• Proceedings of the Membrane Society of Korea Conference
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• 2004.11a
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• pp.139-141
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• 2004

• Proceedings of the Membrane Society of Korea Conference
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• 2005.05a
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• pp.100-103
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• 2005

• Korean Membrane Journal
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• v.6 no.1
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• pp.55-60
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• 2004

In recent years, an increasing interest in membrane technology has been observed in chemical and environmental industry. Membrane technology has advantages of low cost, energy saving and environmental clean technology comparing to conventional separation processes. Pervaporation is one of new advanced membrane technology applied for separation of azeotropic mixtures, aqueous organic mixtures, organic solvent and petrochemical mixtures. Sodium alginate composite membranes were prepared for the enhancement of long-term stability of pervaporation performance of water-ethanol mixture using pervaporation. Sodium alginate membranes were crosslinked with CaCl$_2$ and coated with polyelectrolyte chitosan to protect washing out of calcium ions from the polymer. The surface structures of PAN and hydrolysed PAN membrane were confirmed by ATR Fourier transform infrared (FT-IR). A field emission scanning electron microscopy (FE-SEM; Jeol 6340F) operated at 15 kV. Concentration profiles for Ca in the membrane surface and membrane cross-section were taken by an energy dispersive X-ray (EDX) analyser (Jeol) attached to the field emission scanning electron microscopy (Jeol 6340F). Pervaporation experiments were done with several operation run times to investigate long-term stability of the membranes.

• Carbon letters
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• v.14 no.1
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• pp.40-44
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• 2013

The bipolar plate is the most important and most costly component of proton exchange membrane fuel cells. The development of a suitable low density bipolar plate is scientifically and technically challenging due to the need to maintain high electrical conductivity and mechanical properties. Here, bipolar plates were developed from different particle sizes of natural and expanded graphite with phenolic resin as a polymeric matrix. It was observed that the particle size of the reinforcement significantly influences the mechanical and electrical properties of a composite bipolar plate. The composite bipolar plate based on expanded graphite gives the desired mechanical and electrical properties as per the US Department of Energy target, with a bulk density of 1.55 $g.cm^{-3}$ as compared to that of ~1.87 $g.cm^{-3}$ for a composite plate based on natural graphite (NG). Although the bulk density of the expanded-graphite-based composite plate is ~20% less than that of the NG-based plate, the I-V performance of the expanded graphite plate is superior to that of the NG plate as a consequence of the higher conductivity. The expanded graphite plate can thus be used as an electromagnetic interference shielding material.

• Macromolecular Research
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• v.13 no.6
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• pp.514-520
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• 2005

Composite membranes of Nafion and sulfonated poly(arylene ether sulfone) were prepared. Sulfonated poly(arylene ether sulfone)s with different degrees of sulfonation were blended with Nafion to reduce the methanol crossover. The morphology, proton conductivity and methanol permeability of the resulting composite membranes were investigated by SEM, EDAX, AC impedance spectroscopy and permeability measuring instrument. The cross­sections of the composite membranes showed a phase separated morphology. The morphology and phase separation mechanism could be controlled by varying the blend ratio and the degree of sulfonation of poly(arylene ether sulfone). These complex morphologies can be applied for reducing methanol crossover. The methanol permeability and proton conductivity of the composite membranes were lower than those of Nafion 117 membrane since the development of an ionic pathway in the blend membrane was more difficult than that in Nafion itself.

• Membrane Journal
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• v.17 no.1
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• pp.14-22
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• 2007

This is the research about the concentration of trace Magnolia flavor components in water by pervaporation. We have investigated the change of selectivity depending on support membrane structure and active layer thickness using prepared PVDF/PDMS composite membrane. Through the pure water flux test for PVDF support membrane, we could indirectly confirm that as the coagulation temperature decreases and the polymer concentration increases, the surface porosity and pore diameter decreases. Appling these results to transport mechanism, we could explain the effect of support membrane structure for the composite membrane. The selectivity increases as the thickness of PDMS active layer increases. We could know that there is a limitation to describe the transport on the active layer by Fick's law through these results.

• Membrane Journal
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• v.31 no.5
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• pp.304-314
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• 2021

Climate change results in unusual weather pattern and affects annual rain fall severely. At the same time, growing industrialization leads to higher energy demand and leakage from petrochemical industry and tanker leads to water pollution. In this scenario, finding out solution to generate clean water is highly essential. For oil/water separation, there are several methods available such as chemical precipitation and adsorption but membrane separation technique is considered to be a more cost and energy efficient process. Amphiphilicity nature of membrane are enhanced by making composite membrane with 2D material such as MXene, resulting in good electrical conductivity and hydrophilicity. This review is mainly classified into two sections: pure MXene and modified MXene. A variety of polymer is used to prepare composite membranes and MXene is modified to further enhance the properties suitable for particular applications.

• Membrane Journal
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• v.15 no.2
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• pp.141-146
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• 2005

In this study, carbon composites were prepared using carbon graphite, thermoset resin, and carbon black. Oxygen permeability was measured using the continuous flow gas permeation analyzer as a function of composition and processing conditions. The experimental results showed that the oxygen permeability increased as the carbon black content increased, whereas the oxygen permeability decreased as the pressing time increased. The oxygen permeability was not affected by the processing pressure.

• Korean Membrane Journal
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• v.10 no.1
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• pp.20-25
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• 2008

Proton conducting composite membranes were prepared by solution blending of poly(vinylidene fluoride-co-chlorotrifluoroethylene)-graft-poly(sulfopropyl methacrylate) (P(VDF-CTFE)-g-PSPMA) graft copolymer and heteropolyacid (HPA). The P(VDF-CTFE)-g-PSPMA graft copolymer was synthesized by atom transfer radical polymerization (ATRP) using direct initiation of the secondary chlorines of P(VDF-CTFE). FT-IR spectroscopy revealed that HPA nanoparticles were incorporated into the graft copolymer via hydrogen bonding interactions. The water uptake of membranes continuously decreased with increasing HP A concentration up to 45wt%, after which it slightly increased. It is presumably due to the decrease in number of water absorption sites due to hydrogen bonding interaction between the HP A particles and the polymer matrix. The proton conductivity of membranes increased with increasing HPA concentration up to 45wt%, resulting from both the intrinsic conductivity of HP A particles and the enhanced acidity of the sulfonic acid of the graft copolymer.

• Membrane Journal
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• v.33 no.6
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• pp.447-453
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• 2023

The performance of computer systems and the development of various computer simulation programs have made it possible to analyze chemical systems composed of more complex elements, and accordingly, research using molecular dynamics simulation is being actively conducted. Research on calculating the gas permeation characteristics of polymer membranes by molecular dynamics, which was previously conducted mainly through experiments, is receiving attention for gas barrier membranes used in food packaging and pharmaceuticals. Recently, there has been a report that a gas barrier effect appears when a coating film is made using silk fibroin, and in this study, a study was conducted using molecular dynamics simulation to confirm whether an oxygen barrier effect appears when a composite film is made using silk fibroin. We built a single model, calculated the gas permeation characteristics, and compared it with the experimental value to confirm that the model reflects the actual experimental results. Actual composite membrane models were then built and the gas movement path within the polymer was analyzed. As a result, oxygen molecules were found that they could not pass through and was blocked in the fibroin region. Therefore, the composite membrane with silk fibroin has excellent oxygen barrier property and is expected to be useful in food packaging, etc.