Preparation Of Magnetic Polymer Nanospheres And Modified

Magnetic polymer nanospheres are a kind of novel functional materials, which have exhibited extensive application prospect in biomedical fields, such as tumor targeted therapy, cell separation, because of behaving properties of magnetic materials, polyemer materials and nano-materials. On the basis of previous research, Magnetic polymer nanospheres with small size, good dispersibility, high magnetite content and functional groups were prepared by the one-step miniemulsion polymerization, and a new method was developed in this paper. Moreover, the properties of the magnetic nanospheres were characterized by TEM, FT-IR, TG and VSM. The main content of this paper is described as following:(1) The Fe3O4 nanoparticles were prepared by co-precipitation in the presence of KH550 and oleic acid/undecylenic acid, respectively, and their properties were characterized and analyzed. The results showed that compared with Fe3O4 modified by KH550, Fe3O4 nanoparticles modified by oleic acid/undecylenic acid had better dispersibility, smaller and more uniform particle size, which also had high magnetite content, superparamagnetism, good miscibility with oil phase. And this kind of Fe3O4 nanoparticles dispersing in octane formed Fe3O4 ferrofluids which were fit for preparing magnetic polymer nanospheres.(2) Fe3O4/P(St) magnetic microspheres with good dispersibility, high magnetite content (46.7%), strong magnetic responsiveness were prepared by the one-step miniemulsion polymerization, whose saturation magnetization reached 36.9emu/g.(3) On the basis of synthesis technics of Fe3O4/P(St) magnetic microspheres, the magnetic nanospheres with epoxy groups and carboxyl groups were prepared by introducing functional monomers such as methyl methacrylate(MMA), glycidyl methacrylate(GMA), 4,4'-azobis(4-cyanopentanoic acid)(ACPA), respectively. The results showed that the average particle size of magnetic Fe3O4/P(St/MMA/GMA) nanosphers with good dispersibility and high magnetite content (29.7%)was about 80nm, whose saturation magnetization reached 22.5 emu/g. And the epoxy groups can be found. Moreover, magnetic Fe3O4/P(St/ACPA) nanospheres with carboxyl groups had good dispersibility, small particle size(70nm), high magnetite content (39%) and large saturation magnetization(27.9emu/g).The two kinds of surface-functionalized superparamagnetic nanospheres were all useful for magnetic targeted carriers.(4) Magnetic Fe3O4/P(St) nanospheres were prepared by the two-step miniemulsion polymerization which was developed on the basis of the one-step miniemulsion polymerization. The effects of various polymerization parameters, such as the preparation way of St-miniemulsion, the magnetic fluid concentration, the initiator, the hexadecane dosage, the surfactant dosage on the properties of magnetic Fe3O4/P(St) nanospheres were discussed in detail. The results showed that by optimizing the technics parameters, superparamagnetic Fe3O4/P(St) nanospheres with better dispersibility, smaller and more uniform particle size(70nm) were produced which had high magnetic content(43.2%)and large saturated mangnetization (35.4emu/g). Moreover, superparamagnetic Fe3O4/P(MMA) microspheres with good dispersibility, high magnetic content(56.7%), and large saturated mangnetization (46.8emu/g) were prepared by modified two-step mini emulsion polymerization.