Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-12-02T22:22:37Z No. of bitstreams: 1 RailsonCarlosSouzaDaLuz_DISSERT.pdf: 1903685 bytes, checksum: 25e6da7dbbb38a3b765693998acaeaac (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2015-12-09T19:40:45Z (GMT) No. of bitstreams: 1 RailsonCarlosSouzaDaLuz_DISSERT.pdf: 1903685 bytes, checksum: 25e6da7dbbb38a3b765693998acaeaac (MD5) / Made available in DSpace on 2015-12-09T19:40:45Z (GMT). No. of bitstreams: 1 RailsonCarlosSouzaDaLuz_DISSERT.pdf: 1903685 bytes, checksum: 25e6da7dbbb38a3b765693998acaeaac (MD5) Previous issue date: 2014-08-18 / Este trabalho objetiva avaliar a influencia da goma xantana e carboximetilcelulose (CMC) no processo de filtra??o dos fluidos de perfura??o base ?gua, considerando as mudan?as conformacionais sofridas pelos polieletr?litos com a adi??o do sal (NaCl) em diferente concentra??es (0,17; 0,34 e 0,51). Foi tamb?m avaliado o comportamento do fluido com a adi??o do carbonato de c?lcio (CaCO3). Procurando um melhor entendimento entre os pol?meros utilizado e o CaCO3, as analises de adsor??o polim?rica foram realizadas por meio de um m?todo de deple??o. A maior porcentagem de adsor??o da Goma Xantana neste material pode justificar a forma??o de um reboco fino e imperme?vel para fluidos de perfura??o que contenham esse pol?mero. / This study aimed mainly to evaluate the influence of xanthan gum (XG) and carboxymethylcellulose (CMC) in the filtration process of water-based drilling fluids, considering the conformational changes suffered by the polyelectrolyte with the addition of sodium chloride (NaCl) in different concentrations (0.17, 0.34 and 0.51 mol.L-1). It was also evaluated the behavior of the fluid by the addition of calcium carbonate (CaCO3) in pure water and in brine. Seeking a better understanding of the interaction between the polymers used and CaCO3, polymer adsorption analyzes were performed using a depletion method, which yielded a higher percentage of adsorption of Xanthan Gum in this material (29%), which can justify the formation of a thin and waterproof filter cake for drilling fluids containing this polymer. However, the best values of apparent viscosity (20 and 24 mPa.s) and volume of filtrate (8.0 and 8.1 mL) were obtained for the systems consisting of xanthan gum, CMC and CaCO3, in NaCl aqueous solutions concentrations of 0.34 and 0.51 mol.L-1, respectively. The values can be related to the presence of CMC that increases the apparent viscosity and reduces the volume of filtrate. In addition, the CaCO3 added acts as a bridging agent, promoting the formation of a less permeable filter cake

Made available in DSpace on 2014-12-17T15:42:30Z (GMT). No. of bitstreams: 1 KeilaRS_TESE.pdf: 2025404 bytes, checksum: f62ed0f0a6e3ff3ceed81829e8165b40 (MD5) Previous issue date: 2014-05-16 / Petr?leo Brasileiro SA - PETROBRAS / The role of carboxymethylcellulose (CMC) in association to calcium carbonate particles (CaCO3) in most water-based drilling fluids is to reduce the fluid loss to the surrounding formation. Another essential function is to provide rheological properties capable of maintaining in suspension the cuttings during drilling operation. Therefore, it is absolutely essential to correlate the polymer chemical structure (degree of substitution, molecular weight and distribution of substituent) with the physical-chemical properties of CaCO3, in order to obtain the better result at lower cost. Another important aspect refers to the clay hydration inhibitive properties of carboxymethylcellulose (CMC) in drilling fluids systems. The clay swelling promotes an undesirable damage that reduces the formation permeability and causes serious problems during the drilling operation. In this context, this thesis consists of two main parts. The first part refers to understanding of interactions CMC-CaCO3, as well as the corresponding effects on the fluid properties. The second part is related