• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.164-169
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• 2008

In this study, the facilitated transport membranes, poly (ether ether)ketone (SPEEK)-Ag salts layers on top of polycarbonate supports membrane, were prepared and tested for the separation of propylene/propane. SPEEK was synthesised using PEEK and $H_2SO_4$. Experiments were porformed at room temperature and feed pressures up to 30 psig. The SPEEK-Ag salt membranes showed good selectivity for propane over propylene. With increasing the concentration of SPEEK in MeOH, 5~20 wt%, the thickness of SPEEK membrane on the polycarbonate increased. The selectivity and permeance of SPEKK-Ag membrane for propylene/propane were changed by membrane thickness and concentration of Ag salts.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.2
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• pp.164-175
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• 2022

In this work, sulfonated poly (ether ether ketone) (SPEEK) composite membranes including strontium zirconate (SrZrO₃) were fabricated by the electrospinning method. Fourier-transform infrared spectroscopic analysis and X-ray diffraction analysis were used to identify the chemical structure and the crystallinity of SrZrO₃ and electrospun composite membranes. The thermal stability of the pure SPEEK and SPEEK/SrZrO₃ electrospun composite membranes were investigated by using thermogravimetric analysis. The physicochemical properties and proton conductivity were enhanced with the addition of different weight ratio of SrZrO₃ nanofiller (2, 4 and 6 wt%) in SPEEK polymer. The optimized SPEEK/SrZrO₃-4 electrospun membrane containing 4 wt% of SrZrO₃ showed a high proton conductivity compared to other electrospun SPEEK/SrZrO₃ composite membranes. The results indicate that electrospun composite membranes incorporating these perovskite nanofillers should be explored as potential candidates for use in proton exchange membrane fuel cells.

• Journal of the Korean Electrochemical Society
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• v.12 no.2
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• pp.167-172
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• 2009

Direct methanol fuel cells(DMFCs) are receiving significant attention in the portable power source and electric vehicular transportation because of its high energy efficiency as liquid fuel, low cost, and no requirement of fuel reforming process. In this study, we synthesized the Sulfonated poly(ether ether ketone) (SPEEK) to evaluate the possibility of use as a proton exchange membrane for DMFC. And poly(vinylidienedifluoride) (PVDF) was used to increase proton conductivity in SPEEK and simultaneously to prevent methanol transport through the cross linked membrane. Furthermore, in order to improve the electrical composite properties for DMFC applications.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.87-90
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• 2005

This paper presents an evaluation of the effect of titanium dioxide nanoparticles in sulfonated poly(ether ether ketone) (SPEEK) with sulfonation degree of 57%. A series of inorganic-organic hybrid membranes were prepared with a systematic variation of titanium dioxide nanoparticles content. Their water uptake, methanol permeability and proton conductivity as a function of temperature were investigated. The results obtained show that the inorganic oxide network decreases the proton conductivity and water swelling. It is also found that increase in inorganic oxide content leads to decrease of methanol permeability. In terms of morphology, membranes are homogeneous and exhibit a good adhesion between inorganic domains and the polymer matrix. The properties of the composite membranes are compared with standard nafion membrane.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.295-300
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• 2007

A new characterization method using a porous plug model was proposed to determine the degree of sulfonation (DS) of ionomer binder with respect to the membrane used in membrane-electrode assemblies (MEAs) and to analyze the fraction of proton pathways through ionomer-catalyst combined electrodes in MEAs for polymer electrolyte fuel cells (PEFCs). Sulfonated poly(ether ether ketone) was prepared to use a polymeric electrolyte and laboratory-made SPEEK solution (5wt.%, DMAc based) was added to catalyst slurry to form catalyst layers. In case of the SPEEK-based MEAs in this study, DS of ionomer binder for catalyst layers should be the same or higher than that of the SPEEK membrane used in the MEAs. The porous plug model suggested that most of protons were via the ionomer binder (${\sim}92.5%$) bridging the catalyst surface to the polymeric electrolyte, compared with the pathways through the alternative between the interstitial water on the surface of ionomer binder or catalyst and the ionomer binder (${\sim}7.3%$) and through only the interstitial water on the surface of ionomer or catalyst (${\sim}0.2%$) in the electrode of the MEA comprising of the sulfonated poly(ether ether ketone) membrane and the 5wt.% SPEEK ionomer binder. As a result, it was believed that the majority of proton at both electrodeds moves through ionomer binder until reaching to electrolyte membrane. The porous plug model of the electrodes of MEAs reemphasized the importance of well-optimized structure of ionomer binder and catalyst for fuel cells.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.85.2-85.2
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• 2010

