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1.
Ho Bum Park Sang Yong Nam Ji Won Rhim Jung Min Lee Sun E. Kim Jung Ran Kim Young Moo Lee 《应用聚合物科学杂志》2002,86(10):2611-2617
Sulfonated polysulfone (SPS) membranes were prepared, and the gas‐transport properties of the resulting ionic polymers were examined. Gas‐transport measurements were made on dense films of these polymers with a continuous flow technique. The sulfonation of polysulfone and the metal‐cation exchange of SPS were confirmed with Fourier transform infrared spectroscopy and electron spectroscopy for chemical analysis. The SPS membranes exchanged with the monovalent metal ions showed higher permeability coefficients than the SPS membranes exchanged with the multivalent metal ions, whereas the selectivities of all the metal‐cation‐exchanged sulfonated polysulfone (MeSPS) membranes for O2/N2 and CO2/N2 gas pairs were higher than those of SPS membranes. When the MeSPS membranes with metal cations of similar ionic radii were compared, the ideal selectivities of O2/N2 and CO2/N2 through MeSPS with divalent cations were higher than those through MeSPS with monovalent cations. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2611–2617, 2002 相似文献
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A solid state method of Nafion®/ceramic nanocomposite membrane preparation is described. A nanocomposite powder from Nafion pellets and a zirconium phosphate ceramic is formed by mechanical milling. The nanoparticles are then consolidated into membrane form by mechanical pressing. Cross‐sectional analysis by scanning electron microscopy indicates that the ceramic particles exist in agglomerates that are evenly dispersed across the membrane. Dynamic mechanical analysis and tensile testing found the membranes to be mechanically equivalent, and in some cases superior, to a commercial extruded membrane. Increasing ceramic content is accompanied by an increase in modulus and shift in the alpha peak to higher temperature. Maximum water uptake of the membranes, as measured by thermal gravimetric analysis, is double that of values reported for the commercial membrane, and complete dehydration is postponed to higher temperature. The proton conductivity of fully hydrated membranes, measured by the 4‐probe method at 60°C in water, is comparable with that of the extruded membrane. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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To improve durability of Nafion® membranes, samples were modified via an in situ sol‐gel polymerization of titanium isopropoxide to generate titania quasi‐networks in the polar domains. The incorporated titania reduced water uptake but equivalent weight was essentially unchanged. Fuel cell performance of the modified membrane was inferior to that of the unfilled membrane although these were considered as model studies with focus on mechanical durability. Mechanical analysis of contractile stress buildup during drying from a swollen state in samples clamped at constant length demonstrated considerable reinforcement of Nafion® by the titania structures. Tensile studies showed that at 80°C and 100% relative humidity the dimensional change of the composite membrane is one half and the initial modulus is three times higher than that of the unmodified membrane. During an open circuit voltage decay test the voltage decay rate for the modified membrane is 3.5 times lower than that of control Nafion®. Fluoride emission for the composite is at least an order of magnitude lower than that of the control Nafion® membrane indicating reduced chemical degradation. These model studies indicate that this in situ inorganic modification offers a way to enhance fuel cell membrane durability by reducing both physical and chemical degradation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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Minoru Iwata Takeharu Adachi Miwa Tomidokoro Michiyoshi Ohta Takaomi Kobayashi 《应用聚合物科学杂志》2003,88(7):1752-1759
Sol–gel reaction of tetraethoxysilane (TEOS) with fumed silica–polyacrylonitrile (PAN) membrane was carried out to prepare hybrid gas permeable membranes for oxygen and nitrogen separation. Various amounts of fumed silica microparticles with a few μm diameters were compounded in PAN–dimethylsulfoxide (DMSO) solution. After casting of the viscous compound solution on a flat sheet with 100 μm thickness, DMSO was evacuated under vacuum at 80°C. Then, the silica–PAN composite membranes were treated with TEOS for 1 day at 40°C in methanol. Air permeation was examined and compared in silica–PAN composite membranes with and without TEOS treatment. The latter hybrid membranes showed selective oxygen permeability, which depended on amounts of fumed silica in the membrane. The TEOS hybrid PAN membranes have a high ability of oxygen permselectivity for O2/N2 gas mixture with α(O2/N2) = 13–17, when the silica content was in the range of 13–20 wt %. This is attributed to siloxane network formation in hybrid silica–PAN composite membranes. Favorable siloxane network formation resulted in high oxygen permeability of the hybrid composite membranes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1752–1759, 2003 相似文献
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A new membrane was synthesized containing pure alginate, crosslinking agent (CaCl2), and plasticizer (glycerol). Characterization studies of the membrane were applied to determine the characteristics and morphology using field emission scanning electron microscope, EDX, FTIR, XRD, and atomic force microscopy analysis. The half‐cell performance test of the membrane was verified by several tests, including proton conductivity and methanol permeability. The best membrane had high proton conductivity (10.1 × 10?3 S cm?1) and very low methanol permeability (1.984 × 10?7 cm2 s?1), which consequently resulted in very high selectivity (5.0907 × 104 Ss cm?3). Glycerol had a positive modification and good influence on the alginate characteristics. Furthermore, the poor mechanical properties of the alginate biopolymer were enhanced by calcium chloride and glycerol inside the polymer. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46666. 相似文献
