오랜 기후변화와 관련하여 지구온난화를 늦추고자 온실가스 중 대부분의 비율을 차지하고 있는 이산화탄소를 분리 및 저장 할 수 있는 연구가 활발하다. 본 연구에서는 고 투과성을 지닌 Polyhedral oligomeric silsesquioxane(POSS)와 이산화탄소에 대한 선택도를 지닌 Poly(ethylene glycol)을 이용하여 POSS-PEG 공중합체를 합성하였고 이를 다공성 지지체 위에 코팅하여 복합막을 제조하였다. 특성평가로는 NMR과 FT-IR 스펙트럼으로 합성의 유무를 확인한 뒤 복합막에 N2,O2,CO2 세 종류의 기체를 투과 특성함으로써 성능을 확인하였다. single gas를 투과시켰을 때 CO2/N2 선택도 24, Mixture gas를 투과시켰을 때 최대 70%의 CO2 분리성능을 나타내었다.

We developed a facile methodology for fabricating a free-standing mixed-matrix membrane (MMM) containing covalently incorporated vinyl-functionalized UiO-66-CH=CH2 particles up to 60 wt% by utilizing thiol-ene photopolymerization. FTIR, TGA, SEM, EDX, and XRD strongly supported the fact that the desired MMM containing well-dispersed UiO-66-CH=CH2 particles was successfully produced by C–S bond formation. The MMM was highly flexible and showed improved mechanical properties compared to the pristine polymeric membrane, indicating that the covalently immobilized UiO-66-CH=CH2 particles were homogeneously distributed in the polymer matrix. Gas permeability across the MMM was significantly enhanced compared with the pristine polymeric membrane as diffusion of the gas molecules was facilitated in the porous space of the MOF.

In the present work, AMC/ZnO, AMC/Au, and AMC/Zeo conjugated membranes was prepared by vapor induced phase separation (VIPS) method and used for fouling study. each membrane the nanoparticles [Zinc oxide (ZnO), gold(Au) & Zeolite (Zeo)] was used separately. The prepared membranes are characterized by surface morphology and contact angle to investigate the influence of nanoparticles. The fouling resistant ability of the AMC conjugated membranes was analyzed using bovine serum albumin(BSA) protein and calculated the series model analysis by means of resistance. The fouled membranes was investigated to realize the surface properties considered as essential for fouling propensity. The experimental results correlate the changes in BSA separation efficiency and fouling resistance properties of AMC conjugated membranes with surface morphology.

In the epoxy resin manufacturing process, carcinogenic ECH (epichlorohydrin), IPA (isopropanol) and Biphenol-A materials has been generally used. After the reaction, byproducts containing ECH/IPA/Water is remained along with final product. But, in the recovery process, ECH and IPA forming an azeotropic mixture with water containing feed solution at any temperature condition, the recovery of high purity ECH is difficult only by distillation. Therefore, pervaporation process could be suitable countermeasure due to its mild operation condition for separation of azeotropic mixtures at the point of energy and cost saving. In this study, Alumina-PVA composite membrane was prepared for pervaporation dehydration of ECH/IPA/Water feed mixtures and pervaporation performance and stability of the prepared composite membrane was identified.

반도체 제조공정 중 포토리소그래피는 반도체 제조 중 핵심 기술이며 웨이퍼위에 나노급의 패턴을 제조하는 공정이다. 웨이퍼상의 패턴이 나노급으로 작아지면서 더욱 정밀한 공정을 위하여 photo-resist 용액의 정제 기술이 매우 중요하다. photo-resist 용액 내 soft particle은 포토리소그래피 공정 중 불량을 유발하는데, 현재 개발되어진 멤브레인은 soft particle 제거 성능이 낮다. 따라서 photo-resist 용액 내 soft particle을 제거하기 위하여 PE 지지체 위에 Nylon 고분자를 함침하여 soft particle 정제 특성을 살펴보았다. 또한 팔라듐 나노입자를 합성하여 투과 특성실험에 사용하였다.

Recently developed crosslinked TR (XTR) membranes as an advanced TR material exhibit high permeability and high selectivity stemming from higher rigidity due to a simultaneous and synergetic reaction of crosslinking and thermal rearrangement. The precursor crosslinkable co-HPI precursor can be dissolved in a wide range of commercial solvents indicative of an excellent processibility. Herein, a systematic spinning process, using a newly designed crosslinkable co-HPI precursor to fabricate defect-free XTR-PBOI hollow fiber membranes with inner skin layer will be discussed based on the phase inversion kinetics of nonsolvent-induced phase separation (NIPS) method.

