聚吡咙膜的气体透过性能及应用

论述新型芳族含氮杂环聚吡咙膜的气体透过性能和应用，并与聚酰亚胺(PI)膜的气体分离性能进行比较。揭示出聚吡咙膜的扩散系数与气体分子有效直径之间及溶解系数和临界温度之间呈直线关系，指出气体在聚吡咙膜中的透过主要受扩散因素控制。与类似结构的PI膜相比，聚吡咙膜具有更优异的氧氮分离性能、CO2/CH4分离性能和氢氮分离性能，其透过系数和选择分离系数均高于PI膜，是一类很有发展潜力的聚合物膜材料。     

改性聚苯胺膜的气体分离性能及应用

论述了改性聚苯胺膜的气体透过性能。提出环取代聚苯胺膜由于自由体积增加而具有较大的透气系数。聚苯胺与聚酰亚胺预聚体的共混膜显示了比聚酰亚胺膜和聚苯胺膜更大的渗透系数，而分离系数介于二者之间。苯胺共聚物与乙基纤维素共混膜应用于空气分离，能将空气中氧体积分数从21％提高到46％，且具有中等的富氧空气流量和很好的稳定性，在医疗保健等领域具有很大的应用潜力。     

高选择性聚吡咙气体分离膜的合成及气体分离

基于国内外最新研究文献，系统论述了一类新型含氮芳杂环聚合物膜材料——聚吡咙的合成、制膜及气体分离性能，讨论了单体结构与聚吡咙膜的气体透过行为的关系。指出链刚性是影响聚吡咙膜气体分离性能的重要因素之一，它决定了聚吡咙大分子链的链间距和自由体积分数。室温下聚吡咙膜对氦气、氢气、二氧化碳和氧气的渗透系数最高分别可达166、74．4、63．6和16．4Barrer，对He／CH4，H2／N2，CO2／CH4和O2/N2的分离系数最高分别可达3214，389，150和12．5。由4，4’—(六氟异丙基)—苯二甲酸酐合成的半阶梯聚吡咙膜显示了极好的气体透过性。有些聚吡咙膜的气体选择透过性甚至超越了常规聚合物膜的上限。符合具有商业吸引力的气体分离膜的指标要求，尤其在氧氮分离、二氧化碳和甲烷的分离领域具有很大的应用潜力。     

共轭聚合物膜的渗透汽化性能及应用

论述了大π键共轭聚合物膜的渗透汽化性能和应用，讨论了掺杂和去掺杂态聚苯胺膜、聚(3-甲基噻吩)和聚(N-甲基吡咯)膜对水、甲酸、乙酸、丙酸、甲醇、乙醇、异丙醇的渗透汽化性能以及它们与水的混合液的分离性能。指出掺杂态聚苯胺膜呈亲水性，有利于醇类的渗透；而去掺杂态聚苯胺膜呈疏水性，有利于有机酸类的渗透。聚丙烯酸／聚苯胺及聚酰亚胺预聚体／聚苯胺共混膜对混合液体都具有较好的分离性能，其中的大分子酸会对聚苯胺链节进行掺杂，能有效地克服盐酸小分子掺杂剂易于损失的缺点。共轭聚合物膜可望应用于醇／水混合液、有机酸/水混合液、多组分混合液的分离。     

改性聚苯胺膜在CO_2/CH_4分离中的应用研究

合成了一种由N-乙基苯胺和苯胺共聚的高聚物,并制备了其4种掺杂态共聚物膜。实验中在不同压力、不同进料组成下测试了共聚物膜及聚砜膜对CO2/CH4混合气的分离性能。实验结果表明:掺杂态不同对气体的分离性能有很大影响,其中二次掺杂态的分离系数最高,可达70,而去掺杂态的渗透速率最高,CO2可达2.15 GPU[1 GPU=7.501×10-10cm3/(cm2.s.Pa)],CH4达到0.049 GPU,均高于聚砜膜和文献中报道的聚苯胺膜的值,这是由于N-乙基的引入,改变了聚合物链的柔韧性。     

