Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-27T12:21:51Z No. of bitstreams: 1 CamilaRenataMachadoDeLima_TESE.pdf: 10473326 bytes, checksum: 499183bf400adac799809def0c151a7f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-30T11:35:30Z (GMT) No. of bitstreams: 1 CamilaRenataMachadoDeLima_TESE.pdf: 10473326 bytes, checksum: 499183bf400adac799809def0c151a7f (MD5) / Made available in DSpace on 2017-01-30T11:35:30Z (GMT). No. of bitstreams: 1 CamilaRenataMachadoDeLima_TESE.pdf: 10473326 bytes, checksum: 499183bf400adac799809def0c151a7f (MD5) Previous issue date: 2016-06-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Polieletr?litos carregados opostamente interagem eletrostaticamente para formar os denominados complexos interpolieletrol?ticos (IPEC?s). Ao combinar diferentes tipos de polieletr?litos, estruturas distintas podem ser formadas, o que torna necess?rio a devida caracteriza??o f?sico-qu?mica desses complexos interpolieletrol?ticos. Dessa forma, neste trabalho, inicialmente, foram obtidos complexos interpolieletrol?ticos entre quitosana e poli (4-estireno sulfonato de s?dio) a diferentes raz?es molares, rSA (sulfonato/am?nio), atrav?s da simples mistura das solu??es desses polieletr?litos em meio ?cido: sendo a quitosana o polic?tion e o poli (4-estireno sulfonato de s?dio) o poli?nion. Posteriormente, esses IPEC?s foram caracterizados por medidas de viscosidade, turbidez, condutividade, potencial zeta, al?m das t?cnicas de espalhamento din?mico da luz (DLS) e espalhamento de raios-X a baixo ?ngulo (SAXS). A ampla faixa de dezessete raz?es molares, rSA (0,01; 0,03; 0,05; 0,1; 0,2; 0,3; 0,4; 0,5; 0,6; 0,7; 1,4; 1,7; 2,0; 2,5; 3,3; 5,0 e 10), investigada neste trabalho gerou part?culas coloidais de natureza liof?lica e liof?bica. As medidas de turbidez e condutividade apresentaram um aumento dr?stico quando a raz?o molar teve seu valor igual a 1. O potencial zeta nesta regi?o de rSA = 1 foi de 0, confirmando a neutralidade de carga e uma estequiometria 1:1 entre os polieletr?litos. A partir dos par?metros obtidos pelo DLS e SAXS foi poss?vel caracterizar o processo de forma??o dos IPEC?s. As part?culas s?lidas de IPEC?s obtidas foram caracterizadas por TG, DRX e FTIR, indicando que a complexa??o interpolieletrol?tica inibiu a ocorr?ncia de regi?es cristalinas. Posteriormente, foram realizados experimentos a fim de monitorar e caracterizar o processo de adsor??o de dois f?rmacos, tetraciclina e cromoglicato, em part?culas s?lidas de IPEC?s obtidas a partir de duas raz?es molares diferentes, rSA = 0,7 e 1,43. Isotermas de adsor??o e um modelo cin?tico foram utilizados nos dados experimentais para descrever o processo de adsor??o. As part?culas de IPEC?s obtidas a partir da rSA = 0,7 e rSA = 1,43 mostraram ser bons adsorventes para a tetraciclina. Entretanto, nenhum processo de adsor??o do cromoglicato em part?culas obtidas a partir da rSA = 1,43 foi observado. / Oppositely charged polyelectrolytes interact electrostatically to form the so-called interpolyelectrolyte complexes (IPEC?s). By combining different types of polyelectrolytes, different structures may be formed, which makes necessary the physicochemical characterization of these interpolyelectrolyte complexes. Thus, in this study, initially, were obtained interpolyelectrolyte complexes between chitosan and poly (4-styrene sulfonate of sodium) at different molar ratios, rSA (sulfonate/aminium), by simply mixing the solutions of these polyelectrolytes in acid medium: it is the chitosan as the polycation and poly (4-styrene sulfonate of sodium) as the polyanion. Thereafter, the IPEC?s were characterized by measurements of viscosity, turbidity, conductivity, zeta potential, beyond techniques the dynamic light scattering (DLS) and scattering X-ray small angle (SAXS). The wide range of seventeen molar ratios, rSA (0.01; 0.03; 0.05; 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 1.4; 1.7; 2.0; 2.5; 3.3; 5.0 e 10), investigated in this work generated colloidal particles of lyophilic and liophobic nature. The turbidity and conductivity measurements showed a drastic increase when the molar ratio had its value equal 1. The zeta potential in this region rSA = 1 was 0, confirming the neutral charge and a 1:1 stoichiometry between the polyelectrolytes. From the parameters obtained