, UV 오존으로 처리하였다. 표면처리 후 Cu 리드프레임의 접촉각이 감소함에 따라 Cu 리드프레임/에폭시 컴포지트의 접착강도는 증가하였다. 에폭시 혼합물에 IAcAAM을 첨가함에 따라 Cu 리드프레임/에폭시 컴포지트의 접착강도가 증가하였다. 또한, 에폭시 혼합물에 실리카 함량이 증가할수록 Cu 리드 프레임과 에폭시 컴포지트의 접착강도는 약간 감소하는 경향을 나타내었다.

• Corrosion Science and Technology
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• 제21권2호
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• pp.111-120
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• 2022

To solve the corrosion problem of industrial equipment and other constructions containing metals, corrosion protection can be performed by using coating which provides a barrier between the metal and its environment. Coatings play a significant role in protecting irons and steels in harsh marine and acid environments. This study was conducted to identify an anti-corrosive epoxy coating for carbon steel composite with 0.1, 0.3, and 0.5 wt% concentrations of nanoparticles of SiO₂ using the dip-coating method. The electrochemical behavior was analyzed with open circuit potential (OCP) technics and polarization curves (Tafle) in 3.5 wt% NaCl and 5 vol% H₂SO₄ media. The structure, composition, and morphology were characterized using different analytical techniques such as X-ray Diffraction (XRD), Fourier Transform Infrared spectrum (FT-IR), and Scanning Electron Microscopy (SEM). Results revealed that epoxynano SiO₂ coating demonstrated a lower corrosion rate of 2.51 × 10^-4 mm/year and the efficiency of corrosion protection was as high as 99.77%. The electrochemical measurement showed that the nano-SiO₂ / epoxy coating enhanced the anti-corrosive performance in both NaCl and H₂SO₄ media.

• Structural Engineering and Mechanics
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• 제76권2호
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• pp.175-191
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• 2020

In this study, the effect of Nano silica (SiO2) on the buckling strength of the glass fiber reinforced laminates containing the machining process causes holes were investigated. The tests have been applied on two status milled and non-milled. To promote the mechanical behavior of the fiber-reinforced glass epoxy-based composites, Nano sio2 was added to the matrix to improve and gradation. Nano sio2 is chosen because of flexibility and high mechanical features; the effect of Nanoparticles on surface serenity has been studied. Thus the effect of Nanoparticles on crack growth and machining process and delamination caused by machining has been studied. We can also imply that many machining factors are essential: feed rate, thrust force, and spindle speed. Also, feed rate and spindle speed were studied in constant values, that the thrust forces were studied as the main factor caused residual stress. Moreover, entrance forces were measured by local calibrated load cells on machining devices. The results showed that the buckling load of milled laminates had been increased by about 50% with adding 2 wt% of silica in comparison with the neat damaged laminates while adding more contents caused adverse effects. Also, with a comparison of two milling tools, the cylindrical radius-end tool had less destructive effects on specimens.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2425-2433
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• 2018

This study investigates a new organic based material and its dielectric and mechanical properties. It is a comprehensive nanocomposite comprising a combination of various types of nanofillers with hydrophobic silica nanoparticles (AEROSIL R 974) as a matrix modifier and a polyamide nano nonwoven textile, Ultramid-Polyamide 6, pulped in the electrostatic field as a dielectric barrier. The polymer matrix is an epoxy network based on diglycidyl ether of bisphenol A (DGEBA) and cycloaliphatic diamine (Laromine C260). The designed nanocomposite material is an alternative to the conventional three-component composites containing fiberglass and mica with properties that exceed current electroinsulating systems (volume resistivity on the order of $10^{16}{\Omega}{\cdot}m$, dissipation factor tan ${\delta}=4.7{\cdot}10^{-3}$, dielectric strength 39 kV/mm).

