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采用液相共混法制备了石墨填充聚乙烯醇膜,采用FTIR,SEM,XRD等对石墨填充聚乙烯醇膜的物理和化学结构进行了分析表征,结果表明石墨与聚乙烯醇存在较强的氢键作用,石墨在聚乙烯醇中分散均匀,且具有一定的取向性.考察了石墨填充聚乙烯醇膜在苯和环己烷溶液中的溶胀和吸附行为.采用正电子湮没寿命谱仪表征了石墨聚乙烯醇膜的自由体积特性,计算得到石墨聚乙烯醇膜的表观自由体积分数,并且与渗透通量进行关联性对比.最后,研究了石墨含量和粒径对渗透蒸发分离性能的影响,结果表明,石墨的引入有利于苯的优先透过,石墨填充聚乙烯醇膜对苯和环己烷混合物具有良好的分离效果,苯的渗透通量和分离因子分别可达90.7 g8226;m-28226;h-1和100.1. 相似文献
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以聚乙烯醇(PVA)和正硅酸乙酯(TEOS)为原料,经溶胶-凝胶(sol-gel)法制备了不同二氧化硅(SiO2)含量的 PVA/SiO2杂化膜。傅里叶变换红外光谱(FT-IR)表明,随着SiO2含量增大,1060cm?1和970cm?1处Si—O—Si特征吸收峰的相对强度逐渐加强,说明TEOS与PVA发生了交联反应;同时膜的分解温度从248℃升高到342℃。杂化膜的SiO2含量从10 %增大到40 %,其玻璃态温度从115℃升高到124℃。以水为溶剂,测定了杂化膜的耐溶剂性能,与PVA膜相比,杂化膜的耐溶剂性能显著提高。以质量比为0.950/0.025/0.025的环己烷/环己醇/环己酮为原料,测定杂化膜的分离性能,结果表明SiO2含量从10 %增大到40 %,通量从15.94 g/(m2?h)升高到75.69 g/(m2?h),环己醇的分离因子从1.8升高到2.65。 相似文献
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聚醋酸乙烯酯(PVAc)经醇解反应制备了不同水解度的聚醋酸乙烯酯(PHPVAc),并探索了PHPVAc水解度、成膜技术、测试条件对膜渗透汽化性能影响的规律.实验发现,改变膜材料的水解度、铸膜溶剂组成、操作温度以及料液组成可以调节膜的分离性能,获得较佳的分离效果. 相似文献
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渗透蒸发膜分离有机双元混合物 总被引:2,自引:1,他引:1
本文以聚酰亚胺(PI)均质膜为渗透蒸发膜来分离苯和环己烷混合液,测定其渗透通量及透过液组成,证明PI膜对苯有极强的选择性;平衡溶解度大小影响着渗透通量的大小。在一定范围内,苯在PI膜内的扩散系数与其溶解度成指数关系,并将由此得到塑化因子r,与苯和PI膜的相互作用参数的计算值进行了比较。同时,发现渗透通量、溶解度和扩散系数分别与温度之间符合Arrehenius方程。 相似文献
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共混高分子膜渗透蒸发分离乙醇水溶液 总被引:1,自引:0,他引:1
应用湿法离子交联技术,研制了聚砜酰胺共混聚丙烯酸复合膜,针对乙醇水溶液,测定了膜的分离系数和渗透通量。实验发现,这种共混膜对乙醇-水具有较高的分离选择性。 相似文献
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聚乙烯醇膜的研制及乙醇水溶液的渗透蒸发(PV)分离 总被引:1,自引:0,他引:1
选择以聚乙烯醇(PVA)作膜材料,制成具有一定通量及分离效果的聚乙烯醇均质膜及聚乙烯醇/聚砜复合膜。讨论了膜的抗水性及抗化学腐蚀性。用透射电镜及扫描电镜进行了结构测定,并研究了这两种膜在分离95%(重量浓度)乙醇水溶液时的性能以及温度、交联度对膜性能的影响。实验发现聚乙烯醇均质膜具有较高的分离系数;聚乙烯醇/聚砜复合膜在基本维持均质膜分离性能的前提下,通量有较大提高。还发现经Cr~(3 )的饱和溶液处理后再进一步交联的膜,交联度及稳定性都有提高,分离系数略有下降。 相似文献
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Aromatic copolyester of poly(trimethylene‐co‐ethylene terephthalate) (PTET) with different composition was synthesized and the PTET sample with 60% weight fraction of polytrimethylene (PTET‐60) was amorphous. The compatibility of PTET‐60/cellose acetate (CA) blends and the pervaporation of their membranes for separation of benzene/cyclohexane mixtures were investigated. It was found that PTET‐60 is compatible with CA when the weight fraction of PTET‐60 in PTET‐60/CA blends (WPTET‐60) is lower than 0.35 and more than 0.5. Both the degree of swelling (DS) and the permeation flux (J) of these blend membranes increased with increasing WPTET‐60 from 0 to 0.35, and a maximum value of the separation factor (α) displayed at WPTET‐60 = 0.25. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2832–2838, 2006 相似文献
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Crosslinked polydimethylsiloxane/polyetherimide (PDMS/PEI) composite membranes were prepared, in which asymmetric microporous PEI membrane prepared with phase inversion method was acted as the microporous supporting layer in the flat‐plate composite membrane. The different function composition of the PDMS/PEI composite membranes were characterized by reflection Fourier transform infrared (FTIR) spectroscopy. The surface and section of PDMS/PEI composite membranes were investigated by scanning electron microscope (SEM). The composite membranes prepared in this work were employed in pervaporation separation of benzene/cyclohexane mixtures. Effects of feed temperature, feed composition, concentration of crosslinking agent on the separation efficiency of benzene/cyclohexane mixtures were investigated experimentally. In addition, the swelling rate and stableness of composite membrane during long time operation were studied, which should be significant for practical application. The results demonstrated that the pervaporation method could be very effective for separation of the benzene/cyclohexane mixtures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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Methyl methacrylate–methacrylic acid copolymer (MMA–MAA) membranes ionically crosslinked with Fe3+ and Co2+ ions (MMA–MAA–Fe3+ and –Co2+) were prepared, and characteristics of permeation and separation for a benzene/cyclohexane mixture of 50 wt % benzene through these membranes in pervaporation (PV) were studied. Although the introduction of the metal ions to the MMA–MAA membrane enhanced both benzene permselectivity and permeability for a benzene/cyclohexane mixture, the PV characteristics between the MMA–MAA–Fe3+ and –Co2+ membranes were significantly different. The difference in the PV characteristics between these membranes was strongly governed by the difference of these membrane structures based on the glass transition temperature, contact angle to methylene iodide, degree of swelling, and mixture composition absorbed in the membrane, and so on. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 233–241, 1999 相似文献
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针对苯/环己烷混合物体系的特点,采用两种新型侧链二胺3,5-二氨基苯甲酸苯酯(PDA)和3,5-二氨基苯甲酸-4-三氟甲基苯酯(FPDA),制备了一系列由不同二酐与二胺单体如4,4'-二氨基二苯醚(ODA)和3,5-二氨基苯甲酸(DABA)聚合而成的用于渗透汽化分离苯/环己烷的聚酰亚胺膜,对其结构和各项性质进行了表征,并对膜材料的微观结构与宏观分离性能之间的关系进行了较为深入的研究。随着侧链二胺的引入,聚酰亚胺膜的分离效率随之持续增大,分离能力得以改善。渗透汽化实验结果表明,以6FDA为二酐单体的两类聚酰亚胺膜具有较优异的分离性能。乙二醇交联的6FDA-FPDA/ODA/DABA(1:7:2)膜综合渗透汽化分离性能最优。在50℃时,对于含苯50 %(质量)的苯/环己烷混合物,其渗透通量为9.84 kg·μm·m-2·h-1,分离因子达6.1。 相似文献
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The separation of a phenol-water mixture using a polyurethane membrane by a pervaporation method was investigated. Polyurethane was selected as a membrane material because its affinity for phenol was considered to be high. Polyurethane was prepared by the polyaddition of 1,6-diisocyanatohexane and polytetramethyleneglycol. The polyurethane layer was sandwiched with a porous polypropylene membrane (Celgard® 2500). Pervaporation measurement was carried out under vacuum on the permeate side, and the permeate vapor was collected with a liquid nitrogen trap. The phenol concentration in the permeate solution increased from 0 to 65 wt % with increasing feed concentration of phenol from 0 to 7 wt %. The total flux also increased up to 930 g m-2 h-1 with increasing phenol partial flux. In the sorption measurement at 60°C, the concentration of phenol in the membrane was 68 wt %, which was higher than that of the permeate solution. Therefore, it was considered that the phenol selectivity was based on high solubility in the polyurethane membranes. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:469–479, 1997 相似文献
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采用两步法制备了ZSM-5沸石填充的疏水性端羟基聚丁二烯基聚氨酯(PU)膜,用以分离水中芳香性有机物乙酸异丙酯。对该膜的化学结构、形貌及热稳定性进行了表征,并研究了ZSM-5沸石填充的PU膜的溶胀度及渗透汽化性能。结果表明:添加ZSM-5沸石后,膜的热稳定性明显提高,沸石与膜的相容性较好,且随着添加量的增加,膜的溶胀度降低,分离因子先升后降。在303 K、料液浓质量分数为1%的条件下,ZSM-5添加量为20%(质量分数)时,分离因子达到最高;同时随着料液浓度及操作温度的上升,通量和分离因子都增加。在333 K、料液质量分数为1%的条件下,PU-ZSM-5-20膜的分离因子及通量最高可达288.72 g/(m2·h)和53.21 g/(m2·h)。 相似文献
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NCO‐terminated polyurethane membranes were prepared using diisocyanate, diol, and trimethylolpropane (TMP) using an NCO/OH ratio of 1.6 : 1. Prepolymer was chain‐extended using cellulose acetate butyrate (CAB) in the ratios of 2 : 1, 4 : 1, and 3 : 1 of NCO/OH. Polyurethane (PU) membranes were characterized by differential scanning calorimeter (DSC) and thermogravimetry (TGA) to investigate their thermal properties. Equilibrium sorption studies were carried out at 30°C in water and ethyl acetate media as well as in their binary mixtures. The influence of CAB on pervaporation (PV) separation of an ethyl acetate/water (92/8, w/w, i.e., azeotropic composition) mixture was investigated. Membranes in this study showed a selectivity of 42.42 with a flux value of 0.187 kg/m/h for 3 : 1% NCO/OH containing PU membrane. In order to gain a more detailed picture of the molecular transport phenomenon, we performed the sorption gravimetric experiments at 30°, 35°, 40°, and 50°C to compute diffusion, swelling, sorption, and permeability coefficients of PU membranes in the azeotropic mixture of ethyl acetate and water. Activation parameters for diffusion and permeation were computed from the Arrhenius equation to understand the polymer/solvent interactions. Sorption trends and diffusion anomalies were established through an empirical equation after estimating the diffusion parameters. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3405–3414, 2007 相似文献