Polymer-nanoplatelet hybrid membranes show promise as the next generation of membranes, but in order to make these realizable, methods to produce these materials on a large scale are necessary. Some authors have successfully produced these types of gas separation membranes. Typically these reports have utilized melt blending and in situ polymerization. Few, however, have utilized solution blending for creating membranes via phase inversion (asymmetric membranes). And to date, there have not been any reports regarding the fabrication of asymmetric membranes containing nanoplatelet filler materials. In this work we have developed a solution-based procedure for the formation of hybrid polymer-nanoplatelet dopes for dense film and asymmetric hollow fiber membrane formation. Dense film membrane studies were used to prove the effectiveness of our exfoliation and dispersion process developed for this work. Permeation measurements showed the hybrid membranes have desirable transport properties that are on par with mathematical model predictions. Additionally, TEM characterization provided strong evidence supporting the efficacy of our preparation procedures to produce an exfoliated system of nanoplatelets. We also showed that these procedures are applicable to different polymer systems (cellulose acetate and Torlon) of commercial relevance. Demonstrating the successful production of dense films set the stage for asymmetric hollow fiber membrane formation. We report the first production of asymmetric hollow fiber membranes containing nanoplatelet fillers; indicating that the process can be applied in a realistic membrane formation platform. These accomplishments serve as the groundwork for future nanocomposite formation.

In the past two decades polymer/clay nanocomposites (PCNs) have emerged as promising materials that exhibit remarkably improved properties when compared to conventional composites and pristine polymers. Such improvements strongly depend on the dispersion of clay nanoparticles in the polymer matrix. In spite of great efforts expended in characterizing clay dispersion, effective, simple and quantitative techniques are still needed. This work addresses this challenge by presenting new aspects of 1H solid-state NMR for quantifying clay dispersion in PCNs filled with clay containing paramagnetic ions. Employing these 1H solid-state NMR methods, some structure-processing-deformation relationships of PCNs were derived, and basic insights into nuclear relaxation and spin diffusion in PCNs were gained as well. Detailed models and analyses were described for 1H spin-lattice relaxation in the presence of paramagnetic clays in PCNs. Relaxation recovery was analytically correlated to clay dispersion in two ways: one is the initial relaxation recovery which is related to clay surface area, and the other is the spin-lattice relaxation time which is related to interparticle spacing. These two NMR observables were employed to quantitatively observe the evolution of clay morphology in poly(propylene)/clay (PP/MMT) nanocomposites upon equibiaxial stretching, as well as upon in situ uniaxial deformation. The initial relaxation recovery was independently utilized to determine the polymer-clay interfacial surface area and the degree of clay exfoliation. We demonstrated the capabilities of our models in quantitatively characterizing several materials, including poly(vinyl alcohol), nylon 6, poly(å-caprolactone) (PCL), poly(lactic acid) (PLA) and PP nanocomposites. These results were used to examine the dependence of clay morphology upon processing (strain ratio, strain rate, temperature), deformation (extension), component characteristics (polymer molecular weight, clay surface modification) and clay content. Effects of paramagnetic Fe3+ concentration and external magnetic field strength on 1H spin-lattice relaxation in PCNs were also investigated and discussed. In particular, low field separates the initial relaxation recovery into two stages: one related to clay content and the other related to the polymer-clay interfacial surface area. The low field was observed to enhance the paramagnetic contribution to the spin-lattice relaxation rate, increasing its sensitivity to clay morphology. In addition, measurements of long-distance spin diffusion coefficients for a variety of polymers and paramagnetic characteristics of organically modified clay were explored. Overall, the utility of NMR relaxometry in characterizing PCNs has been significantly expanded and successfully demonstrated in this dissertation.

