以甲氧基聚乙二醇同时作为溶剂、还原剂及修饰剂,在高温下分解乙酰丙酮铁,制备了纳米Fe3O4粒子,采用透射电子显微镜和X射线衍射分析表征材料的形貌和相组成,傅里叶变换红外光谱仪表征材料的表面修饰物,超导量子干涉仪测试合成的纳米粒子的磁性能,纳米粒度与zeta电势分析仪测试磁性纳米粒子在水中的zeta电势.结果表明,纳米Fe3O4粒子的大小为(10.1±1.6) nm,粒度均一,单分散性好,在300 K下具有超顺磁性,饱和磁化强度为45 A·m2/kg.红外结果表明,-COO -共价结合在粒子表面.zeta电势为- 25 mV.其在水中的稳定性与以三甘醇为反应介质、高温分解法制备的纳米Fe3O4粒子作比较,表现出长时间(60d以上)的良好分散性.静电作用及空间位阻效应是其高稳定分散性的原因.%The magnetite nanoparticles were synthesized by thermal decomposition of iron ( Ⅲ ) acetylacetonate (Fe(acac)3) in methoxy polyethylene glycol ( MPEG) , which was used as solvent, reducing agent, and modifying agent in this reaction. The morphologies and phase compositions of the nanoparticles were determined by transmission electron microscopy and X-ray diffraction, respectively. The modification of the nanoparticles was characterized using Fourier transform infrared spectroscopy. Magnetic properties were measured using superconducting quantum interference device (SQUID). The zeta potential of the nanoparticles was determined. The results indicate that the magnetite nanoparticles obtained in this way have a much uniform size and monodispersion. The diameter is about (10. 1 ± 1.6) nm. The nanoparticles show superparamagnetic behavior at 300 K with saturation magnetization of 45 A · m2/kg. The FTIR spectroscopic results prove the existence of -COO- covalently attached to the surface of the magnetite nanoparticles, and the zeta potential results show that the nanoparticles have negative surface about -25 mV. Compared with the magnetite nanoparticles synthesized in triethylene glycol (TREG) , the nanoparticles synthesized in MPEG show a longer dispersion time in deionized water ( for more than 60 days) , due to the steric and electrostatic interactions between the nanoparticles.
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