Made available in DSpace on 2014-12-17T14:06:54Z (GMT). No. of bitstreams: 1 FlaviaMA_DISSERT.pdf: 2525916 bytes, checksum: e66ea09a8c50d8b220412e1d5685d5d1 (MD5) Previous issue date: 2010-03-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In this work have been studied the preparation, characterization and kinetic study of decomposition of the polymerizing agent used in the synthesis under non-isothermal condition ceramics PrMO3 of general formula (M = Co and Ni). These materials were obtained starting from the respective metal nitrates, as a cations source, and making use of gelatin as polymerizing agent. The powders were calcined at temperatures of 500?C, 700?C and 900?C and characterized by X-ray Diffraction (XRD), Thermogravimetric Analysis (TG / DTG/ DTA), Infrared Spectroscopy (FTIR), Temperature Programmed Reduction (TPR) and Scanning Electron Microscopy (SEM). The perovskite phase was detected in all the X-rays patterns. In the infrared spectroscopy observed the oxide formation as the calcination temperature increases with the appearance of the band metal - oxygen. The images of SEM revealed uniform distribution for the PrCoO3 and particles agglomerated as consequence of particle size for PrNiO3. From the data of thermal analysis, the kinetics of decomposition of organic matter was employed using the kinetics methods called Model Free Kinetics and Flynn and Wall, in the heating ratios 10, 20 and 30? C.min-1 between room temperature and 700?C. Finally, been obtained the values of activation energy for the region of greatest decomposition of organic matter in samples that were determined by the degree of conversion (α) / Neste trabalho foi realizado a prepara??o, caracteriza??o e um estudo cin?tico da decomposi??o t?rmica do agente polimerizante utilizado na s?ntese sob condi??o n?o isot?rmica de materiais cer?micos de f?rmula geral PrMO3 (M = Co ou Ni). Esses materiais foram obtidos partindo dos respectivos nitratos met?licos, como fonte de c?tions, e fazendo uso da gelatina como agente polimerizante. Os p?s-obtidos foram calcinados a temperaturas de 500?C, 700?C e 900?C e caracterizados pelas t?cnicas de Difra??o de Raios X (DRX), An?lise Termogravim?trica (TG/DTG/DTA), Espectroscopia na regi?o do infravermelho (FTIR), Redu??o ? Temperatura Programada (RTP) e Microscopia Eletr?nica de Varredura (MEV). A fase perovsquita foi evidenciada em todos os difratogramas de raios X para os materiais de PrCoO3 e PrNiO3. Nos espectros de FTIR foi observado a forma??o do ?xido na medida em que a temperatura de calcina??o aumenta com o aparecimento da banda referente ? liga??o Metal Oxig?nio. As imagens do MEV evidenciaram distribui??o uniforme para o PrCoO3 e part?culas aglomeradas em consequ?ncia do tamanho da part?cula para o PrNiO3. Com os dados da an?lise t?rmica, o estudo ci-n?tico da decomposi??o da mat?ria org?nica foi empregado utilizando-se os m?todos cin?ticos denominados Model Free Kinetics e Flynn e Wall, nas raz?es de aquecimento 10, 20 e 30?C.min-1 entre a temperatura ambiente e 700?C. Foram obtidos os valores das energias de ativa??o para a regi?o de maior decomposi??o da mat?ria org?nica nas amostras que foram determinadas como uma fun??o do grau de convers?o (α)

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-12-14T21:34:11Z No. of bitstreams: 1 SueilhaFerreiraDeAndradeDePaula_DISSERT.pdf: 2031860 bytes, checksum: 1cd1be4d1cd9390854369cac616d8466 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2015-12-15T22:03:32Z (GMT) No. of bitstreams: 1 SueilhaFerreiraDeAndradeDePaula_DISSERT.pdf: 2031860 bytes, checksum: 1cd1be4d1cd9390854369cac616d8466 (MD5) / Made available in DSpace on 2015-12-15T22:03:32Z (GMT). No. of bitstreams: 1 SueilhaFerreiraDeAndradeDePaula_DISSERT.pdf: 2031860 bytes, checksum: 1cd1be4d1cd9390854369cac616d8466 (MD5) Previous issue date: 2014-08-28 / Neste trabalho, os medicamentos de refer?ncia, gen?rico e similar com os princ?pios ativos ?cido Acetil Salic?lico, Paracetamol, captopril, hidroclorotiazida