• Membrane Journal
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• v.9 no.3
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• pp.170-177
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• 1999

Asymmetric membranes for pervaporation were prepared with poly sulfone and sulfonated poly sulfone in order to separate water from 90% by weight butanol solution. Chlorosulfonic acid was reacted with trimethylchlorosilane for using as a sulfonating agent. The prepared polymers were characterized with FT-IR and $^1H$-NMR. The thermal properties of the polymers were examined with DSC and TGA. Back titration method was used for the evaluation of the degree of sulfonation or the ion ex¬change capacity. N-methyl-2-pyrrolidone (NMP) and diethyleneglycol dimethyl ether (DGDE) cosolvent were used for the preparation of asymmetric membranes. The cross section and skin layer of the mem¬branes were examined with scanning electron michroscopy to investigate membrane structure formed with cosolvent composition in the casting solution. In this article, the selectivity of the dense films were not different from each other so much. However, the permeation rates were significantly increased as much as 80 times compared to that of dense film.

• Polymer(Korea)
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• v.24 no.6
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• pp.763-769
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• 2000

The multifunctional cation exchangers, sulfonated polypropylene-g-(acrylic acid/styrene) [PP-g-(AAc/Sty)] were synthesized by the irradiational grafting of AAc and Sty onto PP staple fabric with electron beam accelerator and its subsequent sulfonation. The highest degree of grafting obtained was 190% at a monomer mixture of 30 vol% AAc: 70 vol% Sty and a solvent mixture of 30 vol% water : 70 vol% methanol and the degree of grafting decreased with an increase of the AAc content in the monomer mixture at constant solvent content. Maximum ion exchange capacity of the copolymer was 4.6 meq/g. The Li$^{+}$ adsorption ability of the copolymer synthesized in the study was the best among PP-g- AAc, sulfonated PP-g-Sty, and sulfonated PP-g-(AAc/Sty).).

• Applied Chemistry for Engineering
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• v.19 no.2
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• pp.205-208
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• 2008

Sulfonated polySEBS and sulfonated PS were synthesized by sulfonation at the aromatic group of polySEBS and PS. Novel sulfonated polySEBS/sulfonated PS blending films for the ion exchange membrane of polymer electrolyte fuel cell were prepared from these sulfonated polymers. The proton conductivities of these blending films were varied in $10^{-2}{\sim}10^{-3}S/cm$ with the blending ratio of sulfonated polySEBS/sulfonated PS. Especially, the film prepared from the addition of the sulfonated PS (0.5 g) in the sulfonated polySEBS (10.0 g) has the best proton conductivity (0.07 S/cm) with ion exchange capacity (0.75 meq/g) and water uptake (25%).

• Membrane Journal
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• v.25 no.2
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• pp.171-179
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• 2015

Perfluorinated sulfonic acid ionomers (PFSAs) have been widely as solid electrolyte materials for polymer electrolyte membrane fuel cells, since they exhibit excellent chemical durability under their harsh application conditions as well as good proton conductivity. Even PFSA materials, however, suffer from physical failures associated with repeated membrane swelling and deswelling, resulting in fairly reduced electrochemical lifetime. In this study, pore-filling membranes are prepared by impregnating a Nafion ionomer into the pore of a porous PTFE support film and their fundamental characteristics are evaluated. The developed pore-filling membranes exhibit extremely high proton conductivity of about $0.5S\;cm^{-1}@90^{\circ}C$ in liquid water.

• Membrane Journal
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• v.26 no.2
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• pp.152-158
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• 2016

The Chlor-alkali (CA) membrane cell is a major electrolysis system to produce valued chemicals such as chlorine gas and sodium hydroxide. The CA membrane process has been attracted in the industries, since it has relatively low energy consumption when compared with other CA processes. The key component in CA process is perfluorinated sulfonic acid ionomer membranes, which provide ion-selectivity and barrier properties to produced gases. Unfortunately, there is limited information to determine which factors should be satisfied for CA applications. In this study, the influences of PFSA membranes on CA performances are disclosed. They include ion transport behaviors, gas evolution capability, and chemical/electrochemical resistances under CA operation conditions.

