Fe_3O_4/CdTe/聚氨酯纳米复合物的制备及其性能研究

由共沉淀法和Stober法制备了伯胺基功能化SiO2稳定的Fe3O4磁性纳米粒子Fe3O4@SiO2-NH2;Fe3O4@SiO2-NH2与二异氰酸酯及咪唑阳离子二醇、聚乙二醇的反应使其表面形成阳离子型聚氨酯稳定层;通过阳离子型聚氨酯与CdTe量子点表面修饰的巯基乙酸间的电荷相互作用,制备得到了Fe3O4/CdTe/聚氨酯纳米复合物.用X射线衍射(XRD)、红外吸收光谱(FTIR)、热重分析(TGA)、透射电子显微镜(TEM)、磁强计(VSM)、紫外吸收光谱(UV)、荧光发射光谱(PL)表征了该纳米复合物的结构与性能.结果表明,CdTe量子点均匀地分散在Fe3O4@SiO2磁性纳米粒子周围,所得纳米复合物在溶剂中分散均匀,不团聚,且具有超顺磁性,并保持了CdTe量子点的荧光性能.

PREPARATION OF Fe3O4/CdTe/POLYURETHANE NANOCOMPOSITES AND THEIR PROPERTIES

Fe3O4 magnetic nanoparticles with mean diameter of about 6 nm coated by PEG4000 were prepared by a precipitation method with ferric chloride and ferrous sulfate as starting materials and ammonia for alkalinizing,and the Fe3O4-PEG4000 magnetic nanoparticles obtained were further modified by citric acid through ultrasonic treatment.Afterwards,NH2 end group surface functionalized Fe3O4 magnetic nanoparticles Fe3O4@SiO2-NH2were prepared through Stober method using silane coupling agent.Further,positively charged ionic polyurethane(IPU) was grafted onto the surface of Fe3O4@SiO2 nanoparticles by polymerization of NH2 end group,presynthesized ionic diol,PEG200 and toluylene-2,4-diisocyanate(TDI).Finally,Fe3O4/CdTe/polyurethane(Fe3O4/CdTe/IPU) nanocomposites were prepared by electrostatic interaction of positively charged IPU and thioglycolic acid coated CdTe quantum dots(QDs).The structure of Fe3O4/CdTe/IPU nanocomposites was characterized and verified by XRD,FTIR,TGA,TEM,VSM,UV and PL analyses.It was found through XRD spectra that Fe3O4/CdTe/IPU nanocomposites were a mixture of cubic-structural Fe3O4 nanoparticles,amorphous SiO2 and cubic-structural CdTe QDs.According to the FTIR analyses,the chemical bonds of SiO2,IPU and Fe3O4 indicated that SiO2 and IPU were grafted onto the surface of Fe3O4 nanoparticles.The results of TGA indicated that the coating amount of IPU was about 40%(W/W).TEM analyses showed that the SiO2 coated Fe3O4 nanoparticles were well dispersed which had a relatively uniform diameter of about 20 nm,and the CdTe QDs were arranged around the magnetic nanoparticles.The hysteresis loops proved the superparamagnetic properties of the as-prepared magnetic nanoparticles and nanocomposites.The UV and PL spectra suggested the nanocomposites revealed the properties of the QDs,and the UV irradiation images showed that the QDs moved and aggregated with magnetic nanoparticles in the magnetic field.