• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.27-32
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• 2021

This study was conducted to improve the workability of cementitious composites using nano-bubble water. The used nano-bubble water contains 7% of nano-sized bubbles with an averaged bubble size of 750 nm. Various different types of cementitious composites including ultar-high performance concrete, lightweight cementitious composites, and high-strength mortar have been tested to identify the changes of material properties. From the use of nano-bubble water, it was confirmed that workability has been improved by 3-22%. On the other hand, other material characteristics such as compressive strength did not have noticeable changes. Therefore, it was proposed that the use of nano-bubble water can enhance workability of cementitious composites without having significant impact on other material properties.

• Polymer(Korea)
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• v.32 no.1
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• pp.31-37
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• 2008

The effect of MMT on mechanical properties of CTBN toughened epoxy nanocomposite is studied. In case of CTBN toughened epoxy nanocomposite with modified MMT, it is found that the enhancement of toughness and tensile properties are exhibited in CTBN toughened epoxy nanocomposite with modified MMT From the results of fractured surface morphology of sample, it is clearly shown that the improved mechanical properties can be obtained in CTBN toughened nanocomposite due to the significant energy dissipation mechanism by MMT loading.

• Polymer(Korea)
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• v.38 no.2
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• pp.232-239
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• 2014

Poly(lactic acid)(PLA) nanocomposites containing various nanofillers were synthesized using the solution intercalation method. Organically modified bentonite clay (NSE), octadecylamine-graphene oxide (ODA-GO), and an NSE/ODA-GO complex were utilized as nanofillers in the fabrication of PLA hybrid films. PLA hybrid films with varying nanofiller contents in the range of 0-10 wt% were examined and compared in terms of their thermomechanical properties, morphologies, and oxygen permeabilities. Transmission electron microscopy (TEM) confirmed that most of the NSE and ODA-GO nanofillers were dispersed homogeneously throughout the PLA matrix on the nanoscale, although some agglomerate NSE/ODA-GO complex particles were also formed. Among the three nanofillers for PLA hybrid films, the NSE/ODA-GO complex showed the best improvement in film thermal stability. In contrast, NSE and ODA-GO exhibited the best improvement in tensile mechanical properties and oxygen barrier properties of the PLA hybrid films, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.711-718
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• 2017

Silver nanoparticles were attached by chemical reduction after synthesizing a porous PVK-CTA complex. The PVK-CTA complex was synthesized by polymerizing N-vinylcarbazole in a CTA-chloroform solution using iron(III) chloride as an oxidizing agent and a honeycomb-pattern with uniformly formed macropores was formed by applying steam to the complex surface soaked with a volatile solvent under humid conditions. Using TTF as a reducing agent and PVP as a dispersant, silver nanoparticles were attached on the Honeycomb-pattern complex surface through chemical reduction. The formation of the complex was confirmed by FT-IR and UV-Vis spectrometry, and the degree of thermal decomposition of the complexes was analyzed after N-vinylcarbazole was polymerized by varying its concentration. The uniformity of the pores on the composite surface and the dispersibility of the attached silver nanoparticles were investigated by SEM. The dispersibility of the silver nanoparticles was also analyzed by varying the concentrations of reducing agent and dispersant and precursor.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.313-316
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• 2002

고분자 물질과 유리섬유, 운모, 탄산 칼슘 그리고 점토 광물과 같은 다양한 무기물과의 복합체는 기계적 성질, 열적 성질과 같은 물리적 특성의 향상을 가져올 뿐만 아니라 이와 같은 특성들을 적은 비용으로 향상시킬 수 있는 장점을 가지고 있기 때문에 다양한 방면에서 널리 사용된다[1]. 이에 대해서, 최근 많은 발전을 이루고 있는 나노기술을 고분자와 무기 나노 입자의 복합체에 적용시키는 연구가 활발히 진행되고 있다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.219-220
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• 2003

나일론 6의 열변형온도와 탄성률을 증가시키는 동시에 높은 기체 차단성을 얻기 위하여 Na-montmorillonite (Na-MMT) 또는 유기화제로 개질된 MMT (organo-MMT)를 나일론 6과 melt-compounding함으로써 나일론 6 분자쇄가 MMT 층 내로 intercalation하거나 MMT의 각 층을 완전히 exfoliation시켜 나일론 6/MMT 나노복합체를 제조하는 방법과 Na-MMT 또는 organo-MMT의 존재하에서 $\varepsilon$-caprolactam (CL)을 in situ 중합함으로써 대부분의 MMT가 각각의 층으로 exfoliation 되도록하여 나일론 6/MMT 나노복합체를 제조하는 방법이 널리 쓰이고 있다 [1-2]. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.452-455
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• 2001