PEGDME强化PVDF/PP复合膜的CO2分离性能

膜分离技术具有投资小、设备简单等优点,目前广泛应用于CO2分离等方面,膜材料是膜分离技术的核心。研究表明,聚合物中醚氧基团的存在可有效提高膜对CO2的渗透速率和选择系数。聚乙二醇二甲醚(PEGDME)结构中含有丰富的醚氧基团,同时端基空间位阻提供了较高的CO2扩散系数。本文以液态PEGDME为添加剂,聚偏氟乙烯(PVDF)为共混膜材料,利用聚丙烯(PP)多孔膜为支撑,通过溶剂蒸发法制备出具有良好分离性能的PEGDME-PVDF/PP共混复合膜。结果显示,随着PEGDME含量的升高,复合膜对CO2的渗透速率和CO2/N2选择系数均呈上升趋势,当PEGDME共混含量达到50%时,CO2的渗透速率为42.9GPU,CO2/N2选择性为47.5;随着PVDF浓度的增加,CO2的渗透速率呈下降趋势,CO2/N2的选择系数则缓慢上升;适当降低溶剂蒸发温度,PVDF结晶度降低,有助于提高膜性能;当溶剂蒸发温度为30℃时,PEGDME-PVDF膜对CO2的渗透速率达到84.7GPU,CO2/N2的选择系数达到47.2。     

MOFs基材料制备混合基质膜用于O2/N2分离的研究进展

金属有机框架（metal-organic frameworks,MOFs）材料具有多孔、孔径易于调节、高的比表面积等优点，用于改善传统聚合物膜的缺点，制得的混合基质膜具有较好的气体分离性能。混合基质膜中的填料和聚合物基质的性质、填料和聚合物基质间的界面相互作用等影响着膜的气体渗透性和选择性，本文着重介绍混合基质膜中填料尺寸、形貌和聚合物性质对混合基质膜气体分离性能的影响，以及相应的改性方法，为氧氮分离的MOFs基混合基质膜提供新的思路。     

功能化碳纳米管/聚合物复合分离膜

碳纳米管不仅具有优异的力学性质和超大的比表面积,同时具有优良的传输特性,将其添加到聚合物中制备复合分离膜,具有广阔的应用前景。通过化学改性将碳纳米管功能化,提高其在聚合物中的分散性,制备碳纳米管/聚合物复合膜。本文在介绍了碳纳米管功能化、碳纳米管/聚合物复合膜制备方法的基础上,综述了功能化碳纳米管的加入对复合分离膜亲水性、水通量、机械稳定性以及分离等性能的影响。总结了近年来对碳纳米管在聚合物膜内定向排列的研究进展及碳纳米管定向对复合膜相关性能的影响。由于碳纳米管材料的各向异性,利用电场、磁场及流场等对碳纳米管在聚合物膜内的分布进行定向,从而充分利用其优异的性能,是该类复合膜的研究方向。     

聚甲基氢硅氧烷基气体分离膜的进展

气体分离膜技术与传统的气体分离技术(如胺吸收、变压吸附、深冷分离等)相比，具有无相变、高效、节能、操作简便、无二次污染等特点，在空气中氧、氮的富集、石油炼制、化学品生产及二氧化碳的捕获等领域中具有极大的应用前景。分离膜作为气体膜分离技术的核心，获得高透过性及高选择性的膜材料是气体分离膜研究中的目标。聚甲基硅氧烷由于具有优异的高气体透过性、较低的获得成本、结构可变性较强等特点，已成为气体分离膜材料的一个重要研究方向。对目前用于气体分离膜的聚甲基硅氧烷基气体分离膜的种类及合成进行了研究，分析并讨论了各种聚甲基硅氧烷基气体分离膜在分离过程中的机理和作用，对聚甲基硅氧烷基气体分离膜的未来研究方向进行了展望。     

