Preparo de nanocompósitos maghemita e polianilina assistido por ultrassom

Abstract

Resumo: O estudo de sistemas envolvendo nanopartículas de óxido de ferro e polianilina vem ganhando importância nos últimos anos. Entre esses trabalhos, ainda há um pequeno número de pesquisas que abordam o efeito da sonicação sobre o preparo desses híbridos. Assim, o presente trabalho teve como objetivo avaliar o efeito da sonicação sobre as propriedades de nanopartículas de maghemita revestidas com polianilina, via planejamento fatorial. Os materiais obtidos foram estudados por espectroscopia no infravermelho, difração de raios X e por análise termogravimétrica. As amostras também tiveram a resistividade elétrica e a força magnética investigadas. Os resultados obtidos demonstram que o aumento da potência de sonicação é capaz de produzir um considerável aumento da extensão do grau de dopagem, associado com a diminuição da resistividade das amostras. Por outro lado, a mesma potência de sonicação produziu a destruição de grande parte da maghemita presente, levando a menores forças magnéticas. Palavras-chave: Dispersão ultrassônica, polimerização in situ, planejamento experimental. Preparation of Maghemite and Polyaniline Nanocomposites Assisted by UltrasoundAbstract: The study of systems constituted by iron oxide nanoparticles and polyaniline has increased in the last years. However, few studies are related to the sonication effect on the preparation of these hybrid materials. In this work the effect of sonication on the properties of maghemite/polyaniline hybrids was studied using experimental design techniques. The materials obtained were studied by infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. Samples were also characterized by measuring the electric resistivity and by magnetic force tests. Obtained results show that the increase of the sonication power produces the increase of the doping process and the decrease of the electrical resistivity. The same sonication power produced the destruction of a large amount of the maghemite, leading to lower magnetic forces.

H2S Sensing Material Based on Cotton Fabrics Modified with Polyaniline

“…Among tested materials, the one modified with PAni ES presented the lowest electrical resistivity value. In turn, the other materials presented higher electrical resistivity values, as described in the literature . Again, these confirm the well‐succeeded modification of the fabric with different oxidation stats of PAni.…”

Oil sorbers based on renewable sources and coffee grounds

“…Maghemite Synthesis: The maghemite was synthesized by a co‐precipitation method using alkaline solution as described in the literature . The procedure involved preparing an alkaline solution containing 0.14 mol L −1 of iron chloride (FeCl 3 ) in 200 mL of deionized water.…”

Oil‐spill cleanup: The influence of acetylated curaua fibers on the oil‐removal capability of magnetic composites

“…The syntheses of the maghemite particles were performed as described in previously published reports . Initially, aqueous solutions of HCl (2 M ), FeCl 3 (2 M ), and sodium sulfite (1 M ) were prepared.…”