内部结构不对称磁性复合微球的制备及其影响因素探究

Preparation and Influencing Factors of Inner Asymmetric Structure Composite Microspheres

内部结构不对称复合微球是指无机粒子在复合微球内部呈现规律性、不对称分布的一类微球.采用细乳液聚合的方法一步合成了平均粒径0.8μm、磁含量为46.67%、比饱和磁化强度为23.20 emu/g的内部结构不对称PSt/Fe3O4磁性复合微球.详细考察了Fe3O4纳米粒子表面修饰剂含量、乳化剂、助乳化剂、超分散剂、细乳化时间等因素对于复合微球形貌的影响,探讨了内部结构不对称复合微球的形成机理.同时通过TEM(透射电子显微镜),FTIR(红外光谱),VSM(振动样品磁强计),TG(热失重分析)以及激光粒度仪等表征手段对微球内部形貌、磁化强度及粒径等进行了表征,确定Fe3O4纳米粒子表面性质是微球呈现内部结构不对称的决定性因素.

An inner asymmetric PSt/Fe3O4 composite microspheres, in which most of the inorganic particles encapsulated by polymers gather into cluster in one side of the microsphere and only few particles distribute in the other part of the microsphere, were prepared in one step miniemulsion polymerization. TEM （Transmission Electron Microscopy）, FTIR （Fourier Infrared Spectrum）, VSM （Vibrating Sample Magnetometer）, TGA （Thermogravimetry） and laser particle analyzer were used to characterize the inner structure, magnetic intensity and particle sizes of the novel microspheres. The average particle size of these new mi- crospheres is 0.8 μm, the magnetic content of this new asymmetric composite microspheres is 46.67% and the saturation magnetization is 23.2 emu/g. The influencing factors such as the amounts of oleic acid on the surface of Fe304, emulsifier, co-emulsifier and hyper-dispersant are discussed in this article. And then the mechanism of this process is also investigated. Finally, the surface properties of Fe3O4 particles were con- sidered as the key factor leading to the inner asymmetric structure.