Preparation and Characterization of Niobium Oxide Coated Cellulose Fiber

The Nb₂O₅/cellulose composite was prepared by reacting α-cellulose with NbCl_5-n(OC₂H₅)_n, in nonaqueous solvent, under nitrogen atmosphere and submitting the obtained material to hydrolysis. An increase in the crystallinity degree is observed in the composite material because the precursor reagent reacts with the amorphous phase of the cellulose fibers. Loadings between 4.5 and 16.0% of the oxide were achieved and in every case the oxide particles uniformly cover the fiber surface. Lewis and Brønsted acid sites were determined by using pyridine as the basic molecular probe.     

烯碳材料改性有机高性能纤维：制备、性能及应用

有机高性能纤维是全球化纤工业的重要发展方向之一。提升现有纤维力学性能的同时研发新型结构功能一体化的纤维对提升我国在航天航空等领域的国际地位具有重要意义。以石墨烯和碳纳米管为代表的烯碳材料具备优异的力、电、热学等性能,可用于改性传统有机高性能纤维。通过制备不同物化性质的烯碳材料并设计合理的改性方式,可将烯碳材料优异的性能传递到传统纤维中,形成具备更高力、电、热学等性能的烯碳材料改性有机高性能纤维。本文首先综述了烯碳材料改性有机高性能纤维的制备方式,包括烯碳材料的分散与功能化、烯碳材料对有机高性能纤维的改性方法,阐述了烯碳材料改性有机高性能纤维的力、电、热学等性能以及烯碳材料的增强机理,进而总结了烯碳材料改性有机高性能纤维的应用,并对其现存的挑战和未来的发展做出展望。     

稀土金属氧化物改性整体式钌基氨合成催化剂的制备和性能的研究

研究了稀土金属氧化物La2O3，CeO2，Pr2O3，Nd2O3和Sin2O3对Ru-Bd堇青石催化剂的活性的影响。利用BET，BJH，SEM，XRD，CO化学吸附等测试手段对催化剂进行表征，并对催化剂的反应性能进行评价。SEM测试结果显示La2O3呈“虫卵状”聚集在茧青石表面，而CeO2呈立方CaF2型均匀的覆盖在堇青石表面，Ru粒子呈“孤岛状”均匀地分散在铈改性的堇青石载体表面。茧青石载体经CeO2改性后，催化剂的比表面积、比孔容积以及中、微孔数量均有所提高，孔径分布也得到了明显改善。活性数据显示，适量的稀土金属氧化物均能促进Ru-Ba/堇青石催化剂的活性，其中CeO2的改性效果最好，在10MPa，475℃，5000h^-1时CeO2改性的Ru-Ba／茧青石催化剂的氨合成转化率达到9．9％。研究了CeO2对氨浓度随温度、压力、空速变化趋势的影响。     

纳米孔阵列阳极氧化铝膜的制备和表征

本文通过在0℃、0.5mol·L^-1的草酸溶液中阳极氧化高纯铝片的方法制得了阳极氧化铝(AAO)膜，并用扫描电子显微镜(SEM)和原子力显微镜(AFM)对AAO膜的形貌和结构进行了表征。结果表明，阻挡层AAO膜中大小一致的膜胞在铝/氧化铝界面上排成六方形阵列;有孔层AAO膜中含有高度有序的纳米孔阵列和膜胞阵列，并且孔的直径和膜胞的尺寸都具有较窄的分布。另外，考察了阳极氧化电压对膜胞尺寸、孔径大小、孔密度和膜胞密度的影响，表明在一定的电压范围内，膜胞和孔径都随电压的升高而增大，而孔密度和膜胞密度却随电压的升高而减小。     

Adsorption of Acid Orange II from Aqueous Solution by Plasma Modified Activated Carbon Fibers

As a main composition of dye wastewater, organic pollutant which has a negative effect on the environment can be effectively removed by active carbon adsorption. In the present work, activated carbon fiber (ACF) was modified by a novel modification technology, gilding arc discharge, while its adsorption capacity was studied with the acid orange II (AO II) solution selected as the target wastewater. Several factors, such as air flow rate, distance between samples and the discharge area, pH of the solution and plasma treating time, were investigated with respect to their effects on properties of the plasma-treated ACF, in terms of texture characteristic, surface chemical compositions and adsorption capacities. The results showed that the specific surface area and pore volume of ACF decreased after the plasma treatment, while the amounts of oxygen-containing functional groups on the surface of ACF increased compared with the raw ACF. Moreover, it was observed that the adsorption capacity of the modified ACF was improved by nearly 20.9 %, which was beneficial to the industrial application.     

