Surface Modification And Physical Properties Of Inorganic Nanostructured Units

Nanometer composite materials possess excellent properties and have been widely applied in many fields. So it is the foreland and hot point of the research on nanometer material science. Improving the dispersivity of inorganic nanometer particles in polymer is a challenging subject for scientists for a long time. This paper aims at the surface modification research of lower dimension nanometer materials, raising the compatibility of the particles with resin substrate and stability, and the dispersivity of inorganic nanometer particles in polymer. The analysis of the influence of surface modification on the photo-catalyzing property, microwave-absorption, and conductive property of the complex materials was carried out as well. They can provide basic for the application of organic-inorganic complex materials.Surface decoration for nano-alumina and ultra-fine sericite was studied in this paper. The results show that by means of surface decoration for nanometer powders with silane coupling agents or with the graft copolymerization coating technique, the dispersivity and stability of them in organic media were raised highly, and the compatibility of the particles with resin substrate could be improved. The oil-absorbing value of modified sericite had been raised from 0.71g/g to 1.33g/g.La³⁺, Fe³⁺ co-doped TiO₂ was deposited onto the Al₂O₃ core by micro-emulsion method to prepare the carried TiO₂ photo-catalyst. The influence of doped La³⁺, Fe³⁺ on the photo-adsorption of TiO₂ was investigated. It shows that the co-doped Fe³⁺ and La³⁺ has synergistic effect on TiO₂/Al₂O₃ catalyst. It makes the photo-catalyst produce a bigger red-shifting and a stronger absorption for visible light compared with Fe³⁺ or La³⁺ mono-doped catalyst. And the photo-catalytic ability of the catalyst was improved as well. The decolorizing efficiency of La³⁺ 1.0%- Fe³⁺ 0.3% -TiO₂/Al₂O₃ for methyl orange solution under sunlight irradiation is bigger than that of Fe³⁺ or La³⁺ doped catalysts.The electroless plating technique was used to decorate carbon nanotubes, nanometer silicon carbide, and ultrafine sericite powders. The influence of the pretreatment conditions, process condition, and heat treatment conditions on coating composition, phase structure, morphology, particle size, and dispersion of the modified powders was investigated. The results show that carbon nanotubes, nanometer silicon carbide, and ultrafine sericite powders could be modified by means of electroless plating after being activated with proper pretreatment. By heat treatment the as-plated coating was transformed into Co-P, Ni-P and (Ni, Fe)-P alloy crystalloid from amorphous phases, which made the coating harder, smooth, and densified, and made the magnetic property of the coating varied.The microwave absorption paints were prepared with the metallized CNTs and SiC absorbents. It shows that no matter CNTs and SiC were coated by which kind of magnetic metal, the microwave absorbing paints prepared by the composite particles coated with organic compounds were much better than before. The paints exhibited bigger absorbing rate and wider absorbing peak, and the absorbing peak shifted to lower frequency band.The Ni/sericite was prepared by electroless plating method. It was used as a kind of lighter filler to replace nickel powder at certain mass fraction to prepare the conductive paint. It shows that when the replacing mass fraction was less than 25%, the surface resistivity of the paint closed with that of the nickel conductive paint. The shielding effectiveness (SE) of the conductive paint within 30-100MHz was larger than 30dB. So it can meet the demand for electromagnetic shielding under normal conditions.