Preparation Of Magnetic Polymer Microspheres And Study On Its Adsorption Capability

Polymer microsphere is a new kind of novel functional material, whose diameter is in the nanometer to the micron level. Polymer microsphere has varies of shapes. Its applications have been related to almost all areas and polymer microsphere technique has been widely used. The magnetic polymer microspheres that combine organic polymers and inorganic magnetic materials are prepared by appropriate means, such as surface atom transfer radical polymerization(ATRP). Because of its both special polymer microspheres features and magnetic response, polymer microsphere can be modificated by copolymer, surface modification and be quickly and conveniently separated in the external magnetic field. Therefore, since the1970s, magnetic polymer microspheres have been applied in many areas of biomedicine, magnetic materials, separation engineering, cytology and bio-engineering, cosmetics, stealth technology as a novel functional materials. The main contents of this paper are as follow:Two different sizes of Fe3O4nanoparticles are prepared by two different means: solvothermal and coprecipitation. The solvothennal synthesis Fe3O4particles’ size distribution is quite narrow in200-300nm in diameter, and they have a good dispersibility in solvent. The coprecipitation synthesis Fe3O4particles’ size is in5-30nm in diameter. Their size distribution and dispersibility are not as good as the former’s.By Sol-gel method, TEOS carrys out hydrolysis reaction on the surface of Fe3O4nanoparticles which will be coated with a layer of SiO2. After hydrolysis reaction the Fe3O4@SiO2microspheres become easier to be surface modified, also the microspheres’ oxidation resistance, biocompatibility, dispersion stability are improved.In our work, we successfully prepared ATRP initiator BPE by hydrosilation reaction between triethoxysilane and2-bromo-2-methyl-propionic acid allyl ester (BAAE) in the catalyst (chloroplatinic acid) conditions. In toluene, BPE is well coated on the surface of Fe3O4@SiO2. In the CuBr/BPY cyclohexanone solution we graft pGMA on the microspheres by surface-initiated ATRP. We get the core-shell structure microspheres Fe3O4@SiO2@pGMA. The products are characterized by IR, XRD, TEM, thermogravimetric analysis and magnetic analysis.The prepared magnetic polymer microspheres react with triethylenetetramine. After being modified with triethylenetetramine, we studied the microspheres’ adsorption properties on Cd2+.We get following conclusions:Using ATRP technology to prepare magnetic polymer microspheres is not only able to maintain a certain magnetism, but also obtain the adsorption capability on Cd2+and other heavy metal ions; the product particle size dispersion concentrate upon the range from200-300nm(solvothermal)/5-30nm(coprecipitation); The coating polymer layer’s thickness is about20nm; The saturation magnetization is still as strong as41.9emu/g.