Propriedades mecânicas e térmicas de nanocompósito híbrido de polipropileno com adição de argila e celulose proveniente de papel descartado.

Este trabalho aborda o estudo do comportamento mecânico e térmico do nanocompósito híbrido de polipropileno com uma argila brasileira bentonítica do Estado da Paraíba (PB), conhecida como \"chocolate\" com concentração de 1, 2 e 5 % em massa com a adição de 1 e 2 % em massa de celulose proveniente de papel descartado. Foi utilizado nesse nanocompósito o agente compatibilizante polipropileno graftizado com anidrido maleico PP-g-AM com 3 % de concentração em massa, através da técnica de intercalação do fundido utilizando uma extrusora de dupla-rosca e, em seguida, os corpos de prova foram confeccionados em uma injetora. O comportamento mecânico foi avaliado pelos ensaios de tração, flexão e impacto. O comportamento térmico foi avaliado pelas técnicas de calorimetria exploratória diferencial (DSC) e termogravimetria (TGA). A morfologia dos nanocompósitos foi estudada pela técnica de microscopia eletrônica de varredura (MEV). A argila, a celulose e os nanocompósitos híbridos foram caracterizados por difração de raios X (DRX), fluorescência de raios X (FRX) e espectroscopia no infravermelho (FTIR). Nos ensaios mecânicos de tração houve um aumento de 11 % na tensão máxima em tração e 15 % no módulo de Young, para o nanocompósito com argila, PPA 5 %. No ensaio de impacto Izod, o nanocompósito com argila, PPA 2 % obteve um aumento de 63 % na resistência ao impacto. Para o nanocompósito híbrido PPAC 1 % houve aumento de 8 % na tensão máxima em tração e para o nanocompósito híbrido PPAC 2 % houve aumento de 14 % na resistência ao impacto.

Narrativa española de los años setenta : Visión expandida

Fil: Macciuci, Raquel. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Uso de resíduos de queima de casca de café e argila da região sul da Bahia na obtenção de isolador elétrico cerâmico

The electrical ceramic insulators industry, uses noble raw materials such as siliceous and aluminous clays of white burning, in order to provide plasticity of the mass and contribute to electrical and mechanical properties required of the product, and feldspar with the flux function In literature references the composition of the masses indicates that the clay participates in percentage between 20 and 32, and feldspar 8 to 35, these materials have significant cost. In this research was performed the total replacement of commercial clay, for white burning clay from Santa Luzia region in southern Bahia and partial replacement of feldspar by ash residue of husk conilon coffee burning, from extreme south of Bahia. The objective of replacement these raw materials is to aver its technical feasibility and call attention for the embryo pole of ceramic industry for the existing in the south and extreme south of Bahia, which has significant reserves of noble raw materials such as clay white burning, kaolin, quartz and feldspar, and generates significant volume of gray husk conilon coffee as alternate flux. Clay Santa Luzia is prima noble material whose current commercial application is the production of white roofing. The residue of coffee husk ash is discarded near of production sites and is harmful to the environment. Phase diagrams and statistic design of experiments, were used for optimization and cost savings in research. The results confirmed the expectations of obtaining electrical ceramic insulators, with white burning clay of Santa Luzia and partial replacement up to 35.4% of feldspar, by treaty residue of conilon ash coffee husk burning. The statistic design that showed best results was for formulation with percentages of: clay 26.4 to 30.4%; kaolin 14.85 to 17.1%; feldspar 12.92 to 16.96%; R2 residue 7.08 to 9.2% and Quartz 32.5 to 38.75%, relative to the total mass of the mixture. The best results indicated; 0.2 to 1.4% apparent porosity , water absorption 0.1 to 0.7%, flexural strength 35 to 45MPa , dielectric strength 35-41 kV/cm , the transverse resistivity 8x109 2.5x1010 Ω.cm and for the dielectric constant ε/ε0 7 to 10.4, specification parameters for manufacturing ceramic electrical insulators of low and medium voltage.

