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Pohang, South Korea

Jo E.,Chonnam National University | Yeo J.-G.,Korea Institute of Energy Research | Kim D.K.,Korea Institute of Energy Research | Oh J.S.,Materials Development Center | Hong C.K.,Chonnam National University
Polymer International | Year: 2014

The pore size of carbon nanofiber materials was controlled by using the difference between the solubility parameters in binary polymer blends. The prepared carbon nanofiber webs with controlled meso-sized pores showed significantly improved electrochemical properties, and are applicable as electrode materials in energy storage systems. The relationships between the compatibility in binary polymer blends and the pore sizes of carbon nanofibers (CNFs) prepared from the blends were investigated. Compatibility was determined by the difference between the solubility parameters of each polymer in the polymer blends. Porous CNFs were prepared by an electrospinning and carbonization process using binary polymer blends, consisting of polyacrylonitrile (PAN) as the carbonizing polymer and poly(acrylic acid) (PAA), poly(ethylene glycol), poly(methyl methacrylate) or polystyrene (PS) as the pyrolyzing polymer. The pore size of the CNFs increased with increasing difference in solubility parameter. The CNFs prepared using the PAN/PAA blend, which had the smallest solubility parameter difference, exhibited a pore size of 1.66 nm compared to 18.24 nm for the CNFs prepared using the PAN/PS blend. The prepared CNF webs with controlled meso-sized pores showed a stable cycle performance in cyclic voltammetry measurements and improved impedance characteristics. This method focusing on the compatibility in polymer blends was simple to apply and effective for controlling the pore sizes and surface area of CNFs for application as electrode materials in energy storage systems. © 2013 Society of Chemical Industry. Source

Kim Y.E.,Korea Institute of Energy Research | Moon S.J.,Korea Institute of Energy Research | Yoon Y.I.,Korea Institute of Energy Research | Jeong S.K.,Korea Institute of Energy Research | And 3 more authors.
Separation and Purification Technology | Year: 2014

Abstract This study investigated the characteristics of polyamines that have two or more amino groups in their structure. They are expected to show better performance than existing absorbents due to the increased number of amino groups that can react with CO2. A semi-batch type apparatus was used to measure the absorption capacity of CO2 at the temperature range of 313-353 K. The quantity of heat generated by the absorption of CO2 in the absorbents was measured with a differential reaction calorimeter (DRC) for comparison with those of aqueous solutions of MEA and DEA at 298 K. The absorbents were evaluated from the aspects of the absorption capacity of CO 2 and heat of absorption, and the characteristics according to the increasing number of amino groups were considered. © 2013 Published by Elsevier B.V. Source

Jang K.H.,Materials Development Center | Kim E.-S.,Inha University | Jeon Y.H.,Inha University | Yoon J.-S.,Inha University
Journal of Polymer Engineering | Year: 2012

Na+ montmorillonite (MMT) was modified with benzyldimethyltetradecylammonium chloride (B13) and further with (3-mercaptopropyl)triethoxysilane and vinyltrimethoxysilane to prepare B13-MMT, mercaptomethylorthosilicate modified MMT (MTMO), and vinyltrimethoxysilane modified MMT (VTMO), respectively. The pristine and modified clays were compounded with an HTV-type silicone rubber (GP-30 ®?), and the physical properties and morphology of the resulting rubber composites were examined. Both HTV/ MTMO and HTV/VTMO exhibited an intercalated/exfoliated coexisting morphology, but the degree of exfoliation of the former composite was higher than that of the latter. Moreover, the thermal stability, as assessed by the onset temperature of thermal degradation, as well as the tensile stress, elongation at the break, and tear strength of HTV/MTMO was higher than those of HTV/B13-MMT and HTV/VTMO. However, the cross-linking density of HTV/MTMO was the lowest among the composites examined because the thiol groups of MTMO extinguished and abstracted the radicals formed by the curing agent. Accordingly, the improved mechanical and thermal properties of HTV/MTMO were attributed to the enhanced interactions between HTV and MTMO due to the chemical reaction between the thiol groups of MTMO and the vinyl groups of HTV. Source

Lee S.-Y.,Inha University | Jang D.-I.,Inha University | Bae S.-T.,Materials Development Center | Park S.-J.,Inha University
International Journal of Hydrogen Energy | Year: 2014

To investigate carbon dioxide adsorption behaviors, we prepared mesoporous carbon (MC) materials that incorporated framework nitrogen functional groups via a facile polymerization-induced colloid aggregation (PICA) procedure, where the nitrogen content varied as a function of carbonization temperature. The prepared MCs had high specific surface areas (e.g., 974 m2/g) with well-developed mesopores. The highest carbon dioxide adsorption capacity of 106 mg/g at 25 °C was achieved with the MCs-800 sample (carbonization temperature of 800 °C). We found that the materials prepared in this study were highly effective for carbon dioxide capture, because the nitrogenous functional groups in the MCs enhanced their affinities for acidic carbon dioxide. Copyright © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Source

Kim Y.E.,Korea Institute of Energy Research | Lim J.A.,Korea Institute of Energy Research | Jeong S.K.,Korea Institute of Energy Research | Yoon Y.I.,Korea Institute of Energy Research | And 3 more authors.
Bulletin of the Korean Chemical Society | Year: 2013

The separation and capture process of carbon dioxide from power plants is garnering interest as a method to reduce greenhouse gas emissions. In this study, aqueous alkanolamine solutions were studied as absorbents for CO 2 capture. The solubility of CO2 in aqueous alkanolamine solutions was investigated with a continuous stirred reactor at 313, 333 and 353 K. Also, the heat of absorption (-ΔHabs) between the absorbent and CO2 molecules was measured with a differential reaction calorimeter (DRC) at 298 K. The solubility and heat of absorption were determined at slightly higher than atmospheric pressure. The enthalpies of CO2 absorption in monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and 2-amino-2-methyl-1-propanol (AMP) were 88.91, 70.44, 44.72, and 63.95, respectively. This investigation showed that the heat of absorption is directly related to the quantity of heat for absorbent regeneration, and is dependent on amine type and CO2 loading. Source

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