贵金属纳米颗粒杂化囊泡的制备及拉曼增强效果研究

以超支化聚合物囊泡为模板制备了贵金属纳米颗粒表面功能化的杂化囊泡.模板囊泡通过多巴胺修饰的超支化聚醚HSP-DA在水中自组装形成.在碱性条件下,囊泡表面的多巴胺自聚合生成聚多巴胺,实现囊泡的交联.由于聚多巴胺具有强黏附特性,因此可以将HSP-PDA交联囊泡分别与Au纳米溶胶、Ag纳米溶胶直接混合,得到Au纳米颗粒或Ag纳米颗粒功能化的杂化囊泡.分别测定了2种杂化囊泡的拉曼光谱,发现杂化囊泡产生了明显的表面增强的拉曼光谱(SERS)信号,清晰显示了对应于囊泡模板分子的拉曼信号,表明可以通过SERS来原位检测囊泡的组成.Ag纳米颗粒杂化囊泡展示出更高的SERS灵敏度,可进一步作为探针检测水中浓度为10-7mol/L罗丹明6G分子,得到了显著增强的拉曼光谱,证明所制备的Ag纳米颗粒杂化囊泡可用于目标分子的痕量检测.     

Preparation and Characterization of Modified Cellulose Adsorbents with High Surface Area and High Adsorption Affinity for Hg(II)

Cellulose was modified via chlorination using phosphorous oxychloride followed by functionalization with amine and thiol moieties. The obtained modified cellulose samples were investigated by means of FTIR, TGA, TEM, and nitrogen-adsorption surface area (BET). The BET measurements showed a remarkable increase in the surface area of Cell-N-S (477.7 m²/g) and Cell-N (706 m²/g). The resins gave an uptake capacities of 38 and 7.2mmol/g for Cell-N-S and Cell-N, respectively toward Hg(II) from its solutions. These values are considered much better compared with other reported resins. Regeneration of the resins was achieved effectively using acidified thiourea.     

Extraction and Characterization of Natural Cellulose Fibers from Maize Tassel

This article reports on the extraction and characterization of novel natural cellulose fibers obtained from the maize (tassel) plant. Cellulose was extracted from the agricultural residue (waste biomaterial) of maize tassel. The maize tassel fibers were obtained after treatment with NaOH and were carefully characterized while the chemical composition was determined. The chemical composition of the maize tassel fibers showed that the cellulose content increased from 41% to 56%, following alkali treatment. FT-IR spectroscopic analysis of maize tassel fibers confirmed that this chemical treatment also shows the way to partial elimination of hemicelluloses and lignin from the structure of the maize tassel fibers. X-ray diffraction results indicated that this process resulted in enhanced crystallinity of the maize tassel fibers. The thermal properties of the maize tassel fibers were studied by the TGA technique and were found to have improved significantly. The degradation temperature of the alkali-treated maize tassel fiber is higher than that of the untreated maize tassel fibers. This value convincingly showed the potential of maize tassel fibers for use in reinforced biocomposites and waste water treatment.     

In situ One‐pot Electrochemical Synthesis of Aluminum Oxide/polyaniline Nanocomposite; Characterization and Its Adsorption Properties towards Some Heavy Metal Ions

Aluminum oxide/polyaniline nanocomposite is prepared by a new and one‐pot method including in situ electrooxidation of aluminum and electropolymerization of aniline. The product has been characterized by elemental analysis, FT‐IR spectroscopy, X‐ray diffraction (XRD), Field Emission Scanning Electron Micrographs (FESEM), and Transmission Electron Micrographs (TEM) techniques. ICP‐OES was used for determination of aluminum in the prepared nanocomposite. A porous structure of the prepared composite has been shown by FESEM images. TEM of the product confirms the presence of exfoliated aluminum oxide nanofibers. The adsorption potentials of the prepared nanocomposite towards Cu²⁺, Pb²⁺, Zn²⁺, Cd²⁺, Ni²⁺ and Co²⁺ ions were evaluated in batch adsorption experiments. The results show that the adsorption efficiency is controlled by aqueous phase pH. The experimental data was well interpreted by considering the Langmuir model. The kinetics of the adsorption processes can be well interpreted by pseudo‐second‐order equation.     

Cellulose Nanofibers from Schinus molle: Preparation and Characterization

Schinus molle (SM) was investigated as a primary source of cellulose with the aim of discovering resources to generate cellulose nanofibers (CNF). The SM was put through a soda pulping process to purify the cellulose, and then, the fiber was treated with an enzymatic treatment. Then, a twin-screw extruder and/or masuko were utilized to help with fiber delamination during the nanofibrillation process. After the enzymatic treatment, the twin-screw extruder and masuko treatment give a yield of 49.6 and 50.2%, respectively. The optical and atomic force microscopy, morfi, and polymerization degrees of prepared cellulosic materials were established. The pulp fibers, collected following each treatment stage, demonstrated that fiber characteristics such as length and crystallinity varied according to the used treatment (mechanical or enzymatic treatment). Obviously, the enzymic treatment resulted in shorter fibers and an increased degree of polymerization. However, the CNF obtained after enzymatic and extrusion treatment was achieved, and it gave 19 nm as the arithmetic width and a Young’s modulus of 8.63 GPa.     

