Cette thèse porte sur le traitement de la farine de bois et son utilisation comme renforts de composites à matrice polymère. En effet, l’incompatibilité entre le bois, hydrophile, et les polymères, généralement hydrophobes, est la principale difficulté de mise en oeuvre des composites bois-polymère. Un traitement des renforts bois est alors nécessaire pour améliorer les propriétés mécaniques et hygroscopiques des composites. Un traitement par fluoration directe est ici proposé pour diminuer le caractère hydrophile du bois et augmenter son adhésion avec la matrice polymère. Après une phase de développement et de réglage du traitement, une caractérisation physico-chimique de la farine de bois non-traitée ou fluorée a été réalisée afin d’observer l’effet de la fluoration. Le greffage de fluor sur les constituants du bois a été validé, et une diminution du nombre des sites de sorption de l’eau dans le bois a été constatée. Cette réduction a conduit à une diminution de la teneur en eau du bois après fluoration. En outre, la structure physique des particules et le comportement thermique du bois n’ont pas été modifiés par le traitement. Des composites bois-polyester ont été fabriqués par moulage par compression à chaud, avec des renforts non-traités et fluorés. Ceux-ci ont été testés en traction, en flexion, et en fluage afin d’observer l’influence du traitement sur les propriétés mécaniques des composites. Par ailleurs, une caractérisation hygroscopique a également été conduite. Les résultats montrent que la fluoration directe des renforts permet d’améliorer les propriétés mécaniques et hygroscopiques des composites bois-polyester. / This thesis focuses on the treatment of wood flour used as reinforcement for polymer matrix composites. Indeed, the lack of compatibility between the hydrophilic wood and the hydrophobic polymers is the major difficulty encountered when processing wood-polymer composites. The treatment of the wood reinforcements is necessary to improve the mechanical and hygroscopic properties of the composites. Here, we proposed to apply direct fluorination to wood flour in order to reduce its hydrophilic character and then improve its compatibility with polymer matrix. Physicochemical characterization of the non-treated and fluorinated wood flours was carried out to observe the fluorination effects. The success of the fluorine grafting onto the wood components was confirmed by chemical analyses. Moreover, significant decrease in the number of moisture adsorption sites in wood was observed. This reduction led to a decrease in the equilibrium moisture content of wood after direct fluorination. In addition, the physical structure of the particles and the thermal behaviour of the wood were not modified by the treatment. Wood-polyester composites were processed by hot compression moulding with non-treated and fluorinated reinforcements. These composites were characterized by tensile, flexural and creep tests. Furthermore, a hygroscopic characterisation was also carried out. The results showed an improvement of the mechanical and hygroscopic properties of the composites with the reinforcements fluorination.

The enzymatic degradation of polyethylene terephthalate (PET) occurs at mild reaction conditions and may find applications in environmentally friendly plastic waste recycling processes. The hydrolytic activity of the homologous polyester hydrolases LC cutinase (LCC) from a compost metagenome and TfCut2 from Thermobifida fusca KW3 against PET films was strongly influenced by the reaction medium buffers tris(hydroxymethyl)aminomethane (Tris), 3-(N-morpholino)propanesulfonic acid (MOPS), and sodium phosphate. LCC showed the highest initial hydrolysis rate of PET films in 0.2 M Tris, while the rate of TfCut2 was 2.1-fold lower at this buffer concentration. At a Tris concentration of 1 M, the hydrolysis rate of LCC decreased by more than 90% and of TfCut2 by about 80%. In 0.2 M MOPS or sodium phosphate buffer, no significant differences in the maximum initial hydrolysis rates of PET films by both enzymes were detected. When the concentration of MOPS was increased to 1 M, the hydrolysis rate of LCC decreased by about 90%. The activity of TfCut2 remained low compared to the increasing hydrolysis rates observed at higher concentrations of sodium phosphate buffer. In contrast, the activity of LCC did not change at different concentrations of this buffer. An inhibition study suggested a competitive inhibition of TfCut2 and LCC by Tris and MOPS. Molecular docking showed that Tris and MOPS interfered with the binding of the polymeric substrate in a groove located at the protein surface. A comparison of the Ki values and the average binding energies indicated MOPS as the stronger inhibitor of the both enzymes.