e mebendazol foram adquiridos em farm?cias locais e estudados por Termogravimetria (TG) e Calorimetria Explorat?ria Diferencial (DSC). A decomposi??o t?rmica foi avaliada objetivando obter a partir do M?todo de Ozawa a energia de ativa??o, em atmosfera inerte (de nitrog?nio), utilizando tr?s raz?es de aquecimento distintas (5, 10 e 20 oC min-1). A formula??o farmac?utica do AAS de refer?ncia foi o ?nico que apresentou perfil termogravim?trico diferente dos demais (gen?rico e similar) indicando, provavelmente intera??o entre os excipientes e o princ?pio ativo. Foi observado no gr?fico do log da raz?o de aquecimento pelo inverso da temperatura que n?o houve linearidade dos dados, isto ?, n?o houve correla??o entre os percentuais de perda de massa e a energia de ativa??o envolvida na decomposi??o t?rmica da formula??o farmac?utica do AAS de refer?ncia. A an?lise por calorimetria explorat?ria diferencial foi realizada em atmosfera de nitrog?nio, com raz?o de aquecimento de 10?C min-1. Na an?lise destes mesmos medicamentos, os dados das curvas encontradas sobre o ponto de fus?o foram, exceto para a hidroclorotiazida, s?o condizentes com a literatura. A hidroclorotiazida apresentou um ponto de fus?o bastante inferior ao encontrado na literatura, o que pode ser justificado devido ? intera??o do princ?pio ativo com o excipiente lactose. No estudo da pureza, utilizando a equa??o de Van?t Hoff , os medicamentos de hidroclorotiazida de refer?ncia e mebendazol de refer?ncia, gen?rico e similar apresentaram teor de impureza acima do limite estabelecido nesta equa??o que deve ser superior a 2,5 % mol. / In this work, the reference drugs, generic and similar to the active ingredients acetylsalicylic acid, paracetamol, captopril, hydrochlorothiazide and mebendazole were purchased from local pharmacies and studied by thermogravimetry (TG) and Differential Scanning Calorimetry (DSC). Thermal decomposition was assessed to obtain from the Ozawa method the activation energy in inert atmosphere (nitrogen), using three different heating ratios (5, 10 and 20 o C min-1). The pharmaceutical formulation of the AAS reference was the one who presented different from the others (generic and similar) Thermogravimetric profile indicating likely interaction between the active ingredient and excipients. Was observed at the heating rate of the inverse temperature that no linearity of the data, ie, there was no correlation between the percentage of mass loss and the activation energy involved in the thermal decomposition of the pharmaceutical formulation of the AAS reference log graph. The analysis by differential scanning calorimetry was performed in nitrogen atmosphere with a heating rate of 10 ? C min-1. In the analysis of these same drugs, the data curves found on the melting point were, except for hydrochlorothiazide, are consistent with the literature. Hydrochlorothiazide presented a melting point well below that found in the literature, which may be justified due to the interaction of the active ingredient with the excipient lactose. In the study of purity, using the Van't Hoff equation, the reference drugs hydrochlorothiazide and mebendazole reference generic and showed similar impurity content below the limit established that this equation must be greater than 2.5 mol%

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-02T11:57:41Z No. of bitstreams: 1 StephanieCavalcanteDeMorais_DISSERT.pdf: 2749086 bytes, checksum: d3dadb51bdb3abfd01a69d46c505025d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-02-06T20:51:56Z (GMT) No. of bitstreams: 1 StephanieCavalcanteDeMorais_DISSERT.pdf: 2749086 bytes, checksum: d3dadb51bdb3abfd01a69d46c505025d (MD5) / Made available in DSpace on 2017-02-06T20:51:56Z (GMT). No. of bitstreams: 1 StephanieCavalcanteDeMorais_DISSERT.pdf: 2749086 bytes, checksum: d3dadb51bdb3abfd01a69d46c505025d (MD5) Previous issue date: 2016-07-21 / O estudo da degrada??o t?rmica de pol?meros ? essencial para se determinar a estabilidade