Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-13T19:11:35Z No. of bitstreams: 1 MarianaAlvesLeiteDutra_DISSERT.pdf: 2825637 bytes, checksum: 18b7c74e24edf8e546ebd99e18dff673 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-02-14T00:26:44Z (GMT) No. of bitstreams: 1 MarianaAlvesLeiteDutra_DISSERT.pdf: 2825637 bytes, checksum: 18b7c74e24edf8e546ebd99e18dff673 (MD5) / Made available in DSpace on 2017-02-14T00:26:45Z (GMT). No. of bitstreams: 1 MarianaAlvesLeiteDutra_DISSERT.pdf: 2825637 bytes, checksum: 18b7c74e24edf8e546ebd99e18dff673 (MD5) Previous issue date: 2016-07-18 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / A s?ntese de pol?meros usando solventes org?nicos e nocivos ao meio ambiente tem sido frequente na comunidade cient?fica. O uso de solventes verdes, como a ?gua, agride menos o meio ambiente. Este estudo proporcionou a s?ntese de dois copol?meros de poli(N-isopropilacrilamida-co-laurato de vinila) com diferentes percentuais molares dos mon?meros na cadeia polim?rica e a avalia??o de suas propriedades. A polimeriza??o foi realizada via radicais livres, substituindo o solvente org?nico, THF, pela ?gua e o iniciador, AIBN, por persulfato de pot?ssio (K2S2O8). Para fins de avalia??o da contribui??o do laurato de vinila nos copol?meros, tamb?m foi sintetizado o homopol?mero de NIPAAm, nas mesmas condi??es reacionais empregadas para os copol?meros. As estruturas qu?micas dos pol?meros obtidos foram investigadas por espectroscopia no infravermelho (IV) e resson?ncia magn?tica nuclear de hidrog?nio (1H RMN) e de carbono (13C RMN). Solu??es aquosas dos pol?meros foram analisadas por reometria, espalhamento de luz est?tico (SLS) e din?mico (DLS). Os resultados obtidos por reometria mostraram que a temperatura cr?tica consoluta inferior (LCST) do poli(N-isopropilacrilamida-co-laurato de vinila) contendo 7 mol% de LV foi de 26 ?C, enquanto a do copol?mero contendo 13 mol% de LV foi de 21 ?C, ou seja, mais baixas que a LCST da PNIPAAm (34 ?C). Esse resultado indica que a presen?a do mon?mero hidrof?bico, LV, contribuiu significativamente para a diminui??o da LCST do pol?mero. A partir do espalhamento de luz est?tico (SLS), calculou-se a massa molar ponderal m?dia aparente ( ?w), o raio de giro (Rg) e o segundo coeficiente virial (A2) dos pol?meros. A ?w e o A2 do poli(N-isopropilacrilamida-co-laurato de vinila) contendo 7 mol% de LV foi de 3,0x106 g/mol e 16,1 mol.L.g-2, respectivamente, enquanto que para o copol?mero contendo 13 mol% de LV, os valores obtidos para ?w e o A2 foram de 2,6x106 g/mol e - 4,27 mol.L.g-2, respectivamente. Para a PNIPAAm, os valores obtidos de ?w e A2 foram 3,2x107 g/mol e 0,69 mol.L.g-2, respectivamente. A diminui??o do valor de ?w dos copol?meros em rela??o ao valor da ?w da PNIPAAm foi atribu?da ? redu??o das intera??es pol?mero-solvente no meio, que foi confirmada pela diminui??o do valor do A2 para os copol?meros. As an?lises de DLS, feitas em concentra??o 1g/L no intervalo de temperatura 15 ?C a 40 ?C, indicaram a presen?a de cadeias isoladas e agregados de diversos tamanhos para os pol?meros em solu??o. / The synthesis of polymers using organic solvents harmful to the environment has been frequent in the scientific community. The use of green solvents, such as water, causes less damage to the environment. This study provided the synthesis of two copolymers of poly (N-isopropylacrylamide-co-vinyl laurate), with different molar percentage of monomers in the polymer chain and the evaluation of their properties. The polymerizations were carried out by free radicals, replacing the organic solvent THF by water, and AIBN initiator by potassium