• Journal of Microbiology and Biotechnology
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• v.21 no.10
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• pp.1036-1042
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• 2011

The exopolysaccharide botryosphaeran ($EPS_{GLC}$; a ($1{\rightarrow}3$)($1{\rightarrow}6$)-${\beta}$-D-glucan from Botryosphaeria rhodina MAMB-05) was sulfonated to produce a water-soluble fraction ($EPS_{GLC}$-S) using pyridine and chlorosulfonic acid in formamid. This procedure was then repeated twice to produce another fraction ($EPS_{GLC}$-RS) with a higher degree of substitution (DS, 1.64). The purity of each botryosphaeran sample (unsulfonated and sulfonated) was assessed by gel filtration chromatography (Sepharose CL-4B), where each polysaccharide was eluted as a single symmetrical peak. The structures of the sulfonated and re-sulfonated botryosphaerans were investigated using ultraviolet-visible (UV-Vis), Fourier-transform infrared (FT-IR), and $^{13}C$ nuclear magnetic resonance ($^{13}C$ NMR) spectroscopies. $EPS_{GLC}$ and $EPS_{GLC}$-RS were also assayed for anticoagulation activity, and $EPS_{GLC}$-RS was identified as an anticoagulant.

• Journal of Hydrogen and New Energy
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• v.18 no.4
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• pp.391-398
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• 2007

The covalently cross-linked sulfonated polyetheretherketone (CL-SPEEK) membrane was prepared by four-step synthesis of sulfonation-sulfochlorination, partial reduction, lithiation, and cross-linking, and its electrochemical and mechanical properties were investigated for water electrolysis application. The prepared ion exchange membranes showed good electrochemical and mechanical properties; proton conductivity of 0.116 S/cm at $80^{\circ}C$, water uptake of 44.6%, ion exchange capacity of 1.75 meq/g-dry-memb., tensile strength of 64.25 MPa and elongation of 61.11%. The membrane electrode assembly (MEA) with homemade membranes were prepared by non-equilibrium impregnation-reduction (I-R) method. Especially, the electrochemical surface area (ESA) and roughness factor of CL-SPEEK electrolyte by cyclic voltammetry method were 23.46 $m^2/g$ and 307.3 $cm^2-Pt/cm^2$, respectively. The prepared MEA was used in the unit cell of water electrolysis and the cell voltage was 1.81 V at 1 A/$cm^2$ and $80^{\circ}C$, with platinum loadings of 1.31 mg/$cm^2$.

• Journal of Hydrogen and New Energy
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• v.26 no.3
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• pp.212-220
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• 2015

The engineering plastic of sulfonated polyether ether ketone (SPEEK) as a polymer matrix has been developed in this lab to replace Nafion, solid polymer electrolytes of perfluorosulfonic acid membrane which has several flaws such as high cost, and limited operational temperature above $80^{\circ}C$. The SPEEK was prepared in the sulfonation reaction of polyether ether ketone (PEEK). The organic-inorganic blended composite membranes were prepared by sol-gel casting method with loading the highly dispersed ceria and cesium-substituted tungstosilicic acid (Cs-TSiA) with cross-linking agent contents of 0.01 mL. In conclusion, CL-SPEEK/Cs-TSiA/ceria 1% membrane showed the optimum results such as 0.1882 S/cm of proton conductivity at $80^{\circ}C$, and 99.61 MPa of tensile strength which were better than Nafion 117 membrane.

• Membrane Journal
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• v.24 no.4
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• pp.292-300
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• 2014

Chlorine-resistant sulfonated poly(arylene ether sulfone) random copolymer (SPAES)-thin film composite (TFC) membranes for desalination are prepared using monoglyme as a selective solvent, which dissolves SPAES, but should be inert to porous polysulfone layer (e.g., Udel$^{(R)}$). Different from formic acid and diethylene glycol used as other selective solvents, monoglyme is environmentally friendly and has much lower boiling temperature. After a pretreatment of Udel$^{(R)}$ support film in isopropyl alcohol-glycerine mixture to minimize pore penetration leading to fairly reduced water flux, coating of SPAES solution in monoglyme onto the support and stepwise drying processes are conducted for defect-free TFC formation. The transport behavior through SPAES-TFC membranes is observed, correlating with the effects of sulfonation level, protonation, and physical and chemical crosslinking of SPAES selective layers.

• Polymer(Korea)
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• v.30 no.6
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• pp.486-491
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• 2006

Heterogeneous membranes were prepared by compression molding for the recovery of ammonium ion from waste water. Degree of sulfonation for sulfonated ion exchange resin increased with increasing amount of chlorosulfonic acid. It was 3.32 meq/g at 10 vol%. The tensile strength and elongation of the heterogeneous membrane was decreased with increasing contents of ion exchange resin. The tensile strength for LLDPE matrix membrane was the highest and also the elongation for EVA matrix membranes were the highest. The water content of heterogeneous membrane was increased with increasing contents of ion exchange resin. The maximum value of transport number for PE matrix membrane was 0.973. The electrical resistance of LLDPE matrix membrane was the lowest. It was value of $10.36{\Omega}/cm^2$ at 70 wt% resins.

