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  • 제목/요약/키워드: nanocomposite materials

검색결과 546건 처리시간 0.026초

Nanocomposite magnetic powder materials using mechanochemical Synthesis

  • Soh, Dae-Wha;Mofa, N.N.;Keteguenov, T.A.;Mansurov, Z.A.
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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    • pp.585-587
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    • 2002
  • The materials showing high structure dispersity are developed on the quartz base and they are obtained by mechano-chemical technology. Depending on the processing conditions and subsequent applications the materials produced by mechano-chemical reaction show concurrently magnetic, dielectric and electrical properties. The obtained magnetic-electrical powders classified by aggregate complex of their features as segnetomagnetics, contain a dielectric material as a canγing nucleus, particularly the quartz on that surface one or more layers of different compounds are synthesized having thickness up to 10~50 nm and showing magnetic, electrical and other properties.

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Carboxylated Nitrile Elastomer/Filler Nanocomposite: Effect of Silica Nanofiller in Thermal, Dynamic Mechanical Behavior, and Interfacial Adhesion

  • Mahaling R. N.;Jana G. K.;Das C. K.;Jeong, H.;Ha C. S.
    • Macromolecular Research
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    • 제13권4호
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    • pp.306-313
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    • 2005
  • Surface modified nanofillers are often used as curative-cum reinforcing agents for functional polymers. The polymer nanofiller interaction depends on the curative systems used. In the present study the carboxylic group of the carboxylated nitrile elastomer participated in the reaction with Zn-ion coated nanosilica filler producing a type of ionomeric elastomer. The interaction at the molecular level thus produced a high modulus vulcanizate. In this case, the S and MBT system, as curative, had an edge over the MDA and DPG curative system. Interfacial adhesion was enhanced in the presence of Zn-ion-coated nanosilica filler associated with dynamic mechanical behavior. The inferior properties obtained in the case of the MDA and DPG curative system were due to the decreased reactivity of the silica surface, thus reducing interfacial adhesion.

고압절연용 Epoxy/Organoclay Nanocomposites의 열적, 전기적 특성에 관한 연구 (Thermal, Electrical Characteristics according to Contents Variation of Epoxy/Organoclay Nanocomposites for High Voltage Insulation)

  • 박재준;안준오
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 추계학술대회 논문집
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    • pp.226-227
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    • 2007
  • 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. This paper shows that electrical and thermal properties of epoxy/organoclay nanocomposites insulating materials for dsc, dielectric constant, I-V characteristics, breakdown volatge, can improve significantly with respect to the basic, virgin materials.

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Electrospun Nanocomposite Fiber Mats of Zinc-Oxide Loaded Polyacrylonitrile

  • Nataraj, S.K.;Kim, B.H.;Yun, J.H.;Lee, D.H.;Aminabhavi, T.M.;Yang, K.S.
    • Carbon letters
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    • 제9권2호
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    • pp.108-114
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    • 2008
  • We have demonstrated the feasibility of using electrospinning method to fabricate long and continuous composite nanofiber sheets of polyacrylonitrile (PAN) incorporated with zinc oxide (ZnO). Such PAN/ZnO composite nanofiber sheets represent an important step toward utilizing carbon nanofibers (CNFs) as materials to achieve remarkably enhanced physico-chemical properties. In an attempt to derive these advantages, we have used a variety of techniques such as field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and high resolution X-ray diffraction (HR-XRD) to obtain quantitative data on the materials. The CNFs produced are in the diameter range of 100 to 350 nm after carbonization at 1000C. Electrical conductivity of the random CNFs was increased by increasing the concentration of ZnO. A dramatic improvement in porosity and specific surface area of the CNFs was a clear evidence of the novelty of the method used. This study indicated that the optimal ZnO concentration of 3 wt% is enough to produce CNFs having enhanced electrical and physico-chemical properties.

고상공정에 의해 제조된 AIN-Cu 나노복합재료의 조직 특성과 열팽창계수 측정에 관한 연구 (Microstructural Characteristics and Thermal Expansion Coefficient of AlN-Cu Nanocomposite Materials Prepared by Solid State Processing)

  • 이광민;이지성;이승익;김지순
    • 한국재료학회지
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    • 제11권10호
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    • pp.863-868
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    • 2001
  • The present study was carried out to investigate the effect of MA processing variables on the microstructural properties of composite powders and the coefficient of thermal expansion of pulse electric current sintered AlN-Cu powder compacts. The AlN-Cu powders had a size of less than 15 μm with 25 nm size of copper crystallite after MA 32 hours. The finely distributed AlN-Cu powder compacts were completely achieved after PECS. The residual oxygen was considerably removed after hydrogen reduction treatment. The residual carbon was completely removed to 97%. The CTE of AlN-Cu powder compacts showed a good consistency with Kingery-Tuner model when the volume fraction of copper was less than 60%. When it was more than 60%, the CTE had a good agreement with Series model.

