• Polymer(Korea)
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• v.30 no.6
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• pp.505-511
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• 2006

We tried to prepare polystyrene composite particles containing carbon black by suspension polymerization with water as a reaction medium. Hydrophobic silica was selected as a stabilizer and oil-soluble azobisisobutyronitrile (AIBN), as an initiator. All polymerization reactions were carried out at a fixed temperature of $75^{\circ}C$. Stabilizer concentration was varied from $0.17{\sim}3.33wt%$ compared to water, where particles with $7.96{\mu}m$ in average diameter were obtained at 1.57 wt% of stabilizer. Increase in divinylbenzene concentration, as a crosslinking agent, from $0.1{\sim}1.0 wt%$ compared to monomer exhibited a large increase in average particle diameter Incorporation of 1wt% of carbon black compared to monomer produced an increase in average diameter It is speculated that viscosity lower than that necessary to induce even dispersion of carbon black particles led to poor dispersion, and as a result, large particles. For a styrene mixture containing 3 wt% carton black compared to monomer, enhanced dispersion due to an increase in carbon black concentration reduced average particle diameters. For styrene mixtures containing 1 and 3 wt% carbon black compared to monomer, preparticles before polymerization and polymer composite particles after polymerization showed a similar tendency towards particle formation. When carbon black concentration compared to monomer was increased to 5 and 7 wt%, styrene mixtures exhibited a large increase in viscosity and thus better dispersion of carbon black particles, which led to a decrease in preparticle diameters. However, these particles experienced agglomeration in the polymerization process, and polystyrene composite particles increased in average diameter.

• Particle and aerosol research
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• v.14 no.1
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• pp.9-16
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• 2018

We have developed an electrostatic precipitation (ESP) type air cleaner for indoor air quality and investigated its performances regarding CADR (Clean air delivery rate), single-pass efficiency and gas removal efficiency. The ESP air cleaner used an ACF (Activated carbon fiber) filter for gas removal and the ACF as a high voltage electrode for particle removal. The ESP air cleaner was tested in a chamber with the volume of $1m^3$ regarding CADR and gas removal efficiency. The applied CADR area of the ESP was $1.8m^2$. Gas removal efficiency was tested with 3 gases (Acetaldehyde, Acetic acid, Ammonia). As the results of the gas removal efficiency, the ESP air cleaner shows the removal efficiencies of 90, 98 and 85% for acetaldehyde, acetic acid and ammonia, respectively.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.6
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• pp.42-53
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• 2015

In this study, the influence of Al particle size, as an additive for solid propellant, on the mechanical erosion of the carbon-composite nozzle was evaluated. A new model which can predict the size and distribution of the agglomerated reaction product($Al(l)/Al_2O_3(l)$) was established, and the size of agglomerate were calculated according to the various initial size of Al in the solid propellant. With predicted results of the model, subsequently, the characteristics of mechanical erosion on the carbon-composite nozzle was estimated using a commercial CFD software, STAR CCM+. The result shows that the smaller the initial Al particles are, in the solid propellant, the lower is the mechanical erosion rate of the composite nozzle wall, especially for the nano-size Al particle.

• Polymer(Korea)
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• v.35 no.5
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• pp.451-457
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• 2011

The effect of latex particle size on rheological and electrical properties of latex-blended polystyrene (PS)/multi-walled carbon nanotube (MWCNT) nanocomposites was investigated. Mono-dispersed PS particles synthesized either by emulsifier-free emulsion polymerization or by dispersion polymerization were mixed with MWCNTs under ultrasonication, and freeze-dried to prepare the nanocomposites. As the MWCNT content increased, storage modulus, complex viscosity and electrical conductivity were substantially increased. The increase of storage modulus and complex viscosity was higher for larger PS particles. The effect of particle size on electrical properties was different depending on MWCNT content. With lower MWCNT content, the nanocomposite prepared by smaller PS particles showed higher electrical conductivity, but the opposite result was given as the content increased.

