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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

Síntese e estudo de materiais poliméricos baseados em polimetacrilamida para remoção de metais pesados de soluções aquosas / Synthesis and study of polymers for removal of heavy metals to aqueous solutions

Castro, Rafael Theotonio de 20 February 2018 (has links)
A poluição de corpos d´água por metais pesados é um problema mundial, mas particularmente importante em países que apresentam atividades intensas de mineração, como o Brasil. Os contaminantes, de maneira especial aqueles conhecidos como metais pesados, podem apresentar toxicidade altíssima, como é o caso do cádmio, chumbo e outros. Por esse motivo, os efluentes industriais, quando não devidamente tratados, ainda são uma grande fonte de contaminação do ecossistema que vivemos. Diante dessa atual situação, esforços para o aprimoramento de técnicas de remoção de cátions de metais pesados da água são necessárias e podem ter impacto positivo na Saúde Pública e em outras áreas. Portanto, como solução viável e alternativa para o que já se é feito, o presente projeto propõe a produção e estudo do uso de materiais poliméricos com propriedades distintas para captação de metais pesados de soluções aquosas. Para a síntese dos polímeros foram usadas técnicas de polimerização via radical livre, e posterior hidrólise para geração de copolímeros, com o intuito de aperfeiçoar a capacidade de remoção. Os polímeros tiveram como base a metacrilamida que tem a presença do grupo funcional amida e, após hidrólise, a geração de unidade de ácido metacrílico com presença do grupo funcional de ácido carboxílico, ambos os grupos quando combinados possuem uma elevada capacidade de adsorção de cátions. Paralelamente foi aperfeiçoado um sistema de remoção de cátions de solução aquosa usando polímeros confinados em membranas de diálise. A influência da massa molar média, do grau de hidrólise e da presença do grupo funcional de ácido carboxílico foi estudada. Por fim, foi realizado um estudo da capacidade máxima de remoção de Cu(II), em que os parâmetros temperatura, pH da solução, velocidade e tempo de agitação foram fixados. A capacidade máxima de remoção dos íons de Cu(II) variou entre 1,55-1,71 mmol/g para os copolímeros sintetizados e hidrolisados em laboratório, para o copolímero comercial obteve-se um valor de 2,17 mmol/g, e para o copolímero sintetizado diretamente por PRL a partir dos monômeros metacrilamida e ácido metacrílico a capacidade de máxima de captação foi de 3,87 mmol/g , a partir dos resultados foi possível observar uma relação positiva entre a massa molar média das cadeias e a capacidade de ligação aos cátions metálicos. Foi comprovado também que a presença do ácido metacrílico na cadeia polimérica é fundamental para o aumento da capacidade de ligação do cobre. A partir desses estudos foi possível concluir que os polímeros sintetizados e imobilizados