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联苯二酐型聚酰亚胺的透气性能与分子结构关系的研究李悦生,丁孟贤,徐纪平(浙江大学高分子科学与工程研究所,杭州,310027)(中国科学院长春应用化学研究所)关键词聚酰亚胺,膜,气体分离,透气性,透气选择性联苯二酐(BPDA)型聚酰亚胺具有较高的透气选... 相似文献
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Silicalite-filled poly(siloxane imide) membranes for removal of VOCs from water by pervaporation 总被引:3,自引:0,他引:3
Silicalite-filled poly(siloxane imide) (PSI) membranes were prepared for the separation of volatile organic compounds (VOCs) from water via pervaporation. PSI copolymer was synthesized by polycondensation of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) with a siloxane-containing diamine, e.g., poly(dimethylsiloxane), bis(3-aminopropyl) terminated (PSX), added with 3,3-diaminodiphenyl sulfone (DDS). 2,4,6-Triamine pyrimidine (TAP) was added into the casting solution in order to enhance the compatibility between the polymeric matrix and the filler, silicalite. The PSI membranes were characterized by SEM. The surface morphology for the membrane with the addition of TAP differs from that without TAP. The latter seems to be consisting of particles in the membrane surface. The sorption selectivity of the PSI membranes for chloroform/water solutions was investigated, and there was a highest value for it around 50 wt.% of PSX content. The pervaporation performance of the membranes was studied with the separation of chloroform/water mixture. The silicalite-filled membrane with 120 μm thickness exhibit a high total permeation flux of 280 g m−2 h−1 with separation factor of 52.2 for 1.2 wt.% of the chloroform/water mixture. 相似文献
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A silica membrane was produced by chemical vapor deposition using tetraethoxysilane (TEOS), phenyltriethoxysilane (PTES) or diphenyldiethoxysilane (DPDES) as the Si source. Amorphous silica was deposited in the mesopores of a γ-alumina film coated on a porous -alumina tube, by evacuating the reactant through the porous wall. Hydrogen permeance at a permeation temperature of 600°C was of the order of 10−7 mol m−2 s−1 Pa−1, and was not greatly dependent on the Si sources. The silica membrane produced using TEOS contained micropores permeable to both helium and hydrogen, but CO2 and larger molecules were only slightly permeated through those mesopores which were left unplugged. The silica membrane produced from DPDES showed a single-component CO2 permeance equivalent to that of single-component He, and CO2/N2 selectivity was approximately 9 at a permeation temperature of 30°C. When a mixture of CO2 and N2 was fed, however, CO2 permeance decreased to the level of N2 permeance. The H2/N2 selectivity, determined from single-component permeances to H2 and N2, was approximately 100, and these permeances remained unchanged when an equimolar mixture of H2 and N2 was fed. Thus, the DPDES-derived membrane possessed two types of micropores, abundant pores through which helium and hydrogen permeated and a small number of pores in which molecules of CO2 and N2 were permeable but not able to pass one another. Neither meso or macropores remained in the DPDES membrane. 相似文献
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To separate hydrophilic anions from hydrophobic ones, Type II PPO-based anion exchange membranes were developed. Different from Type I (with both trimethylbenzylammonium and triethylbenzylammonium groups), Type II has an excellent hydrophobicity modifier as fixed groups: dimethyethanolammonium groups, which were introduced into PPO (poly(2,6-dimethyl-1,4-phenylene oxide)) by following benzyl bromination of PPO and subsequent quaternary amination with a dimethylethanolamine (DMEA) aqueous solution. The membrane's intrinsic properties are dependent on DMEA concentration and amination temperature. The optimum conditions for membrane preparation are as follows: amination temperature 70 °C, time 30–48 h, and DMEA concentration 1:3–1:5 (v/v, DMEA to water). The obtained Type II anion exchange membranes had an IEC of 1.5 mmol/g dry membrane, water content of 30%, and membrane area resistance of 30 Ω cm2. The introduced dimethyethanolammonium groups can block hydrated anions from the access to membranes but let hydrophobic anions transport; hence, an effective separation between hydrophilic and hydrophobic anions can be achieved during electro-membrane operation. 相似文献
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Masakazu Yoshikawa Kanako Murakoshi Kana Hanaoka Gilles P. Robertson 《European Polymer Journal》2006,42(10):2532-2539
Novel polymeric materials, having a chiral environment, were obtained by the reaction of lithiated polysulfone with chiral terpenoid myrtenal. The resulting polymers gave self-standing durable membranes. Molecularly imprinted membranes were prepared from the novel myrtenal-containing polysulfones by the presence of print molecules during the membrane preparation process. The d-isomer imprinted membrane showed d-isomer adsorption and diffusivity selectivity, and vice versa. As a result, the d-isomer imprinted membrane transported the d-isomer in preference to the l-isomer, and vice versa. The control non-imprinted membrane also showed permselectivity toward racemic glutamic acid mixtures. The expression of permselectivity for the molecularly imprinted membranes was synergistically due to adsorption and diffusivity selectivity. 相似文献
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Mitsuru Higa Dai Masuda Eisuke Kobayashi Megumi Nishimura Yoko Sugio Takeshi Kusudou Naoki Fujiwara 《Journal of membrane science》2008,310(1-2):466-473
A charge mosaic (CM) membrane has high permselectivity for electrolytes. While there are many reports of attempts to prepare such membranes, it is difficult to make CM membranes for practical applications. We report the preparation of CM membranes from laminated structures of charged-poly(vinyl alcohol) (PVA) membranes. The membranes were prepared by alternately stacking negatively charged base membranes and positively charged base membranes and by cutting the stack of charged layers. Permeation experiments were performed in a dialysis system consisting of the membrane and mixed solutions of KCl and sucrose. Although the salt flux through the membrane was about 30 times less than that through the charge mosaic membrane Desalton® (Tosoh Co. Ltd.), which was prepared using microphase separation, the permselectivity for salt of our membrane is more than 30 times higher than that of Desalton®. 相似文献
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