Highly reinforced pore-filling membranes based on sulfonated poly(arylene ether sulfone)s for high-temperature/low-humidity polymer electrolyte membrane fuel cells

Kim, Kihyun,Kim, Sung-Kon,Park, Jung Ock,Choi, Seong-Woo,Kim, Ki-Hyun,Ko, Taeyun,Pak, Chanho,Lee, Jong-Chan Elsevier 2017 Journal of membrane science Vol.537 No.-

<P><B>Abstract</B></P> <P>A series of pore-filling membranes are prepared by impregnating porous cross-linked benzoxazine-benzimidazole copolymer P(<I>p</I>BUa-<I>co</I>-BI) substrates with sulfonated poly(arylene ether sulfone)s (SPAES)s having different degree of sulfonation for polymer electrolyte membrane fuel cells operating at high-temperatures (>100°C) and low-humidity (<50% RH) conditions. The SPAESs are synthesized by reacting 4,4’-dihydroxybiphenyl with the mixtures of disulfonate-4,4’-difluorodiphenylsulfone and 4,4’-difluorodiphenylsulfone in different ratios. The porous P(<I>p</I>BUa-<I>co</I>-BI) substrates are prepared by extracting dibutyl phthalate (DBP) included in P(<I>p</I>BUa-<I>co</I>-BI) films using methanol. The P(<I>p</I>BUa-<I>co</I>-BI) films are prepared by stepwise heating the casted <I>N,N-</I>dimethylacetamide solution containing the mixtures of poly[2,2′-(<I>m</I>-phenylene)-5,5′-bibenzimidazole] (PBI), 3-phenyl-3,4- dihydro-6-<I>tert</I>-butyl-2<I>H</I>-1,3-benzoxazine (<I>p</I>BUa), and DBP to 220°C. The pore-filling membranes are found to have much improved dimensional stability and mechanical strength compared with the SPAES membranes. Although the proton conductivity values of the pore-filling membranes are slightly smaller than those of the SPAES membrane, their cell performance is superior to that of the SPAES membrane at 120°C and 40% RH conditions because ultrathin pore-filling membranes (15–20µm) having high mechanical strength can be prepared and they can contain a larger content of chemically-bound water.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SPAESs having different degree of sulfonation were synthesized as pore-filling polymers. </LI> <LI> Transparent, ultrathin, and highly-flexible pore-filling membranes were developed. </LI> <LI> Acid-base interaction between the porous substrate and filling SPAES was found. </LI> <LI> Excellent physical stability and mechanical strength of the pore-filling membranes. </LI> <LI> Cell performances of MEAs from the pore-filling membranes were highly improved. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Pore-filled PVDF 이온교환막의 제조 및 응용