Des particules constituées d’un cœur polymère polylactide (PLA), recouvertes d’une couche de polysaccharide adsorbé physiquement (dextrane hydrophobisé par des chaînes alkyle en C6, DexC6) et contenant des substances actives (SA) de type polyphénolique ont été élaborées par différents procédés physico-chimiques discontinus (nanoprécipitation et émulsion-évaporation de solvant) ou continus (procédé microfluidique d’émulsion-diffusion de solvant). L’extrapolation du procédé de nanoprécipitation de l’échelle laboratoire (25 mL) à l’échelle pilote (1 L) a été examinée. Ces particules étaient destinées au traitement des milieux aquatiques, pour la lutte contre le développement des cyanobactéries et des algues. Dans le but de maîtriser les caractéristiques des particules élaborées (distribution de taille, stabilité colloïdale, rendement d’encapsulation en SA ...), l’influence de paramètres physico-chimiques a été étudiée (concentration du PLA dans la phase organique, concentration du DexC6 dans la phase aqueuse, rapport volumique des deux phases, fraction massique SA/PLA …). Les procédés mis au point ont permis d’obtenir des particules dont les diamètres moyens allaient de 0,1 µm à 1 mm, avec des distributions granulométrique bien maîtrisées. Ces objets ont été caractérisés en termes de taux de recouvrement en dextrane, de quantité de SA encapsulée et de morphologie. La stabilité colloïdale des suspensions de nanoparticules a été examinée dans des milieux de force ionique variable. Par ailleurs, nous avons vérifié la possibilité de redisperser les suspensions de particules après lyophilisation. Pour les nanoparticules, l’addition d’un cryoprotecteur s’est avérée indispensable. Les cinétiques de libération des substances actives à partir des particules nano- et micrométriques ont également été suivies et les phénomènes limitant leur libération ont été identifiés.Enfin, des essais sur des milieux de culture contenant des cyanobactéries ont été réalisés. Ils ont montrés que la libération des SA conduisait à des effets algistatiques ou algicides selon les quantités utilisées. / Polysaccharide-covered polyester particles were prepared. The core of particles was made of polylactic acid (PLA) while their surface was covered by dextran chains via the use of water-soluble randomly hydrophobized dextran (DexC6) as a polymeric stabilizer. Polyphenolic active substances were encapsulated inside those particles. Polyphenol loaded PLA particles were designed for preventing cyanobacterias and algae proliferation in aquatic media. Conventional batch processes (nanoprecipitation or emulsion-solvent evaporation) and continuous processes (emulsion-solvent diffusion in microfluidics) were used to elaborate particles with average diameters ranging between 0.1 µm and 1 mm. The scale up of nanoprecipitation from lab scale (25 mL) to pilot scale (1 L) was also studied. The formulation parameters (PLA concentration in the organic phase, DexC6 concentration in the aqueous phase, aqueous phase to organic phase volume ratio, active substance weight fraction…) were optimized in order to obtain particles with well controlled characteristics (average diameter and size distribution, colloidal stability, encapsulation efficiency …). Loaded particles elaborated by different processes were characterized with regards to DexC6 surface coverage, colloidal stability at various ionic strengths, morphology and encapsulation efficiency. We also investigated the re-dispersion ability of particle suspensions after freeze drying and we showed that the use of a cryoprotectant was required in case of nanoparticles. The release of polyphenolic molecules from the elaborated polymeric nano- and microparticles was studied and limiting steps were identified. Finally, the cytotoxicity of nanoparticles toward cyanobacterias was evaluated. It was demonstrated that anti-algal effects were observed depending on the added quantities.

