Preparation and property characterization of PAA/Fe3O4 nanocomposite

PAA/Fe₃O₄ nanocomposites were prepared by mixing nano-Fe₃O₄ and polyacrylic acid (PAA) ethanol solution and then evaporating the solvent. The materials were characterized by transmission electron microscope (TEM), Fourier transform infrared spectroscope (FTIR), thermogravimetry analysis (TGA), dynamic ultra-micro hardness tester (DUMHT) and superconducting quantum interference device (SQUID) magnetometer. Results showed that PAA coordinated with nano-Fe₃O₄ to form a cross-linking structure. The presence of nano-Fe₃O₄ enhanced the thermal stability of the nanocomposite. The elasticity and hardness of the nanocomposite increased, and the indentation depth reduced with the increase of Fe₃O₄ content in the composites. The nanocomposites showed superparamagnetic properties at 300 K. Translated from Acta Scientiarum Naturalium Universitatis Sunyatseni, 2006, 45(5): 47–50 [译自: 中山大学学报 (自然科学版)]     

磁性四氧化三铁纳米粒子的合成及改性

Fe3O4由于有磁性且原料易得、价格低廉而被大量应用于涂料和油墨等领域;纳米Fe3O4粒子还被广泛用作磁记录材料、固定化酶、免疫诊断、靶向药物、催化剂载体、磁性微球和生物探针等。近年来有关磁性Fe3O4纳米粒子的合成和改性已引起人们的广泛关注。     

Fe3O4 @ SPC类芬顿氧化降解苯酚

以钙基蒙脱石（Ca-MMT）为原料，采用一步层间模板法制备了四氧化三铁@硅柱撑蒙脱石催化材料（Fe3O4@SPC），通过XRD、FTIR、BET、SEM对材料的形貌、结构进行表征显示，Fe3O4@SPC具有d001=3.30 nm的晶面间距和4.47 nm的介孔，Fe3O4颗粒主要分散在SPC的外表面。以苯酚为降解目标污染物，考察了Fe3O4@SPC的催化活性和稳定性。结果表明，当苯酚质量浓度为100 mg/L，pH值为2.5，催化剂质量浓度为0.5 g/L，H2O2投加量为0.2 mL，反应时间为120 min时，苯酚的去除率为100％；催化剂经过5次循环使用后，苯酚的降解率依然保持在90%以上。通过GC-MS分析苯酚降解生成的中间体，结合叔丁醇淬灭实验，发现?OH氧化在非均相类芬顿催化氧化降解苯酚体系中起主导作用，推测了苯酚可能的降解路径。     

醇-水共热法制备Fe3O4磁流体

报道了采用醇-水共热法制备稳定Fe3O4磁流体的工艺条件。应用透射电镜。X射线衍射仪。古埃磁天平对所制备的磁流体中的磁性颗粒的粒径。形貌，磁性等进行了表征。并分析了试验条件对制备的影响。     

磁性纳米粒子Fe3O4的制备方法

随着纳米科技不断的发展,磁性材料也逐渐的进入了纳米材料的新纪元。由于纳米粒子具有小尺寸效应、表面效应、量子尺寸效应以及宏观量子隧道效应,导致了磁性纳米材料的磁学性能有了很大的变化,扩展了其应用前景。文章介绍了Fe3O4磁性纳米粒子的四种制备方法:共沉淀合成法,水热合成法,微乳合成法和微乳-凝胶合成法。     

快速配体交换法制备水溶性磁性Fe3O4纳米粒子

为了获得水溶性Fe_3O_4纳米粒子,以聚乙二醇(PEG)磷酸酯为亲水性配体,在甲苯/四氢呋喃/水三元混合溶剂体系下通过快速配体交换法将油酸包覆的油溶性磁性Fe_3O_4纳米粒子转变成聚乙二醇磷酸酯包覆的水溶性Fe_3O_4纳米粒子。考察了四氢呋喃等溶剂在实现快速配体交换中所起到的作用。利用透射电子显微镜(TEM)、动态光散射(DLS)、X射线粉末衍射仪(XRD)、傅立叶红外光谱仪(FTIR)、振动样品磁强计(VSM)对磁性Fe_3O_4纳米粒子进行了分析表征。结果表明:四氢呋喃可以促进PEG磷酸酯与Fe_3O_4纳米粒子表面的有效接触并使得油酸分子从纳米粒子表面快速地脱附下来,此外,还消除了配体交换过程中出现的乳化效应。四氢呋喃的应用实现了快速配体交换法制备水溶性PEG磷酸酯包覆的磁性纳米粒子。     

高温分解法合成Fe3O4磁性纳米微粒

以油酸为表面活性剂，高温分解铁有机物，合成Fe3O4磁性纳米微粒，并对其进行了TEM、XRD分析，结果表明，Re3O4磁性纳米微粒为规则的立方体，平均粒径为10nm，且粒径分布均匀。     