em sacos de diálise são eficientes na remoção de íons de Cu(II), Cd(II) e Pb(II) de soluções aquosas, sendo que o estudo da capacidade de remoção dos outros dois cátions Cd (II) e Pb (II) são perspectivas futuras para estudo. No trabalho, destaca-se, além da eficiência, a praticidade do uso do método desenvolvido. / The water pollution by heavy metals is a worldwide problem, but particularly important in countries with intensive mining activities, such as Brazil. Contaminants, especially those known as heavy metals, such as cadmium, lead and others, may have very high toxicity. For this reason, industrial effluents, when not properly treated, are still a big source of contamination of the ecosystem we live in. In order to deal with this current situation, it is necessary to improve metallic cation removal techniques from water what may have a positive impact on Public Health and other areas. Therefore, as a feasible and alternative solution to current metal removal techniques, the present project proposes the production and study of polymeric materials based on partially hidrolised polymethacrylamide with different characteristic for the capture of heavy metals in aqueous solutions. Free radical polymerization techniques were used to synthesize the polymers followed by hydrolysis for the copolymers generation, in order to improve the removal capacity. The amide functional group and, after hydrolysis, the carboxylic group when combined have a high cation adsorption capacity. At the same time, a cation removal system that uses polymers entrapped in a dialysis membrane was improved. The influence of the average molar mass, degree of hydrolysis and the presence of the carboxylic acid functional group was studied. Finally, a study of the maximum Cu (II) removal capacity was carried out, in which the parameters of temperature, solution pH, speed and agitation time were fixed. The maximum removal capacity of Cu (II) ions ranged from 1.55-1.71 mmol/g for the copolymers synthesized and hydrolyzed in the laboratory, the commercial copolymer yielded a value of 2.17 mmol/g, and for the copolymer directly synthesized by PRL from the methacrylamide and methacrylic acid monomers the maximum capacity was 3.87 mmol/g. From the results it was possible to observe a positive relation between the average molar mass of the chains and the ability to connect to the metal cations. It has also been proven that the presence of methacrylic acid in the polymer chain is fundamental for increasing the copper bonding capacity. From these studies it was possible to conclude that both polymers synthesized and immobilized in dialysis bags are efficient in the removal of Cu (II), Cd (II) and Pb (II) ions from aqueous solutions, and the study of the ability to remove the other two cations Cd (II) and Pb (II) are perspectives to future studies. In the work, it is highlighted, besides the efficiency, the convenience of the developed method.
2

