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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

Preparação e caracterização de eletrólitos sólidos poliméricos a partir dos derivados de celulose - hidroxietilcelulose e hidroxipropilcelulose / Preparation and characterization of solid polymeric electrolytes based on hydroxypropylcellulose and hydroxyethlcellulose

Machado, Gilmara de Oliveira 19 April 2004 (has links)
Esta tese apresenta os resultados da obtenção de eletrólitos sólidos poliméricos a partir dos derivados de celulose - hidroxipropilcelulose (HPC) e hidroxietilcelulose (HEC), ambas comerciais. Para atingir os objetivos do projeto, os dois derivados passaram por diferentes processos sendo que a HEC foi modificada fisicamente por meio de plastificação com glicerol e HPC foi alterada quimicamente. A transformação química consistiu nas reações de oxidação de grupos hidroxila da HPC em grupos cetona que, em seguida, foram submetidos as reações de enxertia com diamina de poli(óxido de propileno) [Jeffamina] resultando em redes por meio de ligações imina. A adição do sal perclorato de lítio, em diferentes concentrações, na matriz plastificada ou entrecruzada, resultou na obtenção de eletrólitos sólidos poliméricos, todos na forma de filmes. A caracterização destes eletrólitos foi realizada com técnicas básicas de caracterização de materiais como: análises térmicas (DSC, TGA), análise térmica dinâmico-mecânica (DMTA), análises estruturais (raios-X), medidas espectroscópicas (IR, UVNIS), análise elementar, microscopia eletrônica de varredura (SEM), e, como a mais importante, medidas de condutividade iônica utilizando a técnica de espectroscopia de impedância eletroquímica (EIS). / The present thesis reports the preparation and characterization of new types of solid polymeric electrolytes (SPE) based on cellulose derivatives such as hydroxypropylcellulose (HPC) and hydroxyethylcellulose (HEC), both commercial products. Aiming to reach this purpose both derivatives were subjected to modification processes, where HEC were physically modified by plasticization process with glycerol and HPC were submitted to chemical reactions. The latter ones were promoted by the oxidation of HPC hydroxyl groups and ketone groups and then subjected to grafting with diamine poly(propylene oxide) (Jeffamine), resulting in the imine bond network formation. Different concentrations of lithium salt were added to the plasticized and grafted samples, resulting in solid polymeric electrolytes, all in the film form. The characterization of these samples was performed by thermal analysis (DSC, TGA and DMTA), X-ray diffraction (XDR), scanning electron microscopy (SEM), ultraviolet/visible/near-infrared spectroscopy (UV/Vis/NIR) and, as most important, measured of ionic conductivity using the technique of electrochemical impedance spectroscopy (EIS).
2

Preparação e caracterização de eletrólitos sólidos poliméricos a partir dos derivados de celulose - hidroxietilcelulose e hidroxipropilcelulose / Preparation and characterization of solid polymeric electrolytes based on hydroxypropylcellulose and hydroxyethlcellulose

Gilmara de Oliveira Machado 19 April 2004 (has links)
Esta tese apresenta os resultados da obtenção de eletrólitos sólidos poliméricos a partir dos derivados de celulose - hidroxipropilcelulose (HPC) e hidroxietilcelulose (HEC), ambas comerciais. Para atingir os objetivos do projeto, os dois derivados passaram por diferentes processos sendo que a HEC foi modificada fisicamente por meio de plastificação com glicerol e HPC foi alterada quimicamente. A transformação química consistiu nas reações de oxidação de grupos hidroxila da HPC em grupos cetona que, em seguida, foram submetidos as reações de enxertia com diamina de poli(óxido de propileno) [Jeffamina] resultando em redes por meio de ligações imina. A adição do sal perclorato de lítio, em diferentes concentrações, na matriz plastificada ou entrecruzada, resultou na obtenção de eletrólitos sólidos poliméricos, todos na forma de filmes. A caracterização destes eletrólitos foi realizada com técnicas básicas de caracterização de materiais como: análises térmicas (DSC, TGA), análise térmica dinâmico-mecânica (DMTA), análises estruturais (raios-X), medidas espectroscópicas (IR, UVNIS), análise elementar, microscopia eletrônica de varredura (SEM), e, como a mais importante, medidas de condutividade iônica utilizando a técnica de espectroscopia de impedância eletroquímica (EIS). / The present thesis reports the preparation and characterization of new types of solid polymeric electrolytes (SPE) based on cellulose derivatives such as hydroxypropylcellulose (HPC) and hydroxyethylcellulose (HEC), both commercial products. Aiming to reach this purpose both derivatives were subjected to modification processes, where HEC were physically modified by plasticization process with glycerol and HPC were submitted to chemical reactions. The latter ones were promoted by the oxidation of HPC hydroxyl groups and ketone groups and then subjected to grafting with diamine poly(propylene oxide) (Jeffamine), resulting in the imine bond network formation. Different concentrations of lithium salt were added to the plasticized and grafted samples, resulting in solid polymeric electrolytes, all in the film form. The characterization of these samples was performed by thermal analysis (DSC, TGA and DMTA), X-ray diffraction (XDR), scanning electron microscopy (SEM), ultraviolet/visible/near-infrared spectroscopy (UV/Vis/NIR) and, as most important, measured of ionic conductivity using the technique of electrochemical impedance spectroscopy (EIS).
3

