聚氨酯渗透汽化膜的研究进展

聚氨酯膜材料具有良好的选择性、渗透性和力学性能等,近年来在渗透汽化领域倍受关注。本文综述了用于渗透汽化分离的聚氨酯及其改性膜的研究情况及最新进展,重点评述了以聚丁二烯、聚酯和聚醚为软段的PU渗透汽化膜材料结构特点、合成方法、分离性能,以及共混、填充和接枝3种改性方法的反应原理,改性思路、对PU膜分子结构和分离性能的影响等;同时分析了不同材料和改性方法在渗透汽化膜分离方面的优点和不足。在此基础上,对用于渗透汽化分离的聚氨酯膜材料发展方向和研究前景进行了展望。     

环糊精修饰沸石改性聚氨酯膜的制备及脱酚性能研究

采用β-环糊精(β-CD)对沸石(ZSM-5)进行化学改性,得到3种β-CD修饰的沸石,并将改性后的沸石填充到聚醚型聚氨酯(PU)中,制备了3种改性膜。采用红外光谱(FTIR)、扫描电镜(SEM)和热重(TG)手段对改性的沸石以及改性膜进行了结构和热性质表征,考察了不同改性沸石填充膜的渗透汽化脱酚性能。结果表明,填充了改性沸石的PU膜可以有效分离苯酚/水混合物中的苯酚,3种改性沸石填充的膜的渗透通量均显著大于未改性沸石填充膜和空白膜,其中以异氰酸酯为桥联结构接枝环糊精沸石填充膜综合分离性能最佳,对于80℃含0.3%的苯酚水溶液,渗透通量为43.35 kg·μm/(m~2·h),分离因子为15.24。     

聚二甲基硅氧烷渗透汽化膜改性技术研究进展

聚二甲基硅氧烷膜改性是渗透汽化领域研究的一个热点问题.综述了共聚、填充、交联、共混和表面改性等聚二甲基硅氧烷(PDMS)渗透汽化膜改性方法及其研究进展,并且展望了渗透汽化膜的研究方向.     

改性聚酰亚胺膜用于甲醇/甲基叔丁基醚的渗透汽化分离

本文以己二酸对聚酰胺羧酸进行改性，制得改性聚酰亚胺膜，用于甲醇／甲基叔丁基醚的渗透汽化分离。研究了制膜液浓度、己二酸含量、原料液组成及温度等条件对膜分离性能的影响，并分析了膜的结构与特征基团的光谱图。     

碳纳米管填充聚氨酯膜的制备及渗透汽化性能研究

渗透汽化膜分离技术在苯酚/水领域引起广泛关注。文章对端羟基聚丁二烯(HTPB)基的聚氨酯膜进行填充改性并研究其对苯酚/水体系的渗透汽化性能。利用物理和化学方法将β-环糊精(β-CD)接枝到羟基碳纳米管(MWNTs-OH)上,制备两种碳纳米管,并对改性后的碳纳米管进行元素分析。将改性后的两种碳纳米管填充到聚氨酯中。研究发现,物理改性羟基化碳纳米管的渗透通量最大,80℃达175.56 kg·μm·m-2·h-1,但是分离因子为2.8;化学改性的羟基化碳纳米管的分离性能较优,80℃下膜的分离因子为3.6,渗透通量为101.73 kg·μm·m-2·h-1。     

渗透汽化有机膜分离异构体混合物的研究进展

综述了近年来用于异构体渗透汽化分离的有机高分子膜研究情况及最新进展,重点评述了各种膜材料的结构特点,改性原理以及在异构体分离方面的优点和不足.最后对用于异构体渗透汽化分离的有机膜研究进行了总结,并对其发展方向进行了展望.     

硬脂酸改性γ-Al_2O_3填充PEBAX膜渗透汽化分离苯胺

利用硬脂酸对纳米γ-Al_2O_3改性,分别制备了聚醚共聚酰胺(PEBAX)均质膜、填充膜、复合膜以及填充型复合膜四种分离膜,探讨了膜在苯胺/正庚烷体系中的溶胀性能和渗透汽化性能。利用FT-IR、XRD分别考察了改性前后γ-Al_2O_3颗粒官能团和晶体结构的变化情况,通过SEM观察膜的形貌结构。溶胀实验结果表明:随着料液中苯胺浓度和料液温度的升高,溶胀度均持续增大,在48 h时达到溶胀平衡,填充量为2%(wt)时填充膜的溶胀效果最好;渗透汽化实验结果表明:膜的渗透通量和分离因子均随料液中苯胺浓度和料液温度的升高而持续增大,填充型复合膜的综合性能最优,其填充量为2%(wt)时分离性能最佳,当苯胺浓度为5000μg×g~(-1)、温度为70℃时,膜的渗透总通量为5.64 kg×m~(-2)×h~(-1),分离因子为3.07。     

