• 한국세라믹학회지
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• 제47권4호
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• pp.338-342
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• 2010

Co, $Fe_3O_4$ and Co/$Fe_3O_4$ nanoparticles were synthesized by a polyol process in order to develop their new applications and improve chemical, magnetic properties. The synthesis involved a polyol process using Fe, Co acetylacetonate as precursors and 1-2 hexadecanediol as the polyol. The synthesized $Fe_3O_4$ and Co/$Fe_3O_4$ nanocomposite particles were monodispersed and self arrayed ranging in size of 8~10 and 10~25 nm, respectively. The Co nanoparticle has a crystallite size of 10~40 nm. The synthesized nanoparticles were characterized by their structural, morphological, compositional and magnetic properties using TEM-EDS, XRD, and PPMS techniques.

• 한국결정성장학회지
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• 제12권2호
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• pp.73-79
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• 2002

코발트, 니켈, 구리 그리고 귀금속분말에 적용할 수 있는 polyol법은 균질한 크기와 형상을 갖는 금속분말합성에 매우 효과적인 공정이다 이 때 polyol은 용매, 환원제 그리고 보호제의 역학을 한다 $AgNO_3$글 촉매제로 첨가하여 비균질계 핵생성 반응을 야기할 경우 서브마이크폰 크기(0.5$\mu$m)의 코발트 분말을 한성학 수 있었다. 또한 촉매제인 Ag 핵의 수출 변화시키므로써 코발트 분말의 입도를 제어할 수 있음을 확인하였다.

• 한국결정성장학회지
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• 제11권6호
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• pp.290-296
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• 2001

균질한 형상, 좁은 입도분포 그리고 순도가 높은 미립 금속분말은 첨단산업분야에서 응용분야가 점차 확대되고 있다. 본 연구에서는 Polyol법을 이용한 마이크론 크기의 단분산 코발트 분말을 합성하였다 Polyol이 환원제 역할을 하였다. 반응온도, 반응시간, 분산제첨가 및 전구체의 농도 등을 변화시켜 코발트의 입자 크기, 형상 그리고 응집현상을 제어하고자 하였다. 최적의 합성조건은 E.G/DiE/G 부피비 1:4,$Co(OH)<_{2}$polyol 몰비 0.08~0.32 반응온도 $210^{\circ}C$, PVP/Co$(OH)_2$ 몰비 0.4이었다.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.2865-2870
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• 2013

Ni-Ag core-shell nanoparticles were synthesized by polyol process and microemulsion technique successfully. In the polyol process, a chemical reduction method for preparing highly dispersed pure nickel and Ag shell formation have been reported. The approach involved the control of reaction temperature and reaction time in presence of organic solvent (ethylene glycol) as a reducing agent for Ag cation with poly(vinyl-pyrrolidone) (PVP. Mw = 40000) as a capping agent. In microemulsion method, the emulsion was prepared by water/cetyltrimetylammonium bromide (CTAB)/cyclohexane. The size of microemulsion droplet was determined by the molar ratio of water to surfactant (${\omega}_o$). The core-shell formation along with the change in structural phase and stability against oxidation at high temperature heat treatments of nanoparticles were investigated by X-ray diffraction and TEM analysis. Under optimum conditions the polyol process gives the Ni-Ag core-shell structures with 13 nm Ni core covered with 3 nm Ag shell, while the microemulsion method gives Ni core diameter of 8 nm with Ag shell of thickness 6 nm. The synthesized Ni-Ag core-shell nanoparticles were stable against oxidation up to $300^{\circ}C$.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.560-563
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• 2008

A modified polyol process is developed to enhance Pt loading during the preparation of Pt/C catalysts. With the help of the zeta potential, the effect of pH on the electrostatic forces between the support and the Pt colloid is investigated. It is shown experimentally that the surface charge on the carbon support becomes more electropositive when the solution pH is changed from alkaline to acidic. However, this change does not affect the electronegative surface charge of Pt colloids already attained and stabilized by glycolate anions. This new behavior caused by the change in the solution pH accounts for the enhanced yield of the process and does not affect the Pt particle size. All our experimental results reveal that this simple modification is a cost effective method for the synthesis of highly Pt loaded Pt/C catalysts for fuel cells.

