• 폴리머
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• 제25권2호
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• pp.151-160
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• 2001

결정성 약제가 함침된 생분해성 고분자학이 고분자(poly(d,1-lactide)), 약제(progesterone) 및 용매(dimethylformamide)로 이루어진 고분자용액을 고형화시켜 제조되었다. 용매에 약제 및 고분자를 용해시켜 준비된 제막용액을 유리판 위에 도포한 후, 이로부터 용매를 증발시켜 고형화시키거나, 또는 고분자 및 함침 약제 모두에 비용매로 작용하는 물과 용액 필름에 존재하는 용매를 교환시켜 용액 필름이 응고되도록 하였다. 제조된 고분자막들은 용액 필름의 응고화 경로에 따라 뚜렷하게 다른 형상을 보여주었다. 진공 상태에서 용매의 증발을 통해 응고화되었을 때, 함침 약제인 프로제스테론은 구의 형상을 보여주며 고형화된 고분자 구조에 둘러싸여 막의 내부에 균일하게 분포되었다. 이에 비해, 비용매인 물에 침지시켜 용매와 비용매의 급속한 확산에 의해 응고화시키거나, 대기에 방치시켜 대기에 존재하는 수증기의 흡수에 의해 고분자 희박 지역의 핵 형성을 통한 용액 필름의 액체-액체 상분리를 유도하며 응고화시킨 경우, 함침된 약제는 고분자막 내부에 편상의 결정 구조를 지니며 막 내부에 불균일하게 분포되었다.

• 멤브레인
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• 제6권4호
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• pp.258-264
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• 1996

폴리아닐린은 ammonium persulfate를 산화제로 하여 IM염산 수용액중에서 산화중합법으로 제조하였다. 탈수소 과정 후, 저분자량의 강산도판트, 및 분자량이 큰 도판트를 사용하여 도핑을 수행하였다. 폴리아닐린의 d-spacing을 $3.72{\AA}$에서 $4.844{\AA}$ 까지 조절할 수 있었는데, 고분자 또는 분자 크기가 큰 도판트를 찾아서 d-spacing이 폴리아닐린의 base film보다 크도록 조절하였다. 폴리아닐린의 물성은 Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), dielectric analyzer (DEA) 등을 사용하여 측정하였다. 본 연구에서는 annealed film으로 산소와 질소가 각각 0.072, 0.0105 barrer의 투과도를 나타내었으며 선택도는 6.87이었다. 고분자량의 도판트로써 도핑한 폴리아닐린의 기체투과특성은 투과도가 증가하고 선택도는 감소하였다.

• Membrane and Water Treatment
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• 제6권3호
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• pp.189-203
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• 2015

Membrane biofouling impedes wide application of membrane bioreactor (MBR) for wastewater treatment. Recently, quorum sensing (QS) mechanisms are accounted for one of major mechanisms in biofouling of MBRs. In this study, vanillin was applied to investigate reduction of biofouling in MBRs. MBR sludge was analyzed to contain QS signal molecules by cross-feeding biosensor assay and HPLC. In addition, the inhibitory activity of vanillin against bacterial quorum sensing was verified using an indicator strain CV026. The vanillin doses greater than 125 mg/L to 100 mL of MBR sludge showed 25% reduction of biofilm formed on the membrane surfaces. Two MBRs, i.e., a typical MBR as a control and an MBR with vanillin, were operated. The TMP increases of the control MBR were more rapid compared to those of the MBR with the vanillin dose of 250 mg/L. The treatment efficiencies of the two MBRs on organic removal and MLSS were maintained relatively constant. Extracellular polymeric substance concentrations measured at the end of the MBR operation were 173 mg/g biocake for the control MBR and 119 mg/g biocake for the MBR with vanillin. Vanillin shows great potential as an anti-biofouling agent for MBRs without any interference on microbial activity for wastewater treatment.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 추계 총회 및 학술발표회
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• pp.11-14
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• 1998

1. Introduction : Research progresses in Chemistry and Chemical Engineering have been made during the last decades with important contributions to the industrial development and to the quality of our life. An interesting case is related to the membrane science and technology continuous impact to innovative processes and products, particularly appropriate for a sustainable industrial growth. Membrane operations have been familiar for many years to biologists and chemists working in their laboratorier or studying biological phenomena. Only recently engineers started to operate in' this area. The preparation of asymmetric CA membranes at University of California, Los Angeles in the early 60s is generally recognized as a crucial moment for membranology (1). Loeb and Sourirajan with their discovery of how to increase significantly the permeability of polymeric membranes without significant changes in their selectivity, made realistic the possibility of their use in large scale operations for desalting brackish and sea water by reverse osmosis and for various other molecular separations in different industrial areas. Reverse osmosis is today a well recognized basic unit operations, togheter with ultrafiltration, crossflow microfiltration,. nanofiltration, all pressure driven membrane processes. Already in 1992 more than 4 milIions m$^3$/day were the total capacity of RO desalination plants and in 1995 more than 180.000 m$^2$ of ultrafiltration membranes were installed for the treatment of wheys and milk (2) (3).