소수성 PE막은 높은 내화학성 및 상대적으로 낮은 가격으로 다양한 산업소재로 사용되고 있다. 이중 다공성 PE소재는 MBR, 2차전지 separator, MF등 다양한 분야에 사용되고 있으며, 목적에 따라 친수화가 필요로 한다. 하지만 PE의 화학적 안정적 구조로 친수화를 하기 위해서는 고에너지의 플라즈마처리가 필요로하지만, 다공성막의 경우 내부까지 친수화를 하기 어려워진다. 이를 해결하기 위해 간단한 용액 함침기술을 통하여 PE막을 친수화하였다. 친수화된 PE막에 수처리용 RO 및 NF막을 계면중합을 통하여 제작하였다. 본 기술을 간단한 화학적처리 방법을 통해 소수성 폴리올레핀의 적용분야 확장에 쉽게 접근할 수 있을 것으로 기대한다.

폴리벤즈이미다졸(PBI)는 현재 상용 고분자들 중에서 가장 내열성이 좋은 이종고리화합물이다. 우수한 기계적, 화학적 물성 때문에 해당 고분자는 나노공학, 전기공학, 광학, 재료공학과 같은 분야 외에도 쓰임새가 다양하다. 본 연구는 폴리벤즈이미다졸 지지체를 제조하기 위하여 전기방사를 이용하였다. PBI 방사 용액의 용매로서 DMAc를 사용하였고, LiCl은 안정제로써 사용하였다. 또한 다양한 전기방사의 조건을 변화시킴에 따라 나타나는 모폴로지를 관찰하고자 하였다. 또한, DBX를 이용한 가교반응을 통하여 보다 화학적으로 강화된 필름을 제조하였다. 나노 섬유의 화학 구조와 성분은 FT-IR와 DSC를 통해 확인하였다. 전기방사 섬유의 모폴로지는 SEM을 통해 확인하였다.

본 연구에서는 고분자인 polyacrylonitrile (PAN) 고분자에 산화 그래핀(Graphene Oxide, GO)을 첨가하여 전기방사법을 통해 나노섬유 복합막(GO-PAN)을 제조하였으며, 과량의 GO를 첨가하기 위해 표면개질 전략을 사용하였다. 계면활성제를 사용하여 GO의 표면을 간단히 변형하면 GO의 안정성 및 분산도 증가로 인해 최종적으로 분리막에 필러의 함량을 3wt%까지 증가시켰다. 이렇게 변형된 GO(mGO)의 PAN 나노섬유막으로의 도입은 원래의 PAN 나노섬유막과 GO-PAN 막에 비해 향상된 친수성과 기계적 강도를 가진다. 따라서 나노필러의 표면 개질은 최종 복합막의 성능에 영향을 미치며 이는 GO의 분산도와 상관관계가 있는 것으로 보인다.

최근 수자원 부족의 문제에 대한 탈출구를 찾기 위해 해수담수화 공정이 지속적인 연구가 이루어지고 있다. 그 중 전기흡착탈이온(EAD) 공정은 이온교환막을 이용한 전기투석법과 이온교환수지를 이용한 이온교환수지법을 혼합하여 이루어지는 공정으로 현재 사용되고 있는 해수담수화 공정의 효율을 더 높이 올려줄 것이라 예상하고 있다. 하지만, 이 공정은 이온교환막 사이에 이온교환수지가 있는 구조이기 때문에 기존 모듈보다 비교적 사이즈가 크다는 단점이 있다. 또한, 이온교환수지의 크기 분포와 당량비가 모듈의 성능에 영향을 준다. 본 연구는 현재 상용화되고 있는 이온교환공정에서 쓰이고 있는 모듈의 문제해결과 성능 향상을 위해 진행되었다. 개질을 통해 이온교환용량을 더욱 향상시키고 일반적인 이온교환수지가 아닌 더 작고 균질한 이온교환능력을 가진 이온교환 나노입자를 제조하여 제막을 진행하였고, 다양한 특성평가가 이루어졌다.