Fe3O4磁性纳米复合材料的制备及载药性能

利用聚乙二醇水溶性高及良好的生物相容性等特性对Fe₃O₄磁性纳米粒子进行表面改性,从而改善Fe₃O₄易于团聚的缺陷。通过一步法制备具有核壳结构的聚乙二醇/Fe₃O₄磁性纳米复合材料,使用FTIR、XRD、TEM和VSM对复合纳米材料的结构、形貌和性能进行了表征。采用超声法合成了阿霉素聚乙二醇修饰的Fe₃O₄磁性纳米包合物,用光度法对磁性纳米复合物的包封率进行了系统的分析,平均包封率为54.83%,并通过四唑盐(MTT)比色法证明了包合物对K150细胞有明显的抑制作用。研究结果表明:合成的磁性纳米复合材料拥有良好的形貌和载药性能,可作为一种新型的药物载体以达到靶向运输的效果,从而提高药物的生物利用度。     

Synthesis and characterization of (Fe3O4/MWCNTs)/ epoxy nanocomposites

A sonochemical technique is used for in situ coating of iron oxide (Fe₃O₄) nanoparticles on outer surface of MWCNTs. These Fe₃O₄/MWCNTs were characterized using a high‐resolution transmission electron microscope (HRTEM), X‐ray diffraction, and thermogravimetric analysis. The as‐prepared Fe₃O₄/MWCNTs composite nanoparticles were further used as reinforcing fillers in epoxy‐based resin (Epon‐828). The nanocomposites of epoxy were prepared by infusion of (0.5 and 1.0 wt %) pristine MWCNTs and Fe₃O₄/MWCNTs composite nanoparticles. For comparison purposes, the neat epoxy resin was also prepared in the same procedure as the nanocomposites, only without nanoparticles. The thermal, mechanical, and morphological tests were carried out for neat and nanocomposites. The compression test results show that the highest improvements in compressive modulus (38%) and strength (8%) were observed for 0.5 wt % loading of Fe₃O₄/MWCNTs. HRTEM results show the uniform dispersion of Fe₃O₄/MWCNTs nanoparticles in epoxy when compared with the dispersion of MWCNTs. These Fe₃O₄/MWCNTs nanoparticles‐infused epoxy nanocomposite shows an increase in glass transition (T_g) temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Magnetic and optical properties of poly(vinylidene difluoride)/Fe3O4 nanocomposite prepared by coprecipitation approach

Poly(vinylidene difluoride) (PVDF)/Fe₃O₄ magnetic nanocomposite was prepared by a simple coprecipitation method, and was characterized by scanning electron microscope (SEM), X‐ray diffraction (XRD), vibrating sample magnetometer (VSM), and ultraviolet visible spectroscopy (UV‐Vis). The SEM images showed that Fe₃O₄ nanoparticles were dispersed in the PVDF matrix as some aggregates with the sizes of 50 nm–2 μm, and the XRD curves showed the incorporation of the Fe₃O₄ nanoparticles in PVDF matrices and the decrease of the crystallinity of the PVDF. VSM results showed that the saturation magnetization (M_s) and remnant magnetization (M_r) of the PVDF/Fe₃O₄ nanocomposite increased with the increase of the Fe₃O₄ content, and that M_s and M_r along the parallel direction were higher than those along the perpendicular direction at the same Fe₃O₄ content. The coercive force (H_c) of the nanocomposite was independent of the Fe₃O₄ content and approximately equal along the parallel and perpendicular direction at the same Fe₃O₄ content. The optical band gap (E_g) of the PVDF/Fe₃O₄ nanocomposite was influenced by the Fe₃O₄ content, and decreased by 0.75 eV compared with that of pure PVDF when the Fe₃O₄ content was 3 wt %. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

纳米Fe3O4磁性颗粒的制备及应用现状

介绍了纳米Fe3O4磁性颗粒的制备工艺,如机械球磨法、水热法、微乳液法、超声沉淀法、水解法等,归纳了各种制备方法的特点。对Fe3O4颗粒当前的应用热点进行了概述,并对纳米Fe3O4的研究前景进行了展望。     

超细Fe_3O_4磁性行为的Preisach模拟

Fe3O4具有类似尖晶石的结构,是目前使用极广泛的磁性材料。近年来的研究使其在磁记录等方面的应用取得了显著的进展。Preisach模型对材料的模拟,主要从自发磁矩的先后翻转顺序出发对材料磁化结构有一个详细的数值解释,考察了材料Barkhausen跳跃的实质问题。本文用改进的Preisach模型对Fe3O4各种磁性行为进行了模拟,如零场冷却(ZFC)磁化强度和加场冷却(FC)磁化强度,以及不同温度下的磁滞回线等实验结果进行了分析模拟。通过对实验拟合得到巴克豪森跳跃谱的相关参数,这些参数很好的反映了材料磁化的物理本质。     

Synthesis of Fe3O4/polyaniline nanocomposite and its application for nitrate removal from aqueous solutions

