Abstract: Fe3O4 nanoparticles, which were prepared by chemical coprecipitation, were modified by 2,2,6,6-tetramethylpiperidinyl-1-oxy bromic salt to form peroxide initiators. The poly[styrene-co-(maleic anhydride)]/Fe3O4 hybrid materials were prepared by “living”/controllable free radical polymerization of styrene(St) and maleic anhydride(MA) in the presence of modified Fe3O4. Nano-Fe3O4 and the hybrid materials were characterized by FT-IR, XRD, TGA, TEM, GPC. The results indicate that its average diameter is about 70 nm. The polymer chains increase with the polymerization time. The results of magnetic performance by vibrating sample magnetometer indicate that the hybrid materials exhibit superparamagnetic properties at room temperature under applied magnetic field. Saturation magnetization decreases with the increasing amount of encapsulated polymers.

Key words: Fe3O4 nanoparticles, hybrid materials, &, ldquo, living&, rdquo, /controlled free radical polymerization