PEMFC is an eco-friendly and sustainable electrochemical generation system to convert chemical energy of fuels into electric energy. Proton exchange membrane(PEM) is key material to decide PEMFC performances. Representative PEM materials is perfluorinated sulfonic acid(PFSA) composed of a chemically stable PTFE backbone and ion conductive side chains. PFSA is classified into long-side chain(LCC-PFSA) and short-side chain(SCC-PFSA). Normally, SCC-PFSA can induce high packing density and gas barrier properties when it is made in PEM state. In spite of these advantages, it is hard to make desirable SCC-PFSA PEMs due to its relatively high Tg and low EW. In this study, the effects of PEM fabrication histories on basic properties of SCC-PFSA ionomers were observed by varying parameters such as casting solvent and thermal annealing condition.

Recently, many efforts to enhance separation performance of the reverse osmosis (RO) membranes have been made. Among them, the post treatment with organic solvent, so called solvent activation, has been recognized as an effective method to improve membrane performance. However, solvent activation enhances water flux along with the loss of NaCl rejection. Furthermore, there have been no clear mechanisms and reliable criteria of the solvent activation effects. In this study, we demonstrate that a new type of organic solvent, benzyl alcohol, can effectively activate the RO membrane to significantly enhance water permeation without deteriorating NaCl. Based on this results, we elucidate the underlying solvent activation mechanism and propose a reliable indicator of the solvent activation effect.

제련 산업의 공정수(15wt% 폐산용액)에는 다양한 희소 및 유가금속이 함유되어 있지만, 회수 처리기술 부족으로 폐기되고 있다. 이에 나노분리막을 적용하여 폐산용액에 잔존하는 금속들을 경제적으로 분리하고자 한다. 본 연구에서는 폐산에 적용 가능한 내산, 내열성을 가지는 나노분리막을 PSf 지지막 위에 수용액상으로 aliphatic amine과 유기상으로 trimesoyl chloride, diisocyanate계를 계면중합하여 제조하였다. 제조막의 2가 이온 플럭스는 15 GFD, 98%의 제거율, 1가 이온은 20% 이하의 제거율을 나타내었다. 내산성 평가는 황산 용액에 일별 노출한 후 투과평가를 진행하였으며, 그 결과 4주 이상 초기 성능을 유지하였다. 내산성 특성은 FTIR, XPS, FE-SEM등의 분석을 통해 확인하였다.

유기용매 나노여과(OSN, organic solvent nanofiltration) 분리막은 폴리이마이드(PI)나 폴리벤질이미디아졸(PBI)과 같은 특수 고분자의 개발, 상업화가 이루어지고 강한 유기용매에 견딜 수 있도록 가교를 통해 분리막의 내구성이 급격하게 향상되면서 저분자량의 합성, 정제 및 농축을 필요로하는 의약, 바이오, 식품산업에 획기적이고 효율적인 분리막 공정으로 주목 받고 있다. 하지만 여전히 고가의 고분자, 가교를 위한 복잡한 프로세스, 다량의 강한 용매 폐수 발생등 상업화를 이루는데 여러 가지 문제점들이 산재하고 있다. 본 연구는 기존 제막 방식에서 벗어나 무독성의 용제를 사용하여 단일공정으로 유기용매 나노여과 분리막을 제막하고 그 특성을 연구하였다.

This study was conducted to investigate quality characteristics of red bean gochujang prepared with different ratios of meju for eight weeks. We determined quality characteristics such as pH, moisture content, total microbial flora counts, amino-type nitrogen content, total polypenol content, and antioxidant activity. The pH decreased by fermentation period, whereas total acidity was 0.36~0.39% in the early stage of fermentation, 0.63~1.16% at four weeks of fermentation, and decreased to 0.43~0.65% after the eighth week of fermentation. Moisture content of the control (no red bean, no rice) decreased 62.13% to 50.93%, but in case of the treatment, it slightly decreased. Total cell counts revealed similar tendency at the beginning of fermentation, and at eight weeks of fermentation. In case of lactic acid bacteria, all samples except RB-1.5 (gochujang added meju made of mixing ratio of rice:soybean:red bean (1:2:1.5) slightly increased. Amino nitrogen and total polyphenol of all samples increased in the fermentation period, especially RB-1.5 sample had the highest levels than other samples. By increasing the amount of red bean, DPPH radical scavenging activities increased. In taste sensing analysis, all treat samples except RB-1.5 revealed lower sourness than the control. Also, in case of bitterness, all samples revealed low content than the control. So, by adding red bean, it can enhance taste and function of gochujang.

