反相微乳液法制备壳聚糖季铵盐/四氧化三铁复合磁性纳米粒子

Preparation of Quarternary Chitosan/Fe_3O_4 Composite Magnetic Nanoparticles by Reversed Microemulsion Method

以环氧丙基三甲基氯化铵(ETA)为季铵化试剂,制备了壳聚糖季铵盐(QC)———N-2-羟丙基三甲基氯化铵壳聚糖,采用AgNO3电位滴定法测定了季铵化度。以柠檬酸钠为改性剂,一步法制备了水基Fe3O4磁性纳米粒子。基于静电自组装作用,采用反相微乳液法制备了QC/Fe3O4复合磁性纳米粒子。通过多种手段对所制备的复合磁性纳米粒子的结构进行了表征、对其性能进行了研究。红外光谱(FT-IR)、热重分析(TG)及X射线光电子能谱(XPS)的结果表明,QC主要包覆于Fe3O4的表面。透射电镜(TEM)、X射线衍射(XRD)结果表明,复合磁性纳米粒子磁核为Fe3O4晶体结构,平均粒径大约为50 nm^60 nm。VSM结果表明,所制备的复合磁性纳米粒子仍具有超顺磁性,比饱和磁化强度为19.4emu/g。

Quarternary chitosan,N-2-hydroxylpropyl trimethyl ammonium chloride chitosan was synthesized using 2,3-epoxypropyl trimethyl ammonium chloride as reagent for quaterization.The degree of quaterization was measured by silver nitrate potential titration method.Water-based Fe3O4 magnetic nanoparticles were prepared using sodium citrate as modifier by one-step method.QC/Fe3O4 composite magnetic nanoparticles were prepared through reversed microemulsion and static self-assembly method.The structure and performance of the composite magnetic nanoparticles were characterized through a series of measures.QC is mainly covered on the surface of Fe3O4 magnetic nanoparticles according to the results of Fourier transform infrared spectroscopy（FT-IR）,thermogravimetry（TG） and X-ray photoelectron spectroscopy（XPS）.The results of transmission electron microscopy（TEM） and X-ray diffraction（XRD） show that the composite magnetic nanoparticles have magnetic core with crystal structure of Fe3O4,and the average particle size is about 50 nm～60 nm.The prepared composite nanoparticles are still superparamagnetic with a specific saturation magnetization of 19.4 emu/g by the results of vibrating sample magnetometer（VSM）.