A key part of the development of new polymeric materials focuses on the use of flame-retardant additives, which help to reduce the inherent flammability of polymers and the production of smoke and toxic gases. The aim of this thesis was the preparation, characterization and application of new polymeric flame-retardant additives, which can lead to intumescent systems when mixed with ¨commodity¨ polymers. The synthesis of this kind of additives was carried out by chemical modification of different polymeric structures (alcohols, polyketones, polyaziridines) with phosphorous moieties, previously described as promoting flame retardance structures, and/or nitrogen containing moieties. The efficacy of some of these additives was tested by blending with polypropylene, one of the most commonly used thermoplastic. Flame retardancy behaviour of the blends, as well their compatibility and mechanical properties were studied, in order to observe how the flame retardant additives may affect the substrate properties. / Una parte fundamental del desarrollo de nuevos materiales poliméricos se centra en la utilización de agentes retardantes a la llama, los cuales contribuyen a reducir la inherente combustibilidad de los polímeros y la producción de humos y de gases tóxicos. El objetivo del presente trabajo ha sido la preparación, characterización y aplicación de nuevos aditivos retardantes a la llama de tipo polimérico que pueden dar lugar al mezclarse con polímeros termoplásticos de gran consumo a sistemas de tipo intumescente. La síntesis de estos additivos se ha llevado a cabo por modificación química de diferentes estructuras polimericas (alcoholes, policetonas, poliaziridinas) con compuestos fosforados, descritos previamente como promotores de retardancia a la llama y/o compuestos con nitrogeno. La eficacidad de algunos de estos additivos ha sido estudiada por mezclarse con polipropileno, uno de los más utilizados termoplasticos.

No description available.

No description available.

There is no abstract available for this thesis. / Department of Chemistry

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Polímeros contendo anéis heterocíclicos, como o imidazol, possuem um grande interesse comercial e científico devido ao seu emprego em diversas áreas. Esses polímeros podem ser obtidos pela modificação química de polímeros comerciais como a poliacrilonitrila. Geralmente, esse tipo de reação é realizada por aquecimento convencional (térmico). Entretanto, mais recentemente, a irradiação por micro-ondas também começou a ser utilizada como fonte de energia para esse fim. Nesta Dissertação foi estudada, comparativamente, a modificação química da poliacrilonitrila comercial com etilenodiamina sob ativação de P2S5, empregando como fonte de aquecimento: o método convencional (térmico) e irradiação de micro-ondas, geradas em forno de micro-ondas doméstico e em reator de micro-ondas (Discover CEM), para produzir o copolímero de poliacrilonitrila e 2-vinil-imidazol. As reações foram efetuadas em diferentes tempos reacionais, em diferentes temperaturas no reator de micro-ondas e em diferentes potências do forno doméstico. Os copolímeros produzidos foram caracterizados por espectroscopia na região do infravermelho (FTIR) e por ressonância magnética de núcleo de hidrogênio (NMR-1H). A poliacrilonitrila foi modificada quimicamente com sucesso em todos os métodos empregados, como foi verificado pela sua análise de FTIR. Os melhores resultados obtidos foram: em 48 h de aquecimento térmico, 20 min de irradiação de micro-ondas em forno doméstico e 20 min a 80C em reator de micro-ondas, no entanto todas as análises indicaram uma derivatização abaixo de 10 % / Polymers containing heterocyclic rings such as imidazole, have a great scientific and commercial interest due to its use in several areas. Such polymers can be obtained by chemical modification of polymers such as polyacrylonitrile commercial. Generally, this type of reaction is carried out by conventional heating (thermal). However, more recently, the microwave irradiation is also being used as an energy source for this purpose. This thesis was studied in comparison, the chemical modification of the commercial polyacrylonitrile with ethylenediamine under activation P2S5, using as the heating source, the conventional method (heat) and the microwave radiation generated in a microwave oven for domestic and reactor micro-wave oven (CEM Discover) to produce the copolymer of polyacrylonitrile and 2-vinyl-imidazole. The reactions were carried out at different reaction times, temperatures in the reactor at different microwave powers and different domestic oven. The copolymers produced were characterized by infrared spectroscopy (FTIR) and nuclear magnetic resonance of hydrogen nucleus (NMR-1H). The polyacrylonitrile was chemically modified with success in all methods employed, as verified by its FTIR analysis. The best results were as follows: 48 h of thermal heating 20 min of irradiation of microwaves in domestic oven and 20 min at 80 C in a microwave reactor, however all analyzes indicated a derivatization below 10%

