• 공업화학
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• 제10권1호
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• pp.148-153
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• 1999

2-bromoterephthaloyl chloride와 1,4-bis(p-hydroxybenzoyloxy)butane을 PMMA 용액내에서 중축합시켜 in situ 복합재료를 제조하였다. 이들의 합성확인 및 열적, 기계적 성질은 FT-IR, FT-NMR, DSC와 DMTA에 의해서, 몰폴로지는 광학현미경과 SEM을 사용하여 조사하였다. 합성된 TLCP는 네마틱상을 보였고, 복합재료내 PMMA의 유리전이온도와 기계적 성질은 TLCP의 농도증가와 함께 증가하였다. TLCP domain은 PMMA 매트릭스내에서 미세 분산되었음을 확인하였고 in situ 중합에 의해 제조된 20 wt % TLCP/PMMA 복합재료는 같은 조성의 용액 블렌딩에 의해서 제조된 재료보다 더 높은 기계적 강도와 미세 분산도를 보였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.204-204
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• 2003

• Membrane and Water Treatment
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• 제10권3호
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• pp.245-250
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• 2019

Prussian blue (PB) is well known for its excellent $Cs^+$ ions adsorption capacity. Due to the high dispersibility of PB in aqueous phase, composite materials imbedding PB in supporting materials have been introduced as a solution. However, building PB particles inside porous supporting materials is still difficult, as PB particles are not fully formed and elute out to water. In this study, we suggest layer-by-layer (LBL) assembly to provide better immobilization of PB on supporting materials of poly vinyl alcohol sponge (PVA) and cellulose filter (CF). Three different PB attachment methods, ex-situ/in-situ/LBL assembly, were evaluated using PB leaching test as well as $Cs^+$ adsorption test. Changes of surface functionality and morphology during PB composite preparation protocols were monitored through Fourier transform infrared spectroscopy and scanning electron microscopy. The results indicate that LBL assembly led to better PB attachment on supporting materials, bringing less eluting PB particles in aqueous phase compared to other synthesis methodologies, such as ex-situ and in-situ synthesis. By enhancing the stability of the adsorbent, adsorption capacity of PVA-PB with LBL improved nine times and that of CF-PB improved over 20 times. Therefore, the results suggest that LBL assembly offers a better orientation for growing PB particles on porous supporting materials.

• 한국주조공학회지
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• 제22권1호
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• pp.35-41
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• 2002

To improve the reliability of solder joints, a composite solder which consists of solder matrix and intermetallic reinforcements was manufactured by a new method. The cast ingot of Sn-6.9Cu-2.9Ag alloy had primary Cu6Sn5 intermetallics in the form of dendrites. After rolling the ingot, the intermetallic dendrites were crushed into fine particles and distributed uniformly throughout the solder matrix. As the rolled strips became thinner, the average size of the crushed particles reached a critical size which did not decrease any more by further rolling. The critical size was nearly the same as the average width of intermetallic dendrite trunk. The crushed intermetallic particles did not melt and remained in solid state during reflow soldering due to their high meltingterm-perature. The coarsening and gravitational segregation of the particles were observed during reflow soldering.

• 한국세라믹학회지
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• 제37권3호
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• pp.280-287
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• 2000

Adsorption behavior and amount of phenolic resin followed silica (SiO2) formation onto silicon nitride(Si3N4) surface were investigated using electrokinetic sonic amplitude (ESA) technique and with UV spectrometer, to fabricate Si3N4/SiC nano-composite based on reaction between SiO2 formed and phenolic resin absorbed onto Si3N4 particle. The amount of SiO2 formed and carbon from phenolic resin absorbed onto Si3N4 surface were calculated quantitatively to adjust the reaction between SiO2 and phenolic resin, resulting in no residual SiO2 and carbon. As a result, pre-heated tempeature for optimized reaction was below 25$0^{\circ}C$, in which there was no residual SiO2 and carbon.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.421-424
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• 2006

Nafion/Pt/Polypyrrole composite membranes were fabricated by chemical in-situ polymerization of pyrrole monomers with Pt precursors in Nafion matrix for DMFC. We demonstrated that positively charged pyrrolinum groups of polypyrrole particles were co-interacted with sulfonic groups of Nafion as verified by FT-IR results. Mutual interaction between $Nafion-SO_3^-$ (or negatively charged Pt precursors) and Polypyrrole$-NH_2^+$ influenced the physical properties of pristine Nafion. Thermal property proton conductivity, methanol permeability, and cell performance of pristine and modified Nafion were analyzed for an application of DMFC membrane. Thermal stabilities of sulfonic groups and side chains in Nafion/Pt/polypyrrole composite membranes were higher than those of Nafion due to mutual interaction between sulfonic groups of Nafion and pyrrolinum groups of polypyrrole. Methanol permeabilities of Nafion/Pt/Polypyrrole composite were reduced more proton conductivities with the increase in the content of Pt particles. As a result of that, the enhancement of cell performance by Nafion/Pt/Polypyrole O2 relative to Nafion was more pronounced under the specific experimental condition such as high temperature and more concentrated methanol solution.