Neste trabalho foi analisado o comportamento de um solo argiloso compactado (CCL) da Fm. Corumbataí e de um geocomposto bentonítico (GCL) composto por bentonita \'NA\', frente a gradientes hidráulicos e químicos. As propriedades físicas e mineralógicas dos solos foram avaliadas, bem como determinados em ensaios de adsorção em lote os parâmetros das isotermas de Freundlich e Langmuir. Foi desenvolvido um equipamento para avaliar o comportamento membrana e poder calcular o coeficiente de eficiência químico-osmótico (\'ômega\') em ensaio de difusão-membrana. Os ensaios de advecção foram executados com o equipamento já existente no departamento de Geotecnia. Em todos os ensaios foram utilizadas soluções monoiônicas de \'KCL\' e \'CU\'CL IND.2\' 2\'H IND.2\'O\'. O valor do factor de retardamento Rd determinado no ensaio em lote (batch test) foi maior que o Rd medido no ensaio de advecção, enquanto que, no ensaio de difusão-membrana, obteve-se o menor valor de Rd. Tanto o GCL quanto o CCL apresentaram comportamento membrana e geração de pressão osmótica para as soluções utilizadas. No entanto, com a solução de \'K POT.+\' as diferenças de pressão se mantiveram durante o ensaio, enquanto que no caso da solução de \'CU POT.+2\' a pressão induzida no corpo de prova do CCL e do GCL tem um pico e logo diminue até zero. O GCL teve um aumento na condutividade hidráulica, no ensaio de advecção, quando permeado com solução de \'CU POT.+2\'. Este comportamento é atribuído ao colapso da dupla camada difusa das partículas de argila. O CCL não apresentou este comportamento. Os resultados deste trabalho sugerem que o CCL da Fm. Corumbataí tem melhor desempenho como barreira que o GCL, nas condições de laboratório e para as soluções usadas. / In this research the behavior of a compacted clayey liner (CCL) of Corumbataí Fm. and a geosynthetic clay liner (GCL) containing \'NA\'-bentonite, was evaluated in presence of hydraulic and chemical gradients. Physical and mineralogical properties of the soils were determined and batch tests were executed to obtain the adsorption parameters of the Freundlich and Langmuir models. A laboratory apparatus was developed for assessment of the membrane behavior allowing determining the chemico-osmotic efficiency coefficient (\'ômega\') in diffusion-membrane test. The advection test was carried out with existent equipment in geotechnical department. Both tests were performed with single salt \'KCL\' and \'CU\'CL IND.2\' 2\'H IND.2\'O\' solutions. The measured value of the retardation factor (Rd) for the batch test is bigger than the Rd measured in advection test while in the diffusion-membrane test, the Rd obtained is the smallest. Both GCL and the CCL exhibit membrane behavior and they generate osmotic pressure with both solutions. However with \'KCL\' solution the difference of pressure are maintained during the test, while in the case of \'CU POT.+2\' solution the induced pressure across the specimen of CCL and GCL have a peak to after decrease to zero. The GCL had an increase in the hydraulic conductivity for a \'CU POT.+2\' solution in the advection test. This behavior is attributed to the collapse of the diffuse double layers of clay particles. The CCL did not exhibit this behavior. The results of this study suggest that the CCL of Corumbataí Fm. has a better performance as clay barrier tha the GCL, considering the solutions used and in the laboratory conditions.

Neste trabalho foi analisado o comportamento de um solo argiloso compactado (CCL) da Fm. Corumbataí e de um geocomposto bentonítico (GCL) composto por bentonita \'NA\', frente a gradientes hidráulicos e químicos. As propriedades físicas e mineralógicas dos solos foram avaliadas, bem como determinados em ensaios de adsorção em lote os parâmetros das isotermas de Freundlich e Langmuir. Foi desenvolvido um equipamento para avaliar o comportamento membrana e poder calcular o coeficiente de eficiência químico-osmótico (\'ômega\') em ensaio de difusão-membrana. Os ensaios de advecção foram executados com o equipamento já existente no departamento de Geotecnia. Em todos os ensaios foram utilizadas soluções monoiônicas de \'KCL\' e \'CU\'CL IND.2\' 2\'H IND.2\'O\'. O valor do factor de retardamento Rd determinado no ensaio em lote (batch test) foi maior que o Rd medido no ensaio de advecção, enquanto que, no ensaio de difusão-membrana, obteve-se o menor valor de Rd. Tanto o GCL quanto o CCL apresentaram comportamento membrana e geração de pressão osmótica para as soluções utilizadas. No entanto, com a solução de \'K POT.+\' as diferenças de pressão se mantiveram durante o ensaio, enquanto que no caso da solução de \'CU POT.+2\' a pressão induzida no corpo de prova do CCL e do GCL tem um pico e logo diminue até zero. O GCL teve um aumento na condutividade hidráulica, no ensaio de advecção, quando permeado com solução de \'CU POT.+2\'. Este comportamento é atribuído ao colapso da dupla camada difusa das partículas de argila. O CCL não apresentou este comportamento. Os resultados deste trabalho sugerem que o CCL da Fm. Corumbataí tem melhor desempenho como barreira que o GCL, nas condições de laboratório e para as soluções usadas. / In this research the behavior of a compacted clayey liner (CCL) of Corumbataí Fm. and a geosynthetic clay liner (GCL) containing \'NA\'-bentonite, was evaluated in presence of hydraulic and chemical gradients. Physical and mineralogical properties of the soils were determined and batch tests were executed to obtain the adsorption parameters of the Freundlich and Langmuir models. A laboratory apparatus was developed for assessment of the membrane behavior allowing determining the chemico-osmotic efficiency coefficient (\'ômega\') in diffusion-membrane test. The advection test was carried out with existent equipment in geotechnical department. Both tests were performed with single salt \'KCL\' and \'CU\'CL IND.2\' 2\'H IND.2\'O\' solutions. The measured value of the retardation factor (Rd) for the batch test is bigger than the Rd measured in advection test while in the diffusion-membrane test, the Rd obtained is the smallest. Both GCL and the CCL exhibit membrane behavior and they generate osmotic pressure with both solutions. However with \'KCL\' solution the difference of pressure are maintained during the test, while in the case of \'CU POT.+2\' solution the induced pressure across the specimen of CCL and GCL have a peak to after decrease to zero. The GCL had an increase in the hydraulic conductivity for a \'CU POT.+2\' solution in the advection test. This behavior is attributed to the collapse of the diffuse double layers of clay particles. The CCL did not exhibit this behavior. The results of this study suggest that the CCL of Corumbataí Fm. has a better performance as clay barrier tha the GCL, considering the solutions used and in the laboratory conditions.