• 에너지공학
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• 제23권3호
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• pp.157-162
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• 2014

해당 연구에서는 수정된 폴리올법을 이용하여 합성한 카본블랙 탄소지지체의 Pt촉매의 전기적, 전기화학적 특성을 평가하였다. 또한 Polyol_Pt/C 촉매는 고분자전해질연료전지의 공기극에 적용하여 산소환원반응성을 측정하였다. 산소환원반응성과 고분자전해질연료전지 성능평가를 통해 상용 Pt/C (JM_Pt/C)촉매와 비교하여 전기화학적인 촉매성능을 비교하였다. 촉매의 활성표면적을 구하기 위해 순환전압전류주사법을 이용하였고, 산소환원반응성을 측정하기 위해 회전원판전극으로 선형주사전류법을 이용하였다. 또한 고분자전해질연료전지 완전지 성능 측정을 진행하였다. 그 결과 Polyol_Pt/C 촉매의 활성표면적 ($196m^2g^{-1}$)은 JM_Pt/C 촉매의 그 값 ($183m^2g^{-1}$) 보다 우수하였다. 촉매들의 산소환원반응성에 경우에도 Polyol_Pt/C 촉매는 JM_Pt/C 촉매보다 우수한 반파장전위 및 한계전류밀도를 나타내었다. 또한 완전지 평가시, MEA 공기극을 위한 Polyol_Pt/C 촉매 담지량을 기존의 0.4에서 0.15로 줄였을 때, 성능저하가 적게 나타났고, 300시간의 장기간 성능 평가에서도 연료전지 성능이 거의 일정하게 유지되었다. 이를 토대로 수정된 폴리올법에 의해 합성된 Polyol_Pt/C 촉매는 경제적인 이용 및 우수한 내구성을 가지고 있음을 밝혀내었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.78.1-78.1
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• 2007

• 한국기계가공학회지
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• 제7권3호
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• pp.61-66
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• 2008

For the production of urethane prepolymer, the effect of process parameters such as diisocyanate MDI and polyol TDI was tested. In this paper, design of experiments has been adopted for studying the effect of the process parameters on the improvement of NCO and viscosity of pre-polymer. As a result of comparison of different parameters, the effect of polyol was stronger than that of isocyanate in comparison of reactivity according to the amounts of isocyanate and polyol. Especially, NCO and viscosity of pre-polymer affected a product safety.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.200-203
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• 2007

Parametric investigation of the polyol process for the preparation of carbon supported Pt nano particles as catalysts for fuel cells was carried out. It was found that the concentration of glycolate anion, which is a function of pH, plays an important role in controlling Pt particle size and loading on carbon. It was observed that Pt loading decreased with increasing alkalinity of the solution. As evidenced by zeta potential measurement, this was mainly due to poor adsorption or repulsive forces between the metal colloids and the supports. In order to modify the conventional polyol process, the effect of the gas purging conditions on the characteristics of Pt/C was examined. By the optimization of the gas environment during the reaction, it was possible to obtain high loading of 39.5wt% with a 2.8 nm size of Pt particle. From the single cell test, it was found that operating in ambient $O_{2}$ at 70oC can deliver high performance of more than 0.6 V at 1.44 A $cm^{-2}$.

• 한국안전학회지
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• 제17권1호
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• pp.68-71
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• 2002

A research on accident loss calculation for polyol process without safety management activities, and safety cost estimation using process risk assessment has been implemented. In order to estimate a magnitude of loss, accident scenarios were made by combining result made from HAZOP Study method with accident possibility analysis results implemented with FTA. Also effect assessment was implement for accident consequence of each scenario. And minimum possible loss cost has been calculated when safety investment do or not. Result from cost-benefit analysis was shown as approximately \335 billion(=USS44,000 billion), as cost after subtracting safety management cost from minimum possible loss cost.