炭膜气体分离性能研究

以酚醛树脂为原料制备了炭支撑膜和炭－炭复合膜，研究了其气体分离性能。结果表明：炭支撑膜分离气体和机理包括努森扩散和粘性流；采用浸涂－干燥－炭化的工艺制备的炭－炭复合膜对Ｈ２／ＣＯ２具有较好的分离性能，Ｈ２／ＣＯ２分离系数达５．６，大于理想努森扩散的分离系数３．７。但在高压差时复合膜上ＣＯ２的表面扩散增强，使Ｈ２／ＣＯ２分离系数下降。     

Surface modification of composite ion exchange membranes by polyaniline

The aim of this work is to develop new selective cation exchange membranes (CEMs) from bivalent to monovalent selectivity by surface functional groups. So, a novel hybrid cation exchange membrane was prepared by polymerization of polyaniline on a composite membrane, made of polyvinylidene fluoride (PVDF) and sulfonated PVDF (S-PVDF). Polyaniline was doped with different doping agents and their effect on total salt extraction and selectivity of bivalent to monovalent cations was evaluated. The chemical and morphological properties of hybrid membranes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ion exchange capacity (IEC), transport number, ion conductivity and water uptake decreased after surface polymerization. Composite membrane has a good selectivity (∼2) for bivalent and excellent removal of both cations. The hybrid membrane, doped with pTSA has a very high selectivity for monovalent ions (∼7.1) and a high removal of monovalent ions.     

Polyaniline/porous carbon electrodes by chemical polymerisation: Effect of carbon surface chemistry

Polyaniline/porous carbon composite electrodes were prepared by chemical polymerisation and characterized in terms of porosity and performance as electrochemical capacitors.To obtain the composite electrodes two methods were used. The first method consisted of mixing, directly, the activated carbon with chemically polymerised polyaniline. The second one consisted of mixing the activated carbon with aniline and subsequent chemical polymerisation. Additionally, the second process was carried out with the porous carbon previously thermally treated in N₂ up to 900 °C in order to remove surface oxygen groups.Changes in porosity with the polyaniline addition were analysed. It has been proved that the method used strongly affects the porous structure. Dealing with the electrochemical performance, polyaniline and carbon mechanically mixed seem to work independently, being the composite behaviour a combination of the corresponding performance of both materials separately. The composites prepared by the second method (polymerisation over carbon) reveal the key role of surface chemistry in polyaniline coating. Aniline reacts with the oxygen complexes and their positive effect in capacitance is not observed.The second method (polymerisation over carbon) using a thermally treated carbon seems to be the best one since a more porous (or thinner) polyaniline film is produced.     

Hybrid sol–gel membranes of polyacrylonitrile–tetraethoxysilane composites for gas permselectivity

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     

Improvement in polyetherimide gas separation membranes through the incorporation of nanostructured metal complexes

Polyetherimide (PEI) gas separation membranes were tailored, at the molecular scale, by the incorporation of nanostructured metallic complexes into the PEI network. The influence of these additives on the micropore size distributions of the membranes produced and on their performance for oxygen/nitrogen separation was investigated. Changing the metal within the same ligand had a significant influence on the microporosity and gas separation performance of these membranes. Magnesium (II) phathalocyanine (MgPc) in PEI membranes was found to be an excellent additive to increase membrane performance for air separation. The performance of these membranes increases with increasing additive concentrations. Membranes with this additive also exhibit an improved stability as determined through the annealing process. Annealing these membranes caused a slight decrease in their gas permeance and total micropore volume but a significant increase in their gas selectivity. The results show that the properties of the nanophase additive and nanophase-polymer interactions play a pivotal role in stabilizing and determining membrane performance for air separation.     

