본 연구에서는 리튬이온전지용 친수화된 세퍼레이터의 전기화학적 성능에 대한 연구를 진행하였다. 리튬이온전지 용 분리막으로 사용되는 폴리올레핀 소재는 소수성이고, 카보네이트 계열의 유기용매를 사용하는 전해액은 친수성을 가진다. 따라서 리튬이온전지는 수계전해액을 사용하기 때문에 폴리올레핀계 분리막에 다양한 친수성 고분자를 도입하여 친수화 처 리하였다. 코팅된 세퍼레이터의 변화를 평가하기 위해, 표면 관찰, 코팅시간에 따른 친수화도, 다공성, 젖음성에 대한 특성평 가를 수행하였다. 최종적으로 리튬이온이 코팅된 세퍼레이터의 저항과., 이온전도도를 측정하여 리튬이온전지 성능평가를 진 행하였다. PMVE로 코팅한 세퍼레이터의 친수화 정도가 우수하며, 세퍼레이터의 기공이 잘 유지되어 우수한 이온전도도를 나타냄으로써 이차전지 배터리에 적용을 위한 잠재성을 가짐을 확인하였다.

Silicon alloys are considered promising anode active materials to replace Li-ion batteries by graphite powder, because they have a relatively high capacity of up to 4200 mAh/g, and are environmentally friendly and inexpensive ECO-materials. However, its poor charge/discharge properties, induced by cracking during cycles, constitute their most serious problem as anode electrode. In order to solve these problems, Si-Ge-Al alloys with porous structure are designed as anode alloy powders, to improve cycling stability. The alloys are melt-spun to obtain the rapidly solidified ribbons, and then ball-milled to make fine powders. The powders are etched using 1 M HCl solution, which gives the powders a porous structure by removing the element Al. Subsequently, in this study, the microstructures and the characteristics of the etched powders are evaluated for application as anode materials. As a result, the etched porous powder shows better electrochemical properties than as-milled Si-Ge-Al powder.

The thermally induced phase separation(TIPS) method offers higher reproducibility with lower tendency for defect formation and narrower pore size distribution, rendering the method more suitable for microfiltration(MF) and ultrafiltration(UF) applications. PVDF is widely used in membrane technology due to their excellent chemical resistance and strong mechanical properties. In case of MF and UF applications, the stretching method has been applied for increasing the performance of membrane by extending pore size. In this work, the effects of dope and bore flow rates and dope composition on the tensile strength of membranes was investigated. A design of experiment(DOE) analysis was used to understand the effects of the stretching parameters such as temperature, stretching ratio and holding time on the membrane performance.

The asymmetric porous polybenzimidazole membranes were prepared to increase the doping level of phosphoric acid to increase ionic conductivity, to block the fuel/oxidant gas permeation to keep open circuit potential and to maintain chemical and mechanical stability to have good durability for proton exchange membrane fuel cells. The poly(benzimidazole) was synthesized and the asymmetric porous membranes were prepared by pore forming agents and proprietary film formation technology. As a result, it showed higher ionic conductivity, low gas permeability and similar chemical and mechanical stability.

The PBI membrane doped with phosphoric acid (PA) is one of the promising candidates for HT-PEMFC. The proton conductivity of PA doped PBI depends on the acid doping level (ADL). The method to fabricate porous PBI membrane using porogen were reported to increase the ADL. However, high ADL cause complete loss of the mechanical strength of the membranes. In this research, the dead-end porous PBI membranes were prepared using progen to increase the mechanical strength than porous PBI membrane and proton conductivity. The dead-end porous PBI membranes were investigated in terms of ionic conductivity, ADL, SEM and mechanical strength.

Membrane application for CO2 capture is competing with other methods such as amine absorption or absorbent, by reasons of low energy and cost effect. Though membrane separation is promising technology, there exists critical challenge: ‘the upper bound.’ Most of researches have focused on improving gas transport properties of selective layer, but we recognized the importance of membrane support layer shich highly affects affinity with coating layer. Here we adjusted several fabrication conditions for highly porous PAN membrane by NIPS method; concentration, temperature, and additive. In this study, experimental results regarding porosity and pore size, are compared to theoretical dusty-gas model. Moreover, we prepared composite membrane and compared fabricated membrane with commercial one in terms of gas permeance and selectivity.

Graphene oxide (GO) has been extensively studied for membrane material for gas and liquid separation due to its outstanding features such as selective CO2 or water vapor transport properties. Although GO membranes can be easily fabricated in the form of thin-film composite membranes by using high-flux polymeric support membranes, it shows relatively low gas permeability due to high tortuosity. Here we report the way to improve gas permeation rate through porous graphene oxide by reducing the gas permeation pathway, with maintaining GO’s two-dimensional structure. We also used polymer, which has high CO2/N2 selectivity, and prepared GO/polymer composite membranes as a function of GO concentration. This study will provide a further insight on how such two-dimensional nanosheets can be harmonized with polymer and improved membrane properties.

