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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estudo estrutural e morfológico de membranas de quitosana e de N,O-carboximetilquitosana

Soares, Geicilene Katrine de Paiva 20 October 2015 (has links)
Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-02-17T17:53:27Z No. of bitstreams: 1 Dissertação - Geicilene Katrine de Paiva Soares.pdf: 25824150 bytes, checksum: 841f81f51a56cad73959f622a066ba0c (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-02-17T17:53:41Z (GMT) No. of bitstreams: 1 Dissertação - Geicilene Katrine de Paiva Soares.pdf: 25824150 bytes, checksum: 841f81f51a56cad73959f622a066ba0c (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-02-17T17:54:08Z (GMT) No. of bitstreams: 1 Dissertação - Geicilene Katrine de Paiva Soares.pdf: 25824150 bytes, checksum: 841f81f51a56cad73959f622a066ba0c (MD5) / Made available in DSpace on 2016-02-17T17:54:08Z (GMT). No. of bitstreams: 1 Dissertação - Geicilene Katrine de Paiva Soares.pdf: 25824150 bytes, checksum: 841f81f51a56cad73959f622a066ba0c (MD5) Previous issue date: 2015-10-20 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work two sets of samples were evaluated according to their morphological and structural point of view. The first set is the powder samples: Chitosan (Q) purchased from Yue Planting – China; N,O-carboxymethyl sodium (NaCMQD) purchased on Dayang Chemicals – China and Heppe Medical – Germany. The second set of samples is in the form of membranes, which were synthesized in the laboratory from powder samples mentioned above: Chitosan Membrane (M-Q); Membrane of N,Ocarboxymethyl Chitosan synthesized from the Carboxymethyl Chitosan obtained at the Dayang Chemicals (M-CMQD) and N, O-carboxymethyl chitosan synthesized from the Carboxymethyl Chitosan obtained at the Heppe Medical (M-CMQH). Using NMR 13C the average degree of acetylation DA and substitution DS was determined for NaCMQD and NaCMQH samples, and as a tool to propose a molecular structure for each sample. The XRD patterns of powder samples (Q, NaCMQD and NaCMQH) and membranes (M-Q, M-CMQD and M-CMQH) showed for sample Q peaks located at (2 = 10:4, 19.8, 22.2, 29.6, 35.3 and 40:9 ), and the peaks related to their respective membrane (M-Q) was located at 2 = 10:4 and 15:1 , between 2 = 19:8 and 35:3 , and between 2 = 38:6 and 44:5 . The same was observed for NaCMQD sample (between 2 = 8:9 and 13:2 , 2 = 20:1 and between 2 = 33:2 and 42:2 ) and its respective membrane M-CMQD, with peaks located between 2 = 10:3 and 13:7 , 2 = 19:8 and 25:7 , 2 = 37:8 and 45:1 . The samples NaCMQH and M-CMQH showed similar XRD profiles (between 2 = 8:9 and 13:3 , 2 = 17:6 and 26:4 , 2 = 35:0 and 43:1 ). The percentage of crystallinity was estimated using the XRD profiles through Peak Fitting Module Program. For samples in the powder form the crystallinity percentages were found around 45, 40 and 30%, respectively. For samples in the form of membrane the crystallinity was about 35, 30 and 30, respectively. Chitosan powder and membrane (Q and M-Q) had higher percent of crystallinity due to the smaller size of its side groups, facilitating regular packing of their chains, since the carboxymethylchitosan showed extensive side groups, as evidenced by NMR¹³C, which hinders the packing of chains, decreasing its crystalline domains. The Le Bail method was performed using the FullProf program to refine the cell parameters initially found in literature, with