Dually cross-linked polymer electrolyte membranes for direct methanol fuel cells

Lee, Won Hyo,Lee, Kang Hyuck,Shin, Dong Won,Hwang, Doo Sung,Kang, Na Rae,Cho, Doo Hee,Kim, Ji Hoon,Lee, Young Moo Elsevier 2015 Journal of Power Sources Vol.282 No.-

<P><B>Abstract</B></P> <P>End-group crosslinkable sulfonated poly(arylene ether sulfone) copolymer (ESPAES) and imidazolium poly(arylene ether sulfone) copolymer (IPAES) are synthesized as a proton exchange membrane and ionic crosslinker, respectively. A novel dually cross-linked membrane (DCM) based on ESPAES is similar to an inter-penetrating network and is prepared <I>via</I> blending IPAES and thermal treatment for direct methanol fuel cell (DMFC) applications. The synergistic effects of end-group crosslinking and ionic crosslinking improve chemical and thermal stability and mechanical properties. In addition, the DMFC performance of the DCM outperforms that of the end-group cross-linked SPAES and Nafion<SUP>®</SUP> 212 due to its excellent fuel barrier property in spite of relatively low proton conductivity, which is derived from the content of the non-proton conducting IPAES copolymer. Consequently, the DCM has great potential as an electrolyte membrane for DMFC applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dually cross-linked membranes (DCMs) fabricated through ionic and end-group crosslinking. </LI> <LI> DCMs achieved improved chemical, thermal and mechanical properties. </LI> <LI> Controlling the blending ratio of the DCMs enhanced their DMFC performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Polymer chain conformation of dually cross-linked membranes.</P> <P>[DISPLAY OMISSION]</P>

Gelation Dynamics of Ionically Crosslinked Alginate Gel with Various Cations

권석현,선정윤,윤주일,석현광,오규환 한국고분자학회 2015 Macromolecular Research Vol.23 No.12

Alginates can be crosslinked with multivalent cations, leading eventually to hydrogel formation. The properties of alginate gel depend on its lock structure, monomeric composition, concentration of polymer and cross linker. Among these, the properties of ionically crosslinked alginate gel can be greatly affected by multivalent cations as cross-linker. Knowledge of gelation dynamics by multivalent cations allows control over gelation characteristics, such as modulus of gel and the time required for equilibrium state, and healing properties. We have studied gelation dynamics of ionically crosslinked alginate gel. According to different types of anions bound with cations, gelation time and equilibrium viscosity was changed due to the solubility kinetics of the cation. The equilibrium viscosity is increased as the size of the cations increased even though the cations have same valency. A theoretical model is introduced to interpret dynamic change of viscosity during gelation.

High performance blend membranes based on densely sulfonated poly(fluorenyl ether sulfone) block copolymer and imidazolium-functionalized poly(ether sulfone)

Kwon, Sohyun,Lee, Boryeon,Kim, Tae-Hyun Elsevier 2017 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.42 No.31

<P><B>Abstract</B></P> <P><B>Abstract</B></P> <P>Novel physically crosslinked polymer membranes were prepared by simply blending densely sulfonated poly(fluorenyl ether sulfone) with imidazolium-functionalized poly(ether sulfone). The blend showed well-defined ionic channels originating from the densely sulfonated structure and was physically crosslinked by ionic interactions. These two factors combined to enhance the physical stability and chemical stability of the prepared membranes while offering a conductivity over 0.24 S/cm at 80 °C for various amounts of crosslinker in the blend. The influence of this crosslinker amount on the chemophysical properties of the blend membranes was studied in a systematic way.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Physically crosslinked polymer membranes were produced. </LI> <LI> Ionic interactions between sulfonate and imidazolium groups were induced. </LI> <LI> The effect of crosslinker content on the blend membranes was investigated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Preparation of anti-bacterial cellulose fiber via electrospinning and crosslinking with β-cyclodextrin