This work investigated the decomposition of aqueous anatoxin-a originated from cyanobacteria using an underwater dielectric barrier discharge plasma system based on a porous ceramic tube and an alternating current (AC) high voltage. Plasmatic gas generated inside the porous ceramic tube was uniformly dispersed in the form of numerous bubbles into the aqueous solution through the micro-pores of the ceramic tube, which allowed an effective contact between the plasmatic gas and the aqueous anatoxin-a solution. Effect of applied voltage, treatment time and the coexistence of nutrients such as NO3 -, H2PO4 - and glucose on the decomposition of anatoxin-a was examined. Chemical analyses of the plasma-treated anatoxin-a solution using liquid chromatography-mass spectrometry (LC-MS) and ion chromatography (IC) were performed to elucidate the mineralization mechanisms. Increasing the voltage improved the anatoxin-a decomposition efficiency due to the increased discharge power, but the energy required to remove a given amount of anatoxin-a was similar, regardless of the voltage. At an applied voltage of 17.2 kV (oxygen flow rate: 1.0 L min-1), anatoxin-a at an initial concentration of 1 mg L-1 (volume: 0.5 L) was successfully treated within 3 min. The chemical analyses using LC-MS and IC suggested that the intermediates with molecular weights of 123~161 produced by the attack of plasma-induced reactive species on anatoxin-a molecule were further oxidized to stable compounds such as acetic acid, formic acid and oxalic acid.

폴리카프로락톤(PCL)에 NaCl을 혼합한 용액을 블레이드법에 의하여 막형태로 제조한 후 NaCl을 추출하는 염출 법을 이용하여 조직공학적으로 사용할 3차원 다공망을 갖는 멤브레인 형태의 지지체를 제조하였다. 본 연구에서는 성형된 멤 브레인의 건조조건과, NaCl 입자의 크기, NaCl의 혼합량을 각각 다르게 하여 제조하였다. 별도로 제작한 고분자용액 공급장 치를 이용하여 PCL/클로로포름(CHCl3) 용액에 NaCl 입자가 균일하게 혼합된 용액을 유리판에 분주하여 필름 어플리케이터 를 사용하여 블레이드법에 의한 멤브레인을 제조하였다. 멤브레인 지지체에는 NaCl 입자에 의한 거대기공과 거대기공을 이 루는 구조벽에서는 CHCl3의 증발에 의한 미세기공이 함께 복합적으로 상호 연결되어 형성되었다.

Co-embedded graphitic porous carbon nanofibers(Co-GPCNFs) are synthesized by using an electrospinning method. Their morphological, structural, electrochemical, and photovoltaic properties are investigated. To obtain the optimum condition of Co-GPCNFs for dye-sensitized solar cells(DSSCs), the amount of cobalt precursor in an electrospinning solutuion are controlled to be 0 wt%(conventional CNFs), 1 wt%(sample A), and 3 wt%(sample B). Among them, sample B exhibited a high degree of graphitization and porous structure compared to conventional CNFs and sample A, which result in the performance improvement of DSSCs. Therefore, sample B showed a high current density(JSC, 12.88 mA/cm2) and excellent power conversion efficiency(PCE, 5.33 %) than those of conventional CNFs(12.00 mA/cm2, 3.78 %). This result can be explained by combined effects of the increased contact area between the electrode and elecytolyte caused by improved porosity and the increased conductivity caused by the formation of a high degree of graphitization. Thus, the Co-GPCNFs may be used as a promising alternative of Pt-free counter electrode in DSSCs.

Porous thick film of alumina which is fabricated by freeze tape casting using a camphene-camphor-acrylate vehicle. Alumina slurry is mixed above the melting point of the camphene-camphor solvent. Upon cooling, the camphene- camphor crystallizes from the solution as particle-free dendrites, with the Al2O3 powder and acrylate liquid in the interdendritic spaces. Subsequently, the acrylate liquid is solidified by photopolymerization to offer mechanical properties for handling. The microstructure of the porous alumina film is characterized for systems with different cooling rate around the melting temperature of camphor-camphene. The structure of the dendritic porosity is compared as a function of ratio of camphene-camphor solvent and acrylate content, and Al2O3 powder volume fraction in acrylate in terms of the dendrite arm width.

Reduction in the amount of Ag salts in the membranes is required for practical applications in the industry. However, since the separation performance is directly related to the amount of Ag salts, it has been difficult to reduce the amount of Ag salts. In this study, we succeeded in preparing polymer/Ag salts/Al(NO3)3 membranes with 30% reduction in the amount of Ag salts by utilizing KIT-6, which is a porous material. When KIT-6 was incorporated into the polymer/Ag salts/Al(NO3)3 membrane, the separation performance for propylene/propane mixed gas increased with a propylene over propane selectivity of 20 and mixed gas permeance of 10 GPU. The enhanced separation performance is attributed to both the coordination of hydroxyl groups in KIT-6 with Ag ions and the porous properties of KIT-6.

A simple method for generating pores in a cellulose acetate (CA) polymer matrix was developed using a combination of an ionic liquid and water pressure treatment. A porous CA membrane was successfully prepared using the ionic liquid (BMIM-BF4) and subsequent water pressure treatment. Pores were generated in the CA polymer matrix when the CA/ionic liquid composite was subjected to water pressure. The characteristics of the thus-generated porous membrane were evaluated using porosimetry. FT-IR and Thermogravimetric analysis (TGA) showed that when the CA polymer was subjected to water pressure, most of the BMIM-BF4 incorporated in the polymer during its preparation was removed, thereby generating the observed pores. In addition, it was observed that the flux varied with water pressure, indicating that the pore size was controllable.