Le projet de thèse a permis de proposer des stratégies "verte" pour la modification chimique de nanofibrilles de cellulose (CNF) afin de leur conférer des propriétés antimicrobiennes. Sept différentes CNF fonctionnalisées ont été produites en tenant compte des principes de développement durable et de la faisabilité industrielle dans le domaine des emballages de nouvelles générations. Dans un premier temps, les CNF ont été fonctionnalisées avec de la cyclodextrine pour contrôler le relargage de molécules actives. Dans d'autres stratégies, des surfaces antimicrobiennes par contact ont été préparées en greffant des molécules naturelles ou en suivant les principes de biomimétisme. Les résultats sont très prometteurs et permettent l'obtention de surface clairement antimicrobienne sans relargage de molécules. Des caractérisations de grandes qualités ont confirmé ces greffages (par exemple, XPS, RMN, QCM-D) ainsi que les propriétés antimicrobiennes (par rapport à la S.aureus ou E.Coli). Une des meilleurs stratégies utilisant des CNF greffées avec des antibiotiques, a été produites à l'échelle laboratoire mais aussi implémentée à l'échelle semi-industrielle, avec pour objectif final la production d'emballages médicaux limitant les maladies nosocomiales. / The present investigation has developed efficient green strategies for the chemical modification of cellulose nanofibers (CNF), in order to impart antimicrobial activities. Seven different functionalized CNF was produced in this context keeping in mind sustainability and industrial feasibility within new generation packaging field. First, CNF was designed with cyclodextrin to control the release of natural active molecules. In other strategies, non-leaching contact active antimicrobial surfaces were prepared using natural active molecules or following biomimetic approaches. Results are very promising and allow obtaining efficient antimicrobial surface without any release. High level characterizations confirm surface grafting (e.g. XPS, QCM-D, NMR) and anti-microbial efficiency (S.aureus, E.Coli). One of the best strategies using antibiotic grafted CNF was produced at lab scale but also implemented at semi industrial scale. The final idea was to produce medical packages limiting the cross contamination in hospitals.

Notre étude aborde deux points importants sur les interactions supramoléculaires dans les polymères : tout d'abord comment des polymères peuvent s'assembler sur des surfaces planes au moyen de d'interactions de type hôte/invité, puis sur les interactions entre polymères à l'échelle de la molécule unique. En particulier nous verrons comment ces interactions à courte portée influent sur l'adhésion des chaînes sur des surfaces chimiquement contrôlées. Notre choix s'est porté sur un polymère d'origine naturelle le chitosane fonctionnalisé respectivement par des B-cyclodextrines (hôte) et des adamantanes (invité) et dont les assemblages forment des gels. Dans une première partie nous montrerons la possibilité de créer des multicouches de polymère par la méthode Layer-by-Layer (LbL) à l'aide des interactions de type hôte/invité, assemblage toutefois limité par les interactions électrostatiques au sein de la structure. Dans une seconde partie nous étudions les interactions multivalentes hôte/invité entre les couches de polymères en mesurant la force d'interaction par AFM. Nous avons pu mettre en évidence les différentes contributions à la force d'interaction et montrer que les interactions hôte//invités dominent les interactions non spécifiques d'un ordre de grandeur / In this study we focused on two important points concerning supramolecular interactions in polymeric systems. First; how polymers self-assemble on planar surfaces through side-chain host-guest interactions. Second; how those polymers interact each other at the level of single chain and how the adhesion properties of polymers on the modified surfaces can be controlled with those short ranged specific interactions. For that purpose a natural polysaccharide, chitosan, was chosen as the polymeric backbone and was specifically modified with host (B-cyclodextrin) and guest (adamanatane) molecules. It is known that those modified polysaccharides interact each other through host-guest units and their supramolecular assemblies exhibiting a gel-like behavior in solution state. In the first part of the study we investigated the feasibility to use supramolecular interactions to construct functional polymer multilayers by using the Layer-by-Layer (LbL) self assembly approach. The driving force with the proposed system is host-guest interactions thus short ranged and sterically demanding as the structural fitting is necessary. Our results show that multiple host-guest interactions along the chitosan chain allow the self assembles of the modified chitosans on guest-attached surfaces. The number of layers is limited and possibly affected by the electrostatic charge of the chitosan backbone. In the second part of the study we used atomic force microscope (AFM) to probe the multivalent host-guest interactions between modified polymer layers by direct force measurement. By this technique, the main contributions to the interaction between modified chitosan layers could be identified. Adhesion properties of the modified chitosans have also been investigated. The work of adhesion is about an order of magnitude larger for those chitosan derivatives that can form host-guest complexes than for those where this is not possible.