• 전기학회논문지
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• 제61권10호
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• pp.1454-1460
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• 2012

In order to develop an new electric insulation material for heavy electric equipments, epoxy/micro/nano composite (EMNC) was prepared by mixing micro-silica with nano layered silicate, where the nano layered silicate was synthesized by our electric field dispersion method, EMNSC was prepared by treating the EMNC with a silane coupling agent. Thermal properties such as glass transition temperature (Tg) and thermal expansion coefficient, and DMA characteristics were studied, and mechanicla properties such as tensile and flexural tests were performed. AC electrical insulation strength was also tested. All properties of EMNSC were modified by treating EMNC with silane coupling agent and it was confirmed that our new developed composites could be used in the heavy electric equipments.

• Elastomers and Composites
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• 제49권1호
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• pp.59-65
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• 2014

본 연구에서는, $71^{\circ}C/40$ 시간의 경화 조건에서 에폭시/산무수물로 구성된 몰딩 컴파운드를 경화시키기 위하여 촉매로서 코발트 (II) 아세틸아세토네이트, 칼륨 아세틸아세토네이트, 철 (III) 아세틸아세토네이트 및 크롬 (III) 옥토에이트와 같은 다양한 금속 착화합물들을 각각 적용하였고, 몰딩 컴파운드의 기계적 강도를 향상시키기 위하여 에폭시 부/경화제 부의 무게비를 조절하였다. 실험 결과에 따라 크롬 (III) 옥토에이트 촉매는 $71^{\circ}C/40$ 시간의 경화조건에서 몰딩 컴파운드의 경화 반응을 완료시킬 뿐만 아니라 크롬 (III) 옥토에이트 촉매가 적용된 컴파운드는 상온에서 적절한 가공성을 나타내었다. 경화된 몰딩 컴파운드의 기계적 특성에서는 에폭시 부/경화제 부의 무게비가 0.9/1에서 0.5/1 사이에서 제조된 컴파운드가 가장 높은 굴곡강도를 나타내었고, 경화제 부의 함량이 증가함에 따라 더 높은 압축 강도를 나타내었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.242-242
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• 2006

Increasingly complex tasks are performed by computers or cellular phone, requiring more and more memory capacity as well as faster and faster processing speeds. This leads to a constant need to develop more highly integrated circuit systems. Therefore, there have been numerous studies by many engineers investigating circuit patterning. In particular, PCB including module/package substrates such as FCB (Flip Chip Board) has been developed toward being low profile, low power and multi-functionalized due to the demands on miniaturization, increasing functional density of the boards and higher performances of the electric devices. Imprint lithography have received significant attention due to an alternative technology for photolithography on such devices. The imprint technique. is one of promising candidates, especially due to the fact that the expected resolution limits are far beyond the requirements of the PCB industry in the near future. For applying imprint lithography to FCB, it is very important to control thermal properties and mechanical properties of dielectric materials. These properties are very dependent on epoxy resin, curing agent, accelerator, filler and curing degree(%) of dielectric materials. In this work, the epoxy composites filled with silica fillers and cured with various accelerators having various curing degree(%) were prepared. The characterization of the thermal and mechanical properties wasperformed by thermal mechanical analysis (TMA), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), rheometer, an universal test machine (UTM).

• 대한토목학회논문집
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• 제34권6호
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• pp.1687-1694
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• 2014

최근 들어 탄소섬유 FRP가 보수/보강재로 많이 활용되고 있다. 본 연구에서는 탄소섬유 FRP 판을 영구 거푸집으로 활용하여 새로운 콘크리트 교량 바닥판 시스템을 개발하기 위하여 CFRP판과 고인성 섬유보강 콘크리트 사이의 부착성능에 대한 평가를 실시하였다. 현장타설 콘크리트와 CFRP 간에 부착을 높이기 위하여 시중에 유통되는 에폭시를 사용하여 규사를 부착하였다. 일반콘크리트의 부착응력은 2.11~5.43MPa으로 나타났고, 고인성 섬유보강 콘크리트인 DC1 (RF4000)과 DC2 (PP)의 부착응력은 각각 3.91~5.60MPa, 2.92~5.21MPa이며, DC3 (RF4000+RSC15)의 부착응력은 4.80~5.58MPa, DC4 (PP+RSC15)의 평균 부착응력은 5.57~5.89MPa으로 나타났다.