铝改性赤泥吸附剂的制备及其除氟效能的研究

以铝工业废矿渣为原材料,通过铝盐改性及焙烧活化处理,制备了水中除氟吸附剂。研究考察了吸附剂吸附氟能力、反应时间、pH值以及投加量对吸附效果的影响。结果表明,铝改性赤泥吸附剂具有较好的除氟效果,未焙烧铝改性赤泥吸附剂及经过200 ℃焙烧活化赤泥吸附剂的饱和吸附量分别达到68.07和91.28 mg·g^-1,远高于原状赤泥的饱和吸附量13.46 mg·g^-1。经吸附后出水氟含量低于1 mg·L^-1的国家饮用水标准。吸附规律符合Langmuir等温方程,溶液pH值显著影响除氟效果,在溶液pH值为7~8时达到最佳去除效果。     

Adsorption of an Isocyanurate Silane on E-Glass Fibers from Ethanol and Toluene

Isocyanurate silane was adsorbed onto E-glass fibers from toluene and ethanol in order to gain a better understanding of the surface processes at the silane-glass interface of composite materials. Use of DRIFT (diffuse reflectance infrared Fourier transform spectroscopy), XPS (X-ray photoelectron spectroscopy), and TGA (thermogravimetric analysis) techniques allowed for the qualitative and quantitative determination of such surface processes. The degree of chemisorption of the silane to the glass surface was investigated by using a sequential washing procedure with solvents characterized by solubility parameters differing from each other. All the analyzing techniques indicated that coupling between the glass and the silane occurred. However, the structure of the silane film depends considerably on the solvent and on the subsequent washing procedure. Copyright 2000 Academic Press.     

Preparation and Characterization of Amine Modified Porous Polymer for Rplc

Abstract

The retention behaviour and selectivity of various aromatic compounds, including halobenzenes and a IkyIbenzenes, were examined on the stationary phase of chloromethylated polystyrene(CMS) beads, of which the chloride group was substituted by the alkylamines: n-hexyl(C₆), n-octyl(C₈), n-decyl (C₁₀),n-dodecyl (C₁₂), n-tetradecyl (C₁₄) or n-hexadecy1 (C₁₆). Changes in the distribution coefficients of benzene derivatives are demonstrated not only by the changes of the eluent compositions but also by the changes of chain length in the stationary phase. In general, a longer alkyl chain in the stationary phase gives longer retention time and different selectivity. The effects of MeOH/H₂O ratios on retention and selectivity was also demonstrated on the C₁₄ stationary phase. Good separations of halobenzenes and alkyIbenzenes were obtained with C₁₄ stationary phase. Moreover, the retention time for samples was shortened by about a half compared to polystyrene stationary phase. These results show the chemical modification of CMS gel with long chain alkyl amines decreases tailing and provides new supports with different selectivities.     

金纳米粒子修饰聚合物固相微萃取整体柱的制备及其性能研究

通过在毛细管聚合物整体柱表面修饰金纳米粒子,制备了一种可选择性捕获含巯基化合物的固相微萃取整体柱.首先制备聚(甲基丙烯酸缩水甘油酯-乙二醇二甲基丙烯酸酯)整体柱,在其表面化学修饰半胱胺;通过半胱胺上的巯基基团将金纳米粒子固定在整体柱的孔表面.以巯基类化合物为探针,评价了固相微萃取整体柱的萃取性能.结果表明,由于Au对巯...     

氧化石墨烯接枝碳纤维新型增强体的制备与表征

利用“Grafting-to”化学修饰法制备氧化石墨烯接枝国产碳纤维新型增强体。利用红外光谱、X射线光电子能谱和原子力显微镜对样品的官能团和表面形貌进行表征;利用接触角测量、单丝拉伸方法研究了接枝前后纤维单丝的润湿性能及拉伸强度,并通过微脱粘法分析了其复合材料的界面剪切强度。结果表明：氧化石墨烯的接枝修饰使国产碳纤维表面粗糙度提高了166%,表面能提高了46.3%,拉伸强度提高了7.8%,复合材料的界面剪切强度提高了111.7%。     

Preparation and Characterization of Modified Cellulose Fiber-Reinforced Polyvinyl Alcohol/Polypyrrolidone Hybrid Film Composites

In this work, cellulose was modified by using 2-(trifluromethyl)benzoylchloride by base catalyzed reaction. Modification of cellulose was confirmed by IR studies. The biodegradable composite films were developed by a film casting method using modified cellulose with poly(vinyl alcohol) and polypyrrolidone in different compositions. Film composites showed good biodegradability. Better barrier and mechanical properties showed by film composites as the percentage of modified cellulose increased. This indicates the importance of modified cellulose as a reinforcing agent. After analyzing these properties of film composites we came to the conclusion that, these biocomposites can be used for membrane and packaging applications.