【作者】 陆婷；

【导师】 陈明清；

【作者基本信息】 江南大学 ， 材料学， 2008， 硕士

【摘要】 本文通过滴加氨水控制Fe （II）与Fe （III）盐混合溶液的pH值,经共沉淀过程制得了Fe₃O₄磁性纳米颗粒。进而用一定量的油酸钠对Fe₃O₄纳米颗粒进行原位改性,得到了表面呈疏水性的磁纳米颗粒。用红外光谱（FTIR）、透射电子显微镜（TEM）、X射线衍射（XRD）等分别分析了亲油性Fe₃O₄纳米颗粒的结构、形态、粒径和粒径分布;用ZETA电位分析了反应介质的pH值对于亲油性Fe₃O₄纳米颗粒稳定性的影响。研究表明:油酸钠的用量对于Fe₃O₄纳米颗粒的性能、粒径和粒径分布有着重要的影响,在优化条件下,得到的Fe₃O₄纳米颗粒的平均直径为12.7nm。在Fe₃O₄纳米颗粒和二乙烯苯（DVB）存在的条件下,以聚乙烯吡咯烷酮（PVP）为稳定剂,乙醇/水的混合体系为反应介质,由偶氮二异丁腈（AIBN）引发甲基丙烯酸甲酯（MMA）和丙烯酸（AA）进行分散共聚,制得了PMMA-PAA交联型磁性复合微球。用FTIR对复合微球的结构进行了定性表征;复合磁性微球的形态、尺寸和尺寸分布用TEM表征;用热重分析（TGA）表征了复合磁性聚合物微球的磁含量和热稳定性;用UV光谱测定了亲油性Fe₃O₄磁性纳米颗粒和磁性复合微球的耐酸性能。结果表明:磁性复合微球中的Fe₃O₄含量可控制在40–70 wt%之间,整体保存规整的球形;通过改变聚合反应条件可将复合微球的粒径控制在100 nm到2μm范围内。磁流体的表面性质,介质的极性,AIBN、DVB和PVP的用量等对磁性复合微球的尺寸和多分散性均有不同程度的影响。通过三元分散共聚反应,制得表面带有-COOH的聚合物微球。用FTIR对聚合物微球的结构进行了表征;用扫描电子显微镜（SEM）、动态激光光散射（DLS）对聚合物微球的形态、粒径以及粒径分布进行了表征。研究发现当乙醇/水（V:V）为7:3,PVP用量占反应物总量的4.1wt%时形成的聚合物微球形态及分散性最佳。氮气保护下,在溶解有聚合物微球的水溶液中,缓慢滴加Fe2+和Fe3+的盐溶液（摩尔比为1:2）,将体系的pH调节至13,通过共沉淀形成Fe₃O₄纳米颗粒,形成表面沉积有Fe₃O₄纳米颗粒的磁性复合微球。用FTIR表征了复合磁性微球的结构;用TEM表征了磁性复合微球的形态;用热重分析（TGA）表征了磁性复合微球的磁含量和热稳定性。更多还原

【Abstract】 Magnetic nanoparticles were synthesized by precipitation method through dropwise adding aqueous solution of ammonia to mixed solution of Fe （II） and Fe （III） salts. The surfaces of Fe₃O₄ nanoparticles were modified by using a certain amount of sodium oleate under in-situ processing, to obtain hydrophobic surface of Fe₃O₄ nanoparticles. The properties of the hydrophybic Fe₃O₄ nanoparticles, such as structures, morphologies, diameter and diameter distribution were characterized by Fourier transformation infrared （FTIR）,transmission electron microscopy （TEM） and X-ray diffraction（XRD） separately. The effect of the reaction medium pH value to the hydrophybic Fe₃O₄ nanoparticles was ananysised by ZETA electric potential.It showed that the amount of the sodium oleate has the important influence on the performance,particle size and size distribution of the Fe₃O₄ nanoparticles.Crosslinked magnetic composite microspheres with poly（crylic acid）-co-poly（methyl methacrylate） （PAA-PMMA） as shell and Fe₃O₄ as core were obtained by dispersion copolymerization initiated with 2,2’-azobisisobutyronitrile （AIBN） in ethanol/water mixed solvent containing poly（vinylpyrrolidone） （PVP） as stabilizer in the presence of Fe₃O₄ nanoparticles and divinylbenzene （DVB）. The organic functional groups of magnetic composite microspheres were characterized by FTIR. The morphologies,diameter and diameter distribution of the microspheres were characterized by Transmission Electron Microscopy. The magnetism content and the thermostability of the microspheres were characterized by thermogravimetric analysis （TGA）. The acid resistance of hydrophybic Fe₃O₄ nanoparticles and magnetic composite microspheres were characterized by Ultra-violet （UV） spectroscopy. The crosslinked microspheres contained 40-70 wt % of Fe₃O₄ through TGA analysis. The average size of the microspheres can be controlled in the 100 nm to 2μm range by changing the polymerization conditions. It was found that the surface properties of Fe₃O₄ nanoparticles, ratio of ethanol to water, amount of AIBN, DVB and PVP can affect size and polydispersity of the composite microspheres.Polymer microspheres with carboxyl group on the surface were prepared by dispersion copolymerization with three monomers. The structures of polymer microspheres were characterized by Fourier transform infrared （FTIR） .The morphologies, diameter and diameter distribution of the microspheres were characterized by Scanning Electron Microscopy （SEM） and Dynamic Laser Light Scattering （DLS）.It was found that when the ratio of ethanol to water was 7:3, the concentration of stabilizer were kept at 4.1wt%, the morphologies and polydispersity of the obtained polymer microspheres were the best.Under the protection of nitrogen, a certain amount of polymer microspheres was dispersed into the water. Then Fe2+ and Fe3+ salt solution （molar ratio was 1:2） was added to the dispersed liquid, control the speed of dropping while instilling the NH4OH. To form Fe₃O₄ nanoparticles which would load on the surface of the polymer microspheres by the method of co-precipitation, just adjust pH to 13.Thus the core-shell composite magnetic microspheres were formed. The structures of magnetic microspheres were characterized by FTIR. The morphologies of magnetic microspheres were characterized by Transmission Electron Microscopy （TEM）. The stability of magnetic microspheres and magnetism content were characterized by thermogravimetric analysis （TGA）.更多还原