硅溶胶填充改性PDMS-PA复合膜

在聚二甲基硅氧烷（PDMS）中填充质量分数为20wt％、25wt％和30wt％的疏水纳米二氧化硅溶胶作为表面皮层,以聚酰胺（PA）为支撑层,制备出改性硅橡胶-聚酰胺（PDMS—PA）复合膜。扫描电镜（SEM）观察发现二氧化硅颗粒均匀分布在PDMS基体中,改性皮层与PA支撑层结合紧密。用5％的乙醇水溶液对改性膜在不同温度下进行渗透汽化测试,发现填充比例为20wt％的膜的分离因子较未改性膜可提升25％,而填充比例为25wt％和30wt％时,膜的分离因子却低于未改性膜。这显示在PDMS中填充某种比例的硅溶胶可改善膜的分离性能。     

填充法改性PDMS膜及其对乙酸/水的渗透汽化分离性能

用CTAB-蒙脱石填充改性PDMS膜,运用XRD, SEM等手段表征了不同填充量的复合膜结构,证明有机柱撑蒙脱石与聚合物形成插层型复合物后,膜的热稳定性明显改善. 研究了填充膜对乙酸/水体系的渗透汽化分离性能,结果表明,随着温度的升高,渗透通量增大而分离因子降低,通量随填充量增加单调上升,分离因子随填充量增加先增大后降低,填充量为7.4(%, w)时达到最大值. 从膜的结构及其与组分的相互作用对填充膜中蒙脱石可能存在的渗透通道作用进行了探讨.     

蒙脱石-聚二甲基硅氧烷复合膜制备及其乙醇/水分离性能

采用CTAB柱撑蒙脱石通过溶液法制备了有机蒙脱石填充聚二甲基硅氧烷（PDMS）膜,研究了填充量等因素对乙醇/水体系渗透汽化分离的影响,通过XRD、SEM等表征手段证明有机蒙脱石与聚合物形成插层型复合物后,膜的机械强度明显改善,膜的分离因子随填充量增加可提高至最大值10。本文从膜的结构及其与组分的相互作用对填充膜中蒙脱石可能存在的渗透通道作用进行了探讨。     

Preparation and pervaporation performance of 3,3‐bis[4‐(4‐aminophenoxy)phenyl] phthalide based polyimide membranes

A series of novel solvent‐soluble polyimides based on the diamine of 3,3‐bis[4‐(4‐aminophenoxy)phenyl] phthalide (BAPP) were prepared. The effects of the dianhydride structures on the pervaporation performance of aqueous alcohol mixtures through these polyimide membranes were studied. The BAPP‐based polyimide membranes exhibited water permselectivity during all process runs. The permeation rate increased with the addition of bulky groups to the polyimide backbone. The effects of the feed solution concentration, feed solution temperature, and carbon atom number of the feed alcohol on the pervaporation performance were also investigated systematically. Optimum pervaporation results, a separation factor of 22 and a permeation rate of 270 g/m² h, were obtained for a 90 wt % feed aqueous ethanol solution through a 3,3′,4,4′‐biphenyl tetracarboxylic dianhydride polyimide membrane at 25°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2046–2052, 2005     

Separation of phenol–water mixture by membrane pervaporation using polyimide membranes

Separation of components of aqueous waste streams containing organic pollutants is not only industrially very important but also is a challenging process. In this study, separation of a phenol–water mixture was carried out by using a membrane pervaporation technique with indigenously developed polyimide membranes. The membranes were found to permeate water selectively. The total flux as well as that of the individual components were measured. The effect of lithium chloride modification of polyimide film on total flux was investigated. The total flux obtained with 2% lithium chloride modification was about 3.6 times higher than that obtained with virgin membrane. The effects of different parameters such as feed composition and temperature on flux, and separation factor were determined. With modified membrane, a separation factor as high as 18.0 was obtained for water at 27°C and with 8.0 wt % phenol solution. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 822–829, 2002     

硅橡胶渗透蒸发分离膜改性研究进展

膜材料改性和膜结构改性作为改变硅橡胶渗透蒸发膜的分离性能（渗透通量和分离因子）、抗污染性、物理化学稳定性的有效手段而吸引了大量的研究和开发兴趣。重点介绍了硅橡胶渗透膜的改性方法研究进展,包括交联法、填充法、溶剂占位法等,并对其发展前景进行了展望。     

Dehydration of ethanol/water mixtures by pervaporation using soluble polyimide membranes

A series of soluble polyimides derived from 3,3′,4,4′‐benzhydrol tetracarboxylic dianhydride (BHTDA) with various diamines such as 1,4‐bis(4‐aminophenoxy)‐2‐tert‐butylbenzene (BATB), 1,4‐bis(4‐aminophenoxy)‐2,5‐di‐tert‐butylbenzene (BADTB), and 2,2′‐dimethyl‐4,4′‐ bis(4‐aminophenoxy)biphenyl (DBAPB) were investigated for pervaporation separation of ethanol/water mixtures. Diamine structure effect on the pervaporation of 90 wt% aqueous ethanol solution through the BHTDA‐based polyimide membranes was studied. The separation factor ranked in the following order: BHTDA–DBAPB > BHTDA–BATB > BHTDA–BADTB. The increase in molecular volume for the substituted group in the polymer backbone increased the permeation rate. As the feed ethanol concentration increased, the permeation rate increased, while the water concentration in the permeate decreased for all polyimide membranes. The optimum pervaporation performance was obtained by the BHTDA–DBAPB membrane with a 90 wt% aqueous ethanol solution, giving a separation factor of 141, permeation rate of 255 g m^?2 h^?1 and 36 000 pervaporation separation index (PSI) value. Copyright © 2006 Society of Chemical Industry     

