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The work reported in this thesis can be broken down into three main areas. The first describes the synthesis of a series of β-substituted thiophenes bearing long, lipophilic chains (either ether, polyether or amido in nature). Cyclic voltammetry studies on the monomers revealed their oxidation potential but did not prove to be a successful method of electropolymerisation. This was achieved using constant current electrolysis and further studies involving FTIR, ESCA and SEM were carried out on the most highly conducting polymer. This polymer was also solution processible in its conducting form. The second area also describes the synthesis of a series of β-substituted thiophenes, but this time the pendant side group consists of bulky phenoxy moieties (liquid crystals, phenol ethers and aminophenol ethers). In this case the cyclic voltammetry studies carried out did appear to provide a successful means of generating polymers. Finally, the synthesis of a series of β-substituted thiophenes bearing pendant macrocyclic substituents (an N-0-5 cycle, an oxo-cyclam and a 14-0-4 cycle) are described. Their cyclic voltammetry behaviour is reported in detail and the results of experiments to determine metal ion selectivity is also described, in the case of the 14-0-4 cycle.

Thesis (Ph. D.)--Syracuse University, 2006. / "Publication number AAT 3251791."

Thesis (Ph.D.)--Brown University, 2008. / Source: Dissertation Abstracts International, Volume: 69-06, Section: B, page: 3587. Adviser: Paul G. williard. Includes bibliographical references.

Yes / A novel fully biosbased poly(lactic acid)-b-poly(lactide-co-caprolactone) (PLA-b-PLCL) with a two-phase structure and long-chain branches was specifically designed and prepared through reactive melt processing. The results showed that PLCL segments were introduced onto PLA chains successfully. With the increase of PLCL content, the blockier distribution of LA/CL chain sequences of the sample was exhibited. PLA-b-PLCL showed two distinct thermal transitions, corresponding to the glass transition of PLA and PLCL domains, respectively, whereas the phase morphology changed from a sea-island to a co-continuous structure with increasing PLCL content. Because of the long-chain branched structure, PLA-b-PLCL samples showed a much higher viscoelasticity, strong molecular entanglement, and obvious strain-hardening behavior, resulting in a high draw ratio of the sample during orientation process, whereas the tensile strength and the modulus of the oriented sample reached up to 173 MPa and 5.4 GPa, respectively, which basically met the requirements of bone screws. Moreover, PLA-b-PLCL showed a triple-shape memory effect at 55 and 120 °C, respectively. For PLA-b-30 wt % PLCL, the recovery ratio can reach up to 98.1% under 55 °C, while high mechanical properties can be maintained, realizing self-reinforcement and self-fastening effect simultaneously as a smart bone fixation material.

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Made available in DSpace on 2014-10-09T12:55:41Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:07Z (GMT). No. of bitstreams: 0 / Em um cenário nacional de grandes dificuldades orçamentárias, soluções criativas que conjuguem os esforços de instituições em prol de uma finalidade comum são sempre desejáveis. Neste trabalho, analisa-se o desenvolvimento de fibras de carbono de alto desempenho para aplicação em ultracentrífugas nucleares e o projeto de Pesquisa Cooperativa que o viabilizou. A fibra de carbono com as características necessárias a empreendimentos desse tipo é um insumo de grande complexidade tecnológica. A produção é concentrada em alguns poucos produtores mundiais e seu comércio é alvo de restrições e salvaguardas internacionais. Não há produção no Brasil. É considerada material de uso dual, ou seja, pode ter tanto aplicações exclusivamente civis, como militares. A Marinha do Brasil utiliza essa fibra na fabricação de ultracentrífugas nucleares, nas quais materiais que conjuguem leveza, rigidez e resistência de alto nível são extremamente desejáveis, pois aumentam a eficiência na separação isotópica. Sua fibra de carbono, importada, é baseada na poliacrilonitrila (PAN), comercialmente mais difundida, mais barata e utilizada em aplicações similares. A necessidade de desenvolvimento nacional é decorrência de dificuldades em sua aquisição. Para tanto, foi organizada uma parceria de pesquisa entre o Centro Tecnológico da Marinha (CTMSP), a UNICAMP, a USP e a empresa RADICIFIBRAS, com apoio financeiro de uma agência governamental (FINEP), para a produção nacional de fibra de carbono baseada na PAN. A pesquisa realizada identificou as práticas de sucesso alcançadas, bem como os referenciais teóricos de Projetos de Pesquisa Cooperativa. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Adhesion promoters are traditionally used to improve the durability between an adhesive or any other organic phase, such as a sealant or a paint, and a metallic substrate. There are many different types of molecules which will act as adhesion promoters, but one class which has attracted considerable attention is that based on the organosilanes, such as y-aminotriethoxysilane, or y-glycidoxypropyl trimethoxysilane. Applications of such adhesion promoters are to be found in sealants, rubbers, primers in packaging and primers for coatings and adhesives. Organosilanes as adhesion promoters are widely used in industry, and until recently have been included in adhesive formulations in an empirical way, because it has been observed that the adhesive properties and hydrolytic stability can be improved. However recent work is leading to an understanding of how the silane molecules specifically interact with metallic and inorganic substrates. Little is known at the present time regarding the mode of operation of such molecules when applied to polymeric substrates. The purpose of the current work was to probe interaction of these molecules with low energy polymer substrates, for example, poly(methyl methacrylate) (PMMA) and poly(ethylene terephalate) (PET), using surface analysis techniques. Two factors which have been identified as controlling the adsorption of the organosilanes onto low energy substrates are the solution chemistry and the surface energy of the polymer. Both have been investigated extensively within this project. The latter was identified by means of investigating a series of substrates, with increasing polar contribution towards the surface free energy. The highest polar component was displayed by corona treated PET, which also displayed the highest levels of adsorption of organosilanes. Investigation of the adsorbed layer of the organosilane on the corona discharge treated PET has led to an understanding of the mechanism of the interaction of the molecules with all of the low energy substrates, and models for such interactions are proposed on the basis of spectroscopic observations.