orthorhombic space group. The refined cell parameters for Q and M-Q samples showed a = 9 ° A, b = 16 °A and c = 10 A° , approximately; for NaCMQD, NaCMQH, M-CMQD and M-CMQH, ten values of refined parameters were a = 13 A° , b = 19 °A and c = 10 A° , approximately. The average size of its crystallites/anisotropy of the samples Q, M-Q, NaCMQD, M-CMQD, NaCMQH and M-CMQH were 29 (4) A° , 16 (4) ° A, 32 (7) ° A, 23 (2) ° A, 20 (1) °A and 24 (1) A° , respectively. The increase of cell parameters a and b in the Carboxymethyl Chitosans occurred due to the insertion of side groups from carboxymethylation of chitosan, resulting in difficulty in packaging of the chains and therefore the crystallinity and the anisotropic dimensions of the crystallites. The morphologies of powders and membranes were evaluated by Scanning Electron Microscopy (SEM). Samples in powder form (Q, NaCMQD and NaCMQH) presented a variety of sizes of its grains, which showed no uniformity. Membranes (MQ, M-CMQD e M-CMQH) were classified according to their pore size and thickness of the fibers through the ImageJ software. All membranes had pores greater than 50 nm (macropores) and the thickness of fibers were found most frequently around 0.15 m (M-Q) between 5 and 10 m (M-CMQD) and about 5 m (M-CMQH). The thermal stability of the samples was assessed by Thermogravimetric Analysis (TGA/DTG). The physical form of the samples as well as their degree of crystallinity have influenced the main thermal events. Among the powder samples, chitosan showed greater thermal stability with a initial temperature of degradation around 283 C. Among the membranes, the M-Q and M-CMQH samples showed similar initial degradation temperature of around 233 C. Thus, this work presents a systematic evaluation of Chitosan and N,O-carboxymethyl chitosan, as well as their respective membranes, showing intrinsic characteristics of these samples according to their structural and morphological point of view. / Neste trabalho dois conjuntos de amostras foram estudados segundo o ponto de vista morfol´ogico e estrutural. O primeiro conjunto representa as amostras em p´ o: Quitosana (Q) adquirida da Yue Planting – China; N,O-carboximetilquitosana s ´odica (NaCMQD) adquirida da Dayang Chemicals – China e da Heppe Medical – Alemanha. O segundo conjunto representa as amostras na forma de membranas, sintetizadas em laborat ´ orio, a partir das amostras em p´o mencionadas anteriormente: Membrana de Quitosana (M-Q), Membrana de N,O-carboximetilquitosana sintetizada a partir da Quitosana obtida da Dayang Chemicals (M-CMQD) e N,O-carboximetilquitosana sintetizada a partir da Quitosana obtida da Heppe Medical (M-CMQH). Atrav´es das medidas de Espectroscopia de Ressonˆancia Magn´etica Nuclear de Carbono 13 (RMN 13C) foi poss´ıvel determinar o grau m´edio de acetilac¸ ˜ao GA e substituic¸ ˜ao GS para as amostras NaCMQD e NaCMQH, bem como propor uma estrutura molecular para cada amostra. Os difratogramas das amostras na forma de p´o (Q, NaCMQD e NaCMQH) e membrana (M-Q, M-CMQD e M-CMQH) foram obtidos atrav´es da difrac¸ ˜ao de raios X (DRX), e mostrou que a amostra Q apresentou uma quantidade maior de picos, localizados em 2 = 10; 4; 19,8; 22,2; 29,6; 35,3 e 40;9 , em relac¸ ˜ao `a sua respectiva membrana MQ com picos localizados em 2 = 10;4 e 15;1 ; entre 2 = 19;8 e 35;3 ; e entre 2 = 38;6 e 44;5 . O mesmo aconteceu para a amostra NaCMQD (entre 2 = 8;9 e 13;2 ; 2 = 20;1 e entre 2 = 33;2 e 42;2 ) e sua respectiva membrana