by DLS and SAXS it was possible to characterize the process of formation of IPEC?s. The solid particles obtained IPEC?s were characterized by TG, DRX and FTIR, indicating that complexation polyelectrolytic inhibited the occurrence of crystalline regions. Subsequently, experiments were conducted to monitor and characterize the adsorption process of two drugs, tetracycline and cromoglycate, in solid particulate IPEC?s derived from two different molar ratios, rSA = 0.7 e 1.43. Adsorption isotherms and a kinetic model were used in the experimental data to describe the adsorption process. The particles IPEC?s obtained from the rSA = 0.7 and rSA = 1.43 appeared to be good adsorbents for tetracycline. However, no adsorption process of the cromoglycate in particles obtained from the rSA = 1.43 was observed.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-12T13:44:03Z No. of bitstreams: 1 PauloReniereSilvaDeSouza_DISSERT.pdf: 18420723 bytes, checksum: 0dee6d1653465093c4081165eec036ad (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-17T11:30:54Z (GMT) No. of bitstreams: 1 PauloReniereSilvaDeSouza_DISSERT.pdf: 18420723 bytes, checksum: 0dee6d1653465093c4081165eec036ad (MD5) / Made available in DSpace on 2017-01-17T11:30:54Z (GMT). No. of bitstreams: 1 PauloReniereSilvaDeSouza_DISSERT.pdf: 18420723 bytes, checksum: 0dee6d1653465093c4081165eec036ad (MD5) Previous issue date: 2016-07-22 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Dispers?es de complexos polieletrol?ticos (PEC) foram preparadas a partir de quitosana e poli(metacrilato de s?dio), atrav?s da mistura de suas solu??es, a diferentes raz?es molares carboxila/amino, rCA. O raio de giro foi determinado por SAXS e revelou que na medida que rCA aumentava as dimens?es das PEC?s decresciam, atingindo um m?nimo a rCA = 0.75, a qual foi considerada a raz?o na qual as dimens?es dos agregados eram m?nimas, sendo seguido de colapso e crescimento de part?culas maiores. Distribui??es de dist?ncia entre pares, P(r), tornaram-se mais estreitas at? rCA = 0.75, aumentando suas larguras a partir deste ponto. Par?metros relacionados ? relaxa??o, retirados de fun??es de correla??o de intensidade (ICF) de DLS identificaram tr?s processos principais de relaxa??o. O processo mais r?pido, relacionado a movimentos aleat?rios de mol?culas de polieletr?lito livres desapareceu, na medida em que rCA aumentou. Os outros dois processos de relaxa??o foram fun??es de rCA e apresentaram mudan?as caracter?sticas a rCA = 0.75. No mesmo valor de rCA, a energia de ativa??o para a taxa de relaxa??o m?dia indicou a ocorr?ncia de uma clara mudan?a na natureza das intera??es nas estruturas de PEC. O di?metro hidrodin?mico, determinado por DLS, foi muito maior que o raio de giro, determinado por SAXS. Part?culas de PEC podem ser descritas, consequentemente, como composta por um caro?o s?lido, rico em material segregado, insol?vel, envelopado por aglomerados sol?veis de PEC, possivelmente na forma de g?is altamente hidratados. / Polyelectrolyte complex (PEC) dispersions were prepared from chitosan and poly(sodium acrylate), NaPMA, by mixing their solutions., at different carboxyl to aminium molar ratio, rCA. Gyration radius was determined by SAXS and showed that, as rCA increased, PEC dimensions decreased and reached a minimum at rCA = 0.75, which was considered the ratio at which PEC cluster dimensions was minimum, following collapse and growth of larger particles. Pair distance distributions, P(r), became narrower up to rCA = 0.75, increasing its width from this point. Relaxation-related parameters from DLS intensity correlation functions (ICF) identified three main relaxation process. The fast process, related to free polyelectrolyte molecules random motion disappeared as rCA was increased. The other two relaxation process were a function of rCA and presented marked changes at rCA = 0.75. At the same value of rCA the energy of activation for the average relaxation rate showed the occurrence of a clear change in the nature of PEC-related interactions. As hydrodynamic diameter, determined by DLS was much larger than the gyration radius determined by SAXS, PEC particles could be described as being composed by a core, rich in segregated, insoluble material, enveloped by PEC soluble clusters, possibly in the form of water-rich gels.