Síntese e estudo de materiais poliméricos baseados em polimetacrilamida para remoção de metais pesados de soluções aquosas / Synthesis and study of polymers for removal of heavy metals to aqueous solutions

Rafael Theotonio de Castro 20 February 2018 (has links)
A poluição de corpos d´água por metais pesados é um problema mundial, mas particularmente importante em países que apresentam atividades intensas de mineração, como o Brasil. Os contaminantes, de maneira especial aqueles conhecidos como metais pesados, podem apresentar toxicidade altíssima, como é o caso do cádmio, chumbo e outros. Por esse motivo, os efluentes industriais, quando não devidamente tratados, ainda são uma grande fonte de contaminação do ecossistema que vivemos. Diante dessa atual situação, esforços para o aprimoramento de técnicas de remoção de cátions de metais pesados da água são necessárias e podem ter impacto positivo na Saúde Pública e em outras áreas. Portanto, como solução viável e alternativa para o que já se é feito, o presente projeto propõe a produção e estudo do uso de materiais poliméricos com propriedades distintas para captação de metais pesados de soluções aquosas. Para a síntese dos polímeros foram usadas técnicas de polimerização via radical livre, e posterior hidrólise para geração de copolímeros, com o intuito de aperfeiçoar a capacidade de remoção. Os polímeros tiveram como base a metacrilamida que tem a presença do grupo funcional amida e, após hidrólise, a geração de unidade de ácido metacrílico com presença do grupo funcional de ácido carboxílico, ambos os grupos quando combinados possuem uma elevada capacidade de adsorção de cátions. Paralelamente foi aperfeiçoado um sistema de remoção de cátions de solução aquosa usando polímeros confinados em membranas de diálise. A influência da massa molar média, do grau de hidrólise e da presença do grupo funcional de ácido carboxílico foi estudada. Por fim, foi realizado um estudo da capacidade máxima de remoção de Cu(II), em que os parâmetros temperatura, pH da solução, velocidade e tempo de agitação foram fixados. A capacidade máxima de remoção dos íons de Cu(II) variou entre 1,55-1,71 mmol/g para os copolímeros sintetizados e hidrolisados em laboratório, para o copolímero comercial obteve-se um valor de 2,17 mmol/g, e para o copolímero sintetizado diretamente por PRL a partir dos monômeros metacrilamida e ácido metacrílico a capacidade de máxima de captação foi de 3,87 mmol/g , a partir dos resultados foi possível observar uma relação positiva entre a massa molar média das cadeias e a capacidade de ligação aos cátions metálicos. Foi comprovado também que a presença do ácido metacrílico na cadeia polimérica é fundamental para o aumento da capacidade de ligação do cobre. A partir desses estudos foi possível concluir que os polímeros sintetizados e imobilizados em sacos de diálise são eficientes na remoção de íons de Cu(II), Cd(II) e Pb(II) de soluções aquosas, sendo que o estudo da capacidade de remoção dos outros dois cátions Cd (II) e Pb (II) são perspectivas futuras para estudo. No trabalho, destaca-se, além da eficiência, a praticidade do uso do método desenvolvido. / The water pollution by heavy metals is a worldwide problem, but particularly important in countries with intensive mining activities, such as Brazil. Contaminants, especially those known as heavy metals, such as cadmium, lead and others, may have very high toxicity. For this reason, industrial effluents, when not properly treated, are still a big source of contamination of the ecosystem we live in. In order to deal with this current situation, it is necessary to improve metallic cation removal techniques from water what may have a positive impact on Public Health and other areas. Therefore, as a feasible and alternative solution to current metal removal techniques, the present project proposes the production and study of polymeric materials based on partially hidrolised polymethacrylamide with different characteristic for the capture of heavy metals in aqueous solutions. Free radical polymerization techniques were used to synthesize the polymers followed by hydrolysis for the copolymers generation, in order to improve the removal capacity. The amide functional group and, after hydrolysis, the carboxylic group when combined have a high cation adsorption capacity. At the same time, a cation removal system that uses polymers entrapped in a dialysis membrane was improved. The influence of the average molar mass, degree of hydrolysis and the presence of the carboxylic acid functional group was studied. Finally, a study of the maximum Cu (II) removal capacity was carried out, in which the parameters of temperature, solution pH, speed and agitation time were fixed. The maximum removal capacity of Cu (II) ions ranged from 1.55-1.71 mmol/g for the copolymers synthesized and hydrolyzed in the laboratory, the commercial copolymer yielded a value of 2.17 mmol/g, and for the copolymer directly synthesized by PRL from the methacrylamide and methacrylic acid monomers the maximum capacity was 3.87 mmol/g. From the results it was possible to observe a positive relation between the average molar mass of the chains and the ability to connect to the metal cations. It has also been proven that the presence of methacrylic acid in the polymer chain is fundamental for increasing the copper bonding capacity. From these studies it was possible to conclude that both polymers synthesized and immobilized in dialysis bags are efficient in the removal of Cu (II), Cd (II) and Pb (II) ions from aqueous solutions, and the study of the ability to remove the other two cations Cd (II) and Pb (II) are perspectives to future studies. In the work, it is highlighted, besides the efficiency, the convenience of the developed method.
3