변홍식,박병규,홍병표,여광수,윤무홍,강남주 한국막학회 2004 멤브레인 Vol.14 No.2

연구에서는 비대칭 polyvinylidene fluoride (PVDF)막을 기질막으로 하여 Pore-filled 이온교환막을 제조하였다. 먼저 다공성 PVDF막의 기공에 80%의 chloromethylate aryl ring을 가지고 있는 poly(vinylbenzyl chloride) (PVBCI)과 1,4- diaminobicyclo[2,2,2]octane (DABCO)을 tetrahydrofuran (THF)와 dimethylforamide (DMF)가 8:2로 혼합된 용액에 녹여서 채워 넣고 겔화시킨 후, 남아 있는 chloromethyl group에 trirnethylamine (TMA, 40 wt% in water)을 이용하여 양이온 암모니움 site를 형성시키면 pore-filled 음이온교환막이 형성된다. 이와 같이 2단계의 제조 방식으로 제조된 pore-filled 막은 크기의 변화가 없으며, 가교도의 조절로써 최종 막의 특성이 간단하게 조절되는 것을 보여주었다. SEM과 AFM의 표면촬영의 결과로부터 기질막의 기공 내에 고분자겔의 존재를 확인하였다. 투과도와 배제율에 많은 영향을 미치는 용매를 조사한 결과 tetrahydrofuran (THF)만을 사용하여 제조한 막보다 THF와 DMF를 함께 사용할 때 더 우수한 막이 제조되었다. 제조된 최종 막의 수투과도 조사결과, 가교도 10% 막의 경우 아주 낮은 압력에서(100 Kpa) 전형적인 한외여과막의 투과도(8∼10 kg/m2hr)를 보여주었으며 배제율 또한 우수한 결과(55∼60%)를 보여주었다. 압력에 대한 pore-filled 이온교환막의 성능을 관찰한 결과 압력이 증가할수록 투과도와 배제율은 함께 증가하였다. In this study, the pore-filled ion-exchange membranes were prepared by using the asymmetric PVDF membrane as a nascent membrane. First, the solution of PVBCI having the chlorornethylate aryl ring of 80 percents and DABCO was made with the mixed solvent of THF and DU (8:2). These mixed solution was then, filled in the pores of PVDF membrane, and left for a day to complete the gelation. Finally the pore-filled anion-exchange membrane is obtained fallowed by the amination of the remaining chloromethyl groups with trimethylamine (TMA, 40 wt% in water) forming the positive ammonium ion sites. This 2 step procedure enabled us to produce the pore-filled membranes without change of size, and to control the properties of final membrane with various degree of cross-linking. The results of SEM and AFM showed the polyelectrolyte existed in the pores of nascent membrane as a certain configuration. From the investigation of the solvent affecting much to the permeability and rejection, it was found that the membranes using mixed solvent of THE and DMF (8:2) showed better performances than the membranes produced by THF only. The result of an investigation for the water permeability of the final membrane at low pressure (100 Kpa) showed a typical ultrafiltration membrane's permeability (8 ∼ 10 kg/m2hr) and good values of rejection (55∼60 percent).

Pore-filling polymer electrolyte membrane based on poly (arylene ether ketone) for enhanced dimensional stability and reduced methanol permeability

Mong, Anh Le,Yang, Sungwoo,Kim, Dukjoon Elsevier 2017 Journal of membrane science Vol.543 No.-

<P><B>Abstract</B></P> <P>We synthesized sulfonated poly (arylene ether ketone) (SPAEK) with an 80% degree of sulfonation (DS) from 4,4-bis(4-hydroxyphenyl) valeic acid and 4,4-difluorobenzophenone. A series of pore-filling membranes were prepared by filling SPAEK into the plasma-treated porous poly (arylene ether ketone) membrane (PAEK) with various pore sizes and porosity. The porous PAEK membrane were obtained by removing the phase separated polylatide (PLA) blocks from the self-arranged PAEK-b-PLA copolymer membranes. The results from synthesis of SPAEK and porous PAEK was characterized using <SUP>1</SUP>H NMR and FTIR, and the morphology of the SPAEK-filled porous PAEK membrane was investigated using SEM and EDX-SEM. The essential properties of pore-filled membranes (e.g., ionic exchange capacity (IEC), proton conductivity, thermal and mechanical stability, and methanol permeability), were examined and collated to those of pristine SPAEK and commercial Nafion 117 membranes. The pore-filled membranes prepared in this study showed enhanced thermal and dimensional stability and reduced methanol permeability compared with the pristine SPAEK and Nafion 117 membranes. The pore-filled membrane with a pore diameter of 50nm showed the highest proton conductivity among all pore-filled membranes and lower methanol permeability than commercial membrane Nafion 117.</P> <P><B>Graphical abstract</B></P> <P>Filling porous PAEK membranes with SPAEK electrolyte is newly developed to enhance the performance of direct methanol fuel cells. From experimental observations, the pore filling membranes show not only a lower methanol permeability and better selectivity than those of pristine SPAEK and Nafion 117 membranes, but also superior thermal and dimensional stabilities.</P> <P>[DISPLAY OMISSION]</P>

Proton conductive cross-linked benzoxazine-benzimidazole copolymers as novel porous substrates for reinforced pore-filling membranes in fuel cells operating at high temperatures

Kihyun Kim,Choi, Seong-Woo,Park, Jung Ock,Kim, Sung-Kon,Lim, Min-Young,Kim, Ki-Hyun,Ko, Taeyun,Lee, Jong-Chan Elsevier 2017 Journal of membrane science Vol.536 No.-