• Journal of the Korean Chemical Society
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• v.37 no.4
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• pp.416-422
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• 1993

As a result of adsorbing phthalocyanine (metal free, ${\alpha}\;and\;{\beta}$-Cu) on zinc oxide in aqueous solution using nonionic surfactant, all of the added dye was adsorbed and Na salt of sulfonated phthalocyanine showed the Langmuir monolayer adsorption. To analyze the effect of adsorption on zinc oxide, photovoltage was measured using surface photovoltmeter. The high photovoltaic effect was observed at intrinsic wavelength of zinc oxide and wavelength of adsorbed phthalocyanine dye. Metal free phthalocyanine, ${\alpha}$-copper phthalocyanine and ${\beta}$-copper phthalocyanine showed the highest photovoltaic effect when the percentage of coverage (${\theta}_{BET}$) for zinc oxide is about 80, while sulfonated phthalocyanine showed the highest photovoltaic effect when the percentage of coverage for zinc oxide is about 30.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.478-484
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• 2016

Polyether ether ketone (PEEK) composite membranes have been intensively investigated for polymer electrolyte membrane water electrolysis (PEMWE). Covalently linked (CL) sulfonated polyether ether ketone (SPEEK) and cellulose polymer composite membranes were prepared and characterized. Polyether ether ketone (PEEK) and cellulose were sulfonated and then were covalently linked by 1,4-diiodobutane to produce covalently linked SPEEK and cellulose polymer composite membranes. The composite membranes showed better thermostability and electrochemical properties than SPEEK. The membranes were prepared by sol-gel casting method. CL-SPEEK/Cellulose composite membrane featured 0.2453 S/cm of proton conductivity at $80^{\circ}C$ which was better than that of Nafion.

• Journal of Energy Engineering
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• v.25 no.3
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• pp.66-72
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• 2016

In this study, a sulfonated poly(arylene ether ketone) block copolymer was prepared from hydrophilic oligomer and hydrophobic oligomer. The structure of the prepared membrane was characterized by $^1H$-NMR, FT-IR and GPC. The $M_w$(weight-average molecular weights) of the polymer was $209,700g\;mol^{-1}$ and the molecular weight distribution($M_w/M_n$) of 1.25 was obtained. The prepared membrane showed excellent thermal stability with gradual weight loss up to $200^{\circ}C$. The proton conductivity of SPAEK block copolymer reached the maximum of $9.0mS\;cm^{-1}$ at $90^{\circ}C$ under 100% relative humidity (RH). From the observed results, it is necessary to do more aggressive attempt to study the possibility of application as an ion-conductive composite electrolyte.

• Membrane Journal
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• v.25 no.5
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• pp.406-414
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• 2015

In this study, partially fluorinated cation exchange membranes were prepared by direct sulfonation of Poly(VDF-co-hexafluoropropylene) copolymers (PVDF-co-HFP) followed by a casting method for application in the Membrane capacitive deionization (MCDI). The structure of sulfonated PVDF-co-HFP (SPVDF) was confirmed by Fourier-transform infrared (FT-IR) and $^1H$ Nuclear magnetic resonance ($^1H$ NMR) analysis. For quantitative analysis of the chemical composition, the X-ray Photoelectron Spectroscopy (XPS) was used. The membrane properties such as water uptake, ion exchange capacity and electrical resistance were measured. It was suggested that the optimum direct sulfonation condition of PVDF-co-HFP ion exchange membranes was $60^{\circ}C$ and 7 hours for temperature and duration of sulfonation, respectively. The water uptake of the SPVDF ion exchange membrane was 21.5%. The ion exchange capacity and electrical resistance were 0.89 meq/g and $3.70{\Omega}{\cdot}cm^2$, respectively. It was investigated that if it is feasible to apply these membranes in MCDI at various cell potentials (0.9~1.5 V) and initial flow rates (10~40 mL/min). In the MCDI process, the maximum salt removal rate was 62.5% in repeated absorption-desorption cycles.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.05a
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• pp.88-90
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• 2003