• Textile Coloration and Finishing
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• v.3 no.4
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• pp.22-28
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• 1991

Perfluoropropene was plasma polymerized in the form of thin film on PET fabrics to give hydrophobic and barrier properties without affecting air permeability. Changes in surface characteristics were detected by application of ESCA, IR, SEM and contact anglemeter. The surface properties was changed markedly to be water and stain repellent although the effect was not much sensitive to the differences of chemical components of the thin films formed at different experimental conditions. The protective barrier characteristics of the thin film was also applicable to suppress the amounts of dyes extracted from fabrics in laundering.

• Membrane and Water Treatment
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• v.8 no.5
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• pp.463-481
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• 2017

Bacteria have been considered as a major foulant that initiates the formation of biofilm on the polymeric membrane surface. Some polymeric membranes are naturally antibacterial and have low fouling properties, however, numerous efforts have been devoted to improve their antibacterial performance. These modifications are mostly carried out through blending the membrane with an antibacterial agent or introducing the antibacterial agent on the membrane surface by chemical grafting. Currently, a significant number of researches have reported nanocomposite membrane as a new approach to fabricate an excellent antibacterial membrane. The antibacterial nanoparticles are dispersed homogenously in membrane structure by blending method or coating onto the membrane surface. Aim of the modifications is to prevent the initial attachment of bacteria to membrane surface and kill bacteria when attached on the membrane surface. In this paper, several studies on antibacterial modified membranes, particularly for water treatment, will be reviewed comprehensively. Special attention will be given on polymeric membrane modifications by introducing antibacterial agents through different methods, such as blending, grafting, and coating.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1628-1632
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• 2010

Porous ${\eta}-Al_2O_3$ was synthesized by modified sol-gel method using ionic liquid as a templating material. The addition of ionic liquid assisted to increase the surface area of alumina. However, the acidity of aluminas prepared with ionic liquids was hardly affected regardless the change of its structural properties. Among the ionic liquids used in this study, 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][$PF_6$]) was the most effective ionic liquid to produce porous ${\eta}-Al_2O_3$ particles. The catalytic performance of these aluminas has been investigated in dehydration of methanol to produce dimethyl ether. The alumina prepared with [Bmim][$PF_6$] outperformed the other aluminas except ${\eta}-Al_2O_3$ without modification in this reaction.

• Carbon letters
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• v.16 no.1
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• pp.34-40
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• 2015

In this study, in order to improve the thermal and electrical properties of epoxy/graphene nanoplatelets (GNPs), surface modifications of GNPs are conducted using silane coupling agents. Three silane coupling agents, i.e. 2-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane (ETMOS), 3-glycidoxypropyltriethoxysilane (GPTS), and 3-glycidoxypropyltrimethoxysilane (GPTMS), were used. Among theses, GPTMS exhibits the best modification performance for fabricating GNP-incorporated epoxy composites. The effect of the silanization is evaluated using transmission electron microscopy (TEM), scanning electron microscopy, thermogravimetric analysis, and energy dispersive X-ray spectroscopy. The electrical and thermal conductivities are characterized. The epoxy/silanized GNPs exhibits higher thermal and electrical properties than the epoxy/raw GNPs due to the improved dispersion state of the GNPs in the epoxy matrix. The TEM microphotographs and Turbiscan data demonstrate that the silane molecules grafted onto the GNP surface improve the GNP dispersion in the epoxy.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.103-105
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• 2003

A chiral stationary phase (CSP) was synthesized by the modification of the chitosan using N-nicotinoyl phenylalanine and 3, 5-dimethylphenylisocyanate . The CSP based on the chitosan was then characterized in terms of their chemical structure and physical properties. To test its performance as a CSP, the silica powder with 5 ${\mu}{\textrm}{m}$ of diameter were coated with the CSP to pack a column for High Performance Liquid Chromatograph (HPLC). Using the packed column, several racemates were tried to separate under various separation conditions with different compositions of eluents.

• Nuclear Engineering and Technology
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• v.29 no.1
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• pp.58-67
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• 1997

A numerical study has been peformed to investigate the flow and mixing characteristics of a chemical injection tank in the chemical and volume control system (CVCS) of Yonggwang 5&6 (YGN 5&6). This study was undertaken to provide a basis for modification of the previous design (YGN 3&4) which gave a lot of difficulties in installation and operation of the chemical injection system during the start-up test because it needs a special reciprocating pump with a high actual head. For the tank of length-to-diameter ratios (L/D) of 1,2 and 3, each with and without a baffle inside, calculation results were obtained by solving the unsteady laminar two-dimensional elliptic forms of governing equations for the mass, momentum and species concentration. Finite-difference method was used to obtain discretized equations, and the SIMPLER solution algorithm, which was developed based on the staggered grid control volume, was employed for the calculation procedure. Results showed that the baffle is very effective in enhancing the mixing in the tank and that a baffle should be installed near the tank entrance in order to 110 chemicals into the reactor coolant system (RCS) within the operating time required.