The aim of this work was to investigate the sorption characteristics of Fe₃O₄ coated on polyaniline (Fe₃O₄/PAn) for the removal of NO₃^? ions from aqueous solutions. The sorption of NO₃^? ions by the batch method was carried out. The optimum conditions of sorption were found to be a Fe₃O₄/PAn dose of 0.4 g in 100 mL of NO₃^? solution, a contact time of 10 min, pH and temperature 7 and 40°C, respectively. Temperature had a negative effect on the removal efficiency. Three equations, i.e., Morris–Weber, Lagergren, and pseudo‐second‐order, were tested to track the kinetics of the removal process. The Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models were subjected to sorption data in order to estimate sorption capacity, intensity, and energy. The thermodynamic parameters ΔH, ΔS, and ΔG were evaluated. They showed that the adsorption of NO₃^? onto Fe₃O₄/PAn was feasible, spontaneous, and exothermic under the studied conditions. It can be concluded that Fe₃O₄/PAn has potential to remove NO₃^? ions from aqueous solutions at different concentrations. The system Fe₃O₄/Pan was successfully tested for a high removal efficiency of NO₃^? from urban wastewater. J. VINYL ADDIT. TECHNOL., 19:147–156, 2013. © 2013 Society of Plastics Engineers     

纳米Fe3O4颗粒的制备及应用

介绍了纳米Fe3O4颗粒的制备方法,这包括化学共沉淀法、沉淀氧化法、微乳液法、水热法、机器研磨法、多元醇法、超声沉淀法、溶胶-凝胶法等,并比较了各种制备方法的特点;在此基础上,进一步论述了纳米Fe3O4颗粒在生物医学、导电磁性材料、催化剂以及磁记录材料中的应用进展。     

中空Fe3O4纳米微球的制备与表征

用一步水热法制备出Fe3O4纳米颗粒,并最终组装成纳米级的Fe,O。空心球。用FIIR谱表征了样品的相结构,并用TEM和SEM表征样品的形貌,可以看出最后形成的纳米颗粒为空心球,粒径大约为200nm,大小均一。     

Fe_3O_4纳米颗粒的磁后效研究

用Preisach磁滞模型模拟了Fe3O4纳米颗粒的磁后效行为,并与实验测量结果进行了比较。结果表明:理论计算和实验结果符合的较好。其磁化强度随时间单调减小,与时间的对数成线性变化,磁场越接近负的矫顽力时衰减越快。通过Preisach模拟得到体系的涨落场和激活体积,激活体积大于实验测得的平均颗粒尺寸,由此解释了Fe3O4纳米颗粒的反磁化机制。     

Synthesis,characterization, and corrosion inhibition study of polyaniline‐α‐Fe2O3 nanocomposite

Polyaniline (PANI)‐α‐Fe₂O₃ nanocomposites (NCs) have been synthesized by chemical oxidative in situ polymerization of aniline in presence of α‐Fe₂O₃ nanoparticles at 5°C using (NH₄)₂S₂O₈ as an oxidant in an aqueous solution of sodium dodecylbenzene sulphonic acid (SDBS), as surfactant and dopant under N₂ atmosphere. The room temperature conductivity of NCs decreases and coercive force (H_c) increases with an increase addition of α‐Fe₂O₃ in PANI matrix. The result of FTIR and TGA shows that the interaction between α‐Fe₂O₃ particles and PANI matrix could improve the thermal stability of NCs. NCs demonstrate the superparamagnetic behavior. The performance of PANI and PANI‐α‐Fe₂O₃ NCs as protective coating, against corrosion of 316LN stainless steel in 3.5% NaCl was assessed by potentiodynamic polarization technique. The study shows a good corrosion inhibition effect of both the coatings. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis of new electromagnetic nanocomposite based on modified Fe3O4 nanoparticles with enhanced magnetic,conductive, and catalytic properties

A new method for the fabrication of an electromagnetic nanocomposite based on Fe₃O₄ and polyaniline (PANI) is offered. The authors focused on improvement of the physical and electromagnetic properties of the nanocomposite using a new synthetic method. Supermagnetic Fe₃O₄ nanoparticles were synthesized through coprecipitation method. As a chemical modification, the third generation of poly (amidoamine) dendrimer was grafted on the surface of the nanoparticles. PANI was grafted from –NH₂ functional groups of dendrimer via in situ polymerization of aniline. Finally, Au nanoparticles were loaded on the nanocomposite and its catalytic activity for reduction reactions was studied.     

金属有机骨架材料Fe3O4@ZIF-8作为药物载体的研究

以FeCl_3·6H_2O、乙酸钠、Zn(NO_3)_2·6H_2O、2-甲基咪唑为主要原料,通过水热法合成磁性金属有机骨架材料(Fe_3O_4@ZIF-8),对其进行了FTIR、VSM、SEM、TEM和EDS表征。以材料作为药物载体负载四环素,以负载量作为主要评价指标,考察了振荡时间、Fe_3O_4@ZIF-8用量、四环素溶液pH、四环素初始质量浓度对四环素负载量的影响。结果显示:在涡旋振荡90 s、pH=9、Fe_3O_4@ZIF-8用量5 mg、四环素质量浓度30 mg/L条件下,四环素饱和负载量达到12.296 mg/g。重复利用实验结果表明,Fe_3O_4@ZIF-8材料至少可以重复利用6次。