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The degradation of perfluorosulfonic acid (PFSA) membranes (e.g., Nafion membranes) in polymer electrolyte membrane fuel cells has caused wide widespread concern. However, their degradation behaviors, which lead to the damage of fuel cells, need to be investigated under alternative accelerating environments by the simulation of fuel‐cell operating conditions. Nafion membranes showed a homogeneous degradation behavior during hydrogen peroxide (H2O2) aging, whereas a nonhomogeneous (or crack‐type) degradation behavior occurs for Nafion membranes aged in an H2O2/Fe2+ system (Fenton's reagent), where plenty of the typical microcracks appeared. Interestingly, in the case of nonhomogeneous degradation, the membrane presented a lower fluoride emission rate than that with the homogeneous degradation; this indicates a possible selective attack model of free radicals to both CF2 and the defect end groups in PFSA membranes. In addition, the effects of the different degradation behaviors on the thermal stability and water uptake of membranes were examined by thermogravimetric analyses. H2 crossover and single‐fuel‐cell tests were carried out to evaluate the influence of the degradation behaviors on the fuel‐cell performance. These showed that the membrane with a nonhomogeneous degradation behavior had a higher hydrogen crossover and was more destructive than that with a homogeneous behavior. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
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Layered silicate nanocomposite membranes to be used as electrolyte polymeric membranes in a direct methanol fuel cell were prepared through the mixing of poly(vinyl alcohol) (PVA) with various amounts (2, 4, and 5% w/w) of sodium montmorillonite layered silicate nanoclay. The proton conductivity of the polymer was induced by the reaction of the polymer with sulfosuccinic acid. After that, a solution of the sulfonated PVA–layered silicate nanocomposite was cast into membranes. The proton conductivity and methanol permeability of the membranes were determined with a four-point probe technique and a gas chromatography technique, respectively. In addition, structures of the nanocomposite membranes were characterized with X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared techniques. The mechanical properties of the nanocomposite membranes were also determined with a universal testing machine. From the results, it was found that the water uptake, proton conductivity, and methanol permeability of the membranes initially decreased after a 2% (w/w) concentration of the layered silicate was added. Above this nanoclay loading, the water uptake of the membranes increased again. The results were examined in the light of the interaction between the clay and sulfonated polymer, and the steric effect provided the exfoliation of the nanoclay. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
10.
Norazlianie Sazali Wan Norharyati Wan Salleh Nik Abdul Hadi Md Nordin Zawati Harun Ahmad Fauzi Ismail 《应用聚合物科学杂志》2015,132(33)
In this article, we present a development study of new membrane materials and enhancements of productive membranes to improve the current performance of polymeric membranes. Carbon membranes are a promising material for this matter as they offer an improvement in the gas‐separation performance and exhibit a good combination of permeability and selectivity. Carbon membranes produced from the carbonization of polymeric materials have been reported to be effective for gas separation because of their ability to separate gases with almost similar molecular sizes. In this study, a carbon support membrane was prepared with Matrimid 5218 as a polymeric precursor. The polymer solution was coated on the surface of a tubular support with the dip‐coating method. The polymer tubular membrane was then carbonized under a nitrogen atmosphere with different polymer compositions of 5–18 wt %. The carbonization process was performed at 850°C at a heating rate of 2°C/min. Matrimid‐based carbon tubular membranes were fabricated and characterized in terms of their structural morphology, thermal stability, and gas‐permeation properties with scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and a pure‐gas‐permeation system, respectively. Pure‐gas‐permeation tests were performed with the pure gases carbon dioxide (CO2) and N2 at room temperature at a pressure of 8 bar. On the basis of the results, the highest CO2/N2 selectivity of 75.73 was obtained for the carbon membrane prepared with a 15 wt % polymer composition. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42394. 相似文献
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Fuqiang Hu Ting Li Fei Zhong Sheng Wen Genwen Zheng Chunli Gong Caiqin Qin Hai Liu 《应用聚合物科学杂志》2020,137(36):49079
A composite proton exchange membrane chitosan (CS)/attapulgite (ATP) was prepared with the organic–inorganic compounding of ATP and CS. The composite membranes were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). The mechanical properties, thermal stability, water uptake, and proton conductivity of the composite membranes were fully investigated. The composite membranes exhibited an enhanced mechanical property, dimensional and thermal stability compared to CS membrane, owing to the interface interaction between ATP and CS. The maximum tensile strength of 53.1 MPa and decomposition temperature of 223.4°C was obtained, respectively. More importantly, the proton conductivity of the composite membrane is also enhanced, the composite membrane with 4 wt% ATP content (CS/ATP-4) exhibited the highest proton conductivity of 26.2 mS cm−1 at 80°C with 100% relative humidity, which is 25.1% higher than pure CS membrane. These results may explore a simple and green strategy to prepare CS-based PEMs, which have a great potential in the application of proton exchange membrane fuel cells. 相似文献
