%0 Generic
%9 Master's Thesis
%A SONG, Pingsan
%D 2010
%F pittir:6779
%K  anisotropic; dispersion polymerization; emulsion polymerization; magnetic; swelling
%T Synthesis of Symmetrical and Anisotropic Core-Shell Magnetic Composite Particlesand Progress in Controllable Migration of Magnetic Core in Composite Particles
%U http://d-scholarship-dev.library.pitt.edu/6779/
%X In this work, a two-step method is developed to synthesize both symmetrical and anisotropic magnetic composite particles. First of all, magnetic-polymer seed particles are synthesized from iron oxide, styrene and methyl methacrylate by emulsion polymerization. Then magnetic composite particles are produced from synthesized seeds and styrene by seeded dispersion polymerization. The anisotropy of the magnetic composite particles could be achieved by the addition of a small amount of tetrahydrofuran (THF) into the alcohol-based polymerization medium. Moreover, two solvent compositions were found to be effective to swell the synthesized magnetic composite particles and enable the migration of magnetic cores inside the polymer spheres. The structure of magnetic core or the morphology and monodispersity of the composite particles were not destroyed during this swelling process. One mixture solvent contains THF, ethylene glycol (ETG), ethanol and water, with particles protected by a suitable amount of poly vinyl pyrrolidone-40 (PVP-40), and the other is a mixture of ETG and THF.