• Particle and aerosol research
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• v.9 no.4
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• pp.201-208
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• 2013

Copper (II) and Nickel (II) mimic complexes of enzyme carbonic anhydrase were evaluated under ambient condition for carbon dioxide capture and conversion process. The synthesized complexes were characterized by ATR-FTIR and UV-DR spectroscopy. It was found that all the complexes have biomimetic activity towards $CO_2$ using para-nitrophenyl acetate (p-NPA) hydrolysis as the model reaction. Interestingly, the proper geometry obtained by the restricted orientation of tripodal N atoms in Cu (II) complex of 2,6-bis(2-benzimidazolyl) pyridine showed the highest activity (1.14 au) compared to others. The $CO_2$ bio-mineralization to $CaCO_3$ was carried out via in-vitro crystallization approach. Results indicate that the biomimetic complexes have a role in determining $CaCO_3$ morphology. The present observations establish a qualitative insight for the design of improved small-molecule catalysts for carbon capture.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.1
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• pp.141-148
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• 2008

This study was conducted to evaluate the effect of PAC(Powder Activated Carbon) retention time on stable operation of high concentration powered activated carbon(HCPAC-MBR) in the treatment of secondary domestic wastewater. The pilot scale HCPAC-MBR system was operated at two different SRTs, 25 days and 100 days. The main drawback of HCPAC-MBR system was the rapid increase of trans-membrane pressure. The increase rate of trans-membrane pressure was proportional to SRT value at constant flux. This result seemed to be caused by reduced amount of EPS adsorbed on the PAC in the reactor by decreasing the SRT of the PAC. The particle size of the PAC was also influenced by SRT. The PAC size was decreased as SRT was increased. The change of particle size could be one reason for the change of trans-membrane pressure. The pore volume in the cake-layer formed on the membrane surface became to be increased by reducing SRT, because the cake-layer was highly composed of the PAC. Therefore, increased pore volume might play a role to reduce the trans-membrane pressure. The removal rate of E260 and TOC was also inversely proportional to SRT value.

• Journal of the Korean Ceramic Society
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• v.35 no.3
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• pp.231-238
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• 1998

Cr3C2 -dispersed TiC composites were prepared via HPCS(high pressure-self combustion sintering) pro-cess using mixtures of Ti, Cr and a carbon source for the purpose of increasing the facture toughness and sinterability of TiC. In this study the microstructure and properties of the composites were investigated in terms of relation to the carbon source the particle size of Ti and the amount of Cr. It was found that car-bon black was the most effective carbon source among the various carbon sources tested and the reaction was more effective as the particle size of Ti decreased. Among the sintered composites of Ti-C-Cr system the one with 30wt% Cr showed the best physical properties with 0.5% in apparent porosity 98.8% in re-lative density 18.2 GPa in hardness and 4.46 MPa.m1/2 in fracture toughness. In addition it was observed that the lattice constant of TiC decreased gradually with increasing the amount of Cr.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.652-655
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• 2009

The bimodal porous carbons were synthesized by using imprinting method with templates of SBA-15 particle and silica sphere and applied as supporting materials for the electro-catalyst of polymer electrolyte fuel cell (PEFC). The silica spheres with diameter size of 100 nm and SBA-15 particle having 200 nm -250 nm diameter and 700 nm -900 nm length were synthesized in this work. The bimodal porous carbons (S100) were prepared by using the silica spheres and SBA-15 as templates and mesophase pitch as a carbon source. The PtRu nanoparticle of ca. 1.9 nm were supported on the bimodal porous carbon support and the resulting PtRu/S100 catalysts was tested by the cyclic voltammetry. The use of bimodal porous carbon showed in comparable electro-catalytic activities with commercial catalyst. Though unclear effects of bimodal porosity of supports could be obtained in the scope of this study, morphological advantage in electrical conductivity can be considered on the electro-catalytic activity.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.459-462
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• 2006

Formic acid recently attracted attention as an alternative fuel for direct liquid fuel cells(DLFCs) due to its high theoretical open circuit voltage(1.45V). In this paper, a novel chemical strategy is described for the preparation and characterization of carbon-supported and surface-alloys, which were prepared by using a successive reduction process. After preparing Au colloid nanoparticles, the deposition of Au colloid nanoparticles occurred spontaneously in the carbon black-dispersed aqueous solution. Then nano-scaled Pt layer were formed on the surface of carbon-supported Au nanoparticles. The Au-Pt[x] showed the higher electrocatalytic activity than those of the particle-alloys and commercial one (Johnson-Matthey) for the reaction of formic acid oxidation when the mass-specific currents were compared. The increased electrocatalytic activity might be attributed to the effective surface structure of surface-alloys, which have a high utilization of active materials for the surface reaction of electrode.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.16-22
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• 1997

When platinum wan impregnated on carbon by methanol, surfactant have an important effect on the stability of platinum colloid. As the increase of amounts of surfactant enhanced the stability of platinum colloid, the particle size of platinum on carbon was diminished. But, after heat treatment, residue of surfactant remained in electrode to decrease current density of oxygen reduction. To remove surfactant, as temperature of heat treatment enhanced, platinum particle was aggromerated and current density was decreased.