• Membrane Journal
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• v.26 no.2
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• pp.146-151
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• 2016

Sulfonated poly (arylene ether sulfone) (SPAES) random copolymers have merits such as high proton conductivity, relatively low production cost, and thermochemical resistance when applied as polymer electrolyte membranes for fuel cells. However, it is difficult to directly employ SPAES copolymers into practical fuel cell membrane applications owing to their low chemical stability and dimensional instability under harsh operation conditions. A plausible solution is to impregnate SPAES copolymers into support films (e.g., electrospun polyimide support) with interconnected pore structures and high thermochemical toughness. In this study, a SPAES copolymer with a swivel group, which induces high free volume for fast ion transport, is chosen as ionomers to prepare pore-filling membranes (PFMs). The feasibility of the resulting membranes is evaluated via membrane characterizations.

• Membrane Journal
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• v.21 no.1
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• pp.30-38
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• 2011

Composite membranes based on sulfonated poly(aryl ether) sulfone (SPAES) with different sulfated zirconia nanoparticles ($s-ZrO_2$) ratio are synthesized and investigated for the improvement of the hydration and the proton conductivity at high temperature and no humidification for fuel cell applications. X-ray diffraction technique is employed to characterize the structure and the size of $s-ZrO_2$ nanoparticles. The sulfation effect of $s-ZrO_2$ nanoparticles is verified by FT-IR analysis. The properties of the SPAES composite membranes with the various $s-ZrO_2$ ratio are evaluated by ion exchange capacity and water content. The proton conductivities of the composite membranes are estimated at room temperature with full hydration and at the various high temperature without external humidification. The composite membrane with 5 wt% $s-ZrO_2$ shows the highest proton conductivity. The proton conductivities are $0.9292\;S\;cm^{-1}$ at room temperature with full hydration and $0.0018\;S\;cm^{-1}$ at $120^{\circ}C$ without external humidification, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.329-331
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• 2006

연료전지용으로 많이 사용되는 전불소계 고분자인 Nafion은 좋은 기계적, 화학적 안정성 및 높은 이온전도도에도 불구하고 고가의 생산단가, 높은 메탄올 투과도, 그리고 MEA 재활용 문제 등으로 인해 상업적 응용에 제한이 있다. 본 연구는 불소그룹을 함유한 술폰화된 아릴렌이서계 블록 공중합체 고분자 전해질막의 제조 및 연료전지 특성에 관한 것이다. 이러한 고분자를 제조하기 위하여 양말단에 불소계 비닐기를 가지면서, 상온에서 술폰화 가능한 biphenyl계 단량체와 술폰화가 불가능한 sulfonyl계 단량체를 각각 합성하였으며, 이들로부터 다양한 몰조성과 분자량을 갖는 올리고머를 포함한 일련의 perfluorocyclobutane기를 포함하는 블록 공중합체를 열적 고리화 부가중합을 사용하여 합성하였다. 제조된 블록 공중합체를 상온에서 술폰화제인 chlorosulfonic acid를 이용하여 선택적으로 후술폰화시켜 강산 이온기인 sulfonic acid를 블록 올리고머에 도입하였다. 합성된 고분자들의 연료전지 특성을 Nafion-115와 비교하였다. 술폰화가 되는 올리고머 블록의 비율 증가에 따라 이온교환능력이 증가하였고, 그에 따라 높은 함수율과 이온 전도도를 나타내었으며 건조 및 습윤 상태에서도 기계적 강도가 우수하였다. 최적화된 블록공중합체를 대상으로 MEA를 제조하여 연료전지 초기성능을 측정한 결과 Nafion과 유사한 전기화학적 성능을 나타내었다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.147-147
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• 2010

An electrolyte membranes for high temperature/low humidity is a demand for the proton exchange membrane fuel cells (PEMFCs). In this work, we prepared hybrid membranes, which have novel glass content in the hydrophilic and hydrophobic part of sulfonated poly(arylene ether sulfone) (SPAES) by in-situ sol-gel synthesis of various functional silane. The effect of silicate from functional silane content on the proton conductivity, water uptake of the hybrid membranes under high temperature and low humidity was quantitatively identified. The silicate content contributed to the enhancement of not only proton conductivity, but also water retention ability for PEMFCs operation.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.195-196
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• 2009

