| The structure of materials was one of the important factors that affect materialsproperties. As a special kind of nano structures, hollow microsphere had a large internalvolume and micro/nano shell. Compared with other spherical materials, hollow micro/nanospheres could be used as catalysts, drug delivery carrier, coating, microreactor andphotoelectric materials due to the characteristics of low density and high specific surfacearea. Rare earth materials had excellent optical, electrical and magnetic properties, butmany applications of rare earth oxides were limited by their features of morphology andcomposition. Because of the advantages combination of the inorganic nano hollow spheresand rare earth compounds, rare earth oxide hollow spheres had both the quantum sizeeffect and specific morphological effects, would be more widely applied.Rare earth hollow nanospheres were prepared by using polymer spheres as hardtemplates; Ceria oxide (CeO2), Yttrium Oxide (Y2O3) and Gadolinium Oxide (Gd2O3)hollow spheres were respective prepared by using homogeneous precipitation, sol-gel andself-assembly technologies; then their properties and functionalization were preliminaryresearched. The main contents and results in this thesis as follows:1. Uniform polymer microspheres had been synthesized by dispersion polymerizationmethod with styrene and methyl methacrylate monomer. The optimum reaction had beenfound through the studies of the effects of reaction time and stabilizer concentration on thesize and size distribution of particles. The conversion of system improved when lengthenreaction time prolonged or increased stabilizer concentration. When stabilizerconcentration increased, the diametter of microsphere decrease; the diametter distributiongot a best value at1.5%PVP. The optimal conditions was the PVP content of1.5%, theAIBN content of1%, the monomer content of10%, and the reaction time of6h.2. Using PMMA and PS spheres as templates, CeO2/polymer composite core-shellspheres were obtained by self-assembled and homogeneous precipitation with Cerium (Ⅲ)nitrate hexahydrate precursor. CeO2hollow spheres were obtained after calcined at600℃.The impact of adding PVP during the preparation of the composite microspheres had been discusses, the composite microspheres got more smooth surface and uniform size afterPVP added. Compared with pure butyl rubber, adding CeO2hollow nanospheres in butylrubber as packing materials can obviously improved its low frequency damping capacity indifferent frequency(0-180HZ).3. PMMA/Y(OH)CO3composite microspheres were prepared with uniform PMMAmicrospheres by inorganic precursor homogeneous precipitation and self-assembly. ThenY2O3hollow spheres were prepared by different temperature calcined. The mechanism ofY2O3hollow spheres was analyzed, and the XRD results showed that the obtained Y2O3hollow spheres were all pure cubic crystal system under900℃, the cladding degree bestwhen the dosage of Y(NO3)36H2O was1mmol. The results reveal that the face-centeredcubic-phase Y2O3hollow nanospheres with diameter in the range of0.9-1.5μm, the thinshell thickness about80-100nm and composed with Y2O3nanoparticles.The compositematerials were obtained by adding Y2O3powder or hollow spheres into butyl rubberrespectively. Compared its damping capacity, the composite materials which adding Y2O3hollow spheres was better.4. PS/Gd2O3composite microspheres had obtained by self-assembled and sol-gelmethod with Gadolinium (Ⅲ) nitrate hexahydrate precursor, PS spheres as templates andtriethanolamine as precipitater. Then Gd2O3hollow spheres were obtained by calcined at800℃. The thin shell of Gd2O3hollow spheres composed with cubic-phase Gd2O3nanoparticles, and its thickness was100nm. The influence of (NH4)2SO4on the morphologyof composite spheres and hollow spheres was studied. Gd2O3hollow spheres had welldecolorizing effect to degrade methyl orange simulation effluents. And after reacting6h,the decolorization rate over85%. |
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