Optimisation d'un vecteur en immunothérapie avec les cellules dendritiques : micelles de copolymères à blocs double-hydrophiles / Optimization of a vector for immunotherapy with dendritic cells : double hydrophilic block copolymer micelles

Mebarek, Naila 06 December 2013 (has links)
L'objectif de cette thèse repose sur le développement de micelles de polymères polyioniques, vecteurs de molécules thérapeutiques en immunothérapie avec des cellules dendritiques (DCs). Elles sont préparées à partir d'un copolymère à blocs double-hydrophiles, l'acide polyméthacrylique-b-polyoxyde d'éthylène (PMAA-b-POE) et d'un contre ion de charge opposée. De taille nanométrique, elles sont capables d'encapsuler des molécules thérapeutiques selon une association tripartite originale et de se désassembler à pH acide pour permettre leur libération dans le milieu endosomal.Le premier axe de travail a porté sur l'évaluation de la propriété des copolymères à induire un échappement endosomal en fonction de leur masse molaire en utilisant deux modèles membranaires (liposomes et globules rouges). La complexation des copolymères de masses molaires différentes avec la poly-L-lysine comme contre-ion a permis l'obtention de micelles avec des propriétés d'échappement endosomal variables. Cette propriété est intéressante car en fonction de la stratégie thérapeutique adoptée, elle orientera le choix de la masse molaire du copolymère pour la formulation des micelles.Le second axe a consisté en l'application de ces micelles pour la vectorisation d'un peptide modèle (peptide OVA) dans les DCs. La capacité des micelles à encapsuler le peptide et à le libérer au niveau des compartiments endosomaux a été évaluée par des techniques de spectrofluorimétrie et de microscopie confocale. Enfin, l'efficacité de présentation du peptide formulé dans les différentes micelles a été mise en évidence et a montré l'amélioration de la présentation par les DCs du peptide formulé dans les micelles comparé au peptide non formulé. Cette présentation est nettement supérieure en utilisant les micelles composées de copolymères de masse molaire élevée qui n'entraînent pas d'échappement endosomal.Le troisième axe de recherche a reposé sur la transfection des DCs avec des micelles de siRNA dirigés contre la protéine de surface CD86. Seules les micelles composées de copolymères de faible masse molaire ont permis l'encapsulation du siRNA et la baisse de l'expression de la protéine CD86 à la surface des DCs. Afin d'optimiser la capacité des micelles à encapsuler et transfecter les DCs, la formulation des micelles a été optimisée en remplaçant la PLL par un autre polycation la polyethylene imine PEI. Ces micelles polyioniques à base de copolymère PMAA-b-POE apparaissent donc comme des vecteurs de molécules d'intérêt thérapeutique prometteurs pour les cellules dendritiques en immunothérapie ou en thérapie génique. / The aim of the thesis work is based on the development of polymeric micelles vectors of therapeutic molecules in immunotherapy with dendritic cells (DCs). They are composed of a double hydrophilic blocks copolymers, poly(methacrylic acid)-b-poly(ethylene oxide) (PMAA-b-PEO) and an oppositely charged polyion. They are caracterized by a nanometric size, a capacity to encapsulate therapeutic molecules according to a tripartite association and are able to disassemble at acidic pH allowing the release of their cargo.The first part of this work has focused on the evaluation of the endosomal escape property of copolymers based on their molecular weight by using two membrane models (liposomes and red blood cells). Complexation of different molecular weight copolymers with poly- L- lysine as counter ion allowed the formation of micelles with variable endosomal escape properties. This property is interesting because according to the adopted therapeutic strategy, it will guide the choice of the copolymer micelles for formulation.The second part consisted of the application of these micelles for the vectorization of a model peptide (OVA peptide) in DCs. The ability of micelles to encapsulate and release this peptide in the endosomal compartments was assessed by fluorescence spectroscopy and confocal microscopy techniques. Finally, the effectiveness of the OVA presentation formulated in the different type of micelles has been demonstrated and shown that the peptide presentation by DCs was improved when it was formulated in micelles compared to unformulated peptide. This presentation was much higher using micelles composed of high molecular weight copolymers that do not involve endosomal escape.The third part of the research was based on the transfection of DCs with siRNA directed against CD86 protein surface. Only micelles composed of low molecular weight copolymers allowed the encapsulation of siRNA molecules and decreased the expression of CD86 protein on DCs surface. To increase the ability of micelles to encapsulate and transfect DCs, the micelle formulation was optimized by changing the PLL with another polycation PEI.These polyion micelles based PMAA-b-PEO copolymers appear as vectors of therapeutic molecules for promising strategies with dendritic cells such as vaccination and gene therapy.
4

Термодинамика взаимодействия полиакриламида с полиакриловой и полиметакриловой кислотами : магистерская диссертация / Thermodynamics of the interaction of polyacrylamide with polyacrylic and polymethacrylic acids