강영웅,최용근,김형주,송영한,김형섭 한국의류학회 2015 Fashion and Textiles Vol.2 No.1

In the study, we successfully produced electrospun cellulose fibers crosslinked with β-CD. For electrospinning, cellulose was dissolve in 1-ethyl-3-methylimidazolium acetate and DMF was added to the prepared solution for better spinnability. The prepared cellulose fiber was immersed in the solution containing β-CD, crosslinking agent and sodium hypophosphite. In order to understand the effect of a crosslinking agent, two different types of the agents, BTCA (1,2,3,4-butanetetracarboxylic acid) and citric acid with various concentrations were used for cross-linking. The crosslinking degree was increased with the concentration of the crosslinking agents, for the both agents. The cross-linked web changed into membrane like morphology when the concentration of the cross-linking agent was higher than 5 wt%. The concentration of crosslinking agent also gave influence on the crystallinity, the thermal property and the antibacterial activity of fibers. Due to the cross-linking the crystallinity was decreased. The cross-linked fiber showed selective bacterial behavior according to the bacterial strain and the cross-linking agent.

Thermal Properties of Crosslinked Poly(1-vinyl-3-allylimidazolium) by Electron Beam Irradiation

김준범,이정수 한국고분자학회 2018 폴리머 Vol.42 No.2

Ionic liquids (ILs) have attracted widespread interest in recent years because of their favorable characteristics. A highly crosslinked poly(1-vinyl-3-allylimidazolium) (C-PVAm) was synthesized by free radical polymerization and quaternization followed by radiation processing. An allyl group was covalently incorporated into the polymer matrix to enhance the properties of the PVAm. The chemical structures of the synthesized pristine and crosslinked PVAm containing a C=C bond were confirmed by 1H NMR and FTIR spectra. The thermal properties of the C-PVAm analyzed by differential scanning calorimetry (DSC) were significantly improved because of the thermal stability of the crosslinked networks.

가교결합형 poly(POEM-co-AMPSLi-co-GMA) 전해질의 합성과 물리화학적 특성

최다인,류상욱,Choi, Da-In,Ryu, Sang-Woog 한국전기화학회 2014 한국전기화학회지 Vol.17 No.1

In this study, crosslinked poly(POEM-co-AMPSLi-co-GMA)s were prepared by epoxy coupling of GMA after radical copolymerization of AMPS, POEM and GMA followed by acid-base titration reaction between sulfonic acid of AMPS and $Li_2CO_3$. It was observed that the crystalline melting temperature of POEM was effected by mol% of components and shifted to lower value by lithiation of AMPS group. The ionic conductivity of crosslinked polymer electrolyte was decreased by addition of GMA but maintained over $1.0{\times}10^{-6}S\;cm^{-1}$ until 16 mol%. Particularly, the self-doped polymer electrolyte with 2 mol% of GMA showed its ionic conductivity as high as $4.08{\times}10^{-6}S\;cm^{-1}$ at room temperature and electrochemical stability up to 6 V. In addition, 0.11 MPa of modulus and 270% of elongation were obtained from the free standing film of crosslinked polymer electrolyte. 본 실험에서는 다양한 조성의 AMPS, POEM 및 GMA를 함유하는 공중합체를 합성하고, AMPS의 술폰산기와 $Li_2CO_3$와의 산염기 반응 및 에폭시기의 가교반응을 유도하여 가교결합된 poly(POEM-co-AMPSLi-co-GMA) 전해질을 제조하였다. POEM의 결정융점은 AMPS 및 POEM의 몰분율에 따라 변화되는 특징을 관찰할 수 있었으며, 리튬이온이 도입된 이후 대체적으로 감소되는 경향이 나타났다. 가교된 고분자의 이온전도도는 GMA의 함량이 증가할수록 다소 감소되는 결과가 나타났지만, 16 mol%까지는 $1.0{\times}10^{-6}S\;cm^{-1}$ 이상의 값을 보여주었다. 특히, 자기-도핑형 전해질임에도 불구하고 2 mol%에서 최대 $4.08{\times}10^{-6}S\;cm^{-1}$의 높은 상온이온전도도가 얻어졌으며, 상온에서 6 V까지 우수한 전기화학적 안정성을 보여주었다. 또한 가교된 고분자전해질은 필름성형이 가능하며, 0.11 MPa의 탄성계수 및 270%의 변형율을 보여주었다.