O uso da microfluídica na área de análises genéticas possibilita não apenas a diminuição de custos, mas também menor manipulação de amostras e reagentes e ainda maior portabilidade das análises. Com isso aumenta a possibilidade da sua utilização em locais remotos, sem a infraestrutura de um laboratório bem equipado. Dispositivos capazes de usar apenas a força centrifuga para movimentação de fluidos juntamente com a utilização de válvulas passivas para controle dos fluidos pode potencializar a sua utilização nos diagnósticos Point-of-Care. Este trabalho teve como objetivo o desenvolvimento de um microdispositivo descartável de poliéster para análises genéticas, visando a extração e amplificação do DNA alvo, de forma rápida, barata, integrada e automatizada. Os resultados confirmam a viabilidade dos dispositivos poliéster-toner (PeT) e poliéster-fita dupla face (PeDF) automatizados de extração, obtendo por meio da extração dinâmica em fase sólida de amostras complexas, DNA com qualidade compatível à técnica da reação em cadeia de polimerase (PCR). Esses resultados foram confirmados por meio da amplificação por PCR dos genes β-globina nas amostras de sangue e urina, e o gene malB nas amostras de Escherichia coli. Também foi confirmado a compatibilidade dos dispositivos de PeT para amplificação por PCR mediado por infravermelho (IV-PCR) do gene malB presente no DNA genômico de bactéria E. coli. Por fim, os dispositivos de extração e amplificação foram interligados para obtenção de um dispositivo integrado e automatizado formado pela combinação de dispositivos fabricados com diferentes filmes e métodos, PeT e PeDF. O controle de todas as soluções no interior dos dispositivos foi realizado por meio da força centrífuga combinada a válvulas passivas, sem qualquer necessidade de equipamento adicional. Portanto, podemos concluir que o dispositivo integrado PeDF - PeT possui grande potencial para aplicações em análises genéticas de forma mais barata, portátil e com menor manipulação das amostras pelo analista. / The development of microfluidics for genetic analysis allows not only cost reduction but also reduces sample and reagents handling, and increases the chances of a portable analysis. With this, increasing the possibility to use the techniques on remote places without the infrastructure of an equipped laboratory. Microdevices capable of using the centrifugal force in combination with passive valves to fluidic control can promote Point-of-Care analysis. The primary goal of this thesis was to associate these tools for the development of a disposable microdevice for genetic analysis, aiming faster, inexpensive, integrated and automated DNA extraction and amplification. The results confirmed the viability of PeT and PeDF automated microdevices, for DNA dynamic solid phase extraction, in providing high-quality DNA compatible to PCR analysis using complex samples. These results were confirmed by the β-globin PCR amplification using blood and urine samples, and the malB gene amplification in Escherichia coli samples. We have also verified the compatibility of the PeT microdevices with IV-PCR for malB gene amplification in genomic E. coli DNA. The extraction and amplification modules were interconnected to obtain an integrated and automated microdevice by the combination of devices made with different films and microfabrication methods, PeT and PeDF. The fluidic control in the devices was made using the centrifugal force combined to passive valves, with no requirement of any extra equipment. Therefore, we can conclude that the integrated PeDF - PeT microdevice has a great potential for cheaper and portable genetic analysis application, with less operator manipulation.

O uso da microfluídica na área de análises genéticas possibilita não apenas a diminuição de custos, mas também menor manipulação de amostras e reagentes e ainda maior portabilidade das análises. Com isso aumenta a possibilidade da sua utilização em locais remotos, sem a infraestrutura de um laboratório bem equipado. Dispositivos capazes de usar apenas a força centrifuga para movimentação de fluidos juntamente com a utilização de válvulas passivas para controle dos fluidos pode potencializar a sua utilização nos diagnósticos Point-of-Care. Este trabalho teve como objetivo o desenvolvimento de um microdispositivo descartável de poliéster para análises genéticas, visando a extração e amplificação do DNA alvo, de forma rápida, barata, integrada e automatizada. Os resultados confirmam a viabilidade dos dispositivos poliéster-toner (PeT) e poliéster-fita dupla face (PeDF) automatizados de extração, obtendo por meio da extração dinâmica em fase sólida de amostras complexas, DNA com qualidade compatível à técnica da reação em cadeia de polimerase (PCR). Esses resultados foram confirmados por meio da amplificação por PCR dos genes β-globina nas amostras de sangue e urina, e o gene malB nas amostras de Escherichia coli. Também foi confirmado a compatibilidade dos dispositivos de PeT para amplificação por PCR mediado por infravermelho (IV-PCR) do gene malB presente no DNA genômico de bactéria E. coli. Por fim, os dispositivos de extração e amplificação foram interligados para obtenção de um dispositivo integrado e automatizado formado pela combinação de dispositivos fabricados com diferentes filmes e métodos, PeT e PeDF. O controle de todas as soluções no interior dos dispositivos foi realizado por meio da força centrífuga combinada a válvulas passivas, sem qualquer necessidade de equipamento adicional. Portanto, podemos concluir que o dispositivo integrado PeDF - PeT possui grande potencial para aplicações em análises genéticas de forma mais barata, portátil e com menor manipulação das amostras pelo analista. / The development of microfluidics for genetic analysis allows not only cost reduction but also reduces sample and reagents handling, and increases the chances of a portable analysis. With this, increasing the possibility to use the techniques on remote places without the infrastructure of an equipped laboratory. Microdevices capable of using the centrifugal force in combination with passive valves to fluidic control can promote Point-of-Care analysis. The primary goal of this thesis was to associate these tools for the development of a disposable microdevice for genetic analysis, aiming faster, inexpensive, integrated and automated DNA extraction and amplification. The results confirmed the viability of PeT and PeDF automated microdevices, for DNA dynamic solid phase extraction, in providing high-quality DNA compatible to PCR analysis using complex samples. These results were confirmed by the β-globin PCR amplification using blood and urine samples, and the malB gene amplification in Escherichia coli samples. We have also verified the compatibility of the PeT microdevices with IV-PCR for malB gene amplification in genomic E. coli DNA. The extraction and amplification modules were interconnected to obtain an integrated and automated microdevice by the combination of devices made with different films and microfabrication methods, PeT and PeDF. The fluidic control in the devices was made using the centrifugal force combined to passive valves, with no requirement of any extra equipment. Therefore, we can conclude that the integrated PeDF - PeT microdevice has a great potential for cheaper and portable genetic analysis application, with less operator manipulation.