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Composite membranes of chitosan and titania‐coated carbon nanotubes as promising materials for new proton‐exchange membranes
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Hai Liu Jie Wang Sheng Wen Chunli Gong Fan Cheng Guangjin Wang Genwen Zheng Caiqin Qin 《应用聚合物科学杂志》2016,133(17)
Titania‐coated carbon nanotubes (TCNTs) were obtained by a simple sol–gel method. Then chitosan/TCNT (CS/TCNT) composite membranes were prepared by stirring chitosan/acetic acid and a TCNT/ethanol suspension. The morphology, thermal and oxidative stabilities, water uptake and proton conductivity, and mechanical properties of CS/TCNT composite membranes were investigated. The CNTs coated with an insulated and hydrophilic titania layer eliminated the risk of electronic short‐circuiting. Moreover, the titania layer enhanced the interaction between TCNTs and chitosan to ensure the homogenous dispersion of TCNTs in the chitosan matrix. The water uptake of CS/TCNT composite membranes was reduced owing to the decrease of the effective number of the ? NH2 functional groups of chitosan. However, the CS/TCNT composite membranes exhibited better performance than a pure CS membrane in thermal and oxidative stability, proton conductivity, and mechanical properties. These results suggest that CS/TCNT composite membranes are promising materials for new proton‐exchange membranes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43365. 相似文献
13.
Nanopaper membranes from chitin–protein composite nanofibers—structure and mechanical properties
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Chitin nanofibers may be of interest as a component for nanocomposites. Composite nanofibers are therefore isolated from crab shells in order to characterize structure and analyze property potential. The mechanical properties of the porous nanopaper structures are much superior to regenerated chitin membranes. The nanofiber filtration‐processing route is much more environmentally friendly than for regenerated chitin. Minerals and extractives are removed using HCl and ethanol, respectively, followed by mild NaOH treatment and mechanical homogenization to maintain chitin–protein structure in the nanofibers produced. Atomic force microscope (AFM) and scanning transmission electron microscope (STEM) reveal the structure of chitin–protein composite nanofibers. The presence of protein is confirmed by colorimetric method. Porous nanopaper membranes are prepared by simple filtration in such a way that different nanofiber volume fractions are obtained: 43%, 52%, 68%, and 78%. Moisture sorption isotherms, structural properties, and mechanical properties of membranes are measured and analyzed. The current material is environmentally friendly, the techniques employed for both individualization and membrane preparation are simple and green, and the results are of interest for development of nanomaterials and biocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40121. 相似文献
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The effect of NH3 plasma treatment on glassy poly(methyl methacrylate) (PMMA) membranes on the diffusion process for penetrant gases (CO2, O2, and N2) was investigated from mean permeability data. The mean permeability coefficient for CO2 definitely depended on the upstream pressure, whereas those for O2 and N2 remained constant regardless of the upstream pressure. For O2 transport, the permeability increased a little with increasing treatment power, and for N2 transport, it was not affected by the treatment power. For CO2 transport, NH3 plasma treatment promoted the transport of Langmuir mode, presumably through an increased Langmuir capacity constant for CO2. NH3 plasma treatment for PMMA membranes resulted in an increase in the separation factor of CO2 relative to N2 and in the permeability to CO2. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1068–1072, 2003 相似文献
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In this article, we report the influence of the polyimide molecular weight (1.2 × 105, 2.6 × 105, and 4.1 × 105) on the structure and the gas permeation properties of asymmetric polyimide membranes made by the dry–wet phase‐inversion process. The apparent skin layer thickness of the asymmetric membrane increased with increasing molecular weight, and the thicknesses of the membranes prepared from the three polyimides with a casting polymer solution containing 8.0 wt % butanol were 132, 350, and 739 nm, respectively. That is, the gas permeance in the asymmetric membranes increased with decreasing molecular weight. In contrast, the gas selectivity of the asymmetric membranes did not depend on the skin layer thickness. The solvent evaporation in the dry phase‐inversion process and the nonsolvent diffusion in the dry process were important factors that determined the formation of the asymmetric membrane. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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Gas sorption has been an underutilized technique for characterizing organic–inorganic hybrid (mixed matrix) membranes. Sorption in these membranes, which are composed of rigid inorganic domains, such as zeolites, dispersed in a polymer matrix, should be approximately additive. Sorption in the neat polymers and zeolites were first measured to demonstrate that sorption in mixed matrix membranes is approximately additive in the absence of other effects. Sorption in mixed matrix membranes was demonstrated to be additive. This extends to cases where sorption in one or both phases of the mixed matrix membrane is affected by an outside contaminant. For example, zeolite 4A is extremely hydrophilic and easily affected by contaminants from processing or from the test gases. Zeolite 4A encapsulated within a polymer matrix can still be affected by these same components, and this causes sorption lower than predicted based on that in unaffected polymers and sieves. This sorption analysis has proven to be very important in understanding the permeabilities and selectivities of mixed matrix membranes. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4053–4059, 2007 相似文献
17.