persulfate (K2S2O8). In attempt of evaluating the contribution of vinyl laurate (VL) in copolymers, the NIPAAm homopolymer was also synthesized under the same reaction conditions employed for the copolymers. The chemical structures of the synthesized polymers were determined through infrared (IR) and nuclear magnetic resonance spectroscopy. Aqueous solutions of the polymers were analyzed by rheometry, static light scattering (SLS) and dynamic light scattering (DLS). The results of rheometry showed that lower critical solution temperature (LCST) for poly (N-isopropylacrylamide-co- vinyl laurate) containing 7 mol% of VL was 26 ? C, while the copolymer containing 13 mol% VL was 21 ? C. In other words, lower than the LCST of PNIPAAm (34 ? C). There results indicate that the presence of hydrophobic monomer, VL, contributes significantly in reducing the LCST of the polymer. From the static light scattering (SLS) analysis, it was calculated the weight apparent average molecular weight ( ?w), the radius of gyration (Rg) and the second virial coefficient (A2) of the polymers. The ?w and A2 for poly (N-isopropylacrylamide-co-vinyl laurate) containing 7 mol% of VL were 3.0x106 g/mol and 16.1 mol.L.g-2, respectively, while that for the copolymer containing 13 mol% of VL, the values for ?w and A2 were 2.6x106 g/mol and 4.27 mol.L.g-2, respectively. For PNIPAAm, the values of ?w and A2 were 3.2x107 g/mol and 0.69 mol.L.g-2, respectively. The decrease in the value of ?w of the copolymers relative to the ?w value of PNIPAAm was attributed to the reduction of the polymer-solvent interactions in the medium, which was confirmed by decreasing the value of A2 to the copolymers. Dynamic light scattering (DLS) analysis was performance at polymers concentration of 1g/L in the temperature range 15 ?C to 40 ?C and indicated the presence of isolated chains and aggregates of different sizes for the polymers in solution.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-08-01T11:55:04Z No. of bitstreams: 1 CarolineSuzyDoNascimentoGarcia_DISSERT.pdf: 16990890 bytes, checksum: fc4709c79411594f09f07fcf6dd8768d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-08-02T14:05:58Z (GMT) No. of bitstreams: 1 CarolineSuzyDoNascimentoGarcia_DISSERT.pdf: 16990890 bytes, checksum: fc4709c79411594f09f07fcf6dd8768d (MD5) / Made available in DSpace on 2017-08-02T14:05:58Z (GMT). No. of bitstreams: 1 CarolineSuzyDoNascimentoGarcia_DISSERT.pdf: 16990890 bytes, checksum: fc4709c79411594f09f07fcf6dd8768d (MD5) Previous issue date: 2017-03-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Ap?s o processamento da manga nas ind?strias de polpas e sucos, toneladas de res?duos, como casca e caro?o, s?o descartados sem o devido aproveitamento. Cerca de 15% do peso da manga, a depender da sua variedade, ? devido ao caro?o, a partir do qual ? poss?vel obter o amido. A fim de agregar valor a esse res?duo, este trabalho teve como objetivo a obten??o de um ?ster do amido extra?do da manga (Tommy Atkins), atrav?s da rea??o de transesterifica??o do laurato de vinila (LV) com o amido. Tamb?m foi avaliada a utiliza??o desse amido em fluidos de perfura??o em po?os de petr?leo ? base de emuls?o inversa (A/O), devido ao alto interesse em desenvolver fluidos n?o-aquosos de baixa toxicidade e com elevado desempenho em condi??es de temperatura e press?es elevadas. A s?ntese foi realizada na presen?a de um catalisador b?sico (K2CO3), em dimetilsuf?xido (DMSO), a 110?C e atmosfera de N2(g), durante 3 ou 4 horas. Os produtos obtidos foram purificados por precipita??o em metanol e/ou ?lcool isoprop?lico e caracterizados por espectroscopia no infravermelho com