Adsorção de íons metálicos em meio aquoso, etanólico e cetônico utilizando silsesquioxanos organofuncionalizados

Pós-graduação em Ciência dos Materiais - FEIS

Polióis de substratos vegetais quimicamente modificados com trimetilolpropano

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Preparação e caracterização eletroquímica de material catódico do tipo La2/3-xLi3xTiO3 para aplicações em baterias de Lítio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Síntese, caracterização e estudo da atividade antitumoral de complexos de paládio(II) com ligantes sulfurados e trifenilfosfina

Pós-graduação em Química - IQ

Estudo da influência de argilas organofílicas no processo de biodegradação do PLA

In this study nanocomposites of PLA and organoclays Cloisite 20A and Cloisite 30B were prepared by melt intercalation. The influence from the organoclays on the biodegradation of PLA was evaluated based on the respirometry method. The incorporation of clay Cloisite 20A did not change the mineralization curve of PLA. The nanocomposite with Cloisite 30B, on the other hand, presented a different behavior, indicating a delay in the polymer biodegradation. The materials were characterized by X-ray Diffraction, Thermogravimetric Analysis and Differential Scanning Calorimetry. The materials characterization indicated nanocomposites with an intercalated structure as well as reduced thermal stability and a slight increase in the degree of crystallinity compared to the pure polymer.

Degradação de membrana impermeabilizante de polietileno de alta densidade usada em tanques de armazenamento de vinhaça

High-density polyethylene (HDPE) water-proof membranes are used as coatings in vinasse (leachate from sugar cane) storage tanks. The leachate is pumped into the tanks at temperatures of 80-90 °C. Due to these high temperatures and acidity of the waste, these membranes can be degraded, cracked and then loose the function for which they have been designed. This may cause contamination of the soil and groundwater. This study evaluated the effect of vinasse in HDPE membranes after 4 months of exposure in a controlled environment. An aggressive, alkaline pH liquid (sodium hydroxide) was also used. The objective was to evaluate the membrane resistance in contact with acidic and alkaline residues. Physical and mechanical tests, measurement of the carbon black content and thermo gravimetric analysis (TGA) were used to determine degradation of polymer membranes after chemical immersion. While sodium hydroxide resulted caused only minor changes in the physical properties, vinasse induced a thickness change of 7.8%. With immersion in vinasse, an average decrease in strength and deformability (yield) of 34% and 23.5% were measured, respectively. The stiffness increased by 7.8% (average) and the tear strength decreased by 2.7% (average).

Caracterização e avaliação da citocompatibilidade de nanocompositos baseados em celulose bacteriana e fibroína para aplicação em regenração tecidual

Pós-graduação em Ciências Odontológicas - FOAR

Obtenção e caracterização de filmes finos de Bi3NbO7 pelo método dos precursores poliméricos

Pós-graduação em Engenharia Mecânica - FEG

Estudo de geopolímeros utilizando cinzas residuais do bagaço de cana-de-açúcar

Pós-graduação em Engenharia Civil - FEIS

Matrizes híbridas siloxano-poliéter incorporadas com argila montmorilonita para liberação controlada de fármaco

Pós-graduação em Química - IQ

Cinética de degradação do sistema resina epóxi/fibra de carbono

With the increasing demand for electricity, the retraining of transmission lines is necessary despite environmental restrictions and crossings in densely populated areas to build new transmission and distribution lines. Solution is reuse the existent cables, replacing the old conductor cables for new cables with higher capacity power transmission, and control of sag installed. The increasing demand for electrical power has increased the electric current on the wires and therefore, it must bear out temperatures of 150°C or more, without the risk of the increasing sag beyond the established limits. In the case of long crossings or densely populated areas, sag is due to high weight of the cable on clearance. The cable type determines the weight, sag, height and the towers dimensions, which are the items that most influence the investment of the transmission line. Hence, to reduce both cost of investment and maintenance of the line, the use of a lighter cable can reduce both number and the height of the towers, with financial return on short and long term. Therefore, in order to increase the amount of transmitted energy and reduce the number of built towers and sag, is recommended in the current work substitute the current core material (steel or aluminium) for alternatives alloys or new materials, in this case a composite, which has low density, elevated stiffness (elasticity module), thus apply the pultruded carbon fiber with epoxy resin as matrix systems and perform the study of the kinetics of degradation by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC), according to their respective standards

Avaliação de sistemas de pultrudados com diferentes tipos de matrizes para aplicação em cabos condutores

In the last decades it has been observed a substantial developing of the electrical energy demand in the societies all over the World. In consequence the electrical energy distribution companies are increasing the quantity of electrical energy through the electrical energy conductor cables, which had grown the sag in the towers of energy transmission. Furthermore, the construction of more transmission towers brings a lot of troubles due environmental protection laws. In this way, looking forward to increase the quantity of electrical energy transmitted through electrical cables conductors, reduce the need of constructing new transmission towers and the sag in them, we suggest in this work the replace of the traditional core of the conductors cables commonly used, made of steel, by a core made by a composite material, which one is made by carbon fibers pultruded with polymeric resins as matrix. In a order to evaluate if the resins more commonly used in structural composites can be applied as matrix to make possible to use the composite material as a core, we made carbon fibers systems pultruded with epoxy, phenolic and polyester resins as matrix and a mechanic and physic-chemistry characterization was done on the systems by Tensile and Poisson tests, differential sprobe calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transformed infrared spectroscopy (FTIR), following their correspondents standards

Obtenção de rochas sintéticas a partir de resíduos de vidro comercial e pó de granito

Pós-graduação em Engenharia Mecânica - FEG

A influência da temperatura na secagem forçada da matéria-prima cerâmica da Formação Corumbataí na região do Polo de Santa Gertrudes (SP)

Pós-graduação em Geociências e Meio Ambiente - IGCE

Utilização da cinza de folha de cana-de-açúcar como material pozolânico em matrizes cimentantes

Pós-graduação em Engenharia Civil - FEIS