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In vitro wear behavior between enamel cusp and three aesthetic restorative materials: Zirconia, porcelain, and composite resin

  • Jang, Yong-Seok;Nguyen, Thuy-Duong Thi;Ko, Young-Han;Lee, Dae-Woo;Baik, Byeong Ju;Lee, Min-Ho;Bae, Tae-Sung
    • The Journal of Advanced Prosthodontics
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    • 제11권1호
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    • pp.7-15
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    • 2019
  • PURPOSE. The aim of this study was to identify the effects of three aesthetic restorative materials on the wear between tooth and restoration by a pin-on-disk manner. MATERIALS AND METHODS. Six aesthetic restorative materials were used to prepare disk specimens for wear test, which were Lava Zirconia as zirconia group, Vintage MP and Cerabien ZR as veneering porcelain group, Gradia Direct microhybrid composite containing prepolymerized fillers, Filtek Z250 microhybrid composite containing zirconia glass and colloidal silica particles, and Filtek Z350 nanocomposite as composite resin group. Vertical loss of the worn cusp, change of the surface roughness of the restoration materials, and the surface topography were investigated after wear test under 9.8-N contact load. RESULTS. The porcelain groups (Vintage MP and Cerabien ZR) caused the largest vertical loss of teeth when compared with those of the composite resin and zirconia groups, and Filtek Z250 microhybrid composite results in the second-largest vertical loss of teeth. The surface of Filtek Z350 nanocomposite was deeply worn out, but visible wear on the surface of the zirconia and Gradia Direct microhybrid composite was not observed. When the zirconia surface was roughened by sand-blasting, vertical loss of teeth considerably increased when compared with that in the case of fine polished zirconia. CONCLUSION. It was identified that microhybrid composite resin containing a prepolymerized filler and zirconia with reduced surface roughness by polishing were the most desirable restorative materials among the tested materials to prevent the two-body wear between aesthetic restorative material and tooth.

바나듐 담지된 그래핀 나노복합체를 첨가한 SCR 촉매의 제조 및 활성 평가 (De-NOX evaluation of SCR catalysts adding vanadium-graphene nanocomposite)

  • 정보라;이희수;김억수;김홍대
    • 한국결정성장학회지
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    • 제25권6호
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    • pp.252-256
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    • 2015
  • 질소산화물 (NOX)은 고정원(화력발전소, 산업시설) 및 이동원(자동차, 선박) 등에서 배출되어지며, 발암물질 및 광화학 스모그의 주범으로 작용하고 있다. 선택적 촉매 환원법(SCR)은 NOX를 제거하는 가장 효율적인 방법이며, 상업용으로 사용되어지는 V2O5WO3/TiO2계 촉매에서 V2O5 함량은 0.5~3 wt%, WO3 함량은 5~10 wt%이다. 촉매 성분 중 V2O5의 경우 NOX 환원 반응을 통해 촉매 작용을 촉진시키지만, 과량으로 첨가될 경우, SO2에서 SO3로의 산화 반응을 증가시킨다. 본 연구에서는 높은 탈질 효율을 유지시킴과 더불어, 바나듐의 함량을 줄이기 위하여, 그래핀을 바나듐 담지 matrix로 사용하여 나노복합체를 합성하였으며, 합성된 나노복합체를 첨가하여 Honeycomb형 1 inch SCR 촉매를 제조하였다. 제조된 SCR 촉매는 XRD(X-ray Diffraction), XRF(X-ray Fluorescence Spectrometer), BET(Brunauer, Emmett & Teller) 등의 분석을 통해 물성 평가를 진행하였으며, Micro Reactor(MR)를 이용하여 활성평가를 진행하였다. 그 결과, 촉매 상용 운전 온도인 350C에서 나노복합체가 첨가된 SCR 촉매의 탈질 효율은 77.1 %로 상용촉매의 탈질 효율인 77.8 %와 유사한 효율을 나타내는 것을 확인하였다.

