Preparation Of Superparamagnetic Organic-Inorganic Hybrid Microspheres

Magnetic composite materials not only have some characters of magnetic materials but also their multihollow structure will make them have large smaller density, larger internal space and good surface permeability etc and their walnut-like structure make them possess very large surface area and good prospect at surface modification. Therefore, such materials have many potential applications in catalysis, sewage treatment etc. Focus of this study is to prepare various superparamagnetic organic-inorganic hybrid microspheres with different morphologies via different methods. The main contents of this paper are as follows:1. The amphiphilic magnetic particles are synthesized via co-precipitation method. The amount of oleic acid on the surface of MPs can be controlled by changing the reaction conditions. This part of the work is mainly done by Song Yang in our lab, we has only improved and enriched his work. Using such MPs, the superparamagnetic multihollow composite microspheres are prepared via radiation induced polymerization of styrene. The experimental data indicate that MPs are very important for the final structure of such composite microspheres. All the process can be performed under ambient pressure and at room temperature. Moreover, such products synthesized via y-ray are good for their bio-applications since these products are sterilized.2. Superparamagnetic nanocomposite particles with embedding structure are prepared via radiation polymerization. In this work, y-ray irradiating miniemulsion polymerization was used to prepare hydrophobic nanocomposite particles with DVB as a monomer, cetyl alcohol (CA) as an assistant stabilizer, sodium dodecyl sulfate (SDS) as an emulsifier. We can improve the Fe3O4 encapsulation degree, sharpens the PSD and the diameter of nanocomposite particles, and reduces the number of bared magnetic particles and pure polymer particles via changing the formulation.3. The superparamagnetic walnut-shaped hybrid microspheres were prepared via irradiation emulsion polymerization. In the formulation, DVB is used as a monomer, hexadecane (HD) and sodium dodecyl sulfate (SDS) are respectively used as an assistant stabilizerand an emulsifier. Study shows that the irradiation time, DVB and HD all have significant impact on the morphology of such microspheres.