过滤成膜制备氧化铝中空纤维超滤膜

 介绍了在α－Al2O3中空纤维微滤膜上采用过滤成膜技术制备γ－Al2O3超滤膜的方法．应用热重分析、差热分析、X射线衍射和扫描电子显微镜等测试手段对膜的热稳定性、结构及形貌进行了表征．扫描电子显微镜结果表明，采用过滤成膜方式制备的担载中空纤维超滤膜表面无针孔，无裂纹．气体渗透实验进一步表明，所得中空纤维超滤膜完整、无缺陷，具有一定的气体选择性．经700℃焙烧后的膜在0．3和0．4MPa条件下对氮／氩的分离因子分别为1．133和1．139，说明气体通过膜的扩散以Knudsen扩散传质为主．用等温氮气吸附实验测定了非担载膜的孔径大小和分布，其比表面积为228．9m2／g，最可几孔径约为4．5nm．     

Preparation of a Completely Oriented Molecular Sieve Membrane

Growth of oriented seed crystals on a substrate led to a completely oriented and continuous membrane of LTA-type zeolite. The seed crystals of cubic morphology were dip-coated onto a tilted substrate (see schematic diagram) with the zeolite channels normal to the surface. The substrate was hydrothermally treated in a reaction mixture containing the organic ligand 2,2-bis(hydroxymethyl)-2,2',2"-nitrilotriethanol, which lowers the degree of supersaturation of [Al(OH)(4)](-) ions and preferentially facilitates the intergrowth of the seed crystals.     

催化裂解C2H2制备空心碳球

在高岭土负载的镍催化剂上,于850 ℃催化裂解乙炔制备了直径约500 nm 的空心碳球.用XRD、TEM、SEM和显微激光Raman光谱对所得的碳球及催化剂进行了表征,并初步探讨了反应机理.     

Creation of Well‐Defined “Mid‐Sized” Micropores in Carbon Molecular Sieve Membranes

Carbon molecular sieve (CMS) membranes are candidates for the separation of organic molecules due to their stability, ability to be scaled at practical form factors, and the avoidance of expensive supports or complex multi‐step fabrication processes. A critical challenge is the creation of “mid‐range” (e.g., 5–9 Å) microstructures that allow for facile permeation of organic solvents and selection between similarly‐sized guest molecules. Here, we create these microstructures via the pyrolysis of a microporous polymer (PIM‐1) under low concentrations of hydrogen gas. The introduction of H₂ inhibits aromatization of the decomposing polymer and ultimately results in the creation of a well‐defined bimodal pore network that exhibits an ultramicropore size of 5.1 Å. The H₂ assisted CMS dense membranes show a dramatic increase in p‐xylene ideal permeability (≈15 times), with little loss in p‐xylene/o‐xylene selectivity (18.8 vs. 25.0) when compared to PIM‐1 membranes pyrolyzed under a pure argon atmosphere. This approach is successfully extended to hollow fiber membranes operating in organic solvent reverse osmosis mode, highlighting the potential of this approach to be translated from the laboratory to the field.     

多孔基体负载的碳纳米管复合膜制备及其气体渗透性能

采用改进的浮动催化法在多孔Al2O3基体上制备了垂直取向的碳纳米管阵列, 并用旋转喷涂法将聚苯乙烯填充于碳纳米管的空隙, 进一步将其制备成复合碳纳米管膜, 研究了H2和CO2单组分在碳纳米管复合膜中的渗透性能, 实验结果表明, H2/CO2的理想分离系数随着复合膜中碳管管径的减小而增大, 在管径较小的复合膜中, 气体渗透分离系数高于努森扩散限制, 达到6.25, 具有一定的分离效果. 两种气体在复合膜中的渗透率随着渗透温度的增加而减小.     

分离丙烯/丙烷的超薄聚电解质中空纤维复合膜的制备

以含二氮杂萘联苯结构的聚芳醚砜酮PPESK(Tg为263~305℃)为膜材料,以干-湿纺丝技术制备基膜,外涂法涂覆聚电解质(聚乙烯基吡咯烷酮PVP)并络合Ag 离子,制备了超薄皮层中空纤维复合膜,皮层厚度约为1μm。研究了复合膜聚电解质涂层PVP质量分数、Ag 含量、气体压力差、测试温度和不同过渡金属离子等对复合膜丙烯/丙烷分离性能的影响。结果表明,在压力为200kPa、温度为23℃下,当PVP质量分数为10%、n(Ag )∶n(CO)=1∶1的条件下,复合膜对丙烯渗透率可达16.32GPU,分离系数为4.79。     

