• Proceedings of the Membrane Society of Korea Conference
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• 1991.04a
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• pp.15-18
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• 1991

본 연구에서는 박막화를 위한 수면전개법을 이용하여 기체분리능을 향상시키기 위한 복합막을 개발하고자 수면전개 적층복합막을 제조하여 기체투과특성실험을 행하였다. 실험에 사용한 고분자재질은 투과성이 우수한 Cellulose Acetate(CA)와 Polystyrene(PS)을, 선택성이 우수한 Polyvinylchloride(PVC)이었다. 이들 막에 대한 적층형태와 방법에 대한 효과를 검토하고 blend막과도 기체투과특성을 비교하였다.

• Proceedings of the Membrane Society of Korea Conference
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• 1992.10a
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• pp.7-7
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• 1992

Slip-casting 법으로 제조한 튜브형 다공성 $Al_2O_3$ 담체에 boehmite 입자를 단층 및 다층 졸-겔 침지코팅법과 본 실험실에서 개발한 새로운 가압 졸-겔 코팅법을 이용하여 알루미나 복합막을 제조하였다. 종래의 Yoldas법을 보완한 새로운 졸 제조방법에 의하여 입자크기가 작고 안정한 boehmite 졸을 제조 하였으며 졸의 제조조건에 따른 입자크기 변화와 열처리에 따른 겔의 상전이 및 비표면적 변화, 그리고 pH와 aging에 따른 안정성등을 규명하였다. 졸의 농도와 코팅시간 및 코팅 방법에 따른 코팅특성 등을 비교, 분석하여 복합막 제조에 최적인 코팅용 졸을 이용함으로써 담체 튜브내에 균열이 없고 재현성 있는 복합분리막을 제조할 수 있었다.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.144-147
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• 2004

Organosilicon polymers have long paid attention as functional polymers [1,2]. Among others, poly- (1-trimethylsilyl-1-propyne) [PTMSP] is a polymer, which forms a gas separating membrane with extraordinary high gas permeability. In particular, composite membranes that constituted two different matrices (inorganic and organic) have been recently developed in order to improve the permeation characteristics.(omitted)

• Proceedings of the Membrane Society of Korea Conference
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• 1992.10a
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• pp.49-52
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• 1992

본 연구에서는 기체분리용 고분자 분리막을 박막화하기 위하여 기체의 선택도와 투과도가 서로 상이한 celluloseacetate(CA), polyvinylchloride(PVC) 및 polystyrene(PS) 등의 고분자용액을 사용하여 수면전개법에 수면 전개기구와 박막의 구조적 특성을 연구하였고, 또한 기체 분리막으로서의 이 수면전개막을 개발하기 위하여 CA, PVC, PS 단일 적층막, CA-PVC 복합적 층막, PVC/PS 혼합적층막의 형태로 제막하여 기체분리효과를 검토하였다.

• Proceedings of the Membrane Society of Korea Conference
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• 2005.11a
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• pp.221-222
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• 2005

• Proceedings of the Membrane Society of Korea Conference
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• 2005.11a
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• pp.227-230
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• 2005

• Environmental Engineering Research
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• v.16 no.1
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• pp.29-34
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• 2011

The electric charge on a membrane was investigated by analyzing the experimental rejection of various monovalent and divalent ionic solutes. The characteristics of the separation of ionic solutes using various nanofiltration membranes were obtained from an experimental nanofiltration set-up, with a surface area of $40cm^2$ under the operational pressures between 0.25-0.3 MPa. The state of the membrane electric charge was observed using separation coefficients, i.e., the permeation ratio of monovalent to divalent ions. To confirm the state of the membrane charge observed via the separation coefficient, a calculation using the extended Nernst-Planck equation, coupled with the Donnan equilibrium, assuming different electric charge states of the membrane, was compared with the experimental rejection of ionic solutes. The examination of the characteristics of separation using three types of nanofiltration membranes showed that one of the membranes carried a negative/positive double charge density inside, while other two membranes carried either a positive or negative charge density.

• Food Science and Biotechnology
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• v.18 no.3
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• pp.667-671
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• 2009

Extract of water-soluble polysaccharide (CFWx), showing inhibiting activity on ${\alpha}-glucosidase$, was prepared from the fruiting bodies of Cordyceps militaris by hot-water extraction, and ethanol precipitation. Chemical characteristics of CFWx were as follows: carbohydrate content 30% including 16% of uronic acid; 51% protein content; monosaccharide composition, Man:Glu:Gal (30:43:27); molecular weight $3-5{\times}10^4$. CFWx was further purified by ion-exchange, gel-permeation, and affinity chromatography and $CFWx-AH-{\alpha}$ fraction was isolated. Fundamental structure of $CFWx-AH-{\alpha}$ was deduced as ${\alpha}-(1{\to}4$)-D-glucan with ${\alpha}-(1{\to}3$)- and/or ${\alpha}-(1{\to}6$)-D-glycosidic side chains based on methylation analysis.

• Food Science and Preservation
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• v.5 no.3
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• pp.239-246
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• 1998

Polyimide membrane system was designed for manufacturing nitrogen-enriched gas, and basic technical data was suggested for appling this system to controlled atmosphere storage. The permeability characteristics of pure oxygen and nitrogen could be explained by dual-mode sorption model. There was substantial decrease in the permeation rates of oxygen, which is the more permeable gas, through the polyimide membrane due to the presence of nitrogen in comparison with pure oxygen. However, the permeation rates of nitrogen was increased by the presence of oxygen. The ideal separation factor was in the range of 5 to 6 in the range of temperature and pressure difference studied, and the separation factor of air was lower than the ideal separation factor. The increase of ideal separation factor with increasing temperature is due to the fact that the activation energy for oxygen is larger than that for nitrogen. Nitrogen concentration decreased rapidly with increasing product recovery, and it was found that this is a major operating factor to obtain nitrogen concentration required for controlled atmosphere storage. A relation equation, by which nitrogen concentration in storehouse can be predicted, was suggested under the establishment of a hypothetical model for controlled atmosphere storage process using polyimide membrane system.

• Elastomers and Composites
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• v.33 no.3
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• pp.193-200
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• 1998

It is well known that EPDM(ethylene propylene diene monomer) rubber has inherently excellent resistance to the weathering, ozone, heat, cold and moisture, whereas crosslinked IIR (isobutylene isoprene divlnyl benzene terpolymer) shows proper resistance to the water and gas permeation. Various characteristics of EPDM blend with crosslinked IIR such as curing characteristics, mechanical properties, dispersion of minor component and gas impermeability were explored. The optimum curing time $(t_{90})$ examined with peroxide was decreased by adding small amount of crosslinked IIR to the EPDM rubber. Mechanical properties of blends such as tensile strength, hardness and elongation at break were enhanced by increasing EPDM content. These results might be explained with the affinity of carbon black to the EPDM rubber. On the other hand, the physical properties were not changed significantly after aging, and the increase of crosslinked IIR fraction caused the decrease of compression set to small rate. EPDM rubber shows different behavior with crosslinked IIR in oxygen permeability. By adding 30wt.% crosslinked IIR to the EPDM rubber, the resistance to the oxygen permeation was improved up to three times than that of pure EPDM rubber. Conclusively, EPDM blend containing 30wt.% crosslinked IIR might be commercially applied to the o-ring and electric parts because of its proper resistance to the weathering, ozone and oxygen permeability.