고분자/실리케이트 나노복합체란 고분자 매트릭스에 층상 구조의 점토 광물을 나노 스케일의 시트상의 기본 단위로 박리(exfoliation)ㆍ분산시켜 얻어진 복합체를 말한다. 실리케이트를 구성하는 두께 1nm 정도의 판으로 박리ㆍ분산시키기 때문에 5wt% 정도의 첨가량만으로도 고분자의 획기적인 물성 개선이 가능하다는 장점을 가지고 있다[1]. (중략)

• Elastomers and Composites
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• v.44 no.1
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• pp.22-33
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• 2009

Recently, elastomer-nanocomposites reinforced with low volume fraction of nanofillers have attracted great interest due to their fascinating properties. The incorporation of nanofillers, such as, layered silicate clays, carbon nanotubes, nanofibers, calcium carbonate, metal oxides or silica nanoparticles into elastomers improves significantly their mechanical, thermal, dynamic mechanical, barrier properties, flame retardancy, etc. The properties of nanocomposites depend greatly on the chemistry of polymer matrices, nature of nanofillers, and the method in which they are prepared. The uniform dispersion of nanofillers in elastomer matrices is a general prerequisite for achieving desired mechanical and physical characteristics. In this paper, current developments in the field of elastomer nanocomposites reinforced with layered silicates, silica, carbon nanotubes, nanofibers and various other nanoparticles have been addressed.

• Clean Technology
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• v.27 no.4
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• pp.291-296
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• 2021

Recently, there has been increasing demand for advancing photocatalytic techniques that are capable of the efficient removal of organic pollutants in water. TiO₂, a representative photocatalytic material, has been commonly used as an effective photocatalyst, but it is rather expensive and an alternative is required that will fulfill the requirements of both high performing photocatalytic activities and cost-effectiveness. In this work, ZnO, which is more cost effective than TiO₂, was synthesized by using a microreactor-assisted nanomaterials (MAN) process. The process enabled a continuous production of ZnO nanoparticles (NPs) with a flower-like structure with high uniformity. In order to resolve the limited light absorption of ZnO arising from its large band gap, Ag NPs were uniformly decorated on the flower-like ZnO surface by using the MAN process. The plasmonic effect of Ag NPs led to a broadening of the absorption range toward visible wavelengths. Ag NPs also helped inhibit the electron-hole recombination by drawing electrons generated from the light absorption of the flower-like ZnO NPs. As a result, the Ag-ZnO nanocomposites showed improved photocatalytic activities compared with the flower-like ZnO NPs. The photocatalytic activities were evaluated through the degradation of methylene blue (MB) solution. Scanning electron microscopy (SEM), x-ray diffraction (XRD), and energy-dispersive x-ray spectroscopy (EDS) confirmed the successful synthesis of Ag-ZnO nanocomposites with high uniformity. Ag-ZnO nanocomposites synthesized via the MAN process offer the potential for cost-effective and scalable production of next-generation photocatalytic materials.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.327.2-327.2
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• 2016

유기물/무기물 나노 복합체를 이용한 전자 소자는 간단한 공정과 고집적 및 플렉시블 응용 가능성으로 차세대 전자 소자로서 응용 연구가 많이 시도되고 있다. 무기물의 경우 전하 전송 메커니즘과 전기적 특성에 영향을 미치는 다양한 요인들에 대한 연구가 많이 진행되었지만 유기물의 경우 소자의 특성에 집적적으로 영향을 미치는 요인들에 대한 이론적 연구가 미흡하다. 본 연구에서는 금속/유기물 경계면의 전하전송, 트랩밀도 및 전하 이동도가 소자의 전기적 특성에 어떠한 영향을 미치는지 분석하였다. 유기 메모리 소자의 전하 전송 메커니즘을 분석하기 위해 PMMA에 나노 입자를 분산시킨 유기-나노 복합층을 사용하여 유기 메모리 소자를 제작하였고 SCLC 이론을 이용하여 전기적 특성을 분석하였다. 또한 전극과 유기-나노 복합층 사이에 C60 층을 삽입하여 트랩밀도와 전하이동도가 유기물 전자 소자에 어떻게 영향을 미치는지에 대한 이론적인 연구를 하였다. SCLC 이론을 이용하여 계산한 current density -voltage (J-V) 특성 이론값과 실험값의 비교 분석으로 유기물전자 소자의 전기적 동작 특성에 대한 메커니즘을 규명하였으며, 유기물 메모리 소자에서 트랩밀도와 분포가 전기적 특성에 미치는 영향에 대하여 연구하였다.