• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3749-3754
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• 2012

Nanoporous carbons with a high specific surface area were prepared directly from thermoplastic acrylic resin as carbon precursor and MgO powder as template by carbonization over the temperature range, $500-1000^{\circ}C$. The effect of the carbonization temperature on the pore structure and $CO_2$ adsorption capacity of the obtained porous carbon was examined. The textural properties and morphology of the porous carbon materials were analyzed by $N_2/-196^{\circ}C$ and $CO_2/0^{\circ}C$ adsorption/desorption isotherms, SEM and TEM. The $CO_2$ adsorption capacity of the prepared porous carbon was measured at $25^{\circ}C$ and 1 bar and 30 bar. The specific surface area increased from 237 to $1251m^2/g$, and the total pore volumes increased from 0.242 to $0.763cm^3/g$ with increasing the carbonization temperature. The carbonization temperature acts mainly by generating large narrow micropores and mesopores with an average pore size dependent on the level of carbonization of the MgO-templated nanoporous carbons. The results showed that the MgO-templated nanoporous carbons at $900^{\circ}C$ exhibited the best $CO_2$ adsorption value of 194 mg/g at 1 bar.

• Membrane Journal
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• v.17 no.4
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• pp.329-337
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• 2007

This is the research about a new method to make the internal separation layer with smallest pore size in polyethersulfone (PES) membrane by adding p-toluenesulfonic acid (TSA) and polyvinylpyrolidone (PVP) to polymeric PES solution. The preparation and morphological characterization of PES sheet membranes containing PVP as a hydrophilic swelling material and TSA as a demixing material were performed. As a result by microflow porometery, the PVP and TSA added PES membranes showed good permeabilities and narrow pore size distributions, comparable to those of the commercial membranes. The concentration of PVP affected the PES characteristics on air permeability and surface structure. The concentration of TSA influenced on pore size distribution but do not affect air permeability. The surface images of FE-SEM shows similar pore size when TSA added or not. However, the cross-section images of FE-SEM show that the TSA added PES membranes have a increase of internal layer thickness with smallest pore size.

• Journal of the Korean Vacuum Society
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• v.2 no.4
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• pp.491-500
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• 1993

The adsorption of nitrogen (77K) and carbon dioxide(273K) was performed on a series of activated carbon fiber. Theadsorption iotherm of nitrogen was typical type 1 and that of carbon dioxide was convex. As the specific surface area increases, there are linear increases in BET constant C mean pore diameter, the width of pore size distribution, wide micropore volume, total micropore volume, total pore volume and external surface area, however, narrow micropore volume was nealy constant . The total micorpore volume fraction in total pore volume is above 97%.

• Journal of the Korean Ceramic Society
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• v.32 no.2
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• pp.209-216
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• 1995

In order to investigate the effect o green microstructure on the sintering behavior and properties of AlN ceramics, samples were prepared by slip casting and dry pressing. The slip cast samples had high green density, fine pore size and narrow pore size distribution. They showed much higher sinterability and more homogeneous sintered microstructure compared to the dry pressed samples. Both increased thermal conductivity and flexural strength for samples prepared by slip casting could be attributed to the improved microstructural homogeneity with isolated second phase(s).

• Carbon letters
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• v.8 no.1
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• pp.17-24
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• 2007

Microporous carbons with narrow pore size distribution have been successfully synthesized by using hydrolyzed and calcined silica as templates and phenol formaldehyde (pf) resin as carbon precursor. Phenol formaldehyde-silica micro composites were prepared by solution route. Subsesequently, silica templates were removed by HF leaching. Resulting carbons were steam activated. The porous carbons were characterized by nitrogen adsorption-desorption isotherm, SEM, FTIR analysis, iodine adsorption, thermogravimetry analysis, etc. Adsorption isotherms show that the porous carbon prepared from calcined silica as templates are microporous with 88% pores of size <2 nm porosity and are of type I isotherm, while porous carbon prepared by using hydrolyzed silica are microporous with 89% microporosity, shows hysteresis loop at high relative pressure indicating the presence of some mesoporosity in samples. The microporosity in porous carbon materials has a bearing on the nature of silica templates used for pore formation.