da sua estrutura e depende do estado f?sico em que o pol?mero se encontra. Um estudo comparativo da estabilidade t?rmica da kappa carragenana (KC), poliacrilamida parcialmente hidrolisada (HPAM) e carboximetilcelulose (CMC) foi realizado na tentativa de se estabelecer uma correla??o entre as estruturas qu?micas, estabilidade desses pol?meros e suas energias de ativa??o no estado s?lido e em solu??o. A estabilidade t?rmica dos pol?meros no estado s?lido foi avaliada por termogravimetria/termogravimetria derivada e a energia de ativa??o foi calculada utilizando o m?todo integral de Broido. J? para os tr?s pol?meros em solu??o, foram realizadas medidas de viscosidade em fun??o do tempo nas temperaturas de 40, 60, 80 e 100?C, e tamb?m a 120?C apenas para a HPAM, e constru?do um modelo de decaimento exponencial da viscosidade espec?fica para determina??o da energia de ativa??o. Observou-se uma estabilidade similar dos pol?meros no estado s?lido e em solu??o, com valores de energias de ativa??o superiores no estado s?lido em fun??o do transporte de calor mais eficiente em solu??o. Os resultados obtidos condizem com as particularidades estruturais de cada pol?mero, sendo a HPAM o pol?mero com maior estabilidade e energia de ativa??o de 467,92 kJ mol-1 no estado s?lido e 79,4 kJ mol-1 em solu??o. Entre os pol?meros naturais a rigidez estrutural desempenhou um papel importante, onde a CMC com valores de energia de ativa??o de 293,3 e 55,1 kJ mol-1 no estado s?lido e em solu??o, respectivamente, foi mais est?vel que a KC com valores de 245,0 kJ mol-1 no estado s?lido e 35,8 kJ mol-1 em solu??o. E, por meio da rela??o entre as energias de ativa??o no estado s?lido e em solu??o, foi proposta a possibilidade de utiliza??o de um modelo matem?tico ?til para previs?o do comportamento de outros pol?meros em solu??o a partir da sua an?lise no estado s?lido. / The study of thermal degradation of polymers is essential to determine the stability of the structure and depends on the physical state where the polymer is. A comparative study of the thermal stability of kappa carrageenan (KC), partially hydrolyzed polyacrylamide (HPAM) and carboxymethylcellulose (CMC) was performed in an attempt to establish a correlation between the chemical structures, stability of these polymers and their activation energies in the solid state and solution. The thermal stability of the polymers in the solid state was evaluated by thermogravimetric analysis/derivative termogravimetric and the activation energy was calculated using the integral method Broido. As for the three solution polymers, viscosity measurements were made as a function of time at the temperatures 40, 60, 80 and 100 ?C, and also 120?C only for HPAM, and constructed an exponential decay model of the specific viscosity for determining the activation energy. We observed a similar stability of polymers in the solid state and in solution, with higher activation energies in the solid state due to the more efficient heat transport in solution. The results are consistent with the structural particularities of each polymer, being HPAM the polymer with greater stability and activation energy of 467.9 kJ mol-1 in the solid state and 79.4 kJ mol-1 in solution. Among the natural polymers structural rigidity played an important role, where the CMC with 293.35 activation energy values and 55.1 kJ mol-1 in the solid state and in solution, respectively, was more stable than KC with values of 245,0 kJ mol-1 in the solid state and 35.8 kJ mol-1 in solution. And, by the relationship between the activation energies in the solid state and in solution has been proposed the possibility of using a mathematical model for other useful polymers in solution behavior prediction from the analysis in the solid state.