L’objectif de ce travail est d’adapter une formulation dispersante mise au point par la société Mäder à la dispersion de carbonate de calcium (CaCO3) dans une résine polyester insaturée (UP). Le carbonate de calcium est utilisé en tant que charge dans les matériaux composites à matrice thermodurcissable et en particulier dans les SMC (Sheet Molding Compound). Le rôle de cette formulation est de diminuer les viscosités de résines UP fortement chargées tout en conservant voire en améliorant les propriétés mécaniques des composites formés par un renforcement de l’interface charge / matrice. Trois grands axes ont été développés au cours de ce travail : - le comportement rhéologique d’un mélange CaCO3/résine UP a été déterminé et la formulation dispersante a été optimisée ; - la nature des interactions entre les différents constituants de la formulation dispersante et la surface du CaCO3 a été mise en évidence ; - de nouveaux polymères permettant une dispersion plus efficace de la charge dans la résine ont été synthétisés. Le mélange CaCO3 / résine UP présente un comportement rhéologique complexe. L’optimisation de la formulation dispersante a permis d’augmenter de plusieurs pourcents le taux de charge tout en conservant des viscosités inférieures à celle autorisée par le procédé industriel. L’étude des interactions des constituants de la formulation avec le carbonate de calcium a permis de déterminer les fonctions les plus réactives et de comprendre leur interaction avec la surface de la charge. La synthèse de nouveaux dispersants a également été effectuée. Ces derniers ont ensuite été testés dans l’application et ont montré une efficacité à disperser le CaCO3 dans la résine UP. / The aim of this study is to adapt a dispersive formulation developed by the Mäder group to the dispersion of calcium carbonate (CaCO3) in an unsaturated polyester resin (UP). The CaCO3 is commonly used as filler in the domain of composites especially for Sheet Molding Compound (SMC). This dispersive formulation is able to decrease the viscosity of UP resin containing a high amount of filler. In addition, the mechanical properties of composites could be increased by reinforcing the filler / matrix interface. Three main ways have been studied: - characterization of the rheological behavior of CaCO3 / polyester blends and optimization of the dispersive formulation ; - determination of the interactions between the dispersive formulation components and the CaCO3 surface ; - synthesis of new polymers in order to improve the CaCO3 dispersion in an organic matrix. A complex rheological behavior has been observed for CaCO3 / polyester blends. The dispersive formulation improvement led to an increasing of the filler percentage by keeping the viscosity under the industrial limit. The most reactive functions with the CaCO3 surface have been identified by studying the interactions between the dispersive formulation components and the CaCO3 surface. New dispersing agents have been synthesized. Their efficiency has been demonstrated for the dispersion of CaCO3 in a UP resin.