Controlled synthesis of high performance carbon/zeolite T composite membrane materials for gas separation

A simple approach has been developed to synthesize the carbon/zeolite T composite membrane materials with the high gas separation performance. The precursors of the composite membrane are composed of polyimide matrix and dispersed zeolite T particles. The composite membranes prepared by pyrolysis at 973 K show excellent gas (H₂, CO₂, O₂, N₂, and CH₄) permeability and selectivity (O₂/N₂, CO₂/CH₄) for both single gas and mixed-gas. The gas separation performance of the composite membranes can be controlled in a wide range by only changing the zeolite T particle size. The maximum selectivity of O₂ over N₂ (21/79 mol%) for the composite membranes with the least zeolite T particle (0.5 μm) is 15 with an O₂ permeability of 347 Barrers (1 Barrer = 7.5 × 10⁻¹⁸ m² s⁻¹ Pa⁻¹) and the selectivity of CO₂ over CH₄ (50/50 mol%) reaches a value of 179 with a CO₂ permeability of 1532 Barrers. It is believed that the increase of gas permeability is attributed to the ordered microchannels in the zeolite and the interfacial gaps formed between zeolite and carbon matrix in the composite membranes. And the gas selectivity is tuned by the size of interfacial gaps which are varied with the zeolite particle size. This technique will provide a simple and convenient route to efficiently improve the trade-off relationship between the permeability and the selectivity and enable the construction of carbon-based composite materials with novel functionalities in membrane science.     

Ceramic Supported PDMS and PEGDA Composite Membranes for CO2 Separation

Composite membranes have attracted increasing attentions owing to their potential applications for CO2 separation. In this work, ceramic supported polydimethylsiloxane （PDMS） and poly （ethylene glycol） diacrylate （PEGDA） composite membranes were prepared. The microstructure and physicochemical properties of the compos- ite membranes were characterized. Preparation conditions were systematically optimized. The gas separation performance of the as-prepared membranes was studied by pure gas and binary gas permeation measurement of CO〉 N2 and H〉 Experiments showed that PDMS, as silicone rubber, exhibited larger permeance and lower separation factors. Conversely, PEGDA composite membrane presented smaller gas permeance but higher ideal selectivity for CO2/N2. Compared to the performance of those membranes using polymeric supports or freestanding membranes, the two kinds of ceramic supported composite membranes exhibited higher gas permeance and acceptable selectivity. Therefore, the ceramic supported composite membrane can be expected as a candidate for CO2 separation from light gases.     

Synthesis of silicalite-poly(furfuryl alcohol) composite membranes for oxygen enrichment from air

ABSTRACT: Silicalite-poly(furfuryl alcohol) [PFA] composite membranes were prepared by solution casting of silicalite-furfuryl alcohol [FA] suspension on a porous polysulfone substrate and subsequent in situ polymerization of FA. X-ray diffraction, nitrogen sorption, thermogravimetric analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to characterize silicalite nanocrystals and silicalite-PFA composite membranes. The silicalite-PFA composite membrane with 20 wt.% silicalite loading exhibits good oxygen/nitrogen selectivity (4.15) and high oxygen permeability (1,132.6 Barrers) at 50°C. Silicalite-PFA composite membranes are promising for the production of oxygen-enriched air for various applications.     

界面聚合制备含丙烯氧基团的复合膜用于CO2分离

含有醚氧基团的膜与CO₂分子具有较强的极性作用,可以实现对CO₂/N₂物系的高效分离.其中,含丙烯氧(PO)基团的聚合物链段自由体积较大且不易结晶,是一类具有发展潜力的溶解选择性膜材料.以均苯三甲酰氯为油相单体,含PO基团的多胺为水相单体,通过界面聚合,成功制备了含PO基团的复合膜.分别采用聚醚胺D400、D230及T403为多胺水相单体,考察了膜内PO基团数量和交联度对复合膜分离性能的影响.结果表明,采用D400所制的复合膜由于具有最高的PO基团含量及较低的交联度,因此具有最高的CO₂渗透速率和CO₂/N₂分离因子.之后,考察了单体浓度、酸吸收剂种类以及水相溶液pH对复合膜分离性能的影响.通过优化这些制膜条件,制备出了CO₂/N₂分离性能较好的复合膜.