Tratamento de argila montmorilonítica para a produção de nanocompósitos poliméricos com retardo de propagação de chama

Compared to conventional composites, polymer matrix nanocomposites typically exhibit enhanced properties at a significantly lower filler volume fraction. Studies published in the literature indicate t hat the addition of nanosilicate s can increase the resistance to flame propagation in polymers. In this work, a treatment of montmorillonite (MMT) nano clay and the effect of its ad dition o n flame propagation characteristics of vinyl ester were studied. The resea rch was conducted in two stages. The first stage focused on the purification and activation of the MMT clay collected from a natural deposit to improve compatibility with the polymer matrix . Clay modification with sodium acetate was also studied to improve particle dispersion in the polymer. The second step was focused on the effect of the addition of the treated clay on nanocomposites ’ properties. Nanocomposites with clay con tents of 1, 2, 4 wt. % were processed. T he techniques for the characterization of the clay included X - ray fluorescence (XRF), X - r ay d iffraction (XRD), thermogravimetric a nalysis (TGA), d ifferential scanning c alorimetry (DSC) , s urface area (BET) and Fourier transform infrared spectroscopy (FTIR). For t he characterization of the nanocomposites , the techniques used were thermogravimetric a nalysis (TGA) , differential scanning c alorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) , scanning electron mi croscopy (SEM), transmission electron m icroscopy (TEM), and the determination of tensile strength, modulus of elasticity and resistance to flame propagation. According to the results, the purification and activation treatment with freeze - drying used in thi s work for the montmorillonite clay was efficient to promote compatibility and dispersion in the polymer matrix as evidenced by the characterization of the nanocomposite s . It was also observed that the clay modifica tion using sodium acetate did not produce any significant effect to improve compatibilization of the clay with the polymer. The addition of the treated MMT resulted in a reduction of up to 53% in the polymer flame propagation speed and did not affect the mechanical tensile strength and modulus o f elas ticity of the polymer, indicating compatibility between the clay and polymer. The effectiveness in reducing flame propagation speed peaked for nanocomposites with 2 wt. % clay, indicating that this is the optimum clay concentration for this property. T he clay treatment used in this work enables the production of vinylester matrix nanocomposites with flame - retardancy properties .

Aplicação da perlita expandida modificada com ortofenantrolina na remoção do negro de eriocromo T em águas residuais geradas em laboratórios de ensino de química

In this study, we carried out the study of Eriochrome black T removal using expanded perlite modified orthophenanthroline by adsorption technique. The study of the adsorption process was performed by investigating the effect of the initial dye concentration, contact time and pH range of the solution (acidic and alkaline) in the adsorption process, for a so-called synthetic effluent (aqueous solution of black eriochrome T) and a real effluent (generated from the test for determining the water hardness, by complexation titration). The materials were characterized by Thermogravimetry / Differential Thermal Analysis (TG / DTA), absorption spectroscopy in the infrared (IR), X-ray Diffraction (XRD) and scanning electron microscopy (SEM). By analysis of XRD observed thinking on orthophenanthroline the modified expanded perlite. And by IR analysis showed an increase in intensity and a detailed enlargement of the absorption band related to the axial deformation of the OH bond of silanol groups of perlite (Si-OH). In the equilibration time of the study, in the evaluated time range (5-230 min) was not possible to observe the existence of a balance of time, probably attributed to the type of interaction between the Eriochrome black-T and the expanded perlite modified orthophenanthroline, being an interaction of surface origin. In the study effect of the initial concentration of the adsorbate in the case 2,0x10-4 mol / L natural pH (pH 5) gave the highest removal percentage value of eriochrome T black color with 63.74 % removal in 20 minutes of contact. In evaluating the effect of varying the pH of Eriochrome black T solution in the adsorption process, it was found that the more acidic the environment, the greater the percentage stain removal, being a result of acid-base interaction between the adsorbate and the adsorbent. In T Eriochrome black removal study in real effluent we used the optimized conditions by studying with synthetic sewage. The dye removal at pH 10, natural pH of the effluent was no significant reaching the maximum amount of color removal percentage of 8.12%, obtained already at pH 3 with maximum color removal 100.00% of color, once more proving that eriochrome black T and effectively interact better with the adsorbent at acid pH values (pH 5 or 3), and most efficiently at pH 3. thus one can mention that the perlite expanded (an amorphous aluminosilicate naturally acid) modified with orthophenanthroline (one Bronsted base) consists of a master and effective removal of coloring material in the acid-type aqueous solution, the conditions expressed in this study, can be applied as an adsorbent of this dye also mums real effluent.

Estudo de tensoativos na organofilização de argila bentonítica para uso em fluido de perfuração à base de óleo

Due to the great challenges encountered in drilling wells, there is a need to develop fluids with appropriated properties and able to meet all the requirements of drilling operations. The physicochemical and rheological properties must be carefully controlled so that a fluid can exercise all its functions. In perforations sensitive to contact with water and "offshore", it becomes necessary the use of oil based drilling fluids, but the bentonite clay cannot be used without a previous surface modification so that their surfaces become hydrophobic. Lately, the oil companies in Brazil use imported organoclays in the preparation of oil-based drilling fluids. The study aimed to modify a calcium clay to increase the affinity of the same organic phase of oil-based drilling fluids, applying three surfactants (OCS, CTAB and UTM 150) at different concentrations. The results indicated that the surfactants UTM 150 and CTAB showed better results compared to OCS. Considering the type of surfactant and concentration as variables used in the statistical analysis, the results indicated that only the surface tension and concentration of calcium oxide in response to organophilization process showed statistically significant effects. The organophilizated clay has potential for application in oil-based drilling fluids.