Vapor permeation separation of MeOH/MTBE through polyimide/sulfonated poly(ether-sulfone) hollow-fiber membranes

Mixtures ofmethanol/MTBE were separatedwithpolyimide/sulfonatedpoly(ether-sulfone) hollow-fiber membranes. The separation was attempted by vapor permeation instead of pervaporation, which had been used by most researchers. The separation properties of the hollow-fiber membranes and operating conditions are discussed. The results showed that separation factors ofthe blended polyimide/sulfonated poly(ether-sulfone) hollow-fiber membranes were extremely high for the methanol/MTBE mixtures.     

Preparation of 6FDA-based polyimide composite membrane by CVDP process

Preparation of polyimide composite membranes by a chemical vapor deposition and polymerization process (CVDP) was studied for the development of pervaporation or gas separation membranes. Hexafluoroisopropylidene-2,2-bis [phethalic acid anhydride] (6F-dianhydride) (6FDA) and 4,4′-diaminodiphenyl ether (ODA) were used as monomers and were simultaneously deposited on an asymmetric polyimide membrane in vacuum of 10⁻⁶ Torr. The deposited layer of the monomers was converted to polyimide by heating at 250°C at 3 h in an ordinary vacuum oven, and its separation performance for water-ethanol and CO₂−N₂ systems was characterized.     

界面聚合在渗透汽化膜分离领域的应用进展

蒸馏、萃取等传统分离方法能耗高,污染环境,而渗透汽化由于低能耗、高效、环保等优势,为共沸物、近沸点混合物的分离提供了新的思路,但渗透汽化膜制备过程中面临的最大问题是获得性能优异且稳定的膜材料。在众多制备方法中,界面聚合法具有反应活性高、常温下生成膜层稳定、制备活性层致密等特点而备受关注。通过对界面聚合过程的调控,可以优化活性层,从而制备出兼具高通量和高选择性的渗透汽化膜。本文综述了界面聚合的原理、在渗透汽化膜制备方面的优势和近年来国内外的研究进展,详细阐述了复合膜制备过程中底膜的选择与改性、界面聚合条件的调控对渗透汽化膜结构和分离性能的影响机制,并对界面聚合制备渗透汽化膜所面临的问题及前景进行了总结与展望。     

陶瓷支撑的有机复合膜及其在渗透汽化中的应用(英文)

Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic-supported polymer composite pervaporation membranes.The separation materials of polymer/ceramic composite membranes presented here include hydrophobic polydimethylsiloxane(PDMS) and hydrophilic poly(vinyl alcohol)(PVA),chitosan(CS) and polyelectrolytes.The effects of ceramic support treatment,polymer solution properties,interfacial adhesion and incorporating or blending modification on the membrane structure and PV performance are discussed.Two in-situ characterization methods developed for polymer/ceramic composite membranes are also covered in the discussion.The applications of these composite membranes in pervaporation process are summarized as well,which contain the bio-fuels recovery,gasoline desulfuration and PV coupled proc-ess using PDMS/ceramic composite membrane,and dehydration of alcohols and esters using ceramic-supported PVA or PVA-CS composite membrane.Finally,a brief conclusion remark on polymer/ceramic composite mem-branes is given and possible future research is outlined.     

有机硅烷改性PDMS/Silicalite渗透汽化杂化膜制备及其分离性能

采用硅烷偶联剂对全硅沸石Silicalite-1进行表面改性,以聚二甲基硅氧烷(PDMS)为基体,制备了渗透汽化PDMS/Silicalite杂化膜. 用FT-IR, TGA等对改性的效果和杂化膜的热稳定性能进行了表征,并以低浓度乙醇/水体系为研究对象,以渗透通量和分离因子为评价指标,考察了料液组成、进料温度、循环流速、膜下游侧真空度等因素对改性杂化膜分离性能的影响. 结果表明,硅烷改性沸石所制杂化膜对低浓度乙醇/水体系的分离因子比空白膜和未改性杂化膜分别提高136%和45%. 随料液中乙醇浓度从5%增加到69%,膜分离因子从22降低到7,而其他因素对膜的选择性影响较小.     

渗透蒸发膜改性技术的研究进展

物理改性和化学改性作为改变渗透蒸发膜的分离性能 (渗透通量和分离因子 )、抗污染性、物理化学稳定性的有效手段而吸引了大量的研究和开发兴趣。这些改性方法在不少场合下可以联合使用。对常用的改性方法进行了分类介绍 ,简要评述了各种方法的优缺点 ,并列举了一些实例加以具体说明