• Journal of the Korean Electrochemical Society
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• v.7 no.4
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• pp.189-193
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• 2004

Lithium secondary battery with gel polymer electrolyte, which was composed of POAGA and TEGDMA, was prepared and its cell performances were evaluated. Collation time decreased with increasing the contents of the monomer in the POAGA-based gel polymer electrolyte. The polymer electrolyte was stable up to 4.5V electro-chemically and its ionic conductivity was $5.2\times10^{-3}Scm^{-1}$ at room temperature. The lithium-ion polymer battery with $3.0wt\%$ curable monomer and $1.0wt\%$ monomer showed rate-capability, low-temperature performance and cycleability.

• Elastomers and Composites
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• v.39 no.1
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• pp.36-41
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• 2004

Solid polymer electrolytes were prepared by UV irradiation of the blends consisting of poly(ethylene oxide)(PEO), epoxy diacrylate(EDA) and LiClO_4$. Conductivities of the electrolyte films were measured as a function or blend composition, salt concentration and temperature. The electrolyte having the composition of poly(ethylene oxide) (70% by weight)/epoxy diacrylate (30% by weight) with mole ratio of 10 of ethylene $oxide/Li^+$ exhibited a high ionic conductivity of $1.2{\times}10^{-5} S/cm$ at $25^{\circ}C$. This blend is transparent and shows elastomeric properties. Morphological studies by means of differential scanning calorimetry, X-ray diffraction and polarized optical microscopy indicated that the cured epoxy chains in the blends inhibit the crystallization of poly (ethylene oxide) and thereby induce the blend systems to be completely amorphous in certain compositions.

• Polymer(Korea)
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• v.37 no.4
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• pp.547-552
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• 2013

Polyimide (PI) containing carboxyl functional group was prepared and reacted with diaminosiloxane during high temperature film casting. The morphology of resulting film was observed by using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX), which revealed that globular 100 nm-sized PI domains and continuous polysiloxane phase were formed. X-ray photoelectron spectroscopy (XPS) study indicated that air-film interface mainly consisted of polysiloxane blocks. Poly(imidesiloxane) thin layer was thermostable until $400^{\circ}C$ and its pressure- sensitive adhesive property was retained up to $300^{\circ}C$. The comparative experiments revealed that grafting between carboxyl groups of polyimide and aminosiloxane was crucial for formation of microdomain structure and pressure-sensitive adhesive property.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.164-170
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• 2005

To improve functional properties of food proteins, homologous or heterologous ${\beta}-casein$ and 11S globulin(glycinin) from animal and vegetable proteins, respectively, were bio-hybridized using transglutaminase(MTGase). Susceptibility was confirmed by SDS-PAGE, particle size analyzed, and emulsion stability tested using Reddy and Fogler method, To determine how bio-hybridized protein influences emulsion stability, protein bound on oil droplet was investigated using Scanning Electron Microscopy (SEM). formation of bio-hybridized protein band was detected among homologous and heterologous proteins, with heterologous protein forming weak band in oligomer form. Homologous ${\beta}-casein$ protein showed high emulsion stability, while homologous glycinin showed almost no stability. Stability of heterologous ${\beta}-casein$ and glycinin protein was higher than that of glycinin. SEM photographs showed even distribution of bio-hybridized proteins on oil droplet improved stability.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.287-294
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• 2008

Molecularly imprinted polymer (MIPs) membranes were prepared by UV polymerization to separate racemates with opposite physiological activity, and then its separation selectivity of racemates was carried out. Likewise, their properties were examined. Polycarbonate (PC) membrane was polymerized as small spot form in pore inner wall, but anodisc (AD) membrane was polymerized as film form with thickness 500~700 nm onto the membrane surface. Also the study on the separation selectivity of prepared MIPs membranes was carried out in L-Tryptophane (Trp) racemate solution. The results showed that AD MIPs membrane polymerized as a film form, which was achieved by solution polymerizaion consisting of over 90% cross-linking agent (ethylene glycol dimethacrylate; EGDMA) and under 30% dispersing agent (methanol; MeOH), had predominant 3.5 selectivity.