To study the effects of graphite shape and the composite fabricating method on the mechanical properties of graphite/copper (Gr/Cu) composites, a copper composite using graphite flakes or graphite granules as reinforcing phases is fabricated using mechanical mixing or electroless plating method. The mechanical properties of the Gr/Cu composites are evaluated by compression tests, and the compressive strength and elongation of the Gr/Cu composites using graphite granules as a reinforcing phase are compared with those of Cu composites with graphite flakes as a reinforcing phase. The compressive yield strength or maximum strength of the Gr/Cu composites with graphite granules as a reinforcing phase is higher than that of the composites using graphite flakes as a reinforcing phase regardless of the alignment of graphite. The strength of the composite produced by the electroless plating method is higher than that of the composite material produced by the conventional mechanical mixing method regardless of the shape of the graphite. Using graphite granules as a reinforcing phase instead of graphite flakes improves the strength and elongation of the Gr/Cu composites in all directions, and reduces the difference in strength or elongation according to the direction.

ZnO micro/nanocrystals are formed by a vapor transport method. Mixtures of ZnO and TiO powders are used as the source materials. The TiO powder acts as a reducing agent to reduce the ZnO to Zn and plays an important role in the formation of ZnO micro/nanocrystals. The vapor transport process is carried out in air at atmospheric pressure. When the weight ratios of TiO to ZnO in the source material are lower than 1:2, no ZnO micro/nanocrystals are formed. However, when the ratios of TiO to ZnO in the source material are greater than 1:1, the ZnO crystals with one-dimensional wire morphology are formed. In the room temperature cathodoluminescence spectra of all the products, a strong ultraviolet emission centered at 380 nm is observed. As the ratio of TiO to ZnO in the source material increases from 1:2 to 1:1, the intensity ratio of ultraviolet to visible emission increases, suggesting that the crystallinity of the ZnO crystals is improved. Only the ultraviolet emission is observed for the ZnO crystals prepared using the source material with a TiO/ZnO ratio of 2:1.

Porous metals demonstrate not only excessively low densities, but also novel physical, thermal, mechanical, electrical, and acoustic properties. Thus, porous metals exhibit exceptional performance, which are useful for diesel particulate filters, heat exchangers, and noise absorbers. In this study, SUS316L foam with 90% porosity and 3,000 μm pore size is successfully manufactured using the electrostatic powder coating (ESPC) process. The mean size of SUS316L powders is approximately 12.33 μm. The pore properties are evaluated using SEM and Archimedes. As the quantity of powder coating increases, pore size decreases from 2,881 to 1,356 μm. Moreover, the strut thickness and apparent density increase from 423.7 to 898.3 μm and from 0.278 to 0.840 g/cm3, respectively. It demonstrates that pore properties of SUS316L powder porous metal are controllable by template type and quantity of powder coating.

This study investigates the microstructure and wear properties of cermet (ceramic + metal) coating materials manufactured using high velocity oxygen fuel (HVOF) process. Three types of HVOF coating layers are formed by depositing WC-12Co, WC-20Cr-7Ni, and Cr3C2-20NiCr (wt.%) powders on S45C steel substrate. The porosities of the coating layers are 1 ± 0.5% for all three specimens. Microstructural analysis confirms the formation of second carbide phases of W2C, Co6W6C, and Cr7C3 owing to decarburizing of WC phases on WC-based coating layers. In the case of WC-12Co coating, which has a high ratio of W2C phase with high brittleness, the interface property between the carbide and the metal binder slightly decreases. In the Cr3C2-20CrNi coating layer, decarburizing almost does not occur, but fine cavities exist between the splats. The wear loss occurs in the descending order of Cr3C2-20NiCr, WC-12Co, and WC-20Cr-7Ni, where WC-20Cr-7Ni achieves the highest wear resistance property. It can be inferred that the ratio of the carbide and the binding properties between carbide–binder and binder–binder in a cermet coating material manufactured with HVOF as the primary factors determine the wear properties of the cermet coating material.

Molybdenum silicide has gained interest for high temperature structural applications. However, poor fracture toughness at room temperatures and low creep resistance at elevated temperatures have hindered its practical applications. This study uses a novel powder metallurgical approach applied to uniformly mixed molybdenum silicidebased composites with silicon carbide. The degree of powder mixing with different ball milling time is also demonstrated by Voronoi diagrams. Core-shell composite powder with Mo nanoparticles as the shell and β-SiC as the core is prepared via chemical vapor transport. Using this prepared core-shell composite powder, the molybdenum silicide-based composites with uniformly dispersed β-SiC are fabricated using pressureless sintering. The relative density of the specimens sintered at 1500oC for 10 h is 97.1%, which is similar to pressure sintering owing to improved sinterability using Mo nanoparticles.