Obtenção de compósitos de borracha natural com resíduo industrial de couro reticulados com diferentes peróxidos

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Synthesis, thermal and spectroscopic study of light lanthanide nicotinate, in the solid state

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Síntese, caracterização e estudo do comportamento térmico dos oxanatos de lantanídeos(III) e de ítrio(III), no estado sólido

Pós-graduação em Química - IQ

Síntese, caracterização e estudo termoanalítico dos nicotinatos de alguns metais de transição bivalentes no estado sólido

Pós-graduação em Química - IQ

New flexible and transparent solution-based germanium-sulfide polymeric materials

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Thermal stability and thermal decomposition of the antihypertensive drug amlodipine besylate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Síntese, caracterização e avaliação da atividade biológica de metalofármacos de sulindaco com íons lantanídeos (III) no estado sólido

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Síntese e caracterização de complexos de lantanídeos pesados e ítrio(III) como o fármaco ibuprofeno no estado sólido

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Íons terras raras inseridos em matrizes poliméricas de germânio e enxofre para preparação de materiais com propriedades ópticas

Pós-graduação em Química - IQ

Síntese, caracterização e estudo do comportamento térmico dos glicolatos de lantanídeos e ítrio no estado sólido

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Study of sewage sludge aimed at agricultural soil amendment by thermogravimetric analysis and fourier-transform infrared spectroscopy

Thermal degradation and gaseous products evolving from the pyrolysis of sewage sludge, aimed at agricultural soil amendment, were investigated using Thermogravimetric Analysis in conjunction with Fourier Transform Infrared Analysis (TG-FTIR). The materials were studied in temperatures ranging from 30 to 800 ºC. Furthermore infrared spectra of sewage sludge samples were performed as a complementary technique. In parallel the sewage sludge was spiked with ibuprofen in order to test whether the mentioned techniques are able to detect the drug. Thermal analysis showed the range of 200-400ºC as the most characteristic for weight loss, corresponding with the organic matter volatilization, while the range of 500-800ºC was also characteristic and due to the volatilization of carbonates. On the other hand, ibuprofen-spiking tests identified at temperature range (150-250ºC) where the compound totally volatilizes, therefore, in this work, the detection of ibuprofen by TGA was established for concentrations higher than 0.5 g/kg sludge, concentration 102 times higher than the concentrations measured by other authors in regular sewage sludge (Martín, et al., 2010). A correlation has been found between the ibuprofen concentrations in the sludge and the intensity of the absorption bands, both for FT-IR spectra at the maximum emission temperature for ibuprofen (232ºC) as for the FT-IR spectra of the non-pyrolyzed samples.

Study of the carbon dioxide chemical fixation-activation by guanidines

Fixation of CO(2) is one of the most important priorities of the scientific community dedicated to reduce global warming. In this work, we propose new methods for the fixation of CO2 using the guanidine bases tetramethylguanidine (TMG) and 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]-pyrimidine (TBD). In order to understand the reactions occurring during the CO(2) fixation and release processes, we employed several experimental methods, including solution and solid-state NMR, FTIR, and coupled TGA-FTIR. Quantum mechanical NMR calculations were also carried out. Based on the results obtained, we concluded that CO(2) fixation with both TMG and TBD guanidines is a kinetically reversible process, and the corresponding fixation products have proved to be useful as transcarboxylating compounds. Afterward, CO(2) thermal releasing from this fixation product with TBD was found to be an interesting process for CO(2) capture and isolation purposes. (C) 2008 Elsevier Ltd. All rights reserved.

Desenvolvimento de pastas de cimento flexíveis para poços de petróleo submetidos à injeção de vapor utilizando látex do tipo SBR

Novel cementing materials formulations containing flexible polymeric admixtures have been studied aiming at improving the mechanical behavior of oil well cement slurries submitted to steam injection. However, research activities in this sector are still under development. The steam injected directly into the well causes casing dilation, which after a reduction in temperature, tends to return to its original dimensions, resulting in crack formation and hydraulic isolation loss of the well, which will result in shortening of well life. In this scenario, the objective of the present study was to evaluate the mechanical behavior of Portland-based slurries containing SBR latex, applied in oil well cementing of wells submitted to steam injection. Were formulated slurries with densities of 1.797 g/cm3 (15.0 lb/Gal) and 1.869 g/cm3 (15.6 lb/Gal), containing admixtures with a latex concentration of 0; 66.88; 133.76; 200.64 and 267.52 L/m3 (0, 0.5, 1.0, 1.5 and 2.0 gpc). Tests including rheology, fluid loss control, thickening time, API compressive strength and splitting tensile strength, beyond steam injection simulation. Microstrutural characteristics of the slurries were also performed (XRD, TG, FTIR and SEM). The results showed that increasing the polymer concentration increased in the rheological properties and fluid loss, and a decrease in the elasticity modulus of the cement slurries. The results obtained showed that the slurries can be applied in cementing operations of oil wells submitted to steam injection.