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-09-05T19:25:26Z No. of bitstreams: 1 JoaoManuelRegoSilva_DISSERT.pdf: 1561950 bytes, checksum: eb2b7dacfcb7c22d8a44cd6461da9588 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-09-13T23:11:18Z (GMT) No. of bitstreams: 1 JoaoManuelRegoSilva_DISSERT.pdf: 1561950 bytes, checksum: eb2b7dacfcb7c22d8a44cd6461da9588 (MD5) / Made available in DSpace on 2017-09-13T23:11:18Z (GMT). No. of bitstreams: 1 JoaoManuelRegoSilva_DISSERT.pdf: 1561950 bytes, checksum: eb2b7dacfcb7c22d8a44cd6461da9588 (MD5) Previous issue date: 2017-06-29 / A borra oleosa (BO) de petr?leo apresenta um agregado complexo de hidrocarbonetos, impurezas org?nicas, inorg?nicas e ?gua. Um dos principais problemas encontrados atualmente na ind?stria petrolifera ? o gerenciamento (acondicionamento, armazenamento, transporte e destino) de res?duos. Os nanomateriais (catalisadores) mesoporosos e microporosos s?o considerados promissores em processos de refino de petr?leo e como adsorventes para prote??o ambiental. O foco deste trabalho foi estudar a BO de petr?leo oriunda do processamento prim?rio, com aplica??o de degrada??o t?rmica e termocatal?tica com nanomateriais, visando a produ??o de derivados de petr?leo. O catalisador NaY foi sintetizado com uma raz?o molar de sil?cio/alum?nio de 50 (Si/Al = 1,5), usando silicato de s?dio (Na2SiO3) como fonte de sil?cio e aluminato de s?dio (NaAlO2) como a fonte de alum?nio e, posteriormente feito uma troca i?nica para obten??o de sua forma ?cida - HY. As amostras dos materiais nanoestruturados foram caracterizadas por analise termogravim?trica (TG/DTG), difra??o de raios X (DRX), microscopia eletr?nica de varredura (MEV), espectroscopia de absor??o na regi?o do infravermelho com transformada de Fourier (FT-IR). A caracteriza??o mostrou que os materiais sintetizados resultaram em um catalisador nano estruturado de acordo com a literatura existente. A degrada??o t?rmica e catal?tica da borra oleosa de petr?leo foi realizada nas faixas de temperatura de 100, 200, 300, 400 e 500 ?C, variando com o tempo de 0 a 60 min para cada temperatura. As curvas obtidas atrav?s da degrada??o, mostram uma deteriora??o mais acelerada da borra oleosa quando existe a presen?a de catalisador no meio. Esses dados foram corroborados pela energia de ativa??o e foram estudados pelos par?metros de Arrhenius, onde foi poss?vel observar a energia de ativa??o para degrada??o t?rmica e termocatal?tica da borra oleosa. / The oily sludge presents a complete aggregate of hydrocarbons, organic and inorganic impurities, and water. One of the main bottlenecks currently found in oil industry it's the manegement (packaging, storage, transportation and destination) of waste. The nanomaterials (catalysts) mesoporous and microporous are considered promissing in oil refining processes and as absorvents to enviromental protection. The focus of this work was study de oily sludge from primary processing, with applications of thermal degradation and thermocatalytic with nanomaterials, aiming the production of oil derivates. The catalyst NaY was sintetized with a silica/aluminum molar ratio of 50 (Si/Al = 1,5), using sodium silicate (Na2SiO3) as source of silicon e sodium aluminate (NaAlO2), as the aluminum source and, posteriorly was done a ion exchange to obtain its acid form - HY. The samples of the nanostructured materials by thermogravimetric analysis (TG/DTG), X-ray diffraction (DRX), scanning electro micorscopy (SEM), absorption spectroscopy in the infrared region with Fourier transform (FT-IR). The characterizations showed that the synthesized materials resulted in a nanostructured catalyest according to the existent literature. The thermal and catalytic degradation of the oily sludge was performed in the temperature ranges of 100, 200, 300, 400 and 500 ?C, varying with time of 0 to 60 min to each temperature. The curves obtained through degradation showed a faster deterioration of oily sludge when there a presence of catalyst on the midst. These datas were corroborated by the activation energy and were studied by Arrhenius parameter, where was possible to observe the activation energy to thermal and thermo-catalytic degradation of the oily sludge.