to understanding of mechanisms by which CMC adsorption occurs onto the clay surface, where, certainly, polymer chemical structure, ionic strength, molecular weight and its solvency in the medium are responsible to affect intrinsically the clay layers stabilization. Three samples of carboximetilcellulose with different molecular weight and degree of substitution (CMC A (9 x 104 gmol DS 0.7), CMC B (2.5 x 105 gmol DS 0.7) e CMC C (2.5 x 105 gmol DS 1.2)) and three samples of calcite with different average particle diameter and particle size distribution were used. The increase of CMC degree of substitution contributed to increase of polymer charge density and therefore, reduced its stability in brine, promoting the aggregation with the increase of filtrate volume. On the other hand, the increase of molecular weight promoted an increase of rheological properties with reduction of filtrate volume. Both effects are directly associated to hydrodynamic volume of polymer molecule in the medium. The granulometry of CaCO3 particles influenced not only the rheological properties, due to adsorption of polymers, but also the filtration properties. It was observed that the lower filtrate volume was obtained by using a CaCO3 sample of a low average size particle with wide dispersion in size. With regards to inhibition of clay swelling, the CMC performance was compared to other products often used (sodium chloride (NaCl), potassium chloride (KCl) and quaternary amine-based commercial inhibitor). The low molecular weight CMC (9 x 104 g/mol) showed slightly lower swelling degree compared to the high molecular weight (2.5 x 105 g/mol) along to 180 minutes. In parallel, it can be visualized by Scanning Electron Microscopy (SEM) that the high molecular weight CMC (2.5 x 105 g/mol e DS 0.7) promoted a reduction in pores formation and size of clay compared to low molecular weight CMC (9.0 x 104 g/mol e DS 0.7), after 1000 minutes in aqueous medium. This behavior was attributed to dynamic of interactions between clay and the hydrodynamic volume of CMC along the time, which is result of strong contribution of electrostatic interactions and hydrogen bounds between carboxylate groups and hydroxyls located along the polymer backbone and ionic and polar groups of clay surface. CMC adsorbs on clay surface promoting the skin formation , which is responsible to minimize the migration of water to porous medium. With the increase of degree of substitution, it was observed an increase of pores onto clay, suggesting that the higher charge density on polymer is responsible to decrease its flexibility and adsorption onto clay surface. The joint evaluation of these results indicate that high molecular weight is responsible to better results on control of rheological, filtration and clay swelling properties, however, the contrary effect is observed with the increase of degree of substitution. On its turn, the calcite presents better results of rheological and filtration properties with the decrease of average viii particle diameter and increase of particle size distribution. According to all properties evaluated, it has been obvious the interaction of CMC with the minerals (CaCO3 and clay) in the aqueous medium / O papel da carboximetilcelulose (CMC) em associa??o com o carbonato de c?lcio (CaCO3) na maioria dos fluidos de perfura??o base ?gua ? reduzir a perda de fluido para a forma??o. Outra fun??o essencial ? promover propriedades reol?gicas capazes de manter em suspens?o os cascalhos durante a opera??o de perfura??o. Dessa forma, ? absolutamente essencial correlacionar a estrutura qu?mica do pol?mero (grau de substitui??o, massa molar e distribui??o do substituinte) com as propriedades f?sicoqu?micas do CaCO3, de forma a obter o melhor resultado a mais baixo custo. Outro importante aspecto refere-se ?s propriedades de inibi??o da CMC em rela??o ? hidrata??o de argilas presentes na forma??o rochosa. O inchamento de