• Membrane Journal
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• v.13 no.3
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• pp.182-190
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• 2003

Carbon molecular sieve (CMS) membranes were prepared by the pyrolysis of polyvinylpyrrolidone containing polyimide precursors. We have prepared the polymer precursors, pyrolyzed polymer and investigated the effect of pyrolyzing polymer on the characteristics of carbon structures and gas separation properties of the CMS membranes. Thermogravimetric analysis (TGA) showed the two-step decomposition of polymer precursor. First decomposition of the pyrolyzing polymer began around $400^{\circ}C$ while carbonizing polymer showed the decomposition around $550^{\circ}C$. The gas permeabilities through the CMS membranes were enhanced by the introduction of the pyrolyzing polymer and decreased with increased final pyrolysis temperature. The CMS membrane pyrolyzed at $550^{\circ}C$. derived from precursor containing 5wt% PVP as a pyrolyzing polymer showed gas permeability for $O_2$ of 808 Barrers [$10^{-10}cm^3 (STP)cm/cm^2scmHg]$ and $O_2/N_2$ selectivity of 7.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.481-487
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• 2010

Recently membrane-based gas separation has attracted a great deal of research interests due to the growing demands on greener technologies. Current membrane-based gas separation is dominant by polymer membranes and limited mostly to non-condensable gases even though condensable gases such hydrocarbon isomers are much more attractive. This is primarily due to the limitations of polymer materials. Zeolites and their composites with polymer can offer alternative to current polymeric membranes owing to their superior separation and chemical/thermal properties. This review is intended to provide a brief overview on zeolite and zeolite/polymer composite membranes for gas separation applications.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.478-484
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• 2016

Polyether ether ketone (PEEK) composite membranes have been intensively investigated for polymer electrolyte membrane water electrolysis (PEMWE). Covalently linked (CL) sulfonated polyether ether ketone (SPEEK) and cellulose polymer composite membranes were prepared and characterized. Polyether ether ketone (PEEK) and cellulose were sulfonated and then were covalently linked by 1,4-diiodobutane to produce covalently linked SPEEK and cellulose polymer composite membranes. The composite membranes showed better thermostability and electrochemical properties than SPEEK. The membranes were prepared by sol-gel casting method. CL-SPEEK/Cellulose composite membrane featured 0.2453 S/cm of proton conductivity at $80^{\circ}C$ which was better than that of Nafion.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.261-261
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• 2006

Membranes are a central feature of all biological systems and their ability to control many cellular processes is critically important. As a result, a better understanding of how molecules bind to biological membranes is an active area of research. In this report, the interaction between our biomimetic structures and different biological membranes is reported using both model vesicle and in vitro bacterial cell experiments. These results show that lipid composition is more important for selectivity than overall net charge. An effort is made to connect model vesicle studies with in vitro data and naturally occurring lipid compositions.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.643-651
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• 2019

Polybenzimidazole (PBI), an engineering polymer with well-known excellent thermal, chemical and mechanical stabilities has been recognized as an alternative to high temperature polymer electrolyte membranes (HT-PEMs). This review focuses on recent advances made on the development of PBI-based HT-PEMs for fuel cell applications. PBI-based membranes discussed were prepared by various strategies such as structural modification, cross-linking, blending and organic-inorganic composites. In addition, intriguing properties of the PBI-based membranes as well as their fuel cell performances were highligted.

• Membrane Journal
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• v.13 no.1
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• pp.29-36
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• 2003

A characterization of the permeation and separation using single salt solution was carried out with charged composite membranes. Various charged composite membranes were fabricated by blending an ionic polymer with a nonionic polymer in different ratios. In this study, sodium alginate, chitosan and poly(vinyl alcohol) were employed as anionic, cationic and nonionic polymers, respectively. The permeation and separation behaviors of the aqueous salt solutions have been investigated through the charged composite membranes with various charge densities. As the content of the ionic polymer increased in the membrane, the hydrophilicity of the membrane increased, and pure water flux and the solution flux increased correspondingly, indicating that the permeation performance through the membrane is determined mainly by its hydrophilicity. Electrostatic interaction between the charged membrane and ionic solute molecules, that is, Donnan exclusion, was observed to be attributed to salt rejection to a greater extent, and molecular sieve mechanism was effective for the separation of salts under a similar electrostatic circumstance of solutes.

• Macromolecular Research
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• v.17 no.10
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• pp.729-733
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• 2009

Solution casting films of sulfonated poly[styrene-b-(ethylene-r-butylene)-b-styrene] copolymer (sSEBS)-based composite membranes that contained different amounts of organic, nanorod-shaped polyrotaxane were annealed at various temperatures for 1 h. The films' properties were characterized with respect to their use as polymer electrolyte membranes in direct methanol fuel cells (DMFCs). Different aspect ratios of polyrotaxane were prepared using the inclusion-complex reaction between $\alpha$-cyclodextrin and poly(ethylene glycol). The presence of the organic polyrotaxane inside the membrane changed the morphology during the membrane preparation and reduced the transport of methanol. The conductivity and methanol permeability of the composite membranes decreased with increasing polyrotaxane content, while the annealing temperature increased. All of the sSEBS-based, polyrotaxane composite membranes annealed at $140^{\circ}C$ showed a higher selectivity parameter, suggesting their potential usage for DMFCs.

• Membrane and Water Treatment
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• v.6 no.2
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• pp.95-102
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• 2015

The presented research is about characterization of Cellulose Triacetate (CTA) based Polymer Inclusion Membranes (PIMs) which incorporated the commercial extractant Aliquat 336, Tributylphosphate (TBP) as modifier and 2-Nitro Phenyl Pentyl Ether (NPPE) as plasticizer, for the preparation of the membranes. Chemical and physical characteristics of the synthesized membranes especially membrane thickness and side difference effects were investigated. Different surface structures and membrane thickness affect the extraction efficiency of membranes. Membrane extraction experiments were studied where the glass-facing surface of the membranes placed next to feed phase and the air-facing surface to stripping phase. The membrane was characterized by means of AFM, FT-IR and SEM.

• Macromolecular Research
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• v.13 no.2
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• pp.162-166
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• 2005

• Membrane Journal
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• v.29 no.2
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• pp.80-87
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• 2019

Dye-sensitized solar cells (DSSCs) have attracted great attention as sustainable energy devices. The efficiency and long-term stability of DSSCs are greatly influenced by electrode materials and electrolytes. In this review, we focused on the electrolytes of DSSCs. Polymer electrolyte membranes have been proposed as an alternative to conventional liquid electrolytes in DSSCs. Conventional liquid electrolytes can exhibit a high efficiency, but due to some problems such as poor long-term stability of device and leakage of liquid, much interest in polymer electrolyte membranes continues to rise and the papers on polymer electrolytes membranes have been extensively reported recently. This review covers the concept and development of polymer electrolyte membranes for DSSCs, and discusses the efficiency and electrochemical properties of DSSCs, highlighting the modification of polymer matrix, the introduction of additives such as organic-inorganic plasticizers and ionic liquids.