Polymer/clay nanocomposites consisting of an epoxy resin matrix filled with organoclays have been investigated. The main objective of this study was to determine which combination of components led to the greatest enhancement in properties of the epoxy resin. Exfoliation of the clay was desired, as exfoliated nanocomposites are known to exhibit great improvements in mechanical properties [1]. The epoxy resins studied were di-functional DGEBA and tetra-functional TGDDM. The epoxy resin was cured with three different hardeners, these included: the high functionality amine hardener, TETA, and two anhydride hardeners, accelerated MTHPA and pure HHPA. The three organoclays used, contained alkylammonium cations and were also compared to the unmodified clay. Morphology was investigated by XRD and TEM, and the flexural properties of the resulting nanocomposites were studied. The effect that the addition of an organoclay has on the cure of the epoxy resin was investigated using MDSC. Both the temperatures required to cure the resin with, and without, the clay, and any changes in the total heat flow that occurred were studied. The Tg++ of the cured nanocomposites was also measured using MDSC. The heat flow results indicated that the clays added to the epoxy resins act as a physical barrier, which prevents the resin from reaching full cure. In the higher functional resin, the addition of clay resulted in a significant decrease in the total heat flow, suggesting that a large amount of epoxy remains uncured, and, as a result, there should be a reduction in the amount of cross-linking. The lower cross-link density led to a significantly lower Tg and the mechanical properties were also poorer. The reactivity of the hardener towards the resin was found to have the greatest impact on the cured nanocomposite morphology. Intragallery polymerisation occurring at a faster rate than the extragallery polymerisation causes exfoliation. In order to achieve a balance that favours intragallery polymerisation, it was found that the curing reaction was required to be catalysed by the alkylammonium cation of the organoclay, and not catalysed by other means. The DGEBA cured with HHPA provided the largest layer expansion in the clay structure due to the alkylammonium cation catalysing the anhydride ring-opening reaction. The effect was not seen with TGDDM due to the tertiary amine in its structure. The accelerator within the MTHPA assisted extragallery polymerisation of the resin and the TETA cured readily without additional catalysis.

A series of new cobalt(II) beta-keto iminato complexes and cobalt(II) salens have been made and the effect of chirality in the northern, southern and peripheral quadrants of these catalysts, with respect to induced enantiomeric excess, during the ring-opening of 1,2-dioxines has been determined. Synthesis of a series of cobalt beta-keto iminato complexes was achieved after modification of literature procedures used for the synthesis of manganese beta-keto iminato complexes and this procedure was applied to generate ligands with ethyl, t-butyl, (-)-bornyl, (+)-menthyl and (-)-menthyl esters and a methyl side chain. Synthesis of the cobalt salens was also achieved using a modified literature procedure, in respect to the more complex aldehydes made. It was ascertained that chirality in the northern quadrant of these catalysts, obtained by the use of optically pure diamines, was of greatest importance in introducing enantiomeric excess into the products of ring-opening of 1,2-dioxines; namely gamma-hydroxy enones, and chirality in the southern and peripheral quadrants was of lesser, although still significant, importance. The reaction conditions were optimised and the conditions under which the highest enantiomeric excess was introduced were determined. The ideal solvent for the ring-opening was found to be THF with a catalyst concentration between 5 and 10 mol% at a temperature of -15oC. These conditions were found to be applicable to all catalysts and 1,2-dioxines tested. Enantiomeric excess as high as 76 % could be introduced when the optimised reaction conditions were used in large scale syntheses of cyclopropane (61). LC-MS studies indicate the presence of a solvent chelated species present in the reaction mixture when the solvent used is THF, however, the use of non-chelating solvents, such as dichloromethane, did not exhibit this same solvent chelated species. Catalyst dimers were also present in the mixture when analysed by LC-MS. The presence of oxygen in the reaction mixture was found to inhibit rearrangement of the dioxine with catalyst oxygen dimers (two molecules of catalyst bound to a single molecule of oxygen) present when analysed by LC-MS, however, the catalyst could be 're-activated' by de-aeration of the solution and was able to introduce the same enantiomeric excess, as prior to the addition of oxygen was unaffected. It was found that not only cobalt(II) tetradentate complexes were useful in the ring-opening of meso 1,2-dioxines. Achiral iron(II) salen and ruthenium(II) salen were also made and shown to be capable of ring-opening the dioxine. A purchased chiral manganese(III) salen was also shown to be capable of ring-opening the 1,2-dioxine, however, the time taken for the rearrangement to occur led to ring closure of the gamma-hydroxy enone and dehydration of the cyclic hemiacetal. The catalysts were also applied to the enantioselective ring-opening of epoxy-1,2-dioxines for the first time with a high level of success with enantiomeric excesses of between 60 and 90 % introduced with most of the catalysts. To show that these catalysts have the potential for use in the synthesis of potentially bioactive cyclopropyl amino acids, amines, acids and alcohols a small number were prepared, including both racemic and optically enriched or optically pure cyclopropanes. / Thesis (Ph.D.)--School of Chemistry and Physics, 2003.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.

Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Chemistry, 2009. / Includes bibliographical references.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2010. / Härtill 3 uppsatser.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Universiẗat, Diss., 2004--Köln.

Thesis (M.S.)--Brigham Young University. Dept. of Civil and Environmental Engineering, 2005. / Includes bibliographical references (p. 57-61).

Orientador: Ruis Camargo Tokimatsu / Resumo: Ao longo das duas últimas décadas, a contribuição da manufatura aditiva passou da confecção de um mero protótipo de um produto, no início de seu desenvolvimento, para a confecção de qualquer produto direto, presente em todos os setores industriais. Com este avanço, diferentes tecnologias da manufatura aditiva surgiram com o intuito de melhorar alguns parâmetros de produção. Neste meio, a tecnologia de impressão tridimensional 3DP, por consequência de suas várias características intrínsecas, se destaca para atender o setor biomédico, através da técnica de biomodelagem, que contribuem imensamente de forma didática e prática para a performance de cirurgias. Porém, há algumas limitações finais nas peças obtidas por esta tecnologia que devem ser contornadas, focando-se no tratamento adicional necessário destas peças, o pós-processamento, de modo a aprimorá-las, conferindo então sucesso ao destino destas. Neste trabalho, adotou-se a tecnologia de manufatura aditiva 3DP para estudar como a adição de diferentes agentes infiltrantes influenciam no acréscimo de densidade aparente e resistência mecânica de amostras feitas de componentes de gesso, constituídas por corpos de prova cilíndricos e prismáticos, de modo a simular a melhor composição para biomodelos. Para isto, o pós-processamento foi dividido em duas etapas. Na primeira etapa, foram aplicados separadamente nas amostras, quatro tipos de adesivos à base de etilcianocrilato, por gotejamento, e um à base de epóxi, por moldagem com... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre