Preparation Of Coating Iron Nanoparticles And Study On Dielectric Properties Of Itscomposite

In this research, in order to synthesis iron nanoparticles, we use liquid-phase chemical reduction method and thermal decomposition of iron pentacarbonyl iron two ways, then the in-situ polymerization was employed to get the nanoscale iron particles coated, and we obtained iron nanoparticles which are core-shell structure. Iron nanoparticles obtained by liquid-phase chemical reduction method was coated with methyl methacrylate, getting Fe@PMMA nanoparticles; the surface iron nanoparticles obtained by thermal decomposition method is oxidized to be iron oxide and become Fe&Fe3O4particles, and then they are coated with polyaniline, getting particulate Fe&Fe3O4@PANI structure; to study the effect of magnetic field on the magnetic particles, the iron nanoparticles are produced with magnetic field and without magnetic field.Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X radiation diffraction (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM) are utilized to characterize the structure and properties of iron particles we prepared. From these test results, we can know that the polymer coating procedure on iron nanoparticles is successful, which is mean that organic-inorganic core-shell structure is indeed formed, and the coating of polymer layer is excellent; Fe@PMMA nanoparticles have a particle size of about30nm, spherical shape, polymer layer-PMMA is about5nm, Fe&Fe3O4@PANI particles have a diameter of about800nm, the thickness of the polymer layer is about15nm; Iron nano-particles synthesized by chemical reduction method is amorphous α-Fe, and it becomes Fe@PMMA core-shell structure after the polymer coating procedure, while the surface of iron particles prepared by thermal decomposition method is oxidized to iron oxide-Fe&Fe3O4, and it becomes Fe&Fe3O4@PANI structure after covering PANI; comparing nanoparticles produced with magnetic field environment (MagFe@PMMA, Mag Fe&Fe3O4@PANI) with particles produced without magnetic field environment (Nonmag Fe@PMMA, Fe&Fe3O4@PANI) respectively, it is found that the crystal structure, particle morphology were not different, but iron nanoparticles prepared in the magnetic field would tend to string structure and iron nanoparticles prepared without magnetic field do not have this phenomenon; comparing the magnetic field particles with non-magnetic field particles, magnetic properties have a significant difference.To further understand the performance of the coating iron nanoparticles, and the influence of magnetic field on the magnetic particles, composites with epoxy matrix and the iron nanoparticles as fillers are prepared, then the section morphology and dielectric properties of composite materials were studied.By scanning electron microscopy (SEM), a dielectric test (LCR), it is found that the nanoparticles prepared with magnetic field have a better dispersibility in the epoxy resin matrix, when filling relatively small proportion of the nanoparticles, the dielectric constant of composite have a certain decline than pure epoxy, while continueing increasing the amount of iron particles, the dielectric constant would begin to increase; composites with the same weight percentage of iron nanoparticles, it is the composite filled with Fe particles prepared under magnetic field that has a higher dielectric constant.