种子乳液聚合法制备中空多孔聚合物微球

用分散聚合法制得粒径约为3μm的聚苯乙烯种子微球,通过溶胀,种子乳液聚合及萃取得到中空多孔聚合微球,使用扫描电镜检测了其中空多孔形貌和粒径,并讨论了成孔机理。     

高效PLOT碳分子筛石英毛细管柱的研制及其性能研究

选用碳分子筛作吸附剂 ,用液相沉淀法涂渍出高效PLOT碳分子筛石英毛细管色谱柱 ,并对其色谱性能进行了考察。结果表明 ,该色谱柱具有良好的分离特性 ,1次进样可分离出O2、N2、CO、CO2、CH4、C2H2、C2H4、C2H6 等组分;适用于炼厂气、烟道气、水煤气及变压器油溶解气等的分析。     

Fabrication of Hollow Materials by Fast Pyrolysis of Cellulose Composite Fibers with Heterogeneous Structures

A facile method for the fabrication of inorganic hollow materials from cuprammonium cellulose composite filaments based on fast pyrolysis has been developed. Unlike Ostwald ripening, approaches based on the Kirkendall effect, and other template methods, this process yielded hollow materials within 100 s. The heterogeneous structure of the cellulose composite fibers and the gradient distribution of the metal oxides are the main reasons for the formation of the hollow structure. The diameter, wall thickness, and length of the hollow microfibers could be conveniently controlled. With their perfect morphology, these hollow structural materials have great potential for use in various fields.     

聚合物互通多孔材料的乳液模板法制备及其功能化研究*

本文对近年来利用乳液模板制备聚合物互通多孔材料的研究进行了综述,主要介绍以高内相乳液模板制备互通多孔聚合物整体柱和利用双重乳液 (或称多重乳液) 制备多孔或多空聚合物微球的进展;分析目前多孔聚合物材料研究中存在的问题及其研究动态;讨论合成多孔聚合物材料的性能缺陷及其表面功能化改性的相关研究;并对聚合物互通多孔材料潜在的应用和研究前景进行了展望。     

密胺苯二醛多孔聚合物/聚二甲基硅氧烷混合基质膜的制备及气体分离性能

以溶液复合成膜法制备了密胺苯二醛多孔聚合物(MA)/聚二甲基硅氧烷(PDMS)混合基质膜,利用扫描电镜(SEM)表征了混合基质膜的形貌。考察了不同MA用量下MA/PDMS混合基质膜的气体分离性能,结果表明,MA的加入可以在提高PDMS膜渗透系数的同时提高CO_2气体分离选择性;随着混合基质膜中MA含量的增加,混合基质膜的渗透系数均明显提高,气体分离选择性则先增大后减小。双组分混合气体分离测试结果表明,MA/PDMS(1.2%(w,质量分数))混合基质膜对CO_2/N_2和CO_2/CH_4的分离选择性分别是19.2和6.0,CO_2的渗透系数达到8100Barrer,均高于纯PDMS膜。MA/PDMS(1.2%(w))混合基质膜对CO_2/N_2混合气的分离性能突破了Robeson上限。     

含硅聚硼氮烷裂解转化制备氮化硼陶瓷纤维

以低活性含硅聚硼氮烷为先驱体,经熔融纺丝,BCl₃脱硅不熔化处理以及在氨气气氛中高温裂解制备的氮化硼纤维仍含有硅元素,这主要是含硅聚硼氮烷结构中的B-N(SiMe₃)₂和B-N(SiMe₃)-B由于位阻与BCl₃反应脱除SiMe₃不完全所致.而采用HCl首先与含硅聚硼氮烷反应减少其位阻,再通过BCl₃进一步脱硅不熔化处理制备的氮化硼陶瓷纤维经FT-IR、X射线衍射(XRD)分析表明纤维基本不含硅元素,并且扫描电子显微镜(SEM)表明得到的氮化硼陶瓷纤维直径约为11μm,断面致密无孔,室温下抗拉强度为0.45GPa.     

中空纤维担载氧化硅膜的制备及结构研究

采用SXRD,HRTEM,FTIR,SEM和氮气吸附等测试手段对膜结构、形貌、孔径及其分布进行了表征.SXRD和HRTEM结果显示,所制备的膜具有短程有序结构.SEM分析发现膜表面完整.气体渗透实验表明,担载膜具有一定的气体选择性,在0.1MPa下对H₂/N₂和CH₄/N₂的分离因子分别为2.25和1.56,气体透过膜孔的扩散由努森机制所控制.等温氮气吸附实验显示,经500℃热处理后氧化硅膜的最可几孔径小于3.34nm,非担载膜的比表面积为919.8m²/g,孔容为0.43mL/g.     