argilas promove um dano indesej?vel que reduz a permeabilidade da forma??o e causa s?rios problemas durante a perfura??o. Nesse contexto, essa Tese consiste de duas partes principais. A primeira parte refere-se ao entendimento das intera??es CaCO3-CMC, assim como os efeitos correspondentes ?s propriedades do fluido. A segunda parte est? relacionada ao entendimento dos mecanismos pelos quais a adsor??o da CMC ocorre na aresta da argila, onde, certamente, a estrutura qu?mica do pol?mero, for?a i?nica, massa molar e sua solubilidade no meio s?o respons?veis por afetar intrinsecamente a estabiliza??o das camadas da argila. Foram utilizadas no estudo tr?s amostras de carboximetilcelulose com diferentes massas molares e graus de substitui??o: CMC A (9 x 104 gmol DS 0.7), CMC B (2.5 x 105 gmol DS 0.7) e CMC C (2.5 x 105 gmol DS 1.2)) e tr?s amostras de calcita (CaCO3), com diferentes di?metros m?dios de part?culas e curvas de distribui??o em tamanho. O aumento do grau de substitui??o da CMC contribuiu para o aumento da densidade de carga do pol?mero e dessa forma, reduziu sua estabilidade em salmoura, promovendo agrega??o e o aumento do volume de filtrado. Por sua vez, o aumento da massa molar promoveu um aumento das propriedades reol?gicas com a redu??o do volume de filtrado. Ambos os efeitos est?o diretamente ligados ao volume hidrodin?mico da mol?cula do pol?mero no meio. A granulometria das part?culas do CaCO3 influenciou n?o somente as propriedades reol?gicas, devido ? adsor??o de pol?meros em sua superf?cie, mas tamb?m as propriedades de filtra??o. Foi observado que o menor volume de filtrado foi obtido pelo uso da amostra de CaCO3 de menor tamanho de part?cula com a faixa mais ampla de dispers?o em tamanho. Com rela??o ? inibi??o de inchamento de argilas, a efici?ncia da CMC foi comparada a outros produtos comumente empregados (cloreto de s?dio (NaCl), cloreto de pot?ssio (KCl) e um inibidor comercial ? base de amina quatern?ria). A CMC de baixa massa molar (9 x 104 g/mol) propiciou grau de inchamento da bentonita ligeiramente mais baixo que a CMC de alta massa molar (2.5 x 105 g/mol), no decorrer de 180 minutos. Por outro lado, p?de ser visualizado por microscopia eletr?nica de varredura que a CMC de maior massa molar (2.5 x 105 g/mol e DS 0.7) promoveu uma redu??o na forma??o e no tamanho dos poros da argila comparada ? CMC de menor massa molar (9.0 x 104 g/mol e DS 0.7), ap?s 1000 minutos em meio aquoso. Esse comportamento foi atribu?do ? din?mica das intera??es entre a argila e a cadeia polim?rica da CMC ao longo do tempo, que ? resultado da forte contribui??o das intera??es eletrost?ticas e liga??es de hidrog?nio entre os grupos carboxilato e hidroxila localizados ao longo da cadeia polim?rica e os s?tios i?nicos e polares da superf?cie da argila. A CMC adsorve na superf?cie da matriz de argila promovendo a forma??o de uma pel?cula , a qual ? respons?vel por minimizar a migra??o da ?gua para o meio poroso. Com o aumento do grau de substitui??o, foi observado aumento de poros na matriz de argila, sugerindo que a maior densidade de cargas no pol?mero diminui a sua flexibilidade e a adsor??o sobre a matriz argilosa. A an?lise conjunta dos resultados vi indica que altas massas molares da CMC propiciam melhores resultados no controle das propriedades reol?gicas, de filtra??o e de inchamento de argilas, entretanto, efeito contr?rio ? observado com o aumento do grau de substitui??o. Por sua vez, o CaCO3 apresenta melhores resultados de propriedades reol?gicas e de filtra??o com a diminui??o do di?metro m?dio das part?culas e aumento da distribui??o em tamanho. Em todas as propriedades analisadas, foram evidentes os sinais de intera??o da CMC com os minerais (carbonato de c?lcio e argila) presentes no meio aquoso

