Surface Modification Of Magnetic Metal Nanoparticles And Electromagnetic Response Property Of Their Composite

As we know, magnetic metal nanoparticles is considered as a kind of excellent microwave absorbers. However the disadvantages such as apt agglomerate, poor combination with organic basic body and poor chemical stability always affect their absorptive ability. These disadvantages can be ameliorated through the modification by organic compound, thus the nanoparticles can exhibit optimal absorptive ability.The present paper mainly has summarized the study on the surface modification of Fe and Ni nanoparticles, as well as the preparation and characterization of the composites nanoNi/PANI.Surface on Fe nanoparticles were modified by sodium dodecylbenzenesulfonate (SDBS),oleic acid, silane coupling agent(KH-560).The best modification condition was chosen according to the active exponent. The combination manner was analyzed between the modification agents and Fe nanopoarticles. The results showed that oleic acid was much better as a kind of modification agent than the others.Also Fe nanoparticles were treated by methacrylic acid (MAA). Firstly Fe nanoparticles were modified through emulsion in situ polymerization of Methyl methacrylate (MMA), which produced composite particles nanoFe/PMMA. IR results showed that MAA was combined with Fe nanoparticles by chemical bond, and c=c was introduced to the surface of nanoparticles. The composite particles were analyzed. It was noted that MMA graft polymerized on the surface of MAA-nanoFe, and double bonds participated in the polymerization, the composite particles have core-shell structure.On the other hand, SDBS, Oleic acid, KH-550 was selected as the modification agents for Ni nanoparticles. The usage of modification agents was also chosen through active exponent. The combination manner was analyzed between the modification agents and Ni nanopoarticles. The resistivity of the coatings filled with the modified Ni nanoparticles was mensurated and analyzed. The electromagnetic parameter of modified Ni nanoparticles was also analyzed. The results showed that KH-550 is a kind of good modification agent for Ni nanoparticles compared the other two.Ni nanoparticles were treated by acrylic acid (AA), and then were modified through emulsion in situ polymerization of Methyl methacrylate (MMA), the results showed that Ni nanoparticles were surface modified by PMMA successfully.Ni nanoparticles were treated by 4-aminobenzoic acid (ABA), then NanoNi/PANl composite nanoparticles were prepared through in situ polymerization of aniline in the presence of ABA-nanoNi.The composite particles were analyzed, and the electromagnetic parameters of the composites prepared under different m (nanoNi): m (AN) were analyzed .The results showed that ABA was combined with Ni nanoparticles through chemical bond, and was introduced to the surface of Ni nanoparticles, aniline polymerized on the surface of ABA-nanoNi ,the composite particles have core-shell stucture.The analyzed results showed that the electromagnetic parameter, electric loss, magnetic loss of NanoNi/PANI composite particles were changed regularly as the m(nanoNi):m(PANI).The electromagnetic parameter of NanoNi/PANI can be adjusted through regulating m(nanoNi):m(PANI).