• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.189-193
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• 2008

• Membrane Journal
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• v.14 no.1
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• pp.57-65
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• 2004

The effect of porous support layer resistance and PDMS (polydimethylsiloxane) coating thickness on ethylene/nitrogen separation of composite membranes was studied with the model of Pinnau and Wijmans〔1〕. To control the support resistance (or permeance), PES porous membranes were prepared by phase inversion process with various PES/NMP dope concentrations. The thickness of selective PDMS top layer was controlled by using a spin coater. Its cross-section and coating thickness were observed by scanning electron microscope (SEM). Pure gas permeation test was done with ethylene and nitrogen, respectively. The experimental result for olefin/nitrogen separation process matched well with theoretical result from the model used. The result shows that optimization between PDMS coating thickness and support resistance is important to get PDMS composite membranes with best performance.

• Membrane Journal
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• v.31 no.5
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• pp.333-342
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• 2021

A flexible electrochromic device (ECD) is a promising technology that is expected to be applied in various fields such as smart windows. Polymer electrolyte is an important component that determines the bleaching-coloration performance and physical stability of flexible ECDs. In this study, a pore-filled polymer electrolyte membrane (PFPEM) with excellent dimensional stability was developed to effectively fabricate flexible ECDs and improve durability. Polyvinyl acetate, which has excellent adhesion, and polyethylene glycol, which can improve ionic conductivity, were filled in the pores of a porous substrate made of polyethylene, which is inexpensive and has excellent physical and chemical stability. The optimal lithium salt (LiTFSI) content of the prepared PFPEM was determined at about 27 wt%, and it was confirmed to possess excellent dimensional stability, adhesive strength, and ion conductivity close to that of conventional polymer electrolytes. Although the visible light transmittance was lowered by the use of the porous substrate, it was expected to act as an advantage in the colored state.

• Polymer(Korea)
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• v.32 no.6
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• pp.529-536
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• 2008

We manufactured poly (L-lactide-co-glycolide) (PLGA) scaffolds impregnated demineralized bone particle (DBP) and hyaluronic acid (HA) by ice-particle leaching method and tested their ability of sustained release of brain derived neurotrophic factor (BDNF). BDNF (50 and 200 ng) mixed with PLGA, DBP/PLGA, HA/PLGA and DBP/HA/PLGA scaffold. The release profiles of BDNF from BDNF loaded scaffolds were assayed using ELISA. Morphological changes of scaffolds by BDNF release were also observed by SEM. BDNF stably and sustainedly released from DBP/HNPLGA than from PLGA and DBP/PLGA scaffolds. DBP/HA/PLGA scaffolds showed the great structural changes, which demonstrated BDNF release amount from DBP/HA/PLGA scaffolds were highest in all groups. We suggest that BDNF loaded DBP/HNPLGA scaffold would be very useful for nerve regeneration.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.10a
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• pp.55-57
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• 1996

다공성 무기막은 높은투과도와 뛰어난 내열.내화학성, 그리고 경제성 때문에 기존의 PSA공정이나 증류와 같은 고에너지 분리공정을 대체하는 공정으로 각광을 받고 있다. 무기재료막의 제조하는 방법으로 주로 알콕사이드를 사용하는 솔-젤법(1)과 금속(2) 또는 기상반응(3)을 이용하는 화학증착법이 사용된다. 또한 고온에서 수소를 연속적으로 분리하여 화학평형에 기인한 한계를 극복하여 높은 수율을 얻고자하는 막반응기에 관한 연구가 활발히 진행되고 있다. 본 연구에서는 $\alpha$-알루미나 지지체의 미세한 다공성 구조 내부에서 TEOS(Tetraethylorthosilicate)와 산성의 알코올-물 혼합물을 확산시켜 실리카 솔을 생성시킴과 동시에 젤화시켜 기공의 크기를 감소시켜 막을 제조하였다. 이렇게 제조된 막은 높은 투과도와 낮은 수소선택도(selectivity=3-4)를 보였고, 두번째 단계로 silica sol을 제조하여 진공 하에서 dip-coating을 행하였다. 이렇게 2단계로 기공 구조를 개선시킨 실리카 막은 저압에서 상대적으로 높은 수소의 분리도(selectivity=5-7)를 보였으며 여전히 높은 투과도를 갖는다.