Desenvolvimento de filmes nanocompósitos de isolado protéico de corvina (micropogonias furnieri) e argila organofílica

O desenvolvimento de filmes e coberturas é um processo de transformação que utiliza polímeros capazes de formar uma matriz contínua. As proteínas de pescado apresentam propriedades que são vantajosas no preparo de biofilmes, como habilidade para formar redes, plasticidade e elasticidade, apresentando boa barreira ao oxigênio, mas sua barreira ao vapor de água é baixa devido à sua natureza hidrofílica. Estas propriedades podem ser melhoradas aplicando nanotecnologia, incluindo materiais como as nanoargilas. O objetivo do presente trabalho foi desenvolver filmes nanocompósitos a partir de biopolímeros protéicos provenientes de isolados protéicos de corvina (Micropogonias furnieri) e argilas organofílicas. O isolado protéico de corvina (IPC) foi obtido utilizando processo de variação de pH para solubilizar e isolar proteína. Os filmes poliméricos foram desenvolvidos pela técnica de “casting”. Para o desenvolvimento de filmes nanocompósitos de isolado protéico de corvina (IPC) e montmorilonita foi executado um planejamento experimental de 3 níveis e 3 fatores com 3 réplicas no ponto central. Os resultados foram submetidos à metodologia de superfície de resposta (MSR) para estudar os efeitos simultâneos das variáveis independentes, concentração de IPC (IPC = 2; 3,5 e 5 g/100 g de solução filmogênica); concentração de montmorilonita (MMT = 0,3; 0,5 e 0,7 g/100 g de solução filmogênica); e plastificante glicerol (G = 25, 30 e 35 g/100 g de IPC em base seca) sobre as respostas resistência à tração (MPa), elongação (%), força na ruptura (N), permeabilidade ao vapor de água (g mm m-2 d -1 KPa-1 ) e solubilidade (%). O isolado protéico obtido de carne mecanicamente separada de corvina apresentou 97,87% de proteína (em base seca), boa capacidade de retenção de água e solubilidade. Os valores de resistência à tração variaram entre 7,2 e 10,7 MPa e os valores de elongação de 39,6 a 45,8%. Os valores encontrados para PVA no presente trabalho encontram-se entre 3,2 e 5,5 g mm m-2 d -1 KPa-1 . Os filmes nanocompósitos produzidos a partir de IPC e MMT foram promissores, do ponto de vista das propriedades mecânicas, aparência visual e fácil manuseio, bem como baixa permeabilidade ao vapor de água e a baixa solubilidade. Com relação às propriedades mecânicas, a concentração de IPC e MMT foi o principal fator que influenciou no desenvolvimento dos filmes nanocompósitos. O planejamento experimental utilizado determinou que 3,5 g de IPC; 0,5 g de MMT e 30 (g/100g de IPC) de glicerol seriam os parâmetros ideais para desenvolvimento de filmes nanocompósitos utilizando a técnica de “casting”. As coberturas de isolado protéico de corvina (IPC) e as coberturas de IPC e MMT foram aplicadas em mamão minimamente processado para avaliar sua vida- útil. O revestimento com cobertura de isolado protéico de corvina e montmorilonita aplicado em mamão minimamente processado apresentou menor perda de massa 5,26%, menor crescimento microbiano e menor diminuição de firmeza, luminosidade e pH conseqüentemente apresentou os melhores resultados na cobertura de mamão minimamente processado, quando comparados com a amostra controle sem cobertura.