• Korean Journal of Materials Research
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• v.9 no.4
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• pp.362-367
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• 1999

We intended to make the activated carbon fibers which could separate, remove and recover the volatile organic compounds of benzene, toluene, acetone and methanol. Changing activation temperature and time, large specific surface area and narrow pore distribution could be obtained. The activated carbon fibers have large adsorption capacity and selectivility for those organic compounds. We characterized the adsorption capability of the activated carbon fibers for benzene, toluene, acetone and methanol by BET specific surface area and pore size and micropore volume measurements. In the result of activation, the maximum value of BET specific surface area of the fibers was $1100\m^2$/g at $800^{\circ}C$ for 60 minutes and $K_2$O was reduced actively in this condition. Their average pore size was 5.8~5.9$\AA$. The activated carbon fibers prepared in this work had high adsorption rate to saturation and the selectibility for the above organic compounds. The adsorbed amount of acetone and methanol(diameter of$ 4.3\AA$ and $4.4\AA$ respectively) which are smaller than micropore diameter in size was 43~49%, which was larger value than benzene and toluene(in the same diameter as $5.9\AA$).

• Journal of the Korean Ceramic Society
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• v.34 no.4
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• pp.343-350
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• 1997

To fabricate the ceramic/metal(SiC/ Al alloy) composite, SiC preform was prepared by Pressureless Powder Packing Forming Method and 6061 Al alloy was infiltrated into the preform. Uniform compact having an average pore size of 10 ${\mu}{\textrm}{m}$ and narrow pore size distribution was prepared. Phenolic resin solution(40 wt%) was penetrated into the SiC compact, and then the compact was preheated at the temperature of 120$0^{\circ}C$. The pore size distribution and the microstructure of the preform were not changed by preheating. An uniform microstructure without any crack in the preform was obtained in SiC-Al alloy composite. The infiltration of 6061. Al alloy into the preform began at the temperature of 130$0^{\circ}C$ and the amount of infiltration increased in proportion to the infiltration temperature and the soaking time. The increasement rate of the infiltration amount decreased after 3 h. As a result of the infiltration at 140$0^{\circ}C$ for 4 h, Al alloy was well distributed in the interparticle channels and the relative density of the composite was above 98%. The strength and the fracture toughness of the composite were 303 MPa and 21.65 MPam1/2, respectively.

• Journal of the Korean Ceramic Society
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• v.32 no.1
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• pp.113-119
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• 1995

The green body was fabricated by a new forming method, pressureless powder packaing forming method, and the characteristics of sintered specimen were investigated. It was found that alumina ceramics prepared by the present method showed porous structure with narrow pore size distribution, and in case of abrasive powder sintered body, compared with dry-pressed specimen, had the nearly same density. Especially, the specimen prepared with spray-dried granules showed the characteristic that granules were not either deformed or fractured during forming and sintering process. Therefore, it was found that this new forming method was effective method in fabrication of porous ceramics on account of easy control of porosity and pore size and its high thermal stability.

• Bulletin of the Korean Chemical Society
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• v.26 no.7
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• pp.1075-1078
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• 2005

Hydrogen adsorption on various porous materials have been studied with a volumetric method at low temperature in the pressure of 0-760 torr. Their hydrogen uptakes depend at least partly on microporosity rather than total porosity. However, it is also necessary to consider other parameters such as pore size and pore architecture to explain the adsorption capacity. The heat of adsorption and adsorption-desorption-readsorption experiments show that the hydrogen adsorption over the porous materials are composed of physisorption with negligible contribution of chemisorption. Among the porous materials studied in this work, SAPO-34 has the highest adsorption capacity of 160 mL/g at 77 K and 1 atm probably due to high micropore surface area, micropore volume and narrow pore diameter.

• Journal of the Korean Ceramic Society
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• v.40 no.7
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• pp.677-682
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• 2003

The physical properties of sintered body made from 3 kinds of slip, F (Flocculated), M (Moderate), and D (Dispersed) for coal fly ash 70-clay 30 (wt%) were studied in terms of slip states and pore size distribution of sintered bodies. The floc particle size distribution for slip F was wider than slip D and the slip F contained flocs larger than 11 $\mu\textrm{m}$. The pore size distribution of the green body of all slips ranged over 1∼4 $\mu\textrm{m}$. The pores smaller than 1 $\mu\textrm{m}$ almost disappeared during the sintering process, while the larger pore of 2.5∼3 $\mu\textrm{m}$ growed by 1 $\mu\textrm{m}$. The pore distribution for the green body of slip F became a narrow in width and high in height after sintering and the large pore limit in a slip F sintered body was 5.1 $\mu\textrm{m}$ which is smaller than that of other slip. The slip F rather flocculated was favorable over slip D well dispersed, in offering a higher compressive strength. From these results, the mechanical strength of sintered body is dependent on the pore distribution which could be controlled by dispersion state of the slips.