Hamid Reza Afshoun Mahdi Pourafshari Chenar Mohammad Reza Moradi Ahmad Fauzi Ismail Takeshi Matsuura 《应用聚合物科学杂志》2020,137(28):48860
Enhancing the performance of gas separation membranes is one of the major concerns of membrane researchers. Thus, in this study, poly(ether-block-amide) (Pebax)/polyetherimide (PEI) thin-film composite membranes were prepared and their CO2/CH4 gas separation performance was investigated by means of pure and mixed gases permeation tests. To improve the properties of these membranes, halloysite nanotubes (HNT) were added to Pebax layer at different loadings of 0.5, 1, 2, and 5 wt % to form Pebax-HNT/PEI membranes. Scanning electron microscopy, gas sorption, X-ray diffraction, Fourier-transform infrared, and differential scanning calorimetry tests were also performed to investigate the impact of HNT on structure and properties of prepared membranes. Results showed that both CO2/CH4 selectivity and CO2 permeance increased by adding HNT to Pebax layer up to 2 wt %. By increasing HNT loading to 5 wt %, the CO2/CH4 selectivity decreased from 32 to 18, while CO2 permeance increased from 3.25 to 4.2 GPU. Pebax/PEI and Pebax-HNT/PEI membranes containing 2 wt % of HNT were tested using CO2/CH4 gas mixtures at different feed CO2 concentrations and feed pressure of 4 bar. The results showed that with increasing CO2 concentration from 20 to 80 vol %, CO2/CH4 selectivity of Pebax/PEI composite membranes increased by 19%, while, in Pebax-HNT/PEI membrane, CO2/CH4 selectivity decreased by 40%. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48860. 相似文献
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Poly(phenylene oxide)s were synthesized by the oxidative polymerization of 2‐phenyl phenol (PP) and 2‐allyl phenol (AP). The copolymers were also synthesized with 80 mol % PP and 20 mol % AP and with equimolar monomers. The polymers were characterized. Blends of these polymers with poly(vinylidene fluoride) were prepared. These blend membranes were sulfonated, and their suitability for applications in fuel cells was evaluated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 307–311, 2003 相似文献
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Facile preparation of ODPA‐ODA type polyetherimide‐based carbon membranes by chemical crosslinking
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A chemical crosslinking protocol was developed to prepare carbon membranes from 3,3′,4,4′‐oxydiphthalic dianhydride‐4,4′‐oxydianiline (ODPA–ODA) type polyetherimide on the support of phenolic resin sheets. The effects of support pretreatment, membrane‐coating methods and crosslinking protocols on the resultant carbon membranes were investigated. The microstructure, functional group evolution, thermal stability, mechanics, morphology, and gas separation performance of samples were characterized by XRD, FTIR, TGA, mechanical testing technique, and gas permeation technique, respectively. Results have shown that the chemical crosslinking is more beneficial than the popular thermal crosslinking protocol to fabricate supported carbon membranes for the advantage of simple preparation process. In addition, spin‐coating is superior to drop‐coating in terms of good membrane formation on the support. Under the preferred preparation conditions of crosslinker ethylene glycol usage at 10 wt % and spin‐coating, supported carbon membranes can be obtained with good hydrogen separation performance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44889. 相似文献
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A new membrane material having two kinds of CO2 carriers was obtained. Composite membranes were prepared with the material and support membranes. The facilitated transport of CO2 through these membranes was performed with pure CH4 and CO2 as well as CH4/CO2 mixtures containing 50 vol % CO2. The results show that the membranes possess better CO2 permeance than that of other fixed carrier membranes reported in the literature. In the measurements with pure gases, at 26°C, 0.013 atm of CO2 pressure, the membrane with polysulfone support displays a CO2 permeance of 7.93 × 10?4 cm3 /cm2 s cmHg and CO2/CH4 ideal selectivity of 212.1. In the measurements with mixed gases, at 26°C, 0.016 atm of CO2 partial pressure, the membrane displays a CO2 permeance of 1.69 × 10?4 cm3 /cm2 s cmHg and CO2/CH4 selectivity of 48.1. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2222–2226, 2002 相似文献