Adição de resíduo cerâmico em pastas geopoliméricas para cimentação de poços de petróleo

The development of activities the of oil and gas sector have promoted the search for suitable materials for cementing oil wells. In the state of the Rio Grande do Norte, the integrity of the cement sheath tends to be impaired during steam injection, a procedure necessary to increase oil recovery in reservoirs with low-viscosity oil. The geopolymer is a material that can be used as alternative cement, since it has been used in the production of fire-resistant components, building structures, and for the control of toxic or radioactive residues. Geopolymers result from condensation polymer alkali aluminosilicates and silicates resulting three-dimensional polymeric structures. They are produced in a manner different from that of Portland cement, which is made an activating solution that is mixed with geopolymer precursor. Among the few works studied allowed us to conclude that the pastes prepared with metakaolin as precursor showed better performance of its properties. Several studies show the addition of waste clay as a means of reducing cost and improving end of the folder properties. On this basis, the goal is to study the influence of the addition of ceramic waste in geopolymer paste. To develop the study of rheology tests were carried out, filtered, thickening time, compressive strength, free water, specific gravity and permeability, according to the American Pretoleum Institute (API). The results for all formulations studied show that the folders have high mechanical strength to a light paste; low filtrate volume, absence of free water, very low permeability, slurry, consistent with a light paste, and thickening time low that can be corrected with the use of a retardant handle. For morphological characterization, microstructural, physical, chemical and thermal tests were carried out by XRD, MEV, DTA, TG, FTIR. In the trial of XRD, it was found that geopolymer is an amorphous material, with a peak of crystalline kaolinite. In tests of TG / DTA, revealed the presence of a significant event, which represents the mass loss related to water, and also observed the reduction of weight loss by increasing the concentration of ceramic waste. In the trial of MEV, we found a uniform matrix without the presence of other phases. In the trial of FT-IR, we observed the presence of the band related to water. From all results it was determined that the optimum concentration range of use is between 2.5 and 5% of waste ceramic

Caracterização e análise das propriedades da fibra de Macambira (Bromelia Laciniosa)

Concern for the environment and the exploitation of natural resources has motivated the development of research in lignocellulosic materials, mainly from plant fibers. The major attraction of these materials include the fact that the fibers are biodegradable, they are a renewable natural resource, low cost and they usually produce less wear on equipment manufacturing when compared with synthetic fibers. Its applications are focused on the areas of technology, including automotive, aerospace, marine, civil, among others, due to the advantageous use in economic and ecological terms. Therefore, this study aims to characterize and analyze the properties of plant fiber macambira (bromelia laciniosa), which were obtained in the municipality of Ielmo Marino, in the state of Rio Grande do Norte, located in the region of the Wasteland Potiguar. The characterization of the fiber is given by SEM analysis, tensile test, TG, FTIR, chemical analysis, in addition to obtaining his title and density. The results showed that the extraction of the fibers, only 0.5% of the material is converted into fibers. The results for title and density were satisfactory when compared with other fibers of the same nature. Its structure is composed of microfibrils and its surface is roughened. The cross section has a non-uniform geometry, therefore, it is understood that its diameter is variable along the entire fiber. Values for tensile strength were lower than those of sisal fibers and curauá. The degradation temperature remained equivalent to the degradation temperatures of other vegetable fibers. In FTIR analysis showed that the heat treatment may be an alternative to making the fiber hydrophobic, since, at high temperature can remove the hemicellulose layer, responsible for moisture absorption. Its chemical constitution is endowed with elements of polar nature, so their moisture is around 8.5% which is equivalent to the percentage of moisture content of hydrophilic fibers. It can be concluded that the fiber macambira stands as an alternative materials from renewable sources and depending on the actual application and purpose, it may achieve satisfactory results