Made available in DSpace on 2014-12-17T15:42:27Z (GMT). No. of bitstreams: 1 AlineAAO_TESE.pdf: 3075922 bytes, checksum: bd3bdc6aafacdcbe05784c0fbe751097 (MD5) Previous issue date: 2013-08-09 / The mesoporous nanostructured materials have been studied for application in the oil industry, in particular Al-MCM-41, due to the surface area around 800 to 1.000 m2 g-1 and, pore diameters ranging from 2 to 10 nm, suitable for catalysis to large molecules such as heavy oil. The MCM-41 has been synthesized by hydrothermal method, on which aluminum was added, in the ratio Si/Al equal to 50, to increase the generation of active acid sites in the nanotubes. The catalyst was characterized by X-ray diffraction (XRD), surface area by the BET method and, the average pore volume BJH method using the N2 adsorption, absorption spectroscopy in the infrared Fourier Transform (FT-IR) and determination of surface acidity with application of a probe molecule - n-butylamine. The catalyst showed well-defined structural properties and consistent with the literature. The overall objective was to test the Al-MCM-41 as catalyst and thermogravimetric perform tests, using two samples of heavy oil with API ? equal to 14.0 and 18.5. Assays were performed using a temperature range of 30-900 ? C and heating ratios (β) ranging from 5, 10 and 20 ?C min-1.The aim was to verify the thermogravimetric profiles of these oils when subjected to the action of the catalyst Al- MCM-41. Therefore, the percentage ranged catalyst applied 1, 3, 5, 10 and 20 wt%, and from the TG data were applied two different kinetic models: Ozawa-Flynn-Wall (OFW) and Kissinger-Akahrira-Sunose (KAS).The apparent activation energies found for both models had similar values and were lower for the second event of mass loss known as cracking zone, indicating a more effective performance of Al-MCM-41 in that area. Furthermore, there was a more pronounced reduction in the value of activation energy for between 10 and 20% by weight of the oil-catalyst mixture. It was concluded that the Al-MCM-41 catalyst has applicability in heavy oils to reduce the apparent activation energy of a catalyst-oil system, and the best result with 20% by weight of Al-MCM-41 / Os materiais mesoporosos nanoestruturados vem sendo estudados para aplica??o na ind?stria do petr?leo, em especial o Al-MCM-41, devido ? ?rea superficial em torno de 800-1000 m2g-1 e di?metro de poros variando de 2 a 10 nm, adequado para cat?lise de mol?culas grandes como petr?leos pesados. O MCM-41 foi sintetizado pelo m?todo hidrot?rmico, o qual foi adicionado Alum?nio numa propor??o Si/Al igual ? 50, a fim de aumentar a gera??o de s?tios ?cidos ativos nos nanotubos. O catalisador foi caracterizado por difra??o de Raios-X (DRX), ?rea superficial pelo m?todo BET e volume m?dio de poros pelo m?todo BJH atrav?s da adsor??o de N2, espectroscopia de absor??o na regi?o do infravermelho por Transformada de Fourier (FT-IR) e determina??o da acidez superficial com aplica??o de uma mol?cula sonda nbutilamina. O catalisador apresentou propriedades estruturais bem definidas e coerentes com a literatura. O objetivo geral foi testar o Al-MCM-41 como catalisador e realizar ensaios termogravim?tricos, utilizando duas amostras de petr?leo pesado com ?API iguais ? 14,0 e 18,5. Os ensaios foram realizados usando uma faixa de temperatura de 30 900?C, e raz?es de aquecimento (β) variando de 5, 10 e 20 ?Cmin-1. O intuito era verificar os perfis termogravim?tricos destes petr?leos quando submetidos ? a??o do catalisador Al-MCM-41. Para tanto, variou-se o percentual de catalisador aplicado in situ: 1, 3, 5, 10 e 20% em massa e, a partir dos dados termogravim?tricos foram aplicados dois modelos cin?ticos diferentes: Ozawa-Flynn-Wall (OFW) e Kissinger- Akahrira-Sunose (KAS). As energias de ativa??o aparente encontradas para ambos os modelos tinham valores semelhantes e eram menores para o segundo evento de perda de massa conhecido como zona de craqueamento, indicando uma atua??o mais efetiva do Al-MCM-41 nessa zona. Al?m disso, constatou-se uma diminui??o mais acentuada no valor das energias de ativa??o para valores entre 10 e 20% em massa da mistura catalisador-?leo. Concluiu-se que o Al-MCM-41 possui aplicabilidade catal?tica em petr?leos pesados diminuindo a energia de ativa??o aparente de um sistema catalisador?leo, sendo o melhor resultado com 20% em massa de Al-MCM-41