Fonctionnalisation de polymères et applications dans les domaines de l’énergie, de la catalyse, de la cosmétique et de la santé / Functionalization of polymers and applications in the fields of energy, catalysis and health

Morizur, Vincent 03 December 2014 (has links)
Les polymères sont à l’heure actuelle étudiés dans de nombreux domaines comme la chimie, la biochimie, les nanotechnologies, l'électronique, la médecine ou encore les sciences des matériaux et trouvent des applications dans des domaines comme l’industrie automobile, la chimie fine. L’objectif de cette thèse est de réaliser la fonctionnalisation de polymères et de modifier les propriétés de ces matériaux afin d’envisager des nouvelles applications. Nous nous sommes intéressés à des polymères de la famille des poly(aryle éther) et plus particulièrement au poly(éther éther cétone) (PEEK). Ce polymère est connu pour ses propriétés mécaniques, thermiques, électriques ou encore pour sa résistance aux produits chimiques. Dans le premier chapitre, il est question de la fonctionnalisation des différents polymères de départ par des fonctions chlorures de sulfonyle, acides sulfoniques et sulfonamides. Le second chapitre est consacré à la synthèse et à l’étude électrochimique de nouveaux électrolytes polymériques et à de nouvelles membranes pour d’éventuelles applications dans le domaine des batteries au lithium et au sodium, ainsi que dans le domaine des piles à combustible. Dans un troisième chapitre, la préparation de nouveaux catalyseurs métalliques dérivés d’acides sulfoniques polymériques est discutée. Une étude de l’activité catalytique de ces différents catalyseurs a été réalisée sur la réaction d’acylation de Friedel-Crafts. Le quatrième chapitre est consacré à la préparation de nouveaux matériaux ayant des propriétés optiques intéressantes. Enfin dans un cinquième chapitre, la préparation et l’étude de nouveaux matériaux ayant des propriétés antibactériennes sont exposées. / Polymers are now being studied in many fields such as chemistry, biochemistry, nanotechnology, electronics, medicine or material science and have applications in areas such as automotive industry, food industry, fine chemistry. The objective of this thesis is to achieve the functionalization of polymers and modify the properties of these materials in order to consider new applications. We were interested in polymers with the poly(aryl ether) motif, more particularly poly(ether ether ketone) (PEEK). This polymer is known for its mechanical, thermal, electrical properties and for its resistance to chemicals. In the first chapter, we present the functionalization of different polymers by sulfonyl chloride, sulfonic acid and sulfonamide functions. The second chapter is devoted to the synthesis and electrochemical study of novel polymeric electrolytes and new membranes for potential applications in the field of lithium and sodium batteries, as well as in the field of fuel cells. In the third chapter, the preparation of new metal catalysts derived from polymeric sulfonic acids is discussed. A study of the catalytic activity of these different polymeric catalysts was carried out on the Friedel-Crafts acylation reaction. The fourth chapter is devoted to the preparation of new materials with interesting optical properties. Finally, in the fifth chapter, the preparation and the study of new materials with antibacterial properties are reported.

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