술폰화 폴리아릴렌에테르술폰 공중합체를 기본구조로 한, 6F OH를 알코올 단량체로 사용하여 블록 공중합체를 직접 중합법으로 합성하였다. 이때 각각의 소수성-친수성 소중합체들은 동일한 분자량을 이용하여 합성했으며 그때의 두 소중합체의 몰비는 1:1로 하여 블록 공중합체의 술폰화도를 50%로 고정하였다. N-메틸-2피롤리돈(NMP) 용매 상에서 연료전지용 고분자 전해질 막을 제조하여 이온전도도 및 메탄올 투과도등의 측정을 통하여 최종 블록 공중합체 전해질 막의 기본 특성을 파악했다. 소수성-친수성 소중합체의 분자량을 조절함에 따라 최종 전해질 막의 이온 전도도를 향상시킬 수 있음이 확인되었고, 연료전지 성능 테스트 결과에서도 나피온(Nafion 115)과 비슷한 성능을 보였다.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.197-198
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• 2009

고분자 전해질막으로 사용할 수 있는 소수성/친수성 랜덤 멀티블럭 공중합체를 합성하였다. 공중합체는 수산화기를 각 말단에 가지고 있는 소수성 올리고머, 친수성 올리고머 및 반응성이 좋은 커플링 단량체로 친핵성 치환 반응을 활용하여 합성 하였다. 높은 반응성의 커플링 단량체의 존재로 비교적 낮은 온도에서 합성이 됨으로서 고온에서의 에테르-에테르 교환반응에 의한 랜덤화를 억제할 수 있었으며, 높은 중합도의 공중합체를 합성 할 수 있었다. 각 수산화기로 같은 말단으로 조정된 올리고머는 투입 비율의 조정으로 쉽게 이온교환용량을 조정할 수 있었다. 솔루션 캐스팅 방법으로 강도를 가지고 잘 휘어지며 투명한 전해질막을 제조할 수 있었다. 전해질막은 이온전도도, 물흡수율, 부피 변화율, 연료 투과성 등의 측정이 되었다.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05b
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• pp.133-135
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• 2004

A direct methanol fuel cells (DMFCs) using polymer electrolyte membranes are one of the most attractive power sources for a wide range of application from vehicles to portable utilities due to the stable operation at a rarely low temperature, the high energy generation yield and energy density, the simplicity of system.(omitted)

• Journal of the Korean Electrochemical Society
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• v.19 no.2
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• pp.39-44
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• 2016

Oxygen reduction reaction in the fuel cell (ORR) plays a dominant role in the overall reaction. In addition, the low compatibility between the membrane and the binder consisted of different materials, greatly reduces the efficiency of the fuel cell performance. In view of these two problems, geometrically modified copolymers with 9.9_Bis (4-hydroxyphenyl) were synthesized via condensation reaction instead of conventional biphenol and were adopted as hydrocarbon ionomer binders. By utilizing these binders, two kinds of MEAs using fluorinated Nafion membrane and hydrocarbon based membrane were manufactured in order to electrochemical performance evaluation. With current-voltage curves, there was no significant difference in the 0.6 V when two types of membrane were applied. Also, tafel slope became considerably lower as compared to the Nafion membrane. Thus, it is determined that the new hydrocarbon binder is expected to contribute the improvement in performance of fuel cells.

• Membrane Journal
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• v.21 no.4
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• pp.389-397
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• 2011

In this study, polymer composite membranes based on sulfonated poly(arylene ether sulfone) (SPAES) were prepared using a solution casting method with different amount of vermiculite (VMT) content. The dispersion of VMT particles in the SPAES matrix was confirmed by means of a scanning electron microscopy observation. The composite membrane containing less than 1 wt% of VMT has a smooth skin on the top and bottom, which means there is a good dispersion of VMT in the matrix. The water uptake of the composite membranes gradually increases as the temperature increases, and the results confirm that all the adsorbed water is bound water because VMT has a strong water affinity on account of its high cation exchange value. A composite membrane with a VMT content of less than 1 wt% increases the proton conductivity and reduces the methanol permeability. Of all the composite membranes, the membrane SPAES/VMT 1.0 has the best fuel cell performance in terms of membrane selectivity. The performance value of SPAES/VMT 1.0 is double that of Nafion 112, which suggests that SPAES/VMT1.0 could be an excellent candidate for direct methanol fuel cells.

• Journal of the Korean Electrochemical Society
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• v.19 no.2
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• pp.45-49
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• 2016

In order to mitigate oxidative degradation of polymer membrane during fuel cell operation, an organic radical quencher was introduced. Rutin was selected as a radical quencher and mixed with sulfonated poly(arylene ether sulfone) to prepare composite membrane. Physicochemical properties of the composite membranes such as water uptake and proton conductivity were characterized. Hydrogen peroxide exposure experiment, which can mimic accelerated oxidative stability test during fuel cell operation, was adopted to evaluate the oxidative stability of the membranes. The composite membranes containing Rutin showed similar proton conductivity and enhanced oxidative stability compared to pristine ones.