【作者】 屈晶苗；

【导师】 洪若瑜；

【作者基本信息】 苏州大学 ， 应用化学， 2010， 硕士

【摘要】 Fe₃O₄磁性纳米粒子及其磁性流体是重要的磁性纳米材料,本论文系统的研究了Fe₃O₄纳米粒子制备及磁性流体的制备,具体工作分为四部分。（1）在不需要惰性气体保护的条件下制备了纳米粒子,研究了铁离子比例、反应时间、反应温度、浓度等因素对所制备的Fe₃O₄纳米粒子的影响。为改善粒子的形貌和大小,用超声对共沉淀法进行了改进,研究了超声对Fe₃O₄纳米粒子形貌、粒子大小、晶体结构和磁性能的影响。为调节粒径的大小,对纳米粒子进行了水热处理,研究了反应温度、时间、pH值对纳米粒子形貌的影响。（2）利用改进的化学共沉淀法制备了Fe₃O₄磁性纳米粒子,用OL对Fe₃O₄纳米粒子进行了表面改性,制备了高稳定性导热油基磁性流体,研究了不同制备条件如反应温度、时间、OL用量对磁性流体的影响,确定了其最佳制备条件。研究了所制备的Fe₃O₄磁性纳米粒子的形貌、晶体学结构,磁性能等。用磁天平测定了所制备的导热油基磁性流体的磁性能、稳定性等性能。（3）以TE和硅油表面活性剂EY为改性剂制备了硅油基磁性流体。为了提高Fe₃O₄纳米粒子和EY之间的结合性,先在Fe₃O₄纳米粒子表面包裹一层SiO2,使Fe₃O₄纳米粒子表面富含硅羟基。然后EY水解和Fe₃O₄纳米粒表面的硅羟基结合到一起。本研究确定了TE和EY最佳用量,研究了所制备的Fe₃O₄纳米粒子的晶型、形貌、磁性能;研究了所制备的硅油基磁性流体的磁性能、稳定性、流变性等性能。（4）用KT对Fe₃O₄纳米粒子进行了表面改性,并制备了水基磁性流体。对所制备的KT改性的Fe₃O₄纳米粒子及所制备的水基磁性流体进行了一系列表征。研究了磁性流体在交变磁场中的升温特性,考察了磁场大小、不同浓度及改性前后对升温效果的影响。更多还原

【Abstract】 Fe₃O₄ magnetic nanoparticles and magnetic fluid are very important magnetic nanomaterials. In this paper, the preparation of Fe₃O₄ magnetic nanoparticles and magnetic fluid was systematically investigated.（1） The traditional chemical co-precipitation was modified. The Fe₃O₄ nanoparticles were prepared without the protection of inert gas, which simplify the operation process. The reaction conditions such as molar ratio of iron ion, reaction temperature and reaction time were studied and the optimal condition was determined. To improve the crystal structure and tune the particle size, the Fe₃O₄ nanoparticles were treated with ultrasonic. The effect of the ultrasonic on the particle size, morphology, crystal structure and magnetic properties was investigated. To tune the particle size, the Fe₃O₄ nanoparticles were treated with hydrothermal condition. The effect of reaction temperature, time and pH value on the Fe₃O₄ nanoparticle was investigated. The results indicated that the pH value has great effect on the morphology of the Fe₃O₄ nanoparticle. At low pH, it is favorable to get larger spherical nanoparticles. While at high pH, octahedral nanoparticles were obtained.（2） Fe₃O₄ nanoparticles were prepared by modified co-precipitation method without of the protection of inert gas. OL was used to modify the Fe₃O₄ nanoparticles to improve the compatibility between the Fe₃O₄ nanoparticles and the carried liquid. Finally, stable conducting oil based magnetic fluid was obtained. The optimal preparation conditions such as reaction temperature, time and OL dosage were determined. The particle morphology, crystal structure and magnetic properties were investigated. The interaction between the Fe₃O₄ nanoparticles and OL was characterized using Fourier transform infrared （FT-IR） spectroscopy. The stability and magnetic properties were characterized using magnetic balance.（3） Silicon oil based magnetic fluid was prepared using TE and silicon surfactant EY as modifier. To improve the interaction between the Fe₃O₄ nanoparticles and the silicon surfactant, The Fe₃O₄ nanoparticles were firstly coated with a SiO2 layer by the hydrolysis of TE. Then the hydroxyl groups on the surface of the Fe₃O₄ nanoparticles were easily to react with the ethoxy groups on the silicon surfactant. The optimal amount of TE and silicon surfactant EY was determined. The properties of the Fe₃O₄ nanoparticles and the silicon oil based magnetic fluid were investigated. The results indicated that the Fe₃O₄ nanoparticles had well crystal structure, uniform particle size and high saturation magnetization. The silicon oil based magnetic fluid had strong magnetism, high stability and sheer thinning property.（4） KT which has good biocompatibility was used to modify the Fe₃O₄ nanoparticles and water-based magnetic fluid was prepared. The magnetic fluid was characterized by a series of methods. And the heating effect of the magnetic fluid in alternate current magnetic field was investigated. The effect of magnetic field strength, concentration of the magnetic fluid and the modification on the heating effect was studied.更多还原