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-14T21:09:10Z No. of bitstreams: 1 RafaelAraujoDaSilva_DISSERT.pdf: 1302282 bytes, checksum: cb4d89880b246386e0981baae0eea668 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-15T21:55:04Z (GMT) No. of bitstreams: 1 RafaelAraujoDaSilva_DISSERT.pdf: 1302282 bytes, checksum: cb4d89880b246386e0981baae0eea668 (MD5) / Made available in DSpace on 2017-03-15T21:55:04Z (GMT). No. of bitstreams: 1 RafaelAraujoDaSilva_DISSERT.pdf: 1302282 bytes, checksum: cb4d89880b246386e0981baae0eea668 (MD5) Previous issue date: 2015-01-29 / Os fluidos de perfura??o aquosos s?o os sistemas mais utilizados no mundo para a perfura??o de po?os petrol?feros, tendo sido, nas ?ltimas d?cadas, desenvolvidas excelentes formula??es para perfura??o de se??es iniciais com baixa temperatura e baixa press?o. No entanto, as reservas de petr?leo nessas condi??es est?o cada vez mais escassas, surgindo a necessidade operacional de atua??o em condi??es mais severas, ou seja, vem sendo relatada na literatura a necessidade de sistemas aquosos para atua??o em altas temperaturas e altas press?es (ATAP). As altas temperaturas dos po?os de petr?leo favorecem a degrada??o qu?mica dos pol?meros (aditivo comumente presente nas formula??es relatadas, atualmente, na literatura e aplicados em situa??es operacionais), podendo promover a redu??o da massa molar e perdas de viscosidade do sistema. Os microg?is podem ser aplicados em v?rios seguimentos da ind?stria, com destaque na ?rea do petr?leo, situa??o que s?o aplicados na estimula??o de po?os e na recupera??o avan?ada de petr?leo (EOR). Neste trabalho, a aplicabilidade de microg?is de hidroxipropilguar (HPG), obtidos por reticula??o do HPG com ?ons borato, foi avaliada quanto ? resist?ncia t?rmica em fluidos de perfura??o aquosos. A aplica??o de microg?is de HPG no fluido de perfura??o base ?gua aumentou a viscosidade aparente e reduziu o volume de filtrado na temperatura ? 25?C. Entretanto, com o aumento da temperatura para 50 ?C ocorreu redu??o da viscosidade aparente de 85 mPa.s para 25,45 mPa.s. Esses resultados indicam que o emprego de microg?is em fluidos de perfura??o aquosos pode ser uma alternativa promissora, desde que o agente reticulante seja adequadamente selecionado, ou seja, n?o sofra desativa??o com o aumento da temperatura e n?o seja influenciado pela salinidade do meio. / Aqueous drilling fluids are a widely used systemin the world to drill oil wells. This drilling system has been being developed excellent formulations for drilling initial sections with low temperature and low pressure in recent decades. However, the oil reserves in these conditions are increasingly scarce, ending up in the need for drilling fluids with better operational performance in the toughest conditions. Therefore, it has been reported in the literature the need for aqueous systems to operate at high temperatures and high pressures (HTHP). High temperatures of oil wells favor the chemical degradation of polymers (commonly reported in additive formulations currently in the literature and applied in operational situations), that can generate molecular weight reduction and viscosity losses. Microgels can be applied in vast industrie`s segments, highlighted in the oil field, as they are used in the estimulation of wells and in the Advanced Oil Recovery (EOR). In this work, the applicability of hydroxypropyl guar`s microgels (HPG), obtained by crosslinking the HPG with borate ions, was measured as the thermal stability in water based drilling fluids.The application HPG microgels in water-based drilling fluid has increased viscosity and the apparent volume of the filtrate reduced around 25 ? C. However, with the increase of temperature to 50 ?C, the viscosity of drilling fluids based on HPG microgels decreased from 85 mPa.s to 25,45 mPa.s. These results indicate that the use of microgels in aqueous drilling fluids is a promising alternative since the crosslinking agent has been properly selected, i.e., does not undergo deactivation with increasing temperature and is not affected by the salinity of the system.