• Polymer(Korea)
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• v.35 no.6
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• pp.586-592
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• 2011

In this study, we synthesized vinylbenzyl chloride-co-styrene-co hydroxyethyl acrylate (VBC-co-St-co-HEA) copolymer that can be applied to redox the flow battery process. The anion exchange membrane was prepared by the amination and crosslinking of VBC-co-St-co-HEA copolymer. The chemical structure and thermal properties of VBC-co-St-co-HEA copolymer and aminated VBC-co-St-co-HEA(AVSH) membrane were characterized by FTIR, $^1H$ NMR, TGA, and GPC analysis. The membrane properties such as ion exchange capacity(IEC), electrical resistance, ion conductivity and efficiency of all-vanadium redox flow battery were measured. The IEC value, electrical resistance, and ion conductivity were 1.17 meq/g, $1.9{\Omega}{\cdot}cm^2$, 0.009 S/cm, respectively. The charge-discharge efficiency, voltage efficiency and energy efficiency from all-vanadium redox flow battery test were 99.5, 72.6 and 72.1%, respectively.

• Elastomers and Composites
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• v.39 no.4
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• pp.286-293
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• 2004

Ester- and ether-based thermoplastic polyurethanes of different hardness were injection molded at different mold temperatures and effects of mold temperature on the physical properties of TPUs were investigated. Glass transition temperatures of soft segments of TPUs were hardly changed by mold temperatures. The phase separation of soft and hard segments of injection molded TPUs were affected little by mold temperatures. However, crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength of injection molded TPUs decreased with increasing mold temperatures for TPUs of high hardness. However, injection molded TPUs of low hardness showed increases of crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength with increasing mold temperatures. Different physical properties of injection molded TPUs depending on mold temperatures were attributed to different crystallization and physical crosslinking effects of hard segments.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.826-831
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• 2018

This study presents fabrication of bi-compartmental particles labeled by multiple fluorescence. To compartmentalize fluorescent expression at the particle, two fluorescent dyes with less overlap of the excitation and emission spectra are selected. To ensure the fluorescence stability, the fluorescent dyes contain acrylate functional groups in the molecules so that they can be cross-linked together with monomers constituting the particle. Strong fluorescent expression and compartmentalization were observed at the particle fabricated using the selected fluorescent dyes through confocal microscopy. Furthermore, long-term fluorescence stability was verified by measuring fluorescent expression and intensity for 4 weeks. We anticipate that the bi-compartmental particles labeled by multiple fluorescence can be widely used for multi-target drug delivery system, analysis of 3 dimensional Brownian motion, and investigation of 3 dimensional complex self-assembled morphologies.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.230-234
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• 2011

In this work, the primary material for a single layered hardmask which can afford a spin-on process was prepared by the minture of organic and inorganic sources. The preparation of hybrid polymer was attempted by esterification from silanol terminated siloxane compounds and acetonide-2,2-bis(methoxy)propionic acid. The optical, thermal and morphological properties of the test hardmask film was examined in terms of cross-linking agent and additives. In addition, the etch rate of hardmask film and photo resist layer were compared. The hybrid polymer prepared from organic and inorganic materials was found to be useful for hardmask film to form the nano-patterns.

• Journal of Radiation Industry
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• v.17 no.3
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• pp.225-232
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• 2023

In this study, poly(ethylene-co-vinyl acetate)/magnesium hydroxide (EVA/MDH) composites were prepared by electron beam crosslinking. EVA as a matrix resin and MDH as a flame retardant were melt-blended and compression molded to prepare EVA/MDH composites. The prepared EVA/MDH composites were electron beam-irradiated at various absorbed doses of 50~200kGy. The effects of electron beam irradiation on the gel content, tensile strength, elongation-at-break, thermal properties, and flame retardancy of the composites were investigated. The gel content and tensile strength increased, while the elongation-at-break decreased with an increase in the absorbed dose due to the formation of crosslinked network structures. In addition, the thermal stability and flame retardancy improved as the absorbed dose increased. Therefore, the EVA/MDH composites prepared in this study can be used as an insulation material for flame-retardant and heat-resistant wires and cables.