Influência da vermiculita expandida na resistência à compressão e reologia de pastas cimentantes de poços de petróleo

Several problems related to the loss of hydraulic seal in oilwells, causing gas migration and/or contamination of the production zone by water, have been reported. The loss of the hydraulic seal is a consequence of cracks which can be occasioned either by the invasion of gas during the wait on cement or by the expansion of the casing causing the fracture of the cement sheath. In case of the pressure of the formation is higher than the pressure in the annulus, gas can migrate into the slurry and form microannulus, which are channels where gas migrates after the cement is set. Cracks can be also occasioned by the fracture of the cement sheath when it does not withstand the thermal and dynamic loads. In reservoirs where the oil is heavy, steam water injection operation is required in order to get the oil flowing. This operation increases the temperature of the casing, and then it expands and causes the fracture of the cement sheath in the annulus. When the failures on the cement are detected, remedial cementing is required, which raise costs caused by the interventions. Once the use of cement in the construction civil sector is older than its use in the petroleum sector, it is common to bring technologies and solutions from the civil construction and apply them on the petroleum area. In this context, vermiculite, a mineral-clay widely encountered in Brazil, has been used, on its exfoliated form, in the civil construction, especially on the manufacture of lights and fireproof concretes with excellent thermal and acoustical properties. It has already been reported in scientific journals, studies of the addition of exfoliated vermiculite in Portland cements revealing good properties related to oilwell cementing operations. Thus, this study aimed to study the rheological behavior, thickening time, stability and compressive strength of the slurries made of Portland cement and exfoliated vermiculite in 5 different compositions, at room temperature and heated. The results showed that the compressive strength decreased with the addition of exfoliated vermiculite, however the values are still allowed for oiwell cementing operations. The thickening time of the slurry with no exfoliated vermiculite was 120 min and the thickening time of the slurry with 12 % of exfoliated vermiculite was 98 min. The stability and the rheological behavior of the slurries revealed that the exfoliated vermiculite absorbed water and therefore increased the viscosity of the slurries, even though increasing the factor cement-water. The stability experiment carried out at 133 ºF showed that, there was neither sedimentation nor reduction of the volume of the cement for the slurry with 12 % of exfoliated vermiculite. Thus, the addition of exfoliated vermiculite accelerates the set time of the cement and gives it a small shrinkage during the wait on cement, which are important to prevent gas migration

Adição de vermiculita expandida mícron em pastas de baixa densidade para cimentação de poços de petróleo

The northeastern region of Brazil has a large number of wells producing oil using a method of secondary recovery steam injection, since the oil produced in this region is essentially viscous. This recovery method puts the cement / coating on thermal cycling, due to the difference in coefficient of thermal expansion between cement and metal coating causes the appearance of cracks at this interface, allowing the passage of the annular fluid, which is associated with serious risk socioeconomic and environmental. In view of these cracks, a correction operation is required, resulting in more costs and temporary halt of production of the well. Alternatively, the oil industry has developed technology for adding new materials in cement pastes, oil well, providing high ductility and low density in order to withstand the thermo-mechanical loads generated by the injection of water vapor. In this context, vermiculite, a clay mineral found in abundance in Brazil has been applied in its expanded form in the construction industry for the manufacture of lightweight concrete with excellent insulation and noise due to its high melting point and the presence of air in their layers lamellar. Therefore, the vermiculite is used for the purpose of providing low-density cement paste and withstand high temperatures caused by steam injection. Thus, the present study compared the default folder containing cement and water with the folders with 6%, 8% and 10% vermiculite micron conducting tests of free water, rheology and compressive strength where it obtained the concentration of 8 % with the best results. Subsequently, the selected concentration, was compared with the results recommended by the API standard tests of filtered and stability. And finally, analyzed the results from tests of specific gravity and time of thickening. Before the study we were able to make a folder with a low density that can be used in cementing oil well in order to withstand the thermo-mechanical loads generated by steam injection

Desevolvimento de nanocompósitos de poli(metacrilato de metila)/argila processados por mistura no estado fundido

Poly(methyl methacrylate)/clay nanocomposites were prepared by melt mixing using a montmorillonite-rich clay (MMT). The clay in natura was treated with acrylic acid to facilitate the dispersion in the polymer matrix. A masterbatch of PMMA/clay was prepared and combined with the pure PMMA and then subjected to extrusion process using singlescrew and twin-screw extruders followed by injection. Nanocomposites were processed with clay contents of 1, 3, 5 and 8 wt.%. The effect of shear processing on the morphology of the nanocomposites was evaluated by XRD, SEM and TEM. Thermal and mechanical properties of the nanocomposites were investigated through TGA, DSC, HDT, VICAT, tensile and impact tests, to evaluate the effect of the addition of clay to the PMMA matrix. Flammability tests were also conducted to investigate the effect of the addition of clay on the flame retardation properties. SEM images of the nanocomposites indicated the presence of clay agglomerates, which resulted in the reduction of properties such as thermal stability, mechanical strength and impact resistance, and increased the rate of burning for materials processed by both extrusion routes

Efeito da adição de feldspato e/ou resíduo de caulin em formulações à base de argila ilítica

