http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Energy storage electrodes based on NiO nanosheet grown directly on mesoporous TiN films
민효준,김종학 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
We report fabrication of electrode consisting of NiO nanosheets (NiONS) grown directly on a mesoporous TiN (meso-TiN) film templated by the PVC-g-POEM graft copolymer via a solvothermal method. The interconnected mesoporous and ultrathin structure induced large surface area and effective electron pathway enhancing their specific capacitance and electrochemical properties. As TiN film prepared without the PVC-g-POEM showed low porosity, it is clear that templating by PVC-g-POEM caused high electrode performance properties of TiN film. Owing to the properties of the NiO-NS and meso-TiN heteronanostructure, the NiO-NS/meso-TiN supercapacitor exhibited a high capacitance of 104 mFcm<sup>-2</sup>) with excellent cycle stability (86% after 2000 cycles) as well as great flexibility providing an efficient way to design flexible energy storage devices.
민효준,김종학 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
We report mixed-matrix membranes containing nanocage-like hollow H-ZIF polyhedral nanocrystals in poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) copolymer for CO<sub>2</sub>/CH<sub>4</sub> separation. The H-ZIF polyhedral nanocrystals were synthesized via heteroepitaxial growth of a ZIF-8 shell and excavation of ZIF-67 sacrificial templates. Because of the amphiphilic properties of the PVC-g-POEM, the microphase-separated structure has been well induced resulting dispersion of H-ZIF in the membrane. The hollow structure of H-ZIF polyhedral nanocrystals induced decrease of gasdiffusion resistance which leads to high gas separation performance. Furthermore, CO<sub>2</sub>-philic amine groups in the imidazole linkers of the H-ZIF increased CO<sub>2</sub> separation performance. MMM exhibited CO<sub>2</sub> permeability of with 210.6 barrer which is about 5 times higher than that of neat PVC-g-POEM and CO<sub>2</sub>/CH<sub>4</sub> selectivity of 14.3 close to upper bound reported by Robeson in 2008.
민효준,정주환,강미소,김종학 한국막학회 2019 멤브레인 Vol.29 No.3
In this work, we demonstrate a facile process to prepare an electrolyte membrane for the supercapacitor based on a graft copolymer consisting of starch and poly(acrylonitrile) (PAN). The graft copolymer (starch-g-PAN) was synthesized via free radical polymerization initiated by ceric ions. The starch-g-PAN was dissolved in ionic liquid, i.e. 1-ethyl-3-methylimidazolium dicyanamide (EMIM DCA) without any organic solvents at room temperature. The gelation of polymer electrolyte membranes occurred by applying high temperature, i.e. 100°C for 1 hour. The resultant electrolyte membrane was flexible and thus applied to flexible solid supercapacitors. The performance of the supercapacitor based on starch-g-PAN graft copolymer electrolyte reached 21 F/g at a current density of 0.5 A/g. The cell also showed high cyclic stability with 86% of retention rate within 10,000 cycles. The preparation of starch-g-PAN based polymer electrolyte membrane provides opportunities for facile fabrication of flexible solid supercapacitors with good performance.
문승재,민효준,김나운,김종학 한국막학회 2019 멤브레인 Vol.29 No.4
In this paper, we develop a polymeric blend membrane based on CO2-philic poly(2-[3-(2H-benzotriazol-2-yl)- 4-hydroxyphenyl] ethyl methacrylate)-poly(oxyethylene methacrylate) (PBEM-POEM) comb copolymer, which was synthesized by facile free radical polymerization. The PBEM-POEM (PBE) comb copolymer was blended with a commercial oligomer, low-molecular-weight poly(ethylene glycol) (PEG, Mw = 200 gmol-1) with various ratios to prepare CO2/N2 separation membranes. From the result of CO2/N2 separation test of the PBE/PEG blend membranes with the various PEG contents, we could conclude that with increasing PEG content, the CO2/N2 selectivity significantly increased while the CO2 permeability decreased showing trade-off relationship. However, when comparing the performance of the PBE/PEG (9 : 1) with the PBE/PEG (7 : 3) membrane, the CO2 permeance decreased by only 8.3%, while the N2 permeance decreased by 69.1%. Therefore, the CO2/N2 selectivity dramatically increased from 33.8 to 100.3. This could be because the POEM chains, which account for 80% of the PBE copolymer, favorably interact with PEG and lead to a more compact chain structure, which was confirmed by FT-IR, XRD and SEM analysis. The PBE/PEG (7 : 3) blend membrane had the most optimal gas separation performance, showing a CO2 permeance of 170.5 GPU and CO2/N2 selectivity of 100.3.
Chae-Hee Seo,Si-Woo Lim,민효준,김종학,Jeong-hoon Kim 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.114 No.-
Aromatic polyimides are promising membrane materials for gas separation due to their excellent gas separationproperties. Herein, two soluble semi-alicyclic polyimides were synthesized via a one-step thermalimidization process with two semi-alicyclic dianhydrides possessing kink structures: bicyclo[2,2,2] oct-7ene-2,3,5,6-tetracarboxylic dianhydride (BCDA) and 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (DOCDA), and a flexible aromatic diamine: 4,40-Oxydianiline (ODA). Theirhomo- and blended membranes were prepared in various mixing ratios (100/0, 75/25, 50/50, 25/75, and0/100) and their gas permeation properties were investigated for five gases (H2, CO2, O2, N2, and CH4) andselectivity for five gas pairs (H2/CH4, H2/N2, CO2/CH4, CO2/N2, and O2/N2). The homopolyimides (BCDAODA,DOCDA-ODA) exhibited amorphous structure without crystallinity and good solubilities in the castingsolvents. BCDA-ODA showed larger d-spacing/FFV values, higher gas diffusivities/gas solubilities thanDOCDA-ODA, resulted in higher gas permeabilities and lower gas selectivity, which were remarkablyaffected by feed temperature. Also, the gas permeability and selectivity of the blended membranes weredependent upon the BCDA/DOCDA mole ratio. The good gas separation performances of homo- andblended membranes were observed for H2/CH4, H2/N2, CO2/CH4, and O2/N2, which are comparable tothose of commercial membrane materials such as P84, PSF, CA, Matrimid, etc.