• 멤브레인
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• 제18권3호
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• pp.219-225
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• 2008

본 연구에서는 atom transfer radical polymerization (ATRP)에 의해 polydimethylsiloxane (PDMS)와 methyl-methacrylate (MMA)로부터 polydimethylsiloxane-polymethylmethacrylate (PDMS-PMMA) block copolymer를 합성하였다. 합성된 PDMS-b-PMMA copolymer막의 특성은 FT-IR, $^1H$ NMR, GPC, DSC 등을 사용하여 조사하였다. 질소와 수소의 투과도는 각각 $1.2{\sim}l.5$ barrer와 $6.2{\sim}10.5$ barrer를 보였고, 질소에 대한 수소의 선택도는 $5.3{\sim}6.9$ 범위였다. PDMS-b-PMMA copolymer 막의 투과도와 선택도는 PDMS 막보다는 낮은 값을 보였고, PMMA 막보다는 높은 결과를 보였다.

• KEPCO Journal on Electric Power and Energy
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• 제2권1호
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• pp.127-131
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• 2016

Polymer electrolyte membrane for unitized regenerative fuel cells requires high proton conductivity, high dimensional stability, low permeability, and low cost. However, DuPont's Nafion which is a commercial polymer electrolyte membrane has high permeability, high cost, and decreasing proton conductivity and dimensional stability over $80^{\circ}C$. To address these problems, sulfonated poly ether ether ketone (sPEEK) which is a low cost hydrocarbon polymer is selected as matrix polymer for the preparation of polymer electrolyte membrane. In addition, composite membrane with improved proton conductivity and dimensional stability is prepared by introducing sulfonated graphene oxide (sGO). The fundamental properties of polymer electrolyte membranes are analyzed by investigating membrane's water content, dimensional stability, proton conductivity, and morphology. The cell test is conducted to consider the possibility of application of sPEEK/sGO composite membrane for an unitized regenerative fuel cell.

• 한국막학회:학술대회논문집
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• 한국막학회 1997년도 추계 총회 및 학술발표회
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• pp.69-70
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• 1997

Polyimides and related polymers, when synthesized from aromatic monomers, have generally rigid chain structures resulting in a low gas permeability. The rigidity of polymer chains reduces the segmental motion of chains and works as a good barrier against gas transport. To overcome the limit of use as materials of gas separation membranes due to low gas permeability, block copolymers with the incorporation of flexible segments like siloxane linkage and ether linkage have been studied. These block copolymers have microphase-separated structures composed of microdomains of flexible poly(dimethylsiloxane) or polyether segments and of rigid polyimides segments. In case of rigid-flexible block copolymers, the characteristics of both phases for gas permeation are of great difference. The permeation of gas molecules occurs favorably through microdomains of flexible segments, whereas those of rigid segments hinder the permeation of gas molecules. Accordingly the increase of content of flexible segments in a rigid polymer matrix will increase the gas permeability of the membrane linearly. However, this prediction does not satisfy enough many experimental results and in particular the drastic increase of the permeability is observed in a certain volume fraction. It was proposed that the gas transport mechanism is dominated by diffusion rather than gas solubility in a certain content of flexible phase if solution-diffusion mechanism is adopted. However, the transition from solubility-dependent to diffusion-dependent cannot be explained by the understanding of mechanism itself. Therefore, we consider an effective chemical path which permeable phase can form in a microheterogenous medium, and percolation concept is introduced to describe the permeability transition at near threshold where for the first time a percolation path occurs. The volume fraction of both phases is defined as V$_{\alpha}$ and V$_{\beta}$ in block copolymers, and the volume of $\beta$ phase in the threshold forming geometrically a traversing channel is defined as V$_{\betac}$. The formation mechanism of shortest chemical channel is schematically depicted in Fig. 1.

• 전기화학회지
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• 제7권2호
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• pp.89-93
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• 2004

설폰화된 폴리설폰 (sulfonated polysulfone, SPSF)과 Poly(phenylmethyl silsequioxane) (PPSQ)의 유무기 복합 전해 질막을 제조하여 이온전도도와 메탄을 투과 특성을 조사하였다 클로로트리메틸실란과 클로로설폰산의 반응 몰비와 반응시간를 변화시켜 설폰화도가 $37\~75\%$인 SPSF를 합성하였다. SPSF/PPSQ복합 전해막은 SPSF와 PPSQ를 DMF에 용해하여 캐스팅하는 방법으로 제조하였다 이 복합 전해질막의 수소 이온 전도도는 상온에서 $2.8\times10^{-3}\~4.9\times10^{-2}S/cm$이었으며 설폰화도가 증가할수록 전도도는 증가하였다. 제조된 설폰화된 폴리설폰 복합 전해질막의 메탄을 투과도는 이온전도도와 설폰화도에 비례하여 증가하였으며, PPSQ의 함량이 커질수록 메탄을 투과도가 비례적으로 감소하는 것을 확인할 수 있었다. 약 $5wt\%$ PPSO론 포함한 복합 전해질막의 이온전도도 및 메탄을 투과도는 SPSF에 비교하여 거의 동일하지만 함수율을 크게 감소시키는데 효과적이었다.

