• Bulletin of the Korean Chemical Society
• /
• v.34 no.6
• /
• pp.1763-1770
• /
• 2013

A series of the block copolymers were successfully synthesized from post-sulfonated hydrophilic and hydrophobic macromers via three-step copolymerization. The degrees of sulfonation (DS) of the copolymers (10%, 30%, or 50%) were controlled by changing the molar ratio of the hydrophilic and hydrophobic parts. The resulting block copolymers were characterized by $^1H$ NMR and other technologies. The membranes were successfully cast using dimethyl sulfoxide (DMSO) solution at $100^{\circ}C$. The copolymers were characterized to confirm chemical structure by $^1H$ NMR and FT-IR. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrated that all sulfonated block copolymers exhibited good thermal stability with an initial weight loss at temperatures above $240^{\circ}C$. The membranes showed acceptable ion exchange capacity (IEC) and water uptake values in accordance with DS. The maximum proton conductivity was 184 mS $cm^{-1}$ in block copolymer-50 at $60^{\circ}C$ and 100% relative humidity, while the conductivity of Nifion-115 was 160 mS $cm^{-1}$ under the same measurement conditions. AFM images of the block copolymer membranes showed well separated the hydrophilic and hydrophobic domains. From the observed results it is that the prepared block membranes can be considered as suitable polymer electrolyte membranes for the application of polymer electrolyte membrane fuel cells (PEMFC).

• Polymer(Korea)
• /
• v.25 no.1
• /
• pp.49-55
• /
• 2001

The bi-functional ion exchangers, SAPP-g-(AN/St) were synthesized with mixed vinyl monomers(acrylonitrile and styrene) onto PP fabric by the pre-irradiation grafting with E-beam and its subsequent amidoximination and sulfonation. The degree of grafting of PP-g-(AN/St) was increased with decreasing acrylonitrile composition in the mixed monomers. The water uptake of copolymers increased with decreasing in the amidoxime ratio in the copolymers and increased by sulfonation, but decreased by amidoximation. The $UO_2^{2+}$ adsorption capacity of SPP-g-St, APP-g-AN, and SAPP-g-(AN/St) were 12.4, 34.0, and 38.0 mg/g, respectively and the optimum adsorption time is about 50 hrs. As a result of uranium adsorption, the synthesized ion exchanger, which we obtained have also good affinity toward the adsorption or chelating with $UO_2^{2+}$ ions.

• Membrane Journal
• /
• v.21 no.3
• /
• pp.270-276
• /
• 2011

A nascent membrane was prepared by using the solution evaporation method with a solution of sPEEK, EdAn (cross-linking reagent), and PEA (grafting reagent) in DMAc. Then, after the imination and sulfonation process the cross-linked and grafted ion-exchange membrane, CG-sPEEK, was obtained. The sulfonation and imination reactions were confirmed by FTIR analysis. In order to evaluate the possibility of prepared membrane for the use of an ion-exchange membrane in PEMFC, proton conductivity, water uptake and volume change were measured and compared with a commercial membrane, Nafion 115. It was revealed that since the proton conductivity (0.17 S/cm) of prepared membrane were much higher than those of Nafion 115 (0.10 S/cm) the prepared membrane could be used for the ion-exchange membrane in PEMFC. However, the high water uptake (130%) of CG-sPEEK should be reduced for the dimension stability.

• Applied Chemistry for Engineering
• /
• v.9 no.4
• /
• pp.595-602
• /
• 1998

${\alpha}$-sulfonated fatty acid methyl esters[$C_mH_{2m+1}CH(SO_3Na)COOC_nH_{2n+1}$], where hydrophobic group has carbon number of 12~18, were prepard by sulfonation of fatty acid methylester. The mole ratio of $SO_3$ to ester used was 1.3 and the reaction temperature was $70{\sim}90^{\circ}C$. The yield was found to be 97% by mixed gas reaction of inactive gas/gaseous $SO_3$. Studies on bleaching and neutralization processes in the pilot scale provided conditions applicable to industrial synthesis process.

• Journal of Hydrogen and New Energy
• /
• v.23 no.5
• /
• pp.461-467
• /
• 2012

Multi-block sulfonated poly (arylene ether sulfone) (SPES) membranes were synthesized by post-sulfonation and its properties characterized. Two types of oligomers, F-terminated and OH-terminated telechelic oligomers, were synthesized by controlling the feed ratio of dihydroxyl- and difluoro-monomers. Their number of repeating unit (X and Y) was analyzed by GPC and $^1H$ NMR. Copolymerization with F-terminated and OH-terminated telechelic oligomers via nucleophilic aromatic substitution, gave high-molecular-weight multi-block PESs. Each block length was controlled to have different values with X5Y10, X10Y10, X20Y10 and X20Y20. Successful polymerization and its successful sulfonation was confirmed by GPC and $^1H$ NMR. RH dependence of proton conductivity of multi-block SPES membranes was comparable to that of Nafion 212 at high RH conditions.