This thesis describes the design, synthesis and application of artificial metalloenzymes for transition metal catalysed reactions not performed by natural enzymes. Unique cysteine containing protein templates were covalently modified with transition metal ligand complexes that generate catalytic activity, which allows for the use of virtually any protein template. SCP-2L was selected as template for the linear hydrophobic tunnel that traverses the protein, which has high affinity for linear aliphatic molecules. The use of catalysts based on this protein to induce increased activity in the biphasic hydroformylation of linear α-olefins is investigated in this work. For this purpose, unique cysteine containing mutants of SCP-2L were modified with phosphine ligands by application of a novel bioconjugation procedure. Application of rhodium adducts of the phosphine modified protein constructs led to up to a 100 fold increase of the turn over numbers was measured compared to a Rh/TPPTS model system which is used in industry. Furthermore, good selectivity towards the linear product was observed. If it can be confirmed that the found catalytic results truly are the result of substrate encapsulation by the protein scaffold, this system represents the first rationally designed artificial metalloenzyme which exploits the shape selectivity of the protein scaffold to direct the outcome of a catalytic reaction. In addition, a study was performed for the development of enantioselective artificial metalloenzymes. Nitrogen ligands were covalently introduced in SCP-2L and the obtained conjugates were applied in the copper catalysed Diels-Alder and Michael addition reaction. A promising 25% ee was found for the Diels-Alder reaction between azachalcone and cyclopentadiene using one of the created constructs. Further development of these catalyst systems with the use of both synthetic (e.g. optimisation of ligand structure) and biomolecular tools (e.g. optimisation of protein environment) for optimisation can lead to very efficient and enantioselective conversions in the future.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Polímeros contendo anéis heterocíclicos, como o imidazol, possuem um grande interesse comercial e científico devido ao seu emprego em diversas áreas. Esses polímeros podem ser obtidos pela modificação química de polímeros comerciais como a poliacrilonitrila. Geralmente, esse tipo de reação é realizada por aquecimento convencional (térmico). Entretanto, mais recentemente, a irradiação por micro-ondas também começou a ser utilizada como fonte de energia para esse fim. Nesta Dissertação foi estudada, comparativamente, a modificação química da poliacrilonitrila comercial com etilenodiamina sob ativação de P2S5, empregando como fonte de aquecimento: o método convencional (térmico) e irradiação de micro-ondas, geradas em forno de micro-ondas doméstico e em reator de micro-ondas (Discover CEM), para produzir o copolímero de poliacrilonitrila e 2-vinil-imidazol. As reações foram efetuadas em diferentes tempos reacionais, em diferentes temperaturas no reator de micro-ondas e em diferentes potências do forno doméstico. Os copolímeros produzidos foram caracterizados por espectroscopia na região do infravermelho (FTIR) e por ressonância magnética de núcleo de hidrogênio (NMR-1H). A poliacrilonitrila foi modificada quimicamente com sucesso em todos os métodos empregados, como foi verificado pela sua análise de FTIR. Os melhores resultados obtidos foram: em 48 h de aquecimento térmico, 20 min de irradiação de micro-ondas em forno doméstico e 20 min a 80C em reator de micro-ondas, no entanto todas as análises indicaram uma derivatização abaixo de 10 % / Polymers containing heterocyclic rings such as imidazole, have a great scientific and commercial interest due to its use in several areas. Such polymers can be obtained by chemical modification of polymers such as polyacrylonitrile commercial. Generally, this type of reaction is carried out by conventional heating (thermal). However, more recently, the microwave irradiation is also being used as an energy source for this purpose. This thesis was studied in comparison, the chemical modification of the commercial polyacrylonitrile with ethylenediamine under activation P2S5, using as the heating source, the conventional method (heat) and the microwave radiation generated in a microwave oven for domestic and reactor micro-wave oven (CEM Discover) to produce the copolymer of polyacrylonitrile and 2-vinyl-imidazole. The reactions were carried out at different reaction times, temperatures in the reactor at different microwave powers and different domestic oven. The copolymers produced were characterized by infrared spectroscopy (FTIR) and nuclear magnetic resonance of hydrogen nucleus (NMR-1H). The polyacrylonitrile was chemically modified with success in all methods employed, as verified by its FTIR analysis. The best results were as follows: 48 h of thermal heating 20 min of irradiation of microwaves in domestic oven and 20 min at 80 C in a microwave reactor, however all analyzes indicated a derivatization below 10%