단감을 재배하는 농가에서 저장성을 향상 시킬 수 있는 값싸고 쉬운 방법을 개발하기 위해 본 연구를 수행 했다. 농가 관행 LDPE 포장재 내에 동봉할 수 있는 천연소재(대나무활성숯, 왕겨숯, 겔라이트)를 선발하여 상온과 저온환경에서 가용성 고형물 함량, 경도, 식미, 부패도, 연화도의 변화를 1주일 또는 2주일 간격으로 조사 하였다. 대나무활성숯을 동봉한 LDPE 포장 방법이 단순 LDPE 포장 방법 보다 저장성 및 품질을 을 좋게 유지하였다. 대나무활성숯을 동봉한 LDPE 포장 방법은 관행 농법 농가와 유기 농법 농가 모두에서 장기 저장 시 그리고 유통 중 온도변화 시 저장성을 향상 시킬수 있는 값싸고, 손쉬운 방법으로 활용할 수 있을 것으로 판단된다.

To fabricate porous SiC-Si composites for heating element applications, both SiC powders and Si powders were mixed and sintered together. The properties of the sintered SiC-Si body were investigated as a function of SiC particle size and/or Si particle contents from 10 wt% to 40 wt%, respectively. Porous SiC-Si composites were fabricated by Si bonded reaction at a sintering temperature of 1650 oC for 80 min. The microstructure and phase analysis of SiC-Si composites that depend on Si particle contents were characterized using scanning electron microscope and X-ray diffraction. The electrical resistivity of SiC-Si composites was also evaluated using a 4-point probe resistivity method. The electrical resistivity of the sintered SiC-Si body sharply decreased as the amount of Si addition increased. We found that the electrical resistivity of porous SiC-Si composites is closely related to the amount of Si added and at least 20 wt% Si are needed in order to apply the SiCSi composites to the heating element.

본 실험에서는 다양한 PP를 이용하여 필름과 중공사의 형태로 압축과 사출을 통해서 제작되었다. 권취속도를 달리하여 중공사막을 제조하였으며, 코어로는 질소를 사용하였다. 제작된 필름과 중공사막은 만능재료시험기를 이용하여 응력과 변현율을 측정하였다. 그리고 시차주사열량계(DSC)를 이용하여 각각의 샘플의 Tm, Tc, 결정화도를 측정하였고, 냉각속도에 따른 결정화도의 거동을 조사하였다. 전계방출형주사현미경(FE-SEM)을 이용하여 단면, 표면의 모폴로지를 관찰하였다.

The porous metals are known as relatively excellent characteristic such as large surface area, light, lower heat capacity, high toughness and permeability. The Fe-Cr-Al alloys have high corrosion resistance, heat resistance and chemical stability for high temperature applications. And then many researches are developed the Fe-Cr-Al porous metals for exhaust gas filter, hydrogen reformer catalyst support and chemical filter. In this study, the Fe-Cr-Al porous metals are developed with Fe-22Cr-6Al(wt) powder using powder compaction method. The mean size of Fe-22Cr-6Al(wt) powders is about 42.69 μm. In order to control pore size and porosity, Fe-Cr-Al powders are sintered at 1200~1450oC and different sintering maintenance as 1~4 hours. The powders are pressed on disk shapes of 3 mm thickness using uniaxial press machine and sintered in high vacuum condition. The pore properties are evaluated using capillary flow porometer. As sintering temperature increased, relative density is increased from 73% to 96% and porosity, pore size are decreased from 27 to 3.3%, from 3.1 to 1.8 μm respectively. When the sintering time is increased, the relative density is also increased from 76.5% to 84.7% and porosity, pore size are decreased from 23.5% to 15.3%, from 2.7 to 2.08 μm respectively.

This study investigated the microstructure and tensile properties of a recently made block-type Ni-Cr-Al powder porous material. The block-type powder porous material was made by stacking multiple layers of powder porous thin plates with post-processing such as additional compression and sintering. This study used block-type powder porous materials with two different cell sizes: one with an average cell size of 1,200 μm (1200 foam) and the other with an average cell size of 3,000 μm (3000 foam). The γ-Ni and γ’-Ni3Al were identified as the main phases of both materials. However, in the case of the 1,200 foam, a β-NiAl phase was additionally observed. The relative density of each block-type powder porous material, with 1200 foam and 3000 foam, was measured to be 5.78% and 2.93%, respectively. Tensile tests were conducted with strain rates of 10−2~10−4 sec−1. The test result showed that the tensile strength of the 1,200 foam was 6.0~7.1 MPa, and that of 3,000 foam was 3.0~3.3 MPa. The elongation of the 3,000 foam was higher (~9%) than that (~2%) of the 1,200 foam. This study also discussed the deformation behavior of block-type powder porous material through observations of the fracture surface, with the results above.