• Analytical Science and Technology
• /
• v.17 no.1
• /
• pp.60-68
• /
• 2004

The core-shell polyolefin nonwovon fabric (PNF), wherein the PNF comprises at least about 60% of polyethylene having a melting temperature at ${\sim}132^{\circ}C$ and no more than about 40% of second polypropylene having a lower melting temperature at ${\sim}162^{\circ}C$. The sulfonic acid group for battery separators were prepared by radiation-induced grafting of styrene onto PNF and by the subsequent sulfonation of polystyrene graft chains. The sulfonated PNF was characterized by XPS, SEM, DSC, TGA and porosimeter. The electrochemical properties such as electrolyte retension, electrical resistance, and transport number of the $K^+ions$ were evaluated after sulfonation. It was found that the electrolyte retension increased, whereas the electrical resistance decreased with increasing sulfonic acid content. The transport number of $K^+$ in PNF with sulfonic acid of 0.22 ~ 3.60 mmol/g was to be 0.90 ~ 0.93.

• Journal of Adhesion and Interface
• /
• v.15 no.1
• /
• pp.1-8
• /
• 2014

Ion exchange membrane is widely used in various fields such as electro dialysis, diffusion dialysis, redox flow battery, fuel cell. PVC cation exchange membrane using ultrasonic modification was prepared by sulfonation reaction in various sulfonation times. Sulfuric acid was used as a sulfonating agent with ultrasonic condition. We've characterized basic structure of sulfonated PVC cation exchange membrane by FT-IR, EDX, water uptake, ion exchange capacity (IEC), electrical resistance (ER), conductivity, ion transport number and surface morphology (SEM). The presence of sulfonic groups in the sulfonated PVC cation exchange membrane was confirmed by FT-IR. The maximum values of water uptake, IEC, electrical resistance and ion transport number were 40.2%, 0.87 meq/g, $35.2{\Omega}{\cdot}cm^2$ and 0.88, respectively.

• Polymer(Korea)
• /
• v.34 no.2
• /
• pp.137-143
• /
• 2010

A series of partially fluorinated, sulfonated poly(biphenylene-co-sulfone)ether containing perfluorocyclobutane(PFCB) groups were prepared for fuel cell applications through three synthetic steps: synthesis of trifluorovinylether-terminated monomers, thermal cycloaddition and post-sulfonation. Two kinds of trifluorovinylether-terminated monomers were synthesized and statistically copolymerized via thermal cycloaddition to obtain a series of polymers containing 20-60 mol% of biphenyl units(PBS-X). The post-sulfonation of PBS-X was carried out using chlorosulfonic acid(CSA) to obtain copolymers with various sulfonation levels(SPBS-X). All the synthesized compounds, monomers and polymers were characterized by $^1H$-NMR, $^{19}F$-NMR and FT-IR. It was confirmed that the ion exchange capacity(IEC), water uptake and ion conductivity of SPBS-X increased with the increment of sulfonated biphenyl units. Particularly, SPBS-60 showed higher ion conductivity compared to Nafion$^{(R)}$-115 at 25~80 $^{\circ}C$.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2008.05a
• /
• pp.162-162
• /
• 2008

• Membrane Journal
• /
• v.10 no.2
• /
• pp.66-74
• /
• 2000

In consideration that a high tensile strength and ion exchange capacity are maintained as the swelling of membrane is controlled by the coagulation of PSf with the introduction of ion exchange groups and PPSS without the introduction of ion exchange groups, the block copolymer of PSf and PPSS were synthesized. The cation exchange membrane was prepared by sulfonation with CSA and casted. The synthesized block copolymer and cation exchange membrane were characterized by FT-IR and their thermal stability was confirmed by TGA. The optimum sulfonation could be accomplished at a mole ratio of BPSf to CSA 1:3. The best electrochemical properties obtained by the optimal condition were area resistance of 4.37 $\Omega$ㆍ$\textrm{cm}^2$, ion exchange capacity of 1.71 meq/g dry membrane, water content of 0.2941 g $H_2O$/g dry membrane, and fixed ion concentration of 5.81 meq/g $H_2O$. When GBL was used as an additive, area resistance was increased by 13.7 % and ion exchange capacity was increased by 14.6%. When the membrane was fabricated in a form of composite using non woven cloth as a support. the tensile strength of membrane could be improved, but the electrochemical characteristics were not influenced.