Made available in DSpace on 2014-12-17T15:41:41Z (GMT). No. of bitstreams: 1 OldemarRC.pdf: 2134736 bytes, checksum: bf80e72f9b5d1ebc0b3148367e30383f (MD5) Previous issue date: 2007-10-30 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The aim of this work was the preparation of polyols from reactions between castor oil and dietanolamine to increase the hydroxyl content and the network degree in the products to application in electronic devices. The polyols and the mixtures obtained were characterized by nuclear magnetic ressonance. Castor oil (CO) is a natural triglyceride - based polyol possessing hydroxyl groups, which allow several reactions that produce many different products. Among them are the polyurethanes (PU), which have been considered an ideal product for the covering of electricelectronic circuits, due to their excellent electrical, shock-absorbing, solvents resistance and hydrolytic stability properties. About 90% of the fatty acids present in the castor oil are ricinoleic acid (12-hydroxyoleic acid), while the remaining 10% correspond to non-hydroxylated fatty acids, mainly linoleic and oleic acids. The chemical analysis of castor oil indicates a hydroxyl number of 2.7. In this work, a polyol was obtained by the reaction of the CO with diethanolamine (DEA), in order to elevate the hydroxyl value from 160 to 230 or to 280 mgKOH/g, and characterized by nuclear magnetic resonance (NMR) 1H and 13C (Mercury 200). The polyadition of the resulting polyol with isophorone diisocianate (IPDI) was carried out at 60?C, and the reaction kinetics was followed by rheological measurements in a Haake RS150 rheometer. The electrical properties were determined in a HP LCR Meter 4262A, at 1.0 Hz and 10.0 KHz. The chemical analysis showed that the polyols obtained presented hydroxyl number from 230 to 280 mgKOH/g. The polyadition reaction with IPDI produced polyurethane resins with the following properties: hardness in the range from 45 shore A to 65 shore D (ASTM D2240); a dielectric constant of 3.0, at 25?C (ASTM D150). Those results indicate that the obtained resins present compatible properties to the similar products of fossil origin, which are used nowadays for covering electric-electronic circuits. Therefore, the PUs from castor oil can be considered as alternative materials of renewable source, free from the highly harmful petroleum - derived solvents / O presente trabalho teve como objetivo a obten??o de poli?is a partir das rea??es do ?leo de mamona (OM) com dietanolamina (DEA), visando elevar o ?ndice de hidroxila e consequentemente o grau de reticula??o dos produtos finais, cuja aplica??o se destinou ao encapsulamento de circuitos eletroeletr?nicos. A caracteriza??o desses poli?is e respectivas misturas foram feitas utilizando-se a t?cnica da resson?ncia magn?tica nuclear (NMR). O OM (triglicer?deo do ?cido ricinoleico) ? um poliol vegetal natural por apresentar grupo funcional hidroxila que permite v?rias rea??es e produ??o de diferentes produtos. Entre eles est?o as poliuretanas (PU) que t?m sido consideradas como produtos ideais para encapsulamento de componentes de circuitos eletro-eletr?nicos, devido as suas excelentes propriedades com rela??o ? resist?ncia mec?nica e qu?mica. As poliuretanas derivadas do ?leo de mamona podem ser consideradas materiais alternativos de fonte renov?vel e, para as produzidas neste trabalho, n?o foram empregados nenhum tipo de solvente. Cerca de 90% dos ?cidos graxos que comp?em o ?leo de mamona s?o ?cido ricinoleico (?cido 12-hidroxioleico), enquanto os outros 10% s?o ?cidos graxos n?o hidroxilados (?cidos linoleico e oleico). As an?lises qu?micas do ?leo de mamona indicam uma funcionalidade m?dia de 2,7, em rela??o aos grupos hidroxila. A poliadi??o entre o poliol resultante e o isocianato de isoforona (IPDI) teve sua cin?tica aco mpanhada com o aux?lio do re?metro Haake RS 150 ? temperatura de 60 ?C. As propriedades el?tricas foram determinadas em uma ponte HP LCR Meter 4262 A a 1,0 Hz e 10,0 KHz. As an?lises qu?micas mostraram que os poli?is obtidos apresentaram ?ndice de hidroxila entre 230 e 280 mgKOH/g. A rea??o de poliadi??o com IPDI produziu resinas de poliuretana com as seguintes propriedades: dureza entre 45 e 65 shore D (ASTM D2240); constante diel?trica de 3,0 a 25 ?C (ASTM D150). Os resultados, de um modo geral, indicaram que as resinas, cujo extensor de cadeia foi a DEA, apresentaram propriedades compat?veis e em muitos casos superiores, quando comparadas ?s dos produtos atualmente dispon?veis no mercado, sintetizados ? base de trietanolamina (TEA)