<P><B>Abstract</B></P> <P>Proton conductive porous substrates consisting of cross-linked benzoxazine-benzimidazole copolymers are developed for practical application of reinforced pore-filling membranes in polymer electrolyte membrane fuel cells operating at high-temperatures (>100°C) and low relative humidity (<50% RH) conditions. The porous proton conductive substrates are prepared by casting solution mixtures of sodium 3-(4-sulfonatophenyl-3,4-dihydro-2<I>H</I>-1,3 benzoxazine-6-sulfonate (<I>p</I>S) and poly[2,2′-(<I>m</I>-<I>p</I>henylene-5,5′-bibenzimidazole] (PBI) with dibutyl phthalate (DBP) as a porogen, followed by subsequent stepwise heating to 220°C and extraction of DBP from the P(<I>p</I>S-<I>co</I>-BI) films. The resulting porous substrates are found to have mechanically robust cross-linked structures, tunable hydrophilicity, and proton conductivity. A pore-filling membrane is prepared by impregnating the porous substrate with sulfonated poly(arylene ether sulfone) having the degree of sulfonation of 70mol%. The pore-filling membrane exhibits much improved dimensional stability and mechanical strength compared to the linear sulfonated poly(arylene ether sulfone) membrane and its proton conductivity and cell performance are found to be superior to the pore-filling membrane prepared using the porous substrate based on cross-linked benzoxazine-benzimidazole copolymers without any proton conductive acid groups.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Proton conductive benzoxazine having sulfonic acid groups was synthesized. </LI> <LI> Porous cross-linked benzoxazine-benzimidazole copolymer substrates were prepared. </LI> <LI> Tunable hydrophilicity, porosity and proton conductivity of porous substrates. </LI> <LI> Excellent physical stability and mechanical strength of pore-filling membrane. </LI> <LI> Outstanding cell performance of MEA prepared with the pore-filling membrane. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Preparation and Characterization of Pore-filled Membrane Based on Polypropylene with Poly(vinylbenzyl chloride) by Using in-situ Cross-linking Technique

Kwon, Byeong-Min,Ko, Moon-Young,Hong, Byung-Pyo,Byun, Hong-Sik The Membrane Society of Korea 2008 Korean Membrane Journal Vol.10 No.1

Water softening is a very promising field for membranes and especially ultra low pressure membranes. Nanofiltration membranes based on pore-filling technology was prepared by using a new technique: the in-situ cross-linking. This route involves introducing a pre-formed polymer into the pores of a host membrane and then locking the polymer in the pores by in-situ cross-linking with an appropriate reagent. By this way, it is possible to make robust and competitive, pore-filled, anion-exchange membranes with excellent control over the properties of the incorporated gel without affecting the host membrane. In this paper, the possibilities of tuning such membranes for ultra low pressure water softening was examined by altering pore-filling chemistry (by changing cross-linking and aminating reagents). The results showed that tuning the chemistry of the pore-filling has important effects. In particularly, it had been shown that the correct selection of cross-linking reagent was not only essential to get pore-filled membranes but it could control their properties. Moreover, the aminating reagent could improve membrane performance. It was found that an increase in hydrophobicity could improve the Darcy permeability.

Development of highly reinforced pore-filling electrolyte membranes based on cross-linked benzoxazine-benzimidazole copolymers for fuel cells at high temperature and low humidity conditions

김기현,최원재,배중문,김정환,이종찬 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

Highly reinforced pore-filling electrolyte membranes, cosisted of sulfonated poly(arylene ether sulfone) (SPAES) derivatives as pore impregnated proton conducting electrolytes and cross-linked benzoxazine and benzimidazole copolymer as porous substrate, were developed for the application in polymer electrolyte membrane fuel cell operating at high temperature (> 100°C) and low relative humidity (50% RH) conditions. The pore-filling membranes exhibited much improved dimensional and hydrolytic stabilities and mechanical strength than pristine SPAES membranes without much deterioration of proton conductivity. Subsequently, cell performance of membrane electrode assemblies (MEAs) with the pore-filling membranes is much better than that with SPAES membrane at 120°C and 40% RH conditions.