多孔酚醛树脂热解碳材料的制备与结构

用苯酚和甲醛在氨水催化下合成了可溶性酚醛树脂, 经掺杂不同质量比发泡剂(氯化锌)后在惰性气氛下进行热裂解(500～900 ℃), 制备了多孔热解碳导电材料(PPAS); 用FTIR, XRD, TG, SEM, BET等方法对所制备材料进行了结构表征, 详细讨论了发泡剂的加入对热解碳导电材料结构和性能的影响. 研究发现: 酚醛树脂经掺杂一定量发泡剂后再进行热裂解, 一方面加快了酚醛树脂分子间的脱水速度, 降低了热裂解温度范围; 另一方面, 裂解产物内部结构的微晶尺寸和层间距发生了明显变化, 未掺杂发泡剂的裂解产物呈现尖锐棱角的无定形结构, 而掺杂发泡剂的裂解产物则为多孔的球形和椭球形结构; 表面吸附实验测试结果表明, 当酚醛树脂与发泡剂的质量比为1∶3, 升温速率为30 ℃/h, 热裂解温度为600 ℃时, 热裂解产物的比表面积可达2150 m2•g－1, 平均孔径在11 Å左右.     

Preparation and Water Droplet Sliding Properties of Transparent Hydrophobic Polymer Coating by Molecular Design for Self-Organization

Transparent hydrophobic polymer coating was prepared from methacrylate copolymer with molecular modeling in order to improve hydrophobicity and durability. Organic-inorganic hybridization improved the durability of the thin films. Furthermore the control of hydrophobicity and water droplet sliding properties of the flat coating was successfully performed. Water droplet sliding angle depended on the chemical structure of the materials, not on the hydrophobicity, while sliding motion simply depended on the hydrophobicity.     

Preparation and Characterization of Metolachlor Molecularly Imprinted Polymer Coating on Stainless Steel Fibers for Solid-Phase Microextraction

A molecularly imprinted polymer (MIP) with metolachlor as the template molecule was first coated on the surface of stainless steel fibers through chemical bonding. Despite 12 times repeated coating procedures, a homogenous, porous, and highly cross-linked MIP coating was obtained with thickness of 17.4 µm (RSD of 6.1%). The specific selectivity of MIP coating to metolachlor and three metabolites could be concluded with 4.4, 4.1, 3.9, and 2.9 times higher extraction amounts of metolachlor, hydroxymetolachlor, deschlorometolachlor, and desmethylmetolachlor than that of the NIP coating, respectively, and good extraction capabilities for chloroacetanilide herbicides were found with the MIP-coated SPME stainless steel fiber. For validation, the fiber was applied for the extraction of metolachlor, propisochlor, and butachlor in spiked corn and soybean samples, and the recoveries of 90.7–92.6%, 86.4–87.9, and 85.4–87.5% were obtained, respectively.     

Preparation of Carbon Nanotubes by the Catalysis of Polymer Metal Complex on Porous Al203 Matrix

At present, synthesis of carbon nanotubes (CNTs) is normally conducted on a vapor-to-solid interface at ca. 500-3500℃ via various vapor phase methods, such as are discharge, laser ablation, catalytic pyrolysis and chemical vapor deposition, etc.1-2 Recently, channel materials (such as channels of alumina and of AlPO4-5 zeolite) 3 have been utilized as solid-state templates to grow CNTs inside the channel. Here we described a novel method to prepare the carbon nanotubes based on the decomposition of C2H2 gas on the Co-Ni catalyst anchored by polymer complex on the porous A12O3 matrix. The degree of graphitization of synthesized CNTs and catalysts are of great interest.     

Supercapacitor Performance of Hollow Carbon Spheres by Direct Pyrolysis of Melamine-formaldehyde Resin Spheres

The nitrogen and oxygen co-doped hollow carbon spheres(HCSs) were prepared via a simple pyrolysis of solid melamine-formaldhyde resin spheres. The carbonization temperature has an important influence on the specific surface area, pore-size distribution and heteroatom contents of HCSs. The synergistic effects of those physical and chemical properties on supercapacitor performance were systematically investigated. Among the HCSs obtained at different temperatures, HCSs-800(co-doped HCSs at 800 ℃) exhibits the best reversible specific capacitance in 2 mol/L H₂SO₄ electrolyte and meanwhile maintains a high-class capacitance retention capability. The nitrogen heteroatoms were confirmed to play a crucial role in improving capacitance in an acid medium. This kind of nitrogen doped HCSs is a potential candidate for an efficient electrode material for supercapacitors.     

Preparation and Selectivity of Molecularly Imprinted Polymer Coating on the Micro Pore Membrane of Polytetrafluoroethylene

In order to obtain mechanically stable membrane for practical application, the imprinted polymer was synthesized in the pores of polyfluoromembrane, the binding and transport ability of the membrane were studied.