초분자 네트워크를 이용한 열가역성 가교 탄성체

배종우 ( Jong Woo Bae ),오상택 ( Sang Taek Oh ),김구니 ( Gu Ni Kim ),백현종 ( Hyen Jong Baik ),김원호 ( Won Ho Kim ),최성신 ( Sung Seen Choi ) 한국고무학회 2010 엘라스토머 및 콤포지트 Vol.45 No.3

최근에 기존 고무의 장점인 유연성과 충전제에 의한 다양한 기능성과 열가소성 고무의 장점인 리싸이틀 및 성형의 용이성을 동시에 갖춘 초분자 네트워크형 열가역성 가교 탄성체가 소개되고 있다. 수소 결합과 이온 클러스터간의 결합력과 같은 열가역성 결합은 1990년부터 소개되었지만, 초분자 네트워크에서 가교 구조의 결합과 절단을 조절할 수 있는 기술이 시도된 것은 최근의 기술적 성과이다. 본 보문에서는 열가소성 탄성체의 용융 특성과 가교 탄성체의 보강 거동을 가지는 열가역성 가교 탄성체의 특징들을 정리하였다. Recently supramolecular network thermo-reversible crosslinking elastomer having flexibility, various functionality, and advantages of thermoplastic elastomer (TPE) such as recycle and easy processbility is introduced. Although thermo-reversible bonds such as hydrogen bond and ionic cluster is recognized as a common technology since 1990, control technology of bonding and dissociation of crosslink in supramolecular network is a recent technology. In this review, characteristics of thermo-reversible crosslinking elastomer having rheological properties of TPE and reinforcing behaviors of thermoset elastomer are summarized.

High performance blend membranes based on sulfonated poly(arylene ether sulfone) and poly(p-benzimidazole) for PEMFC applications

원미희,김태현,권소현 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.29 No.-

Novel ionically crosslinked blend polymer membranes were developed based on sPES and p-PBI. p-PBIwas used as the key component in polymeric blends with sPES to produce stable but yet still conductiveand miscible membranes. Specific interactions between the acid moiety and the amine moietycontributed to the miscibility of the sPES–PBI blend polymers in DMSO. The properties of the membraneswere better than those of bare membranes, and the conductivity of a 5 wt.% PBI blend membraneexceeded 0.13 S/cm at 80 8C. The influence of the p-PBI content on chemophysical properties of the blendmembranes was investigated systematically

Fluoroalkyl Methacrylate/Acrylic Acid/2-HEMA 공중합체로 제조한 IPMC의 구동 특성에 미치는 가교의 영향

정한모(Han Mo Jeong),라영수(Young Soo La) 한국고분자학회 2005 폴리머 Vol.29 No.5

In Situ Crosslinked Ionic Gel Polymer Electrolytes for Dye Sensitized Solar Cells

심효진,김동욱,이창진,서동학,강영구 한국고분자학회 2008 Macromolecular Research Vol.16 No.5

We prepared an ionic gel polymer electrolyte for dye-sensitized solar cells (DSSCs) without leakage problem. Triiodide compound (BTDI) was synthesized by the reaction of benzene tricarbonyl trichloride with diethylene glycol monotosylate and subsequent substitution of tosylate by iodide using NaI. Bisimidazole was prepared by the reaction of imidazole with the triethylene glycol ditosylate under strongly basic condition provided by NaH. BTDI and bisimidazole dissolved in an ionic liquid were injected into the cells and permeated into the TiO2 nanopores. In situ crosslinking was then carried out by heating to form a network structure of poly(imidazolium iodide), thereby converting the ionic liquid electrolytes to a gel or a quasi-solid state. A monomer (BTDI and bisimidazole) concentration in the electrolytes of as low as 30 wt% was sufficient to form a stable gel type electrolyte. The DSSCs based on the gel polymer electrolytes showed a power conversion efficiency of as high as 1.15% with a short circuit current density of 5.69 mAcm-2, an open circuit voltage of 0.525 V, and a fill factor of 0.43.