Development of Pore-filled Ion-exchange Membranes for Efficient All Vanadium Redox Flow Batteries

Kang, Moon-Sung The Korean Electrochemical Society 2013 한국전기화학회지 Vol.16 No.4

Thin pore-filled cation and anion-exchange membranes (PFCEM and PFAEMs, $t_m=25-30{\mu}m$) were prepared using a porous polymeric substrate for efficient all-vanadium redox flow battery (VRB). The electrochemical and charge-discharge performances of the membranes have been systematically investigated and compared with those of commercially available ion-exchange membranes. The pore-filled membranes were shown to have higher permselectivity as well as lower electrical resistances than those of the commercial membranes. In addition, the VRBs employing the pore-filled membranes exhibited the respectable charge-discharge performances, showing the energy efficiencies (EE) of 82.4% and 84.9% for the PFCEM and PFAEM, respectively (cf. EE = 87.2% for Nafion 1135). The results demonstrated that the pore-filled ion-exchange membranes could be successfully used in VRBs as an efficient separator by replacing expensive Nafion membrane.

Development of Pore-filled Ion-exchange Membranes for Efficient All Vanadium Redox Flow Batteries

강문성 한국전기화학회 2013 한국전기화학회지 Vol.16 No.4

Thin pore-filled cation and anion-exchange membranes (PFCEM and PFAEMs,tm = 25-30 μm) were prepared using a porous polymeric substrate for efficient all-vanadium redox flow battery (VRB). The electrochemical and charge-discharge performances of the membranes have been systematically investigated and compared with those of commercially available ion-exchange membranes. The pore-filled membranes were shown to have higher permselectivity as well as lower electrical resistances than those of the commercial membranes. In addition, the VRBs employing the pore-filled membranes exhibited the respectable chargedischarge performances, showing the energy efficiencies (EE) of 82.4% and 84.9% for the PFCEM and PFAEM, respectively (cf. EE = 87.2% for Nafion 1135). The results demonstrated that the pore-filled ion-exchange membranes could be successfully used in VRBs as an efficient separator by replacing expensive Nafion membrane.

Pore-filling anion conducting membranes and their cell performance for a solid alkaline fuel cell

최영우(Choi, Youngwoo),이미순(Lee, Misoon),박구곤(Park, Gugon),임성대(Yim, Sungdae),양태현(Yang, Taehyun),김창수(Kim, Changsoo) 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.06

AEM which were used for solid alkaline fuel cell(SAFC) were prepared by photo polymerization in method pore-filling with various quaternary ammonium cationic monomers and crosslinkers without an amination process. Their specific thermal and chemical properties were characterized through various analyses and the physico-chemical properties of the prepared electrolyte membranes such as swelling behavior, ion exchange capacity and ionic conductivity were also investigated in correlation with the electrolyte composition. The polymer electrolyte membranes prepared in this study have a very wide hydroxyl ion conductivity range of 0.01 - 0.45S/cm depending on the composition ratio of the electrolyte monomer and crosslinking agent used for polymerization. However, the hydroxyl ion conductivity of the membranes was relatively higher at the whole cases than those of commercial products such as A201 membrane of Tokuyama. These pore-filling membranes have also excellent properties such as smaller dimensional affects when swollen in solvents, higher mechanical strength, lowest electrolyte crossover through the membranes, and easier preparation process compared of traditional cast membranes. The prepared membranes were then applied to solid alkaline fuel cell and it was found comparable fuel cell performance to A201 membrane of Tokuyama.

Application of the Cake-Filtration Theory to Analyze the Permeate Performance in Poly(vinylbenzyl chloride)-Filled Microfiltration Membrane

Park, Young G.,Byun, Hong-sik 한국공업화학회 2002 Journal of Industrial and Engineering Chemistry Vol.8 No.6

In order to experimentally analyze the permeate performance of a membrane synthesized by a pore-filling technique, microfiltration experiments are conducted using pretreated wastewater having high alkality. The conventional cake filtration theory was also used in order to determine the permeability and the resistance of the cake-layer in the membrane. From the experimental results, the hydraulic permeability by diffusive-convective transport was measured as a function of the amount of gellation in the pores, which was enhanced by more than 70% in comparison with the nascent membrane. The transmembrane pressure (TMP) was also reduced by 80% in the newly developed membrane as the ion-exchange capacity increased. The resistance (R_m) in the membrane was reduced by 35% in comparison with the nascent membrane. The gellation of the pore-filled membrane was synthesized by impregnating the pores with a monomer solution, i.e., a crosslinker, followed by polymerization with piperizine. An appreciable enhancement of the permeate flux in the pore filled membrane was noted using pre-treated wastewater under 10 kg_f/cm^2.