• Membrane Journal
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• v.22 no.3
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• pp.191-200
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• 2012

New composite membranes were manufactured by impregnating post-sulfonated poly(arylene ether sulfone)s containing perfluorocyclobutane (PFCB) groups into porous polytetrafluoroethylene (PTFE) films. Two kinds of post-sulfonated poly(arylene ether sulfone)s with two different monomer ratios (sulfonable biphenylene monomer : non-sulfonable sulfonyl monomer = 6 : 4, 4 : 6) were first prepared through three synthetic steps: synthesis of trifluorovinylether-terminated monomers, thermal cycloaddition polymerization and post-sulfonation using chlorosulfonic acid (CSA). The composite membranes were then prepared by adjusting the concentrations (5~20 wt%) of the resulting copolymers impregnated in the PTFE films. The water uptake, ion exchange capacity (IEC) and ion conductivity of the composite membranes were characterized and compared with their unreinforced dense membranes and Nafion. All the synthesized compounds, monomers and polymers were characterized by $^1H$-NMR, $^{19}F$-NMR and FT-IR and the composite membranes were observed with scanning electron micrographs (SEM).

• Journal of the Korean Electrochemical Society
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• v.7 no.2
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• pp.89-93
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• 2004

Sulfonated polysulfone (SPSF) with poly(phenylmethyl silsesquioxane, PPSQ) composite polymer electrolyte membranes were prepared and their proton conductivity, water uptake and methanol permeability of membranes were characterized. By controlling the ratio of $(CH_3)_3SCI\;and\;CISO_3H$ and reaction time, SPSF with $37\~75\%$ degree of sulfonation were synthesized. The increase of sulfonate groups in the base polymer resulted in the increase of the water uptake in the membranes as well as methanol permeability. Composite membranes were prepared by casting of DMF solution of SPSF and PPSQ. The proton conductivity of the composite membrane at room temperature was $2.8\times10^{-3}\~4.9\times10^{-2}S/cm.$ The increase of PPSQ contents in composite membranes resulted in a decrease in water uptake and methanol permeability. Composite membranes containing $5\%$ PPSQ did not make a significant effect on the proton conductivity nO methanol permeability compared with that of pristine SPSF, but a significant decrease of water uptake was observed.

• Journal of Hydrogen and New Energy
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• v.25 no.1
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• pp.1-10
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• 2014

Ceria ($CeO_2$) was used to scavenge free radicals which attack the membrane in the polymer electrolyte membrane water electrolysis (PEMWE) circumstance and to increase the duration of the membrane. In order to improve the electrochemical, mechanical and electrocatalytic characteristics, engineering plastic of the sulfonated polyether ether ketone (SPEEK) as polymer matrix was prepared in the sulfonation reaction of polyether ether ketone (PEEK) and the organic-inorganic blended composite membranes were prepared by sol-gel casting method with loading the highly dispersed ceria and cesium-substituted phophomolybdic acid(Cs-MoPA) with cross-linking agent contents of 0.01mL. In conclusion, CL-SPEEK/$Cs_{(2.5)}$-MoPA/ceria(1%) membrane showed the optimum results such as 0.1095S/cm of proton conductivity at $80^{\circ}C$, 2.906meq./g-dry-membrane of ion exchange capacity and mechanical characteristics, and 49.73MPa of tensile strength which were better than Nafion 117 membrane.

• Journal of Hydrogen and New Energy
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• v.22 no.5
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• pp.579-584
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• 2011

Sulfonated poly (ether sulfone)s containing BFBN were prepared from 2,3-bis(4-fluorophenyl)-2-butenedinitrile , 4,4-sulfonyldiphenol and sulfonated 4,4'-difluorodiphenylsulfone sodium salt using potassium carbonate, and followed acidification reaction with 1M $H_2SO_4$. BFBN was prepared from 4-fluorobenzylcyanide, $CCl_4$, NaOH using trimethylbenzylammoniumchloride . Sulfonated poly(ether sulfone)s containing BFBN were studied by FT-IR, $^1H$-NMR spectroscopy, and thermo gravimetric analysis (TGA). The water uptake of synthesized S-PBFBN membranes exhibit 31~62% compared with 28% of Nafion 211. The S-PBFBN membranes exhibit proton conductivities ($80^{\circ}C$, RH 100) of 53.8~117.4 mS/cm compared with 137.4 mS/cm of Nafion 211.

• Journal of Hydrogen and New Energy
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• v.23 no.5
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• pp.437-447
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• 2012

Ceria ($CeO_2$) was used to scavenge free radicals which attack the membrane in the polymer electrolyte membrane water electrolysis (PEMWE) circumstance and to increase the duration of the membrane. In order to improve the electrochemical, mechanical and electrocatalytic characteristics, engineering plastic of the sulfonated polyether ether ketone (SPEEK) as polymer matrix was prepared in the sulfonation reaction of polyether ether ketone (PEEK) and the organic-inorganic blended composite membranes were prepared by sol-gel casting method with loading the highly dispersed ceria and cesium-substituted tungstophosphoric acid (Cs-TPA) with cross-linking agent contents of 0.01 mL. In conclusion, CL-SPEEK/Cs-TPA/ceria (1%) membrane showed the optimum results such as 0.130 S/cm of proton conductivity at $80^{\circ}C$, 2.324 meq./g-dry-membrane of ion exchange capacity and mechanical characteristics, and 65.03 MPa of tensile strength which were better than Nafion 117 membrane.