• 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.

• Polymer(Korea)
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• v.29 no.5
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• pp.463-467
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• 2005

In order to enhance the actuation force of ionic polymer-metal composite (IPMC) made with the acrylic copolymer of fluoroalkyl methacryate, acrylic acie, and 2-hydroxyethyl methacrylate(HEMA), the hydroxy group of HEMA was corsslinked with 1,3-diethoxy-1,1,3,3-tetramethyldisiloxane. The water uptake was reduced and the mechanical strengths and the actuation force of the membrane was improved by crosslinking. However, current and deformation responses of IPMC were decreased by crosslinking.

• Membrane Journal
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• v.30 no.5
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• pp.326-332
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• 2020

In this study, polymer-fluorinated silica composite hollow fiber membranes were fabricated and applied to a membrane contactor for the recovery of methane dissolved in the anaerobic effluent. To prepare the composite membranes, porous hollow fiber substrates were fabricated with Ultem^®, a commercial polyetherimide (PEI). Subsequently, fluorinated silica particles were synthesized and coated on the surface via strong covalent bonding. Due to the high porosity, our membrane showed a CH₄ flux of 8.25 × 10^-5 ㎤ (STP)/㎠·s at the liquid velocity of 0.03 m/s which is much higher that that of commercial polypropylene membrane designed for degassing processes. This is attributed to our membrane's high porosity as well as a superior surface hydrophobicity (120~122°) resulted from the coating with fluorinated silica nanoparticles.

• Polymer(Korea)
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• v.34 no.5
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• pp.464-468
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• 2010

In this study, a vinylbenzyl chloride (VBC) monomer was successfully grafted onto the several fluoropolymer films including poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP), poly(tetrafluoroethylene-co-perfluoropropylvinyl ether) (PFA), and poly(ethylene-co-tetrafluoroethylene) (ETFE) films by using a simultaneous irradiation method. The results indicated that PVBC graft polymer can be easily grafted onto the ETFE film than other fluorinated films under the same irradiation condition. The grafted films were characterized by using FTIR, TGA, and SEM-EDS instruments. The elongation at the breaking of the grafted films was found to decrease with an increase of degree of grafting (DOG). The PVBC-grafted ETFE films were found to have better mechanical properties than other PVBC-grafted fluorinated films.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.231-237
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• 2014

The supercritical fluids (SCFs) have been widely used for material synthesis and processing due to their remarkable properties including low viscosity, high diffusivity and low surface tension. Carbon dioxide is one of the suitable solvents in SCFs processes in terms of its advantages such as easy processibility (with low critical temperature and pressure), inexpensive, nonflammable, nontoxic, and readily available. However, it has generally low solubility for high molecular weight polymers with the exception of fluoropolymers and siloxane polymers. Therefore, hydrocarbon solvents and hydrochlorofluorocarbons have been used for various SCFs process by its high solubility for high molecular weight polymers. In this report, a PMMA/clay nanocomposites were fabricated by using supercritical fluid process. The $Na^+$-MMT(montmorillonites)was modified by a fluorinated surfactant which is able to enhance compatibility with the chlorodifluoromethane(HCFC-22) and thus, improve dispersability of the clay in the polymer matrix. The PMMA/fluorinated surfactant modified clay nanocomposite shows enhanced mechanical and thermal properties which characterized by X-raydiffraction(XRD), Thermo gravimetric analysis(TGA), Dynamic mechanical analysis (DMA) and Transmission electron microscopy (TEM).

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.40-43
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• 2008

High temperature polymer electrolyte membranes incorporating ionic liquids (ILs) in different polymers such as commercial fluorinated polymers, sulfonated polymers and recasted nafion have been developed. ILs based on imidazolium cation and different anions possess high ionic conductivity and good thermal stability and have been used in the present study. The membranes containing IL show conductivity ${\sim}10^{-2}S\;cm^{-1}$ above $100^{\circ}C$ under anhydrous conditions and are thermally stable up to $250-300^{\circ}C$. IL acts as a conducting medium in these electrolytes and plays the same role as played by water in fully hydrated nafion membranes. Due to high conductivity and good thermal stability, these membranes are promising materials for PEFCs at higher temperatures under anhydrous conditions.

• Proceedings of the Membrane Society of Korea Conference
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• 2005.11a
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• pp.187-191
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• 2005

• Polymer(Korea)
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• v.29 no.5
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• pp.433-439
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• 2005

The copolymers were prepared by the emulsion copolymerization of fluoroalky lacrylate-stearylacrylate-m-isopropenyl-${\alpha},\;{\alpha}'$-dimethylbenzyl isocyanate (TMI) in order to obtain water repellent polymers. The respective copolymerization rates of the three monomers considerably depended upon the use of the nonionic emulsifier and the nonionic-cationic mixed emusifier, and the optimum conditions were obtained. The particle sizes of the copolymers were in the range of 105 to 222nm. The particle sizes of the copolymers prepared by the use of the mixed emulsifiers were smaller than those of the copolymers prepared by the use of the nonionic emulsifier. The reactions of both TMI-N-methyl acetamide and TMI-cellobiose did not take place. However, the reaction of TMI-n-butylamine occurred. The water contact angles before and after washing three times for nylon and poly(ethylene terephthalate) (PET) fabrics coated with the copolymer prepared by the use of mixed emulsifier were about $139^{\circ}\;and\;133^{\circ}$ Therefore, the copolymer showed good durable repellency for nylon and PET.

• Membrane Journal
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• v.25 no.5
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• pp.447-455
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• 2015

In this study, Polysulfone (PSf) and polyetherimide (PEI) as the anion exchange polymers were aminated in the different ratio whereas the polyether ether ketone (PEEK) as the cation exchange polymer was sulfonated. The bipolar membranes of SPEEK (sulfonated PEEK)/APSf (aminated PSf) and SPEEK/APEI (aminated PEI) were prepared by the double-casting method. The surfaces of bipolar membranes were fluorinated in accordance with the amination ratio and applied to produce the hypochlorite. As the amination increased, the hypochlorite concentration is also increased. Typically, for SPEEK/APSf 3 : 1 membrane, the produced hypochlorite concentration was 61.0 ppm and its durability was 220 min for the non-fluorinated membrane while for the fluorinated membrane, the concentration of 58.6 ppm and its durability lasted 570 min. Also for SPEEK/APEI 3 : 1 membrane, the hypochlorite concentrations of 60.1 ppm and 58.3 ppm for before- and after-fluorination, respectively were observed whereas the durability was remarkably developed from 150 min to 440 min. Therefore, the surface fluorination takes an important role for the development of the membrane durability.

• Polymer(Korea)
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• v.25 no.1
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• pp.33-40
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• 2001

Fluorinated polyurethane elastomers were synthesized by two step polyaddition of a perfluorinated polyether diol(trade name of Fomblin $ZDOL^{\circledR}$) and diisocyanates such as 4,4'-diphenyl methane diisocyanate(MDI) and toluene 2,4-diisocyanate(TDI). In order to control the Fomblin moiety of the soft segment in the synthesized elastomers to 10~50%, polyether type polyols such as polypropylene glycol(PPG) and polytetramethylene glycol(PTMG) were mixed during the polymerization reaction. Ethylene diamine or 1,4-butane diol was used as chain extenders. The structure and average molecular weight of the produced polyurethanes were confirmed by using FT-IR, $^1H-NMR$, DSC, and GPC. The surface properties were analyzed by using X-ray photoelectron spectroscopy(XPS) and contact angle meter. From the results of the surface analysis it was concluded that the fluorine groups were localized on the surface rather than the inside of the polyurethane films.