• 미생물학회지
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• 제7권3호
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• pp.125-134
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• 1969

The effect of heat treatment on membrane permeabilities of yeast's cells was studied, the amounts of efflux out of yeast cells were put to analysis, and fraction survival was also counted by viable plate counting method. Effects of nutritional substances on thermally injured yeast cells were also investigated under the highlight of reabsorption mechanism, then the relationship between permeability and surviving action in injured yeast cells are discussed.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
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• pp.140-143
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• 2004

Compatibility of polymeric materials governs their suitability for nearly all potential applications. An aspect of compatibility that is frequently important for fluoropolymers is their ability to isolate fluids by serving as a barrier to mass transport. This property is commonly expressed as permeability. In ideal cases, both solubility and diffusivity are constant at any given temperature and so the permeability is also a constant.(omitted)

• 멤브레인
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• 제32권2호
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• pp.150-162
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• 2022

수처리 및 의약바이오 분야에서 유효물질 분리에 활용되고 있는 알루미나 중공사 분리막은 얇은 두께로 인해 취급 및 적용시 쉽게 파괴되는 단점이 있기 때문에 분리막의 강도를 100 MPa 이상으로 향상시키기 위한 연구가 필요하다. 본 연구에서는 나노입자의 함량을 0, 1, 3, 5 wt%로 증가시켰을 때 제조된 중공사 분리막의 특성을 평가하였다. 그 결과, 나노입자의 함량이 증가함에 따라 중공사 분리막의 강도는 79 MPa에서 115 MPa로 증가하였으며, 밀도는 1.76 g/m³에서 1.88 g/m³으로 증가하였고 기공률과 평균기공크기는 각각 51%에서 48%로, 416 nm에서 352 nm로 감소한 것을 확인하였다. 스폰지구조가 발달하고 스폰지구조의 기공크기가 향상된 알루미나 중공사 분리막은 100 MPa 이상으로 기계적 강도가 향상되었으며, 약 100000 GPU의 높은 질소 투과도 및 약 3000 L/m²h의 높은 물 투과도를 나타내었다. 따라서, γ-알루미나 나노입자를 소결조제로 첨가하는 것은 α-알루미나 중공사 분리막의 기계적 강도를 효과적으로 증진시키고 높은 투과성능을 유지할 수 있는 매우 유효한 방법임을 확인하였다.

• 멤브레인
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• 제25권2호
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• pp.107-114
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• 2015

PTMSP에 0~50 wt% NaA Zeolite를 첨가하여 PTMSP-NaA Zeolite 복합막을 제조하고, PTMSP-NaA Zeolite 복합막의 특성을 FT-IR, $^1H$-NMR, GPC, DSC, TGA, SEM에 의해서 조사하였다. PTMSP-NaA Zeolite 복합막의 수소와 질소에 대한 투과도와 선택성을 NaA Zeolite 함량에 따라 조사하였다. TGA측정에 의하면 PTMSP에 NaA Zeolite가 첨가되었을 때 복합막의 감량이 완결되는 온도는 낮아졌고, 감량(wt%)도 작아졌다. SEM관찰에 의하면 NaA Zeolite는 PTMSP-NaA Zeolite 복합막 내에 $2{\sim}5{\mu}m$ 크기로 분산되어 있었다. PTMSP-NaA Zeolite 복합막에 대한 $N_2$와 $H_2$의 투과도는 NaA Zeolite 함량이 증가하면 증가하였다. 그리고 PTMSP-NaA Zeolite 복합막의 $N_2$에 대한 $H_2$의 선택성은 NaA Zeolite함량이 증가하면 감소하였다.

• Membrane and Water Treatment
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• 제11권5호
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• pp.323-331
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• 2020

With the increasing demand on reverse osmosis (RO) membranes for water purification worldwide, the number of disposed membrane elements is expected to increase accordingly. Thus, recycling and reuse of end-of-life RO membranes should be a global environmental action. In this work, we aim to reuse the spent RO membrane for nanofiltration (NF) and ultrafiltration (UF) process by subjecting the spent membrane to solvent and oxidizing solution treatment, respectively. Our results showed that solvent-treated RO membrane could perform as good as commercial NF membrane by achieving similar separation efficiencies, but with reduced water permeability due to membrane surface fouling. By degrading the polyamide layer of RO membrane, the transformed membrane could achieve high water permeability (85.6 L/㎡.h.bar) and excellent rejection against macromolecules (at least 87.4%), suggesting its reuse potential as UF membrane. More importantly, our findings showed that in-situ transformation on the spent RO membrane using solvent and oxidizing solution could be safely conducted as the properties of the entire spiral wound element did not show significant changes upon prolonged exposure of these two solutions. Our findings are important to open up new possibilities for the discarded RO membranes for reuse in NF and UF process, prolonging the lifespan of spent membranes and promoting the sustainability of the membrane process.

• Macromolecular Research
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• 제8권1호
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• pp.1-5
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• 2000

The valiclity of the simple mathematical model for facilitated transport in a solid state membrane developed previously has been examined againsts the carrier concentration and membrane thick-ness. Membranes are prepared with copolymer of styrene and 4-vinylpyridine as a matrix and Co(salen) as a carrier. 4-Vinylpyridine is incorporated to provide the coordination site for Co(salen) carrier. Oxygen permeability through the facilitated transport membrane is linearly increased with the square of its thick-ness, as predicted by the mathematical model. However, the oxygen permeability does not increase linearly with the carrier concentration. This seems to be due to the deactivation of the carrier by dimerization at high carrier concentrations as well as the reduced chain mobility by coordination of bulky Co(salen) carrier.