• 공업화학
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• 제30권1호
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• pp.74-80
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• 2019

저가습 작동을 위한 수소 이온 교환막 연료전지용 $Nafion/TiO_2$ 복합막을 졸-겔 법을 이용하여 제조하였다. 이때 Nafion막에 $TiO_2$ 나노 입자를 함침시키기 위하여 $TiO_2$ 전구체 용액에 1일부터 7일까지 함침 시간을 달리하여 복합막을 제조하였다. 담금 시간이 증가할수록 Nafion막 내에 함침되는 $TiO_2$ 함량이 증가하였다. $TiO_2$ 함량이 증가함에 따라 막의 표면의 친수성이 증가하면서 접촉각은 감소하는 것을 보여주었다. 물 흡수력(water uptake)과 복합막을 통한 수소 이온 전도도는 담금 시간이 4일인 경우 가장 높게 나타났고 4일 이상인 경우에는 오히려 감소하는 경향을 보여주었다. 담금 시간이 7일인 경우에는 큰 $TiO_2$ 입자들이 막의 표면과 내부에 생성되어 애노드에서 캐소드로의 수소 이온 전도를 방해하게 되는 결과를 초래하였다. 전지 성능 시험 결과 물 흡수력 및 수소 이온 전도도의 결과와 상당히 일치하는 것을 보여주었다. 즉, 0.6 V에서 담금 시간이 1일, 3일, 4일 및 7일인 경우 전류 밀도가 상대 습도(relative humidity, RH) 40%에서 각각 0.54, 0.6, $0.63A/cm^2$ 및 $0.49A/cm^2$를 나타내었다. Nafion 분산액과 $TiO_2$ 입자를 혼합하여 제작한 막과 Nafion 115를 이용하여 RH 40%에서 수행한 전지 성능 결과와 비교할 때 졸-겔 법을 이용하여 제조한 복합막의 경우 약 66%의 전지 성능 향상을 얻을 수 있었다.

• 한국건축시공학회지
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• 제2권2호
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• pp.175-180
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• 2002

"Samsung Composite Shear Wall System" has its basis on "Samung Able System". "Samsung Able System" has some problems not only in the connection structure but also in waterproofing and soundproofing. We developed "Samsung Composite Shear Wall System" in order to solve these matters and expand PC system. "Samsung Composite Shear Wall System" is the compromise and complement of all the merits of full PC, half PC and in-situ concrete system.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.71-72
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• 2014

Green Frame is a building frame system to construct a column-beam structure using composite precast concrete members. To reduce the cost of producing precast concrete, in-situ production of members is required. However, when the structural members are produced on site, it needs a large space for production. So, "Just-In-Time" production method should be adopted. For Just-In-Time to be realized, the early strength of members should be ensured for them to be transported. Thus, steam curing to secure the early strength is applied in Green Frame. Yet, a large-scale steam curing system is not possible for in-situ production of precast concrete. A smaller steam curing system is needed. In this regard, the study is aimed to develop a new steam curing method applicable to the in-situ production of precast concrete.

• Elastomers and Composites
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• 제44권1호
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• pp.34-40
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• 2009

In situ 미니에멀젼 중합으로 실리카/폴리스타이렌 하이브리드 나노복합체를 만들기 위하여 9-데세노 산을 실리카 표면 개질제로 처음 도입하였다. 복합체는 나노크기의 잘 분산된 실리카를 함유하고 있었다. 실리카의 표면 개질 및 폴리스타이렌의 합성 등은 FTIR로 확인하였고 생성 라텍스 중에 존재하는 실리카의 양은 TGA 분석으로 확인하였다. 생성된 하이브리드는 실리카의 양 증가에 따라 유리전이온도가 상승하였다. SEM과 TEM으로 확인한 결과 하이브리드 복합체는 평균 직경이 55 nm 정도로 나타났다. 복합체내의 실리카의 존재는 EDS와 연결된 TEM 등으로 확인되었다.