transformada de Fourier (FTIR), Resson?ncia Magn?tica Nuclear de hidrog?nio (RMN 1H) e de carbono (RMN 13C), an?lise termogravim?trica (TG), testes de solubilidade e microscopia eletr?nica de varredura (MEV). O FTIR confirmou que o laurato de amido foi obtido, atrav?s do deslocamento da banda de carbonila em 1759 cm-1 do ?ster vin?lico no laurato de vinila, para 1743 cm-1, no ?ster saturado do amido modificado, essa banda de ester saturado ? ausente no amido nativo. Atrav?s do RMN 1H foi poss?vel determinar um grau de modifica??o qu?mica de 1,13. O espectro de RMN 13C do derivado de amido apresentou um pico em 173 ppm, que pode ser atribu?do a carbonila de ?ster saturado. A an?lise termogravim?trica mostrou que o amido modificado apresenta maior estabilidade t?rmica que seus precursores e que uma mistura f?sica entre amido e laurato de vinila. Os testes de solubilidade tamb?m confirmaram a modifica??o qu?mica, j? que, ao contr?rio do amido, o produto apresentou solubilidade em tolueno e clorof?rmio, e permaneceu insol?vel em ?gua e DMSO. Os dados do MEV mostraram que, ap?s a modifica??o qu?mica, os dom?nios cristalinos do amido foram desfeitos e o aspecto exibido na micrografia ? desestruturado (amorfo). Os resultados experimentais dos fluidos estudados indicaram que o produto obtido da s?ntese apresentou desempenho superior ao fluido com aditivo comercial no controle do filtrado. / After processing of mango in pulp and juices industries, tons of residues such as shell and seed are discarded without proper use. About 15% of the weight of the mango, depending on its variety, is due to the seed, from which it is possible to obtain the starch. In order to add value to this residue, this study aimed to produce an ester from mango starch (Tommy Atkins), through the transesterification reaction of vinyl laurate (LV) with starch. It was also evaluated the use of this starch in drilling fluids based on invert emulsion (W/ O), due to the high interest in developing nonaqueous fluids of low toxicity and high performance under high temperature and pressure conditions. The synthesis was performed in the presence of a basic catalyst (K2CO3) in dimethyl sulfoxide (DMSO) at 110 ? C and N2(g). The product was purified by precipitation in methanol and characterized by Fourier transform infrared spectroscopy (FTIR), Nuclear Magnetic Resonance of hydrogen (1H NMR) and carbon (13C NMR), thermal gravimetric analysis (TGA), solubility tests and scanning electron microscopy (SEM). FTIR confirmed the starch laurate was obtained, by displacing the C=O band from the vinyl ester at 1759 cm-1, to 1743 cm-1 in vinyl laurate, due to satured ester in the modified starch, this saturated ester band is absent in the native starch. Through 1H NMR it was possible to determine a degree of chemical modification of 1.13. The13 C-NMR spectrum of the starch derivative showed a peak at 173 ppm, which can be attributed to saturated ester carbonyl. Thermogravimetric analysis showed that the modified starch has higher thermal stability than its precursors and than a physical blend of starch and vinyl laurate. Solubility tests also confirmed the chemical modification, since, unlike the starch, the product was soluble in toluene and chloroform, and remained insoluble in water and DMSO. SEM data showed that crystalline domains on starch were broken after chemical modification and the appearance shown in micrograph is unstructured (amorphous). The experimental results of the studied fluids indicate that the obtained product of the synthesis presented superior performance to the fluid with commercial additive in the control of the filtrate.