Made available in DSpace on 2014-12-17T15:42:27Z (GMT). No. of bitstreams: 1 KesiaKVC_TESE.pdf: 1888403 bytes, checksum: 628d99fa0e77dc19c5054fa5d201217e (MD5) Previous issue date: 2013-04-17 / In this work were synthesized and characterized the materials mesoporous SBA-15 and Al- SBA-15, Si / Al = 25, 50 and 75, discovered by researchers at the University of California- Santa Barbara, USA, with pore diameters ranging from 2 to 30 nm and wall thickness from 3.1 to 6.4 nm, making these promising materials in the field of catalysis, particularly for petroleum refining (catalytic cracking), as their mesopores facilitate access of the molecules constituting the oil to active sites, thereby increasing the production of hydrocarbons in the range of light and medium. To verify that the materials used as catalysts were successfully synthesized, they were characterized using techniques of X-ray diffraction (XRD), absorption spectroscopy in the infrared Fourier transform (FT-IR) and adsorption nitrogen (BET). Aiming to check the catalytic activity thereof, a sample of atmospheric residue oil (ATR) from the pole Guamar?-RN was performed the process by means of thermogravimetry and thermal degradation of catalytic residue. Upon the curves, it was observed a reduction in the onset temperature of the decomposition process of catalytic ATR. For the kinetic model proposed by Flynn-Wall yielded some parameters to determine the apparent activation energy of decomposition, being shown the efficiency of mesoporous materials, since there was a decrease in the activation energy for the reactions using catalysts. The ATR was also subjected to pyrolysis process using a pyrolyzer with gas chromatography coupled to a mass spectrometer. Through the chromatograms obtained, there was an increase in the yield of the compounds in the range of gasoline and diesel from the catalytic pyrolysis, with emphasis on Al-SBA-15 (Si / Al = 25), which showed a percentage higher than the other catalysts. These results are due to the fact that the synthesized materials exhibit specific properties for application in the process of pyrolysis of complex molecules and high molecular weight as constituents of the ATR / No presente trabalho foram sintetizados e caracterizados os materiais mesoporosos SBA-15 e Al-SBA-15, Si/Al= 25, 50 e 75, descobertos por pesquisadores da Universidade da Calif?rnia- Santa B?rbara- EUA, tendo di?metro de poros variando entre 2 a 30 nm e espessura das paredes de 3,1 - 6,4 nm, tornando estes materiais promissores na ?rea da cat?lise, especificamente para o refino do petr?leo (craqueamento catal?tico), j? que seus mesoporos facilitam o acesso das mol?culas constituintes do petr?leo aos s?tios ativos, aumentando assim a produ??o de produtos na faixa dos hidrocarbonetos leves e m?dios. Para verificar se os materiais utilizados como catalisadores haviam sido sintetizados com sucesso, os mesmos foram caracterizados atrav?s das t?cnicas de difra??o de raios-X (DRX), espectroscopia de absor??o na regi?o do infravermelho com transformada de Fourier (FTIR) e adsor??o de nitrog?nio (BET). Com o intuito de verificar a atividade catal?tica dos mesmos, utilizou-se uma amostra de Res?duo Atmosf?rico de petr?leo (RAT), proveniente do P?lo de Guamar?- RN, realizando-se atrav?s da termogravimetria o processo de degrada??o t?rmica e catal?tica do res?duo. Mediante as curvas obtidas, observou-se uma redu??o na temperatura de in?cio do processo de decomposi??o catal?tica do RAT. Pelo modelo cin?tico proposto por Flynn- Wall obtiveram-se alguns par?metros para determina??o da energia de ativa??o aparente das decomposi??es, ficando evidenciada a efici?ncia dos materiais mesoporosos, j? que houve uma diminui??o da energia de ativa??o para as rea??es utilizando os catalisadores. O RAT tamb?m foi submetido ao processo de pir?lise utilizando-se um pirolisador com cromatografia gasosa, acoplado a um espectr?metro de massa. Mediante os cromatogramas obtidos, observou-se um aumento no rendimento dos compostos na faixa da gasolina e diesel oriundos da pir?lise catal?tica, com ?nfase para o Al-SBA-15 (Si/Al= 25), que apresentou um percentual superior aos demais catalisadores. Esses resultados se devem ao fato dos materiais sintetizados exibirem propriedades espec?ficas, para aplica??o no processo de pir?lise de mol?culas complexas e com alto peso molecular, como os constituintes do RAT

