Neste trabalho, foram sintetizados materiais binários baseados em copolímeros de metacrilato de metila reticulados com divinilbenzeno contendo partículas de ferro com propriedades magnéticas pela técnica de polimerização em suspensão. Foram estudados os efeitos da concentração de ferro adicionado na polimerização, da razão molar MMA/DVB, do tipo de agente de suspensão e da velocidade de agitação na formação do copolímero. Os copolímeros foram caracterizados quanto à morfologia, à estabilidade térmica, ao teor de ferro incorporado, à distribuição de tamanho de partículas, às propriedades magnéticas, à área superficial, ao volume e ao tamanho de poros. Foram obtidas microesferas poliméricas com propriedades magnéticas que apresentaram bom controle morfológico esférico e partículas de ferro aglomeradas por toda a superfície da microesfera. As análises de propriedades magnéticas mostraram que os materiais obtidos não apresentaram ciclos de histerese, estando assim próximos de um material com propriedades superparamagnéticas, com magnetização de saturação entre 8,0 e 13,0 emu.g-1.

In this work, copolymers based on methyl methacrylate and divinylbenzene containing iron with magnetic properties were produced using the suspension polymerization method. An investigation was performed of the effect from the concentration of iron added to the polymerization, the MMA/DVB molar ratio in the copolymer formation, type of suspension agent and stirring speed on the synthesis of the copolymers. The copolymers morphology, thermal stability, contents of embedded iron, particle size distribution, magnetic properties, surface area, volume and pore size were evaluated. Polymeric microspheres with magnetic properties were successfully obtained. These materials showed good control of the spherical shape and agglomeration of iron particles under the surface of the microsphere. The analysis of magnetic properties pointed to materials with no hysteresis loops, thus being close to a material with superparamagnetic properties with saturation magnetization between 8.0 and 13.0 emu.g-1.

Microesferas poliméricas magnéticas à base de estireno (STY), divinilbenzeno (DVB), acetato de vinila (VAc) e ferro foram preparadas via polimerização em suspensão e semi-suspensão. Foram estudadas as influências da concentração de VAc adicionado na polimerização e da presença de ferro sobre as características das partículas poliméricas. Estas foram caracterizadas por espectroscopia vibracional na região do infravermelho por transformada de Fourier (FT-IR), análise termogravimétrica (TGA/DTGA), microscopia óptica por reflexão (MO), microscopia eletrônica de varredura (SEM) e magnetometria de amostra vibrante (VSM). Foram obtidas com sucesso microesferas poliméricas com propriedades magnéticas à base de estireno, divinilbenzeno e acetato de vinila. Estes materiais apresentaram bom controle morfológico esférico e partículas de ferro aglomeradas por toda a superfície da microesfera. O maior rendimento de microesferas magnéticas foi encontrado na faixa de 288 μm. Apresentaram também boas propriedades magnéticas (22,62 a 73,75 emu.g-1) com comportamento próximo de materiais superparamagnéticos e boa estabilidade térmica (444 °C).

Magnetic polymeric microspheres based on styrene (STY), divinylbenzene (DVB), vinyl acetate (VAc) and iron were prepared through suspension and semi-suspension polymerization. An investigation was made of the influence from the concentration of VAc added to the polymerization and the presence of iron on the properties of the polymeric particles. These particles were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTGA), reflection optical microscopy (OM), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). Polymeric microspheres with magnetic properties based on styrene, divinylbenzene and vinyl acetate were obtained. These materials showed good control of the spheres morphology and aggregated iron particles throughout the microsphere surface. The greater yield of microspheres was found in the range of 288 μm. They also showed good magnetic properties (from 22.62 to 73.75 emu.g-1) with superparamagnetic behavior and good thermal stability (444 °C).

Commercial copolymers based on styrene and divinylbenzene containing sulfonic acid groups were used as support for the incorporation of silver nanoparticles. These nanoparticles were obtained in situ by the reduction of Ag+ by using hydroxylamine in the presence of a protective agent. These materials were characterized with determination of the silver content and their morphological characteristics. The antibacterial activity of the final products against Escherichia coli was evaluated and the results show that the synthesized copolymers had antibacterial effect varying from 54 to 100%. The most efficient composite was made with small, well distributed particles.