• 멤브레인
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• 제7권4호
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• pp.191-198
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• 1997

기체 투과도 및 기계적 강도가 높은 고분자 비대칭막을 상분리법으로 제조하기 위해 막 제조 메카니즘을 규명하는 연구를 수행하였다. 기본적인 연구가 많이 이루어진 폴리스티렌, 이에 비해 용매와의 관계가 덜 알려져 있는 폴리아미드이미드인 Torlon과 3,3'4,4'-benzophenontetracarboxylic diahmydride와 1,4-phenylene diarnine로 이루어진 폴리이미드를 여러 용매에 녹여 얻어진 캐스팅 용액으로부터 비대칭막을 제조하였다. 용매와 비용매와의 혼합열과 막 구조의 관계로부터, 막의 구조를 결정하는 데에는 용매와 비용매의 혼합열이 크게 영향을 미침을 알 수 있었다. 이 결과로부터 폴리술폰 막의 구조를 용매 첨가제를 사용하여 조절하였다. 캐스팅 고분자 용액이 비용매를 만날 때 용매와 비용매와의 혼합열이 두 물질의 교환 속도에 영향을 미쳐 결국에는 막의 구조에 영향을 미치는 데에 대한 이론적인 고찰도 아울러 수행하였다.

• 한국수소및신에너지학회논문집
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• 제32권5호
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• pp.308-314
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• 2021

Chemical durability issue in polymer electrolyte membranes has been a challenge for the commercialization of polymer electrolyte membrane fuel cells (PEMFCs). In this study, we proposed a manufacturing method of Nafion composite membrane containing a stable polyimide antioxidant to improve the chemical durability of the membrane. The thermal casting of the Nafion solution with poly (amic acid) induced polyimide reaction. We evaluated proton conductivity, oxidative stability with ex-situ Fenton's test, and fluoride ion emission to analyze the effect of polyimide antioxidants. We confirmed that incorporating the polyimide antioxidant improves the chemical durability of the Nafion membrane while maintaining inherent proton conductivity.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.156-163
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• 2018

High-performance mixed-matrix membranes that comprise both zeolitic imidazolate framework-8 (ZIF-8) and graphene oxide (GO) were synthesized with a solution casting technique to realize excellent $CO_2/CH_4$ separation. The incorporation of ZIF-8 nanocrystals alone in ODPA-TMPDA polyimide can be used to significantly enhance $CO_2$ permeability compared with that of pure ODPA-TMPDA. Meanwhile, the addition of a GO nanostack alone in ODPA-TMPDA contributes to improved $CO_2/CH_4$ selectivity. Hence, a composite membrane that contains both fillers displays significant enhancements in $CO_2$ permeability (up to 60%) and $CO_2/CH_4$ selectivity (up to 28%) compared with those of pure polymeric membrane. Furthermore, in contrast to the ZIF-8 mixed-matrix membrane, which showed decreased mechanical stability, it was found that the incorporation of GO could improve the mechanical strength of mixed-matrix membranes. Overall, the synergistic effects of the use of both fillers together are successfully demonstrated in this paper. Such significant improvements in the mixed-matrix membrane's $CO_2/CH_4$ separation performance and mechanical strength suggest a feasible and effective approach for potential biogas upgrading and natural gas purification.

• 멤브레인
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• 제32권5호
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• pp.304-313
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• 2022

활성 의약품 성분(APIs)의 존재가 수생 생태계와 인간의 건강에 위험하다는 증거가 있다. 물에 항생물질인 테트라사이클린과 같은 API가 존재하면 미생물에 항균제 내성(AMR)이 발생해 개인과 사회에 막대한 비용이 발생한다. TiO₂ 또는 비스무트 기반 촉매와 같은 촉매가 내장된 막은 유기 유출물을 분해하고 폐수로부터 분리한다. 촉매의 광촉매 활성은 귀금속 도핑 및 탄소성 물질의 첨가 및 다른 반도체와의 헤테로 접합 형성으로 향상될 수 있다. 광촉매의 회수는 고분자 막에서 광촉매의 고정화를 통해 가능하다. 이 검토에서는 물 속 항생제의 분해가 논의된다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.56-57
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• 2006

The ultra pH-sensitive polymeric mixed micelles based on poly(L-histidine) chemistry and constructed from block copolymers containing polyHis, present four functionalities as decreasing pH: ligand exposure at pH 7.0, micelle destabilization below pH 6.8, enhanced DOX release and endosomal membrane disruption. The first functionality is expected to endow tumor pH specificity to nonspecific ligands and the rest ones may help to treat solid tumors that are hard-to-treat by conventional chemotherapy (resistant tumors). The concept was proven in vitro studies and in vivo model.

• Membrane and Water Treatment
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• 제9권4호
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• pp.221-231
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• 2018

A new procedure to produce poly(vinylidene fluoride)/boron nitride hybrid membrane is presented for application in membrane distillation (MD) process. The influence of hexagonal boron nitride (h-BN) incorporation on the performance of the polymeric membranes is studied through the present investigation. For this aim, h-BN nanopowders were successfully synthesized using the simple chemical vapor deposition (CVD) route and subsequent solvent treatments. The resulting h-BN nanosheets were blended with poly(vinylidene fluoride) (PVDF) solution. Then, the prepared composite solution was subjected to phase inversion process to obtain PVDF/h-BN hybrid membranes. Various examinations such as scanning electron microscopy (SEM), wettability, permeation flux, mechanical strength and liquid entry pressure (LEP) measurements are performed to evaluate the prepared membrane. Moreover, Air gap membrane distillation (AGMD) experiments were carried out to investigate the salt rejection performance and the durability of membranes. The results show that our hybrid PVDF/h-BN membrane presents higher water permeation flux (${\sim}18kg/m^2h$) compared to pristine PVDF membrane. In addition, the experimental data confirms that the prepared nanocomposite membrane is hydrophobic (water contact angle: ${\sim}103^{\circ}$), has a porous skin layer (>85%), as well competitive fouling resistance and operational durability. Furthermore, the total salt rejection efficiency was obtained for PVDF/h-BN membrane. The results prove that the novel PVDF/h-BN membrane can be easily synthesized and applied in MD process for salt rejection purposes.