Le remplacement de monomères d'origine pétrosourcée par des analogues biosourcés améliore la durabilité et diminue la dépendance aux ressources fossiles. De plus, de nouvelles caractéristiques et propriétés sont souvent découvertes. Les polyesters aliphatiques biosourcés ont déjà partiellement remplacé les produits traditionnels. Dans le contexte du projet Sorago, une résine entièrement biosourcée pour les revêtements de prélaquage des produits intérieurs a déjà été introduite sur le marché (Estetic® bio Air, Arcelor Mittal). Pour permettre l'utilisation du produit dans des applications extérieures, sa résistance à la lumière UV et à l'humidité sont à améliorer. Cela pose deux problèmes : Une disponibilité limitée de monomères pouvant introduire de la rigidité dans la résine et la relation entre la structure de la résine et sa dégradation. La vanilline a été choisie comme synthon pour la gamme des monomères rigides et biosourcées. La transformation de sa fonction aldehyde par réaction de Perkin et sa réactivité a été examinée. Dans une série des copolymerisations, l'influence des conditions de réaction sur la composition du produit final a été proposée. Une relation structure-propriétés concernant la température de la transition vitreuse et la viscoélasticité des plusieurs monomères biosourcées a été établie, et comparée avec celle des monomères petrosourcées. Une série des prototypes avec des propriétés très variées a été soumise à un test de vieillissement rapide. Leur dégradation a été suivie sur la base de leur rétention de brillance, par FTIR et par des tests de µ-dureté et d'épaisseur des films. La performance des prototypes biosourcés s'est révélée inférieure à celle d'une résine standard pétrosourcée mais aucune évidence qui suggère que cela est du à la présence des monomères biosourcées n'a été détectée. Cela suggère que la création d'une résine biosourcée et suffisamment durable pour l'extérieur sera possible / Moving away from petroleum and towards biobased materials not only leads to greater sustainability and lower dependence on diminishing fossil resources, but can also catalyse the discovery of new properties. Aliphatic polyesters based on renewable resources have already started to replace traditional products. Within the Sorago project, a fully biobased resin for interior coil coatings has recently been proposed on the market (Estetic® Bio Air, Arcelor Mittal). In order to extend the possible use of the biobased product to exterior applications, an improvement of its resistance to humidity and UV radiation is crucial. This presents two challenges: The limited availability of monomers which provide rigidity in the resin structure and the relationship between the resin composition and its weatherability. Vanillin was chosen as a possible extension to the range of rigid, biobased monomers for polyesterification reactions. The transformation of its aldehyde and its reactivity was studied in terms of catalytic activation and through a series of copolymerisations which revealed the influence of the reaction conditions on the composition of the product. A structure-property relationship concerning the coating glass transition temperature and visco-elastic behaviour of the coating was furthermore established for a series of renewable monomers and contrasted with petroleum based equivalents. Series of prototypes with a wide variety of properties were then subjected to accelerated weathering tests. Their degradation was followed directly by gloss retention and different mechanisms were revealed using FTIR, µ-hardness and film thickness measurements. While the performance of the biobased coating was subpar, no evidence linking its degradation to the presence of renewable monomers was found, suggesting that the creation of a sufficiently durable and renewable exterior coating will be possible

In order to reach the Swedish environmental quality objectives, the Environmental ProtectionAgency has expressed a desire that consumption must be highlighted. The difficulty of assessingthe environmental impact of consumption lays in various calculation approaches, but one way toillustrate consumption is life cycle assessment (LCA). IVL, Swedish Environmental ResearchInstitute (IVL) has an ongoing project together with Chalmers about Urban Metabolism, wheredifferent branches of consumption are highlighted. In the current situation, the textile industryaccounts for approximately 2-10% of Europe's environmental impacts and until now, no complete LCA model over the Swedish textile consumption has been developed. The main goal of this thesis was to develop a LCA model for the Swedish textile consumption and to study the environmental impact that the consumption entails. Using data from StatisticsSweden, net consumption between 2000 and 2013 was analysed. The results showed thatclothing and household textiles account for the largest proportion of consumed textiles (68%) and cotton, wool, viscose, polyester and nylon are the most common fibres. With the GaBi software a general life cycle model for the years 2000, 2007 and 2013 