Cette thèse s'inscrit dans le contexte de l'exploitation des matériaux bio-sourcés dans des applications à haute valeur ajoutée et vise à valoriser un produit de transformation d'une plante herbacée appelée Alfa ou « Stipa tenacissima », très abondante en Tunisie. L'idée principale de ce travail est d'étudier et d'exploiter les pâtes d'Alfa produites à l'échelle industrielle, dans l'objectif de rechercher de nouvelles voies de valorisation. L'application potentielle envisagée concerne l'utilisation des fibres d'Alfa comme éléments de renfort dans des bio-composites à base de matrices polymères. Après une synthèse bibliographique, la première partie de ce travail a été consacrée à l'étude des tiges et des pâtes d'Alfa (caractérisations chimiques, analyses morphologiques, mesure des charges électriques, cinétiques de raffinage des pâtes, etc.). En outre, l'effet du raffinage sur les propriétés physiques des papiers produits à partir des fibres d'Alfa a été étudié. Dans un second temps, nous nous sommes intéressés à la valorisation des fibres d'Alfa, transformées en papier, comme renfort dans des composites à matrices polymères biodégradables. Nous avons choisi une technique d'imprégnation des papiers préparés dans des solutions de polymères biodégradables pour l'élaboration de ces composites et nous avons étudié deux polymères : la polycaprolactone (PCL) et l'acide L-polylactique (PLLA). Les propriétés structurales, morphologiques, thermiques et mécaniques de ces nouveaux composites ont été analysées et discutées. Par ailleurs, nous avons proposé une méthode originale de modification de surface des fibres d'Alfa selon un protocole simple à trois séquences, combinant un traitement par micro-ondes et un traitement chimique des papiers préparés. Enfin, l'effet de cette modification de surface du renfort sur les propriétés des composites a été évalué et analysé. / This thesis aims at valorizing herbaceous plant called Alfa or "Stipa tenacissima" in added value application. This raw material is very abundant in Tunisia. Thus, the main idea of this work is to use Alfa fibers as reinforcing elements in polymer matrices-based bio-composites The literature review revealed that this plant has not been extensively studied, which motivated undertaking a comprehensive study of these fibers. Thus, a systematic and deep study of the chemical composition, the morphological properties, the electrical charges, the kinetics of pulp refining as well as the physical properties of the paper produced from these fibers was performed and gave several rational insights on Alfa fibers in the context of papermaking. The second part was devoted to the use of Alfa fibers, as reinforcing fiber mat in composite materials based on biodegradable polymer matrices. In this context, we have chosen an impregnation technique of the prepared paper films in solutions of two biodegradable polymers: polycaprolactone (PCL) and poly-L-lactide (PLLA). The structural, morphological, thermal and mechanical properties of these new composites were analyzed and discussed. In addition, we have proposed an original microwave-assisted grafting of surface chemical modification of Alfa fibers. In this context, stearic acid was used as a coupling agent. Finally, the effect of the surface modification of the reinforcement on composites properties was assessed and analyzed.