|
Functionalized magnetic nanoparticles on the one hand with ordinary polymer microsphere surface functionality, on the other hand has a magnetic response, so the cell separation, immobilized enzymes, cancer chemotherapy, hyperthermia and radiotherapy has an extremely wide field of biology application prospects. This paper focuses on the use of fine magnetic particles prepared by emulsion polymerization high content, good dispersion, coating effect is obvious, surface-containing functional groups (carboxyl, amino), particle size got NM grade functionalized magnetic nanoparticles. (1) oleic acid OA and UA undecylenate as modifier, by chemical coprecipitation a small particle size and uniform (8 nm), magnetic particle content of up to 85.9%, a saturation magnetization of 42.5 emu / g, lipophilic good, can stably dispersed in n-octane in the Fe 3 O 4 magnetic fluid. (2) to Fe 3 O 4 magnetic fluid as raw material for the polymerization of styrene monomer St, prepared by emulsion polymerization using a fine not functionalized Fe 3 O 4 / P (St) magnetic microspheres. The results show that the magnetic microsphere dispersion, coating effect is obvious, magnetic particle content of 35.1%, the saturation magnetization of 29.5 emu / g, facilitate the subsequent functional (carboxyl, amino) Preparation of magnetic nanoparticles. (3) using the miniemulsion polymerization method, with two ways system of carboxylated magnetic nanoparticles, First, with carboxyl azobiscyanovaleric acid ACPA as initiator, directly on the surface of magnetic nanoparticles bring carboxyl; Second, through functional monomers methyl methacrylate MMA copolymer with the main monomer styrene St, synthetic ester group with Fe 3 O 4 / P (St / MMA ) magnetic nanoparticles, and then through the hydrolysis of carboxyl magnetic nanoparticles to achieve, that is to bring the surface of the sphere carboxyl indirectly. Mainly on the magnetic fluid in the Fe 3 O 4 solid content, DVB crosslinker presence or absence of functional monomer and emulsifier SDBS ratio of MMA and initiator KPS and other factors on indirect carboxylated magnetic nanoparticles size, shape, magnetic particle content, coating effect. The results show that the carboxylated prepared by direct magnetic nanoparticles into a ball bad, poor dispersion. The Fe 3 O 4 / P (St / MMA) Indirect carboxyl (esterified) magnetic nanoparticles, were prepared by dispersion, coating integrity, particle size small and uniform (50 nm), magnetic particle content of up to 60.9%, a saturation magnetization of 50 emu / g, were superparamagnetic, having an ester group carboxyl functional groups indirect magnetic nanoparticles. (4) using the miniemulsion polymerization method, by functional monomer acrylamide monomer styrene AM and Main St copolymer synthesized with amide groups Fe 3 O 4 / P (St / AM) magnetic nanoparticles, and then by Hoffman degradation of amino magnetic nanoparticles to achieve, that is to bring the surface of the sphere amino indirectly. Experimental study of magnetic fluid Fe 3 O 4 of the solids content, presence or absence of DVB crosslinker functional monomers AM and the ratio of emulsifier and initiator SDBS KPS and other factors on magnetic nanoparticles size, shape, magnetic particle content, coating effect. The results of the dispersion prepared, covering the complete particle size of 60 nm, the magnetic particle content of 36.8%, a saturation magnetization of 27 emu / g, were superparamagnetic, a functional group having an amide group, an indirect magnetic nanoparticles amino .
|