• Journal of the Korean Wood Science and Technology
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• v.10 no.4
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• pp.38-52
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• 1982

The effect of propylene oxide, butylene oxide, furan resin, and vinylpyrrolidinone in controlling wood dimensional stability have been examined. Wood in the green or ovendry condition was treated with various chemical treatments using a vacuum-pressure procedure, and treated specimens were tested for tangential sweelling, moisture gain, and changes in sorption hysteresis. Results' indicate that propylene oxide, and butylene oxide enhanced with the crosslin king agent trimethylol propane trimethacrylate and applied to ovendry wood were the most efficient chemical treatments in controlling tangential sweeling caused by liquid water or water vapor, and in reducing water vapor adsorption. The sorption behavior of treated wood as depicted by the ratios of sorption was "very favorable" in most instances. In the particular case of furan resin treatments, ratios of sorption were improved from 25 to 100 percent as compared to those of untreated wood.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.365-382
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• 2023

A lithium metal anode with high energy density has the potential to revolutionize the field of energy storage systems (ESS) and electric vehicles (EVs) that utilize rechargeable lithium-based batteries. However, the formation of lithium dendrites during cycling reduces the performance of the battery while posing a significant safety risk. In this review, we discuss various strategies for achieving dendrite-free lithium metal anodes, including electrode surface modification, the use of electrolyte additives, and the implementation of protective layers. We analyze the advantages and limitations of each strategy, and provide a critical evaluation of the current state of the art. We also highlight the challenges and opportunities for further research and development in this field. This review aims to provide a comprehensive overview of the different approaches to achieving dendrite-free lithium metal anodes, and to guide future research toward the development of safer and more efficient lithium metal anodes.

• Polymer(Korea)
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• v.30 no.2
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• pp.140-145
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• 2006

The mort commonly available substrate material is glass in the display fibrication process. However, glass is not desirable due to its heaviness and fragility. Recently, plastics such polysulfone (PSF), polyethesulfone (PES), polycarbonate (PC), polyethylene terephthalate (PET) and cyclic olefin polymers (COP) have been investigated to replace glass as a substrate material for display fibrication. Plastic substrates are advantageous in that they are lightweight, huh impart resistance, flexibility, and ability for roll to roll manufacturing process. But many plastics have poor chemical resistance in organic solvent. The chemica resistance is also lequired because they are exposed to solvents for various chemical treatments din the manufacturing process. So, we have an interest in the chemical modification of PSF to improve chemical resistance. We introduced crosslinkable imide moieties using chloromethylation method for the modification of PSF which could be overcome above shortcomings for display substrate based on plastic film. We prepared the cross-linked polysulfone films which were represented chemical resistance in HeOH, THF, DMSO and NMP. The thermal properties were measured by TGA, DSC and TMA. As the results, we have confirmed to enhance of the thermal property. They had low coefficient of thermal expansion (CTE) which decreased to 15% and had increased $T_g\;from\;180^{\circ}C\;to\;252^{\circ}C$. Cross-linked polysulfone films with imide side-chain had good optical properties and chemical resistance so that they could be used as flexible display substrate.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.175-186
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• 2018

Carbon nanomaterials (CNMs), particularly carbon nanotube and graphene-based materials, are rapidly emerging as one of the most effective adsorbents for wastewater treatment. CNMs hold great potential as new generation adsorbents due to their high surface to volume ratio, as well as extraordinary chemical, mechanical and thermal stabilities. However, implementation of pristine CNMs in real world applications are still hindered due to their poor solubility in most solvents. Hence, surface modification of CNMs is essential for wastewater treatment application in order to improve its solubility, chemical stability, fouling resistance and efficiency. Numerous studies have reported the applications of functionalized CNMs as very promising adsorbents for treating organic and inorganic wastewater pollutants. In this paper, the removal of organic dye and phenol contaminants from wastewater using various type of functionalized CNMs are highlighted and summarized. Challenges and future opportunities for application of these CNMs as adsorbents in sustainable wastewater treatment are also addressed in this paper.