PET 나노복합재료의 제조 및 특성분석 (The preparation and characterization of poly(ethylene terephthalate)(PET)/layered silicate nanocomposite)

  • 천상욱;손세범;곽승엽
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2003년도 추계학술발표대회 논문집
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    • pp.21-24
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    • 2003
  • In general, to enhance physical properties of PET-layered silicate nanocomposites (PetLSNs), it has been well known that the organic modifiers should introduce into gallery regions. However, the organic modifiers in(PetLSNs) may result in thermal decomposition by melt processing at high temperature, and it necessarily lead to deteriorate various physical properties of final products. Therefore, in this study, (PetLSNs) excluding and including organic modifiers were prepared by solution method (SPetLSNseomandSPetLSNsiom) and we (focused on the effects of the organic modifiers in Pet LSNs with exfoliation structure on the crystallization behaviors, the optical transparency, the thermal stability and the mechanical property. The absence and existence of organic modifiers in SPetLSNseomandSPetLSNsiom were investigated by EA and TGA, and nano-structure of silicate layers in SPetLSNs was evaluated by using WXRD, SAXS and TEM. SPetLSNseomandSPetLSNsiom were mixed with neat PET as masterbatches by melt method (MPetLSNseomandMPetLSNsiom), and also neat PET was mixed with organically modified layered silicates (OLS) by conventional direct melt method (DPetLSNs)at270C. As results, it was found that MPetLSNseom,MPetLSNsiom,andDPetLSN showed a exfoliated structure and exhibited faster crystallization rate, better thermal stability and mechanical property than those of neat PET due to the dispersed and detaminated silicate layers in PET matrix. Whereas, considering organic modifiers effect, MPetLSNseomandDPetLSN exhibited slower crystallization rate, poorer optical, thermal and mechanical properties, in comparison to $M-P_{et}LSNs_{eom}> due to the thermal decomposition of organic modifier in DPetLSNs during melt method.

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MWCNT종류와 유동 형태가 폴리카보네이트/MWCNT 나노복합체의 전기전도도에 미치는 영향 (Effects of MWCNT type and flow type on the electrical conductivity of polycarbonate/MWCNT nanocomposites)

  • 부이 둑낫;손영곤
    • 한국산학기술학회논문지
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    • 제19권9호
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    • pp.13-19
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    • 2018
  • MWCNT (다중벽 탄소 나노튜브)의 종류와 유동 형태가 폴리카보네이트 (PC)/MWCNT 나노 복합체의 전기 전도도에 미치는 영향을 관찰하였다. MWCNT의 종류가 바뀌면 사출 성형으로 제조된 PC/MWCNT의 전기 전도도가 크게 변하는 것을 관찰하였다. MWCNT 의 종횡비가 클수록 사출 성형품의 전기 전도도는 낮았고 압축 성형으로 제조한 시료의 전기 전도도는 MWCNT의 종류에 상관없이 비슷하였다. 이 결과는 MWCNT의 변형과 크게 상관있는 것으로 조사되었다. 종횡비가 클수록 외부 응력이 작용할 때 MWCNT의 배향도가 올라가고 MWCNT들의 접촉에 의한 전도성 길 (path)가 끊어져서 전기전도도가 낮아지는 것으로 생각된다. 연신력과 전단 속도가 큰 조건에서 제조된 시료의 전기 전도도가 크게 낮아지는 것을 관찰하였다. 이는 높은 전단력과 연신력에서 MWCNT의 배향이 높아지고 그 결과 MWCNT 들의 접촉이 단절되면서 전기 전도도가 낮아지는 것임을 다양한 실험으로 부터 알 수 있었다. 여러 실험 결과 들을 MWCNT의 배향과 전도길 변화와의 연관성의 관점으로 토의하였다.

리튬 이차전지 음극용 CNT/Co3O4 나노복합체의 전기화학적 특성 (Electrochemical Property of CNT/Co3O4 Nanocomposite for Anode of Lithium Batteries)

  • 윤대호;박용준
    • 전기화학회지
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    • 제17권3호
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    • pp.187-192
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    • 2014
  • 본 논문에서는 리튬이온 이차전지의 음극에 사용될 수 있는 CNT/Co3O4 나노복합체의 합성과 전기화학적 특성에 대해 보고하고 있다. 고용량을 가진 산화물 음극 중 하나인 Co3O4의 부족한 전기 전도성을 보완하고 상변이 과정에서 발생하는 응력(stress)를 완충하기 위해 CNT와의 복합화가 시도되었다. 그 결과 카본나노튜브 표면에 수 nm 크기의 Co3O4를 균일하게 분산시켜 복합화 하는데 성공하였으며 제조된 CNT/Co3O4 나노복합체는 우수한 고율특성과 안정적인 사이클 특성을 나타내었다. 또한 기존의 상용화된 음극물질인 흑연 보다 높은 방전용량을 가지고 있어 리튬이온 이차전지의 음극물질로 활용될 수 있는 가능성을 보여주었다.