Preparação de microesferas poliméricas do tipo casca-núcleo à base de metacrilato de metila e metacrilato de glicidila com propriedades magnéticas

Abstract

Magnetic polymeric microspheres with core-shell morphology were synthesized by seeded polymerization technique in suspension. The core was made of poly(methyl methacrylate) (PMMA) and a mixture of magnetite (Fe3O4), maghemite (Fe2O3) and goethite (FeO (OH)). The shell was composed by poly(glycidylmethacrylate) (PGMA). These particles were characterized by infrared spectrometry (FTIR), thermal analysis (TGA / DTA), optical microscopy (OM), scanning electron microscopy (SEM-EDS), light scattering (LS) and magnetometry sample vibrating (VSM). The results of the cores showed that the use of semi suspension and the reaction time (4h) improved the uniformity of the copolymer particles sizes. Core-shells with good magnetic properties (≈7.12 emu/g) and good thermal resistance (≈300ºC) were obtained when stirring speed of 600 rpm was employed. The light scattering experiments showed that the particle size of these materials has been changed from 5-100 microns (core) to 10-120 microns (core-shell). Images of scanning electron microscopy were useful to show the formation of shell made of poly(glycidymethacrylate)(PGMA) and the core made of magnetic poly(methylmethacrylate) (PMMA-M). The best results were obtained when sodium dodecyl sulfate(SDS) concentrations above the critical micelle concentration (CMC) and monomers ratio 1:10 (shell) were used. The materials synthesized in this Thesis have the potential to be modified and employed in magnetic separation processes in biotech and environmental field