M-CMQD com picos localizados entre 2 = 10;3 e 13;7 ; 2 = 19;8 e 25;7 ; 2 = 37;8 e 45;1 . J´a as amostras NaCMQH e M-CMQH apresentaram perfis de DRX semelhantes (entre 2 = 8;9 e 13;3 ; 2 = 17;6 e 26;4 ; 2 = 35;0 e 43;1 ). O percentual de cristalinidade foi estimado utilizando-se os perfis de DRX, atrav´es do programa Peak Fitting Module. Para as amostras na forma de p´ o, Q, NaCMQD e NaCMQH, os percentuais de cristalinidade foram encontrados em torno de 45, 40 e 30%, respectivamente. Para as amostras na forma de membrana, M-Q, M-CMQD e M-CMQH, a cristalinidade ficou em torno de 35, 30 e 30%, respectivamente. A quitosana em p´o e membrana (Q e M-Q) apresentaram maior percentual cristalinidade possivelmente devido ao menor tamanho de seus grupos laterais, facilitando o empacotamento regular de suas cadeias, j´a que as carboximetilquitosanas apresentaram grupos laterais extensos, como constatado por RMN 13C, o que dificulta o empacotamento das cadeias, diminuindo seus dom´ınios cristalinos. O ajuste Le Bail foi realizado atrav´es do programa FullProf para refinar os parˆametros de cela inicialmente encontrados em literatura, com sistema cristalino ortorrˆombico. Os parˆametros de cela refinados para as amostras Q e M-Q apresentaram a = 9 ° A, b = 16 °A e c = 10 A° , aproximadamente; para as amostras NaCMQD, M-CMQD, NaCMQH e M-CMQH, os valores dos parˆametros refinados forama = 13 ° A, b = 19 °A e c = 10 A° , aproximadamente. O tamanhome´dio de seus cristalitos e suas respectivas anisotropias para as amostras Q, M-Q, NaCMQD, M-CMQD, NaCMQH e M-CMQH foram de 29 (4) ° A, 16 (4) ° A, 32 (7) ° A, 23 (2) ° A, 20 (1) °A e 24 (1)A° , respectivamente. O aumento dos paraˆmetros de cela a e b nas carboximetilquitosanas ocorreu devido `a inserc¸ ˜ao de grupos laterais provenientes da carboximetilac¸ ˜ao da Quitosana, resultando em dificuldade de empacotamento das cadeias e, consequentemente, na cristalinidade e nas dimens˜oes anisotr´opicas dos cristalitos. As morfologias dos p´os e membranas foram avaliadas atrav´es da Microscopia Eletrˆonica de Varredura (MEV). As amostras em forma de p´o (Q, NaCMQD e NaCMQH) apresentaram uma variedade de tamanhos de seus gr˜aos, os quais n˜ao apresentaram uniformidade. As membranas (M-Q, M-CMQD e M-CMQH) foram classificadas de acordo o tamanho dos seus poros e espessura de suas fibras atrav´es do programa ImageJ. Todas as membranas apresentaram poros maiores que 50 nm (macroporos) e as espessuras de suas fibras foram encontradas com maior frequˆencia em torno de 0,15 m (M-Q), entre 5 e 10 m (M-CMQD) e em torno de 5 m (M-CMQH). A estabilidade t´ermica das amostras foi avaliada atrav´es da An´alise Termogravim´etrica (TGA/DTG). A forma f´ısica das amostras, bem como o seu grau de cristalinidade, influenciou os principais eventos t´ermicos. Entre as amostras em p´ o, a quitosana apresentou maior estabilidade t´ermica com temperatura inicial de degradac¸ ˜ao de 283 C. Entre as membranas, as amostras M-Q e M-CMQH apresentaram valores similares de temperatura inicial de degradac¸ ˜ao em torno de 233 C. Dessa forma, este trabalho apresentou uma avaliac¸ ˜ao sistem´atica de Quitosana e N,O-Carboximetilquitosana, bem como de suas respectivas membranas, evidenciando caracter´ısticas intr´ınsecas das amostras segundo o ponto de vista estrutural e morfol´ogico, esperando-se contribuir de maneira significativa com a comunidade cient´ıfica com os dados aqui apresentados.

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