Preparation of Hollow polymers embedded with Magnetic nanoparticles and Their Application to Recoverable Catalyst

Abstract

The synthesis of organic-inorganic hybrid materials composed of magnetic materials and polymers can be applied to various applications as sensors, imaging agents, storage media, and catalysis in biotechnology and microelectronics. Typically the hollow spherical particles are of great technological importance because of their potential utility for use as confined reaction vessel, as drug carriers, and as protective shells. The research objective of this thesis is fabrication of monodispersed hollow polymers embedded with magnetic nanoparticles by core-shell emulsion polymerization and apply this magnetic hollow polymer to recoverable catalyst. In chapter 2, monodispersed hollow polymers embedded with Fe3O4 nanoparticles were successfully been prepared by core-shell emulsion polymerization regardless of the kind of surface coating materials of magnetic nanoparticles, although the location of magnetic nanoparticles in the hollow polymer was somewhat different. The resultant magnetic hollow polymer presents excellent colloidal stability. The interior void size can be controlled by adjusting the particle size of the core polymer and the shell thickness can be adjusted by varying the amount of styrene monomer over the iron oxide nanoparticles. These magnetic polystyrene microspheres are superparamagnetic and highly magnetized as much as 4.69 emu/g microsphere. These magnetic hollow polymers showed catalytic activity for the trimethylsilyl protection of hydroxyl group and reused for six consecutive cycles without significant loss of catalytic activity through a simple magnetic separation. In chapter 3, monodispersed silver nanoparticles embedded in magnetic hollow polymers were successfully prepared by emulsion polymerization. This hollow microsphere was superparamagnetic and magnetized as much as 4.28 emu/g microsphere. And hollow microspheres embedded with silver and magnetic nanoparticles were characterized by XRD, UV-vis, TEM, SEM, TGA, EDX. The loading amounts...