Made available in DSpace on 2014-12-17T14:16:25Z (GMT). No. of bitstreams: 1 AcariliaES_Dissert_01.pdf: 1640327 bytes, checksum: 9c4568aff953d538d26000691eb0407d (MD5) Previous issue date: 2009-03-10 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Colon-specific drug delivery systems have attracted increasing attention from the pharmaceutical industry due to their ability of treating intestinal bowel diseases (IBD), which represent a public health problem in several countries. In spite of being considered a quite effective molecule for the treatment of IBD, mesalazine (5-ASA) is rapidly absorbed in the upper gastrointestinal tract and its systemic absorption leads to risks of adverse effects. The aim of this work was to develop a microparticulate system based on xylan and Eudragit? S- 100 (ES100) for colon-specific delivery of 5-ASA and evaluate the interaction between the polymers present in the systems. Additionaly, the physicochemical and rheological properties of xylan were also evaluated. Initially, xylan was extracted from corn cobs and characterized regarding the yield and rheological properties. Afterwards, 10 formulations were prepared in different xylan and ES100 weight ratios by spray-drying the polymer solutions in 0.6N NaOH and phosphate buffer pH 7.4. In addition, 3 formulations consisting of xylan microcapsules were produced by interfacial cross-linking polymerization and coated by ES100 by means of spray-drying in different polymer weight ratios of xylan and ES100. The microparticles were characterized regarding yield, morphology, homogeneity, visual aspect, crystallinity and thermal behavior. The polymer interaction was investigated by infrared spectroscopy. The extracted xylan was presented as a very fine and yellowish powder, with mean particle size smaller than 40μm. Regarding the rheological properties of xylan, they demonstrated that this polymer has a poor flow, low density and high cohesiveness. The microparticles obtained were shown to be spherical and aggregates could not be observed. They were found to present amorphous structure and have a very high thermal stability. The yield varied according to the polymer ratios. Moreover, it was confirmed that the interaction between xylan and ES100 occurs only by means of physical aggregation / Sistemas c?lon-espec?ficos t?m atra?do o interesse da ind?stria farmac?utica devido ? possibilidade de tratarem enfermidades, como as doen?as inflamat?rias intestinais (DII), que compreendem um problema de sa?de p?blica em muitos pa?ses. Apesar de ser considerada uma mol?cula bastante eficiente para o tratamento das DII, a mesalazina (5-ASA) ? rapidamente absorvida no trato gastrintestinal superior e sua absor??o sist?mica leva ? incid?ncia de s?rios efeitos adversos. Este trabalho teve como objetivos produzir um sistema polim?rico microparticulado ? base de xilana e Eudragit? S-100 (ES100) para libera??o c?lon-espec?fica de 5-ASA e avaliar a intera??o entre os pol?meros constituintes do sistema, al?m de aprofundar a caracteriza??o f?sico-qu?mica e tecnol?gica da xilana. A xilana foi extra?da a partir de sabugos de milho e caracterizada quanto ao rendimento, granulometria, cristalinidade, propriedades reol?gicas e comportamento t?rmico. Em seguida, 10 formula??es contendo 5-ASA foram preparadas em diferentes propor??es de xilana e ES100 atrav?s da secagem por aspers?o das solu??es polim?ricas com NaOH 0,6N ou tamp?o-fosfato pH 7,4, como solvente. Al?m disso, 3 formula??es constitu?das de microc?psulas de xilana produzidas por reticula??o polim?rica interfacial foram revestidas por ES100 atrav?s de secagem por aspers?o em diferentes propor??es polim?ricas e empregando-se NaOH 0,6N ou tamp?o-fosfato pH 7,4, como solvente. As micropart?culas foram avaliadas quanto ao rendimento, morfologia, granulometria, homogeneidade, aspecto visual, cristalinidade e comportamento t?rmico. A intera??o entre os pol?meros foi investigada atrav?s da espectroscopia na regi?o do infravermelho e de an?lises t?rmicas. A xilana extra?da apresentou-se como um p? muito fino, com tamanho m?dio inferior a 40μm, e com colora??o opaca levemente amarelada. A avalia??o das propriedades reol?gicas da xilana permitiram a caracteriza??o desse pol?mero, em seu estado original de p?, como um material de baixa densidade, fluxo restrito e bastante coesivo. Foram obtidas micropart?culas esf?ricas e sem presen?a de agregados, com estrutura amorfa, em sua maior parte, e bastate est?veis a temperaturas elevadas. Al?m disso, confirmou-se que a intera??o entre xilana e ES100 ocorre apenas por agrega??o f?sica