Манас Кызы, А., Manas Kyzy, A. January 2020 (has links)
С помощью объемного варианта сорбционного метода изучена сорбция воды пленками ПАА, ПАК, ПМАК и смесями ПАА-ПАК, ПАА-ПМАК разного состава. Измерены теплоты смешения образцов с водой с использованием микрокалориметра типа Тиана-Кальве. Рассчитаны разности химических потенциалов воды ∆µ1, полимеров и смесей ∆µ2, энергии Гиббса смешения полимеров с водой ∆gm. Определены энергии Гиббса, энтальпии и энтропии смешения компонентов в полимерных композициях. Показано, что сорбционная способность систем ПАА-ПАК, ПАА-ПМАК определяется их структурой и сродством к воде. ПАК ведет себя как плотноупакованный полимер, имеющий высокое сродство к воде, а сорбция воды ПМАК свидетельствует о менее плотной упаковке цепей и меньшему сродству к воде. Сорбция воды смесями немонотонно изменяется с составом композиции. Установлено, что смешение всех систем с водой сопровождается уменьшением энергий Гиббса (Δgm < 0), величина ∂2g/∂ω22 > 0, что указывает на образование термодинамически устойчивых систем. Чем б льше сорбционная способность полимера или смеси, тем более отрицательны величины Δgm. Обнаружено, что растворение в воде всех изученных систем сопровождается экзотермическим тепловым эффектом. Отклонения энтальпий смесей от аддитивности положительны для всех систем кроме смеси ПАА-ПМАК с ωПАА < 0,2, что свидетельствует о хорошем взаимодействии полимеров друг с другом. Установлено, что энергии Гиббса смешения ПАА с ПАК и ПМАК полученные двумя методами: с помощью расчета по энергиям Гиббса растворения систем и с помощью уравнения Флори-Хаггинса, хорошо коррелируют друг с другом. Показано, что что смешение ПАА с ПАК сопровождается экзотермическим тепловым эффектом во всей области составов и уменьшением энергии Гиббса вплоть до содержания 90% ПАА. При этом ∆gx и ∆hx близки по величине, и энтропийный вклад в совместимость компонентов T∆sx очень невелик. Таким образом, термодинамическая совместимость ПАА с ПАК обусловлена, главным образом, энергетическим взаимодействием компонентов. Обнаружено, что смеси ПАА-ПМАК образуются с отрицательной энергией Гиббса смешения (∆gx<0) и знакопеременной энтальпией смешения: при содержании ПАА менее 20% ∆hx > 0,а при содержании более 20% – ∆hx<0. Энтропия смешения положительна во всей области составов. / Using the volumetric version of the sorption method, water sorption was studied with PAM, PAA, PMAA films and PAM-PAA, PAM-PMAA mixtures of various compositions. The heats of mixing samples with water were measured using a Tiana-Calve type microcalorimeter. The differences between the chemical potentials of water ∆µ1, polymers and mixtures ∆µ2, Gibbs energy of mixing polymers with water ∆gm are calculated. The Gibbs energies, enthalpy, and entropy of mixing of the components in polymer compositions are determined. It was shown that the sorption ability of PAM-PAA, PAM-PMAK systems is determined by their structure and affinity for water. PAA behaves as a close-packed polymer with a high affinity for water, and the sorption of PMAA water indicates a less dense packing of chains and a lower affinity for water. Sorption of water mixtures non-monotonously changes with the composition. It was found that the mixing of all systems with water is accompanied by a decrease in Gibbs energies (Δgm <0), the value ∂2g/∂ω22> 0, which indicates the formation of thermodynamically stable systems. The greater the sorption capacity of the polymer or mixture, the more negative the Δgm values. It was found that dissolution of all the studied systems in water is accompanied by an exothermic thermal effect. Deviations of the enthalpies of the mixtures from additivity are positive for all systems except the PAM-PMAA mixture with ωPAM <0.2, which indicates a good interaction of the polymers with each other. It was established that the Gibbs energies of mixing PAM with PAA and PMAA were obtained by two methods: using the Gibbs energies of dissolution of systems and using the Flory-Huggins equation, they correlate well with each other. It was shown that the mixing of PAM with PAA is accompanied by an exothermic thermal effect in the entire composition range and a decrease in Gibbs energy up to the content of 90% PAM. Moreover, ∆gx and ∆hx are close in magnitude, and the entropy contribution to the compatibility of the components of T∆sx is very small. Thus, the thermodynamic compatibility of PAM with PAA is mainly due to the energy interaction of the components. It was found that PAM-PMAA mixtures are formed with a negative Gibbs mixing energy (∆gx <0) and an alternating mixing enthalpy: with a PAM content of less than 20%, ∆hx> 0, and with a content of more than 20%, ∆hx <0. The entropy of mixing is positive throughout the composition field.

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