• Polymer(Korea)
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• v.38 no.2
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• pp.150-155
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• 2014

Polycaprolactone (PCL) is a synthetic biodegradable polymer with excellent mechanical properties. $TiO_2$ (titanium dioxide) has a hydrophilic, high density and excellent biocompatibility. In this work, we produced three-dimensional porous scaffolds with PCL and $TiO_2$ nanoparticles using a salt-leaching method. Physical properties of the scaffolds were analyzed by FE-SEM, FTIR, TGA and compressive strength. Interestingly, the addition of $TiO_2$ nanoparticles decreased the water absorption and swelling ratio of the porous scaffolds. However, the compressive strength was increased by $TiO_2$. CCK-8 assay, which is generally used for the analysis of cell growth, shows that $TiO_2$ nanoparticles have no cytotoxicity. Taken together, we suggest that the PLC/$TiO_2$-scaffold can be used for biomedical applications.

• Polymer(Korea)
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• v.34 no.5
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• pp.474-479
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• 2010

We developed laminated cylindrical scaffolds composed of poly(lactide-co-glycolide)(PLGA) and keratin, and investigated their potential for tissue engineering and disk regeneration. The scaffold was designed to have two parts, i.e. inner cylinder and outer disk, to mimic a natural disk. The outer disk was composed of PLGA and the inner cylinder was prepared using PLGA film or PLGA/keratin hybrid film. In this study, we investigated the effects of keratin on the growth and proliferation of annulus fibrous(AF) cells in the cylindrical scaffolds. Scaffolds containing PLGA/keratin films showed a significantly higher cell proliferation and expression of collagen I and II than the counterpart with PLGA films. Keratin containing scaffolds also exhibited an excellent mechanical strength, demonstrating that keratin influences the proliferation of annulus fibrous cells. The results provide valuable information on PLGA/keratin films for tissue engineered disk regeneration.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1013-1014
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• 2013

• Proceedings of the Membrane Society of Korea Conference
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• 1998.04a
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• pp.44-45
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• 1998

1. 서론 : 공기의 산소/질소 분리용 고분자막은 높은 선택도와 높은 투과도를 동시에 요구한다. 이 두가지 조건을 만족시키는 새로운 소재 개발과 기존의 고분자물질을 수식하는 연구가 진행되고 있으나 trade-off 현상으로 인하여 선택도가 증가되면 투과계수가 감소되고, 투과계수가 증가되면 선택도가 감소되는 경향이 있다. 다공성 지지체의 표면에 selective thin layer를 coating한 복합막은 투과저항을 줄여 투과속도는 증가시킬 수 있으나 선택도는 고분자 고유의 80%정도까지 감소되는 것으로 알려져 있다. (생략)

• Proceedings of the Membrane Society of Korea Conference
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• 1997.04b
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• pp.30-31
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• 1997

기체분리용 막에서 높은 투과성능을 얻기 위해서는 다공성 지지체 표면에 얇은 skin layer를 갖는 막을 제조하는 것이 가장 중요하다. 이 skin layer는 결함이 없고 가능한 한 얇아야 고선택도를 유지하면서 투과도를 높일 수 있다. 이러한 skin layer를 갖는 비대칭막을 wet phase inversion method를 이용하여 제조하는 연구를 하였다. 본 연구에서는 wet phase inversion method를 이용하여 표면에 skin layer를 갖는 polyimide 비대칭 평막을 제조하는데 있어서 제막조건에 따른 막 구조 조정과 투과특성을 평가하고자 하였다.