Síntese de óxidos mistos AMn2O4 (A=Co, Cu e Ni) preparados por autocombustão para controle de emissões de compostos orgânicos voláteis

Os compostos orgânicos voláteis (COVs) são substâncias que possuem elevada pressão de vapor ebaixa solubilidade em água e são reconhecidos por serem um dos maiores responsáveis pela poluição atmosférica,tanto por sua natureza tóxica quanto por serem os precursores do ozônio e do smog fotoquímico. Oobjetivo deste trabalho foi sintetizar óxidos mistos sob as mesmas condições de preparação e avaliar suaspropriedades e atividade, visando a obtenção de catalisadores eficientes do ponto de vista ambiental na oxidaçãodo tolueno, que constitui um dos COVs mais abundantes na atmosfera. Óxidos com estrutura de espinélioAMn2O4 (A=Co, Cu e Ni) foram preparados pelo método de autocombustão sob as mesmas condiçõesde síntese e suas propriedades físico químicas foram avaliadas por DRX, BET, FTIR e MEV. A relação entreas propriedades a as atividades dos espinélios na oxidação do tolueno foi avaliada e os catalisadores de Cu eCo foram os mais promissores, com conversões de 99 e 92%, respectivamente. Esta maior atividade foi atribuídaao possível efeito sinérgico entre o Mn3+ e as fases Co2+ e Cu2+ presentes nas estruturas dos óxidos.Não foi verificada relação direta entre os resultados obtidos para a atividade e área específica.Palavras-chave: Óxidos mistos de manganês; autocombustão; estrutura espinélio; tolueno; oxidaçãocatalítica

Preparation and Characterization of Zein and Zein-Chitosan Microspheres with Great Prospective of Application in Controlled Drug Release

Biomaterials applied as carriers for controlled drug delivery offer many advantages over the conventional systems. Among them, the increase of treatment effectiveness and also a significant reduction of toxicity, due to their biodegradability property, are some special features. In this work, microspheres based on the protein Zein (ZN) and ZN associated to the natural polymer Chitosan (CHI) were prepared and characterized. The microspheres of ZN and ZN/CHI were characterized by FT-IR spectroscopy and thermal analysis, and the morphology was analyzed by SEM images. The results confirmed the incorporation of CHI within the ZN-based microspheres. The morphological analysis showed that the CHI added increased the microspheres porosity when compared to the ZN microspheres. The chemical and physical characterization and the morphological analysis allow inferring that ZN/CHI microspheres are good candidates to act as a carrier for controlled drug release

Preparation and characterization of composites from plastic waste and sugar cane fiber

Abstract This study presents the preparation and characterization of composite materials using Plastic Waste from Hydrapulper (PWH) from paper industries extruded with sugar cane fiber residues from ethanol industries. The factorial design showed that composite material with 40% of sugar cane fiber, pressed with 5 ton was the optimized condition. The main findings attested that the composite is resistant up to 250 °C and its hardness is increased compared to the raw PWH. The material presented woodsy aspect although water absorption has increased. So, this study offers a good alternative for the use of plastic waste generated as a by-product of recycled paper industry as well as a destination to the sugar cane bagasse

Mechanical recycling of tags and labels residues using sugarcane bagasse ash

Abstract In this study, an alternative method for recycling residues of labels and stickers (parings) containing biaxically oriented polypropylene (BOPP) and polyurethane-based glue was discussed. The recycling of this type of material is complicated, once the separation and the milling processes are difficult to be accomplished, due to the presence of a large amount of glue. In this study, sugarcane bagasse ash was used to enable the milling process of stickers residues. Composites were prepared with post-consumer polypropylene extrusion with different polypropylene/parings ash ratio. These materials were analyzed by tensile, three point flexural, hardness, density, water absorption, Izod impact tests, thermogravimetric analysis, environmental exposure and scanning electron microscopy. Addition of sticker residues/ash to the polypropylene matrix makes the material more rigid and does not affect significantly thermal and degradation properties. Thus, the recycling process proposed in this paper is environmentally and economically viable

Physico-chemical properties of meso-tetrakis(p-methoxyphenyl)porphyrin (TMPP) incorporated into pluronicTM p-123 and f-127 polymeric micelles

The physicochemical properties (solubilization, structural organization and stability) of meso-tetrakis(p-methoxyphenyl)porphyrin (TMPP), a promising photosensitizer for photodynamic therapy, solubilized in polymeric micelles of tri-block copolymers PluronicTM P-123 and F-127, were studied. The formulations obtained by the solid dispersion method led to monomerization of TMPP in these copolymers. Solubility studies showed that P-123 solubilizes double the photosensitizer than F-127. The self-aggregation phenomenon was affected by the [TMPP]/[poloxamer] ratio and medium temperature. The decrease in the temperature of these systems promoted the formation of different kinds of TMPP aggregates intrinsically connected with the structural changes occurring in the micelles

Physico-chemical properties of meso-tetrakis(p-methoxyphenyl)porphyrin (TMPP) incorporated into pluronicTM p-123 and f-127 polymeric micelles

The physicochemical properties (solubilization, structural organization and stability) of meso-tetrakis(p-methoxyphenyl)porphyrin (TMPP), a promising photosensitizer for photodynamic therapy, solubilized in polymeric micelles of tri-block copolymers PluronicTM P-123 and F-127, were studied. The formulations obtained by the solid dispersion method led to monomerization of TMPP in these copolymers. Solubility studies showed that P-123 solubilizes double the photosensitizer than F-127. The self-aggregation phenomenon was affected by the [TMPP]/[poloxamer] ratio and medium temperature. The decrease in the temperature of these systems promoted the formation of different kinds of TMPP aggregates intrinsically connected with the structural changes occurring in the micelles