Made available in DSpace on 2014-12-17T15:42:26Z (GMT). No. of bitstreams: 1 ZilvamMS_TESE_reduzido.pdf: 9108618 bytes, checksum: 613dad3fd1a359dce84e2af73b067934 (MD5) Previous issue date: 2013-02-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Surfactant-polymer interactions are widely used when required rheological properties for specific applications, such as the production of fluids for oil exploration. Studies of the interactions of chitosan with cationic surfactants has attracted attention by being able to cause changes in rheological parameters of the systems making room for new applications. The commercial chitosan represents an interesting alternative to these systems, since it is obtained from partial deacetylation of chitin: the residues sites acetylated can then be used for the polymer-surfactant interactions. Alkyl ethoxylated surfactants can be used in this system, since these non-ionic surfactants can interact with hydrophobic sites of chitosan, modifying the rheology of solutions or emulsions resultants, which depends on the relaxation phenomenon occurring in these systems. In this work, first, inverse emulsions were prepared from chitosan solution as the dispersed phase and cyclohexane as the continuous phase were, using CTAB as a surfactant. The rheological analysis of these emulsions showed pronounced pseudoplastic behavior. This behavior was attributed to interaction of "loops" of chitosan chains. Creep tests were also performed and gave further support to these discussions. Subsequently, in order to obtain more information about the interaction of chitosan with non-ionic surfactants, solutions of chitosan were mixed with C12E8 and and carried out rheological analysis and dynamic light scattering. The systems showed marked pseudoplastic behavior, which became less evident when the concentration of surfactant was increased. Arrhenius and KWW equations were used to obtain parameters of the apparent activation energy and relaxation rate distribution, respectively, to which were connected to the content of surfactant and temperature used in this work / As intera??es tensoativo-pol?mero s?o amplamente usadas quando s?o necess?rias propriedades reol?gicas para aplica??es espec?ficas, como a produ??o de fluidos para explora??o do petr?leo. Estudos das intera??es de quitosana com tensoativos cati?nicos tem chamado aten??o por serem capazes de causar mudan?as nos par?metros reol?gicos dos sistemas abrindo espa?o para novas aplica??es. A quitosana comercial representa uma alternativa interessante para estes sistemas, uma vez que ela ? obtida a partir da desacetila??o parcial da quitina: os s?tos acetilados residuais podem, ent?o, ser usados para as intera??es pol?mero-tensoativo. Tensoativos alquil etoxilados podem ser utilizados neste sistema, pois estes tensoativos n?o i?nicos podem interagir com s?tios hidrof?bicos da quitosana, modificando a reologia de solu??es ou emuls?es resultantes, os quais dependem do fen?meno de relaxa??o ocorrendo nestes sistemas. Neste trabalho, primeiramente, foram preparadas emuls?es inversas de solu??o de quitosana como fase dispersa e cicloexano como fase cont?nua usando CTAB como tensoativo. A an?lise reol?gica destas emuls?es mostrou pronunciado comportamento pseudopl?stico. Esta pseudoplasticidade foi atribu?da ? intera??o por la?os loops de cadeias de quitosana. Ensaios de flu?ncia tamb?m foram executados e deram maior suporte a estas discuss?es. Em seguida, a fim de se obter maiores informa??es sobre as intera??es da quitosana com tensoativos n?o i?nicos, solu??es de quitosana foram misturadas com C12E8 e levadas ?s an?lises reol?gica e de espalhamento din?mico de luz. Os sistemas tiveram elevado comportamento pseudopl?stico, o qual se tornava menos evidente, quando o teor de tensoativo foi aumentado. Equa??es de Arrhenius e de KWW foram usadas para obter par?metros de energia de ativa??o aparente e de distribui??o da taxa de relaxa??o, respectivamente, aos quais foram relacionados em fun??o do teor de tensoativo e da temperatura, usados neste trabalho