There is widespread effort to develop polymer membranes in place of Nafion for high temperature polymer electrolyte membrane fuel cell(PEMFC). In our study, SiO2 membranes are arranged by electrospinning method. For impregnation solution, the modified sulfonated poly(ether ether ketone)(SPEEK) polymer is prepared from sulfonation, sulfochlorination, partial reduction and lithiation reaction. The modified polymer is cross-linked with 1,4-diiodobetane in NMP solvent and then blended with Heteropoly acid(HPA). The characterization of membranes is confimed by FT-IR, Thermogravimetry(TGA), water uptake test and single cell performance test for PEMFC, etc. The composite membrane shows satisfactory thermal and mechanical properties. Beside, The membrane exhibits good ion exchange capacity and high proton conductivity. As a result, The composite membrane is promising as an alternative membrane in high temperature PEMFC.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.409-411
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• 2005

A series of inorganic-organic hybrid membranes were prepared with a systematic variation of titanium dioxidenanoparticles content. Their water uptake, methanol permeability and proton conductivity as a function of inorganic oxide content were investigated. The results obtained show that the inorganic oxide network decreases the proton conductivity and water swelling. It is also found that increase in inorganic oxide content leads to decrease of methanol permeability. In terms of the morphology, membranes are homogeneous and exhibit a good adhesion between inorganic domains and the polymer matrix. The properties of the composite membranes are compared with the standard nation membrane.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.3
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• pp.246-251
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• 2017

To fabricate a hydrocarbon polymer electrolyte composite membrane incorporated with Pt nanoparticle, the polymer electrolyte membrane made of a sulfonated-fluorinated hydrophilic-hydrophobic block copolymer (SFBC) and sulfonated poly (ether ether ketone) (SPEEK) blend in the wight ratio of 1 : 1 was synthesized, and a simple drying process was used in order to incorporate Pt nanoparticle into the SFBC/SPEEK film by reducing platinum (II) bis (acetylacetonate), Pt $(acac)_2$. The distribution of the Pt nanoparticles was observed by transmission electron microscopy (TEM), and mechanical and thermal properties were tested by universal testing machine (UTM) and thermogravimetry analyzer (TGA). Cation conductivity, ion exchange capacity (IEC) and I-V characteristics were estimated.

• Membrane Journal
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• v.27 no.5
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• pp.449-457
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• 2017

In this study, the 10 stages stacked module was designed by increasing the number of unit cells in the membrane capacitive deionization(MCDI) process. The aminated polysulfone and sulfonated poly(ether ether ketone) were synthesized and coated on porous carbon electrode by casting method. The salt removal efficiency was measured for the 10 stage stacked module under the operation conditions of adsorption voltage and time, desorption voltage and time, flow rate and concentration of feed water, and di-valent solutions including $CaSO_4$, $MgCl_2$ and tap water. Typically, when 100 mg/L of NaCl as the feed was used, the salt removal efficiency was 98.3% at a flow rate of 100 mL/min, the adsorption condition of 1.2 V/3 min and desorption condition of -0.5 V/5 min.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.6
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• pp.673-681
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• 2023

Hydrocarbon-based polymer membranes to replace perfluorinated polymer membranes are being continuously researched. However, hydrocarbon-based membranes have a problem in that they are less durable than fluorine-based membranes. In this study, we sought to compare the annealing effect to improve the durability of sulfonated poly(ether ether ketone) (SPEEK). After membranes formation, thermogravimetric analysis and tensile strength were measured to compare changes in membranes properties due to annealing. After manufacturing the membrane and electrode assembly (MEA), the initial performance and chemical durability was compared with unit cell operation. During the 24-hour annealing process, the strength increased due to the increase in-S-O-S-crosslinking, and the sulfonic acid group decreased, leading to a decrease in I-V performance. By annealing, the hydrogen permeability was reduced to less than 1/10 of that of the nafion membrane, and as a result, open circuit voltage (OCV) and durability was improved. The SPEEK membranes annealed for 24 hours showed higher durability than the nafion 211 membranes of the same thickness.