The red pottery industry in Piauí state is well developed and stands out at the national context for the technical quality of its products. The floor and wall tile industry, however, is little developed since the state has only one company that produces red clay-based ceramic tiles. This thesis aims at using the predominantly illitic basic mass of the above mentioned industry, with the addition of feldspar and/or kaolin residue in order to obtain products of higher technical quality. Kaolin residue consists basically of kaolinite, muscovite mica and quartz; the feldspar used was potassic. In this experiment, basic mass (MB) was used for experimental control and fifteen formulations codified as follows: F2, F4, F8, F16, F32, FR2, FR4, FR8, FR16, FR32, R2, R4, R8, R16 and R32. All raw materials were dry-milled, classified, formulated and then humidified to 10% water. Thereafter, test samples were produced by unixial pressing process in a rectangular steel matrix (60.0 x 20.0 x 5.0) mm3 at (25 MPa). They were fired at four temperatures: 1080°C, 1120°C, 1160°C, with a heating rate of 10°C/min during up to 10 min in an electric oven, and the last one in an industrial oven with a peak of 1140°C, aim ing to confirm the results found in laboratory and, finally, technological tests were performed: MEA, RL, AA, PA, TRF and PF. The results revealed that the residue under study can be considered a raw material with large potential in the industry of red clay-based ceramic tiles, since the results found both in laboratory and in the industry have shown that the test samples produced from the formulations with up to 4% feldspar and those produced with up to 8% feldspar and residue permitted a reduction in the water absorption rate and an increase in the mechanical resistance while those samples produced with up to 4% residue had an increase in the mechanical resistance when compared to those produced from the basic mass and that the formulation with 2% feldspar and residue presented the best technological properties, lowering the sintering temperature down to 1120°C

Influência da vermiculita expandida na formulação de pastas leves para evitar a migração de gás em cimentação de poços petrolíferos

The gas migration during the cementing of wells is one of the main problems of oil wells engineering. Its occurrence can cause severe problems since shortly to loss of control of the well after cementation. Recently, 20/04/2010 In an accident of major proportions in the Gulf of Mexico, among other factors, faulty cementing operation provided the gas migration, causing the accident, in which 11 people died and 17 were injured occurred. Besides the serious consequences that can be caused by gas migration, remediation of the problem, which is made by injecting cement in damaged areas, usually involves additional costs and is not always effective. Therefore, preventing gas migration to be preferred. Some methods are used to prevent the migration of the pressurized gas as the annular space, application of pressure pulses, reducing the height of the cement column compressible cement pastes of low permeability, pastes and to control free filtered water, and binders of thixotropic cement expandable and flexible. Thus, the cement pastes used to prevent gas migration must meet the maximum these methods. Thus, this study aimed to formulate a cement paste to prevent gas migration, using the expanded vermiculite, and evaluate the behavior of the folder trials necessary for use in oil wells. Free water content, rheological properties, compressive strength, loss of liquid phase sedimentation of solids, specific weight, thickening time and gas migration: The following tests were performed. The results show that meets the specifications paste formulated for use in oil wells and the use of expanded vermiculite contribute to the absorption of free water, thixotropy and low density. The absorption of free water is proven to result in zero percentage test free water content, thixotropy is observed with the high value of the initial gel strength (Gi) in testing rheological properties and low density is proven in test weight specific

NEGOCIOS INMOBILIARIOS Y LA TRANSFORMACIÓN METROPOLITANA DE SANTIAGO DE CHILE: DESDE LA RENOVACIÓN DEL ESPACIO CENTRAL HASTA LA PERIFERIA EXPANDIDA

En los últimos años asistimos a una importante modificación de las metrópolis latinoamericanas, representada por la expansión de los condominios cerrados en su periferia y por una producción de grandes torres en altura, al interior de las aglomeraciones urbanas, vinculadas a los edificios corporativos de las grandes empresas y también a otros usos, como el residencial, de oficinas y hotelero. A su vez, estas últimas intervenciones están en directa relación con la necesidad de recuperación de las áreas centrales y pericentrales y con las renovadas estrategias del capital financiero que apunta a los negocios inmobiliarios en búsqueda de rentabilidades con mayor velocidad de retorno. En este contexto la comunicación busca adentrarse en los principales cambios morfológicos de escala metropolitana asociados a los negocios inmobiliarios que se materializan distintas localización de la aglomeración urbana de Santiago de Chile, tomando para ello datos empíricos de primera fuente, que dicen relación con las inversiones e intereses que tienen los agentes económicos intervinientes en el proceso y las respectivas respuestas del poder público.