wasdeveloped. The model included 25 different clothing and household articles. For each article, themodel covers raw material extraction, product manufacturing, use phase and waste management.The environmental impact categories; Acidification Potential (AP), Eutrophication Potential(EP), Global Warming Potential (GWP), Human Toxicity Potential (HTP), TerrestrialEcotoxicity Potential (TETP) as well as energy and water use were analysed. The model showedthat the production phase (including raw material production) has a great influence on theenvironmental impacts, but the use phase was equally important in certain impact categories.The major processes affecting the life cycle were energy use in manufacturing of the fabric,production of natural fibres, detergent as well as energy consumption in tumble dryers. Withconscious decisions the consumer has great opportunities to influence the overall environmentalimpacts. In addition, increased recycling and reuse can potentially decrease the environmentalimpacts from the production stage. The model is considered good enough for the results to be reliable and useful in order to predictthe environmental impacts of the Swedish textile consumption. The results are also validatedwith results from other studies which increases credibility. / Det står idag klart att endast två av Sveriges 16 miljömål kommer att nås till 2020. För attSverige ska uppnå sina miljömål har Naturvårdsverket uttryckt en önskan om att konsumtionmåste belysas. Svårigheten med konsumtionens miljöpåverkan är att den inte kan mätas direktmen ett sätt att angripa problemet är att studera konsumtion genom livscykelanalys.IVL, Svenska Miljöinstitutet (IVL), har tillsammans med Chalmers ett pågående projekt omUrban Metabolism där olika typer av konsumtion nu belyses. Textilier är en typ av konsumtionoch i Europa står den marknaden för 2-10 % av den totala miljöpåverkan. Då textilkonsumtionenär relativt stor i Europa är det därför intressant att studera hur den svenska textilkonsumtionenser ut. Denna studie ämnade att skapa en modell för svensk textilkonsumtion och studera dessmiljöeffekter. Med data från Statistiska centralbyrån kunde nettokonsumtionen mellan 2000-2013 beskrivas. Statistiken visade att kläder och hushållstextilier står för den största delenkonsumerade textilier (68 %) och att bomull, ull, viskos, polyester och nylon är de fibrer somanvänds mest. Med programvaran GaBi gjordes en generell livscykelanalysmodell för åren 2000, 2007 och2013. 25 olika kläder och hushållsartiklar ingick och processerna råvaruframställning,tillverkning av produkt, användning och avfallshantering studerades.Miljöpåverkanskategorierna försurning, övergödning, global uppvärmning, humantoxicitet,ekotoxicitet samt energi-och vattenanvändning analyserades och resultatet visade attproduktionsfasen (inklusive råvaruframställning) har stor påverkan på resultatet. I vissakategorier var även användningsfasen en betydande faktor. De processer som påverkadelivscykelanalysen mest var energianvändningen i tygtillverkningen och naturfibrerna samttvättmedlet och energianvändningen hos torktumlaren i användningsfasen. Med medvetna valhar konsumenten stor möjlighet att påverka de övergripande miljöeffekterna och med en ökadåtervinning och återanvändning kan miljöeffekterna i produktionsfasen minska. Modellen som togs fram är inte fulländad och vissa processer kan förbättras för att utvecklamodellen vidare. Däremot antas modellen vara tillräckligt bra för att resultatet ska vara trovärdigtoch användbart i syfte att studera den svenska textilkonsumtionens miljöeffekter. Resultaten kandessutom styrkas med resultat från andra studier vilket ökar trovärdigheten.

Dans cette étude, plusieurs voies ont été explorées dans l’objectif d’utiliser des polyesters aliphatiques issus de ressources oléagineuses comme additifs pour le renfort au choc du poly(L-lactide) (PLLA). Dans un premier temps, des poly(ester-amide)s (PEAs) ont été synthétisés à partir de dérivés de l’huile de ricin. La relation structure-propriétés des PEAs obtenus a été clairement établie. La dispersion des PEAs (à différents taux) par extrusion à l’état fondu dans une matrice de PLLA a ensuite été effectuée, démontrant un accroissement de la résilience de ces mélanges en comparaison au PLLA seul. Une étude systématique reliant la structure d’une large gamme de polyesters aux propriétés des mélanges polyesters/PLLA, a ensuite été réalisée. Une forte dépendance de la résilience des mélanges polyesters/PLLA avec la cristallinité de l’additif polyester a été observée et quantifiée.Une amélioration des propriétés mécaniques du PLLA a également été obtenue par polymérisation par ouverture de cycle du lactide amorcée par un poly(acide ricinoléique) di-hydroxy téléchélique. Les copolymères triblocs ainsi formés ont été caractérisés d’un point de vue morphologique et mécanique.Enfin, un travail exploratoire utilisant l’ADMET comme méthode de polymérisation a été conduit, permettant la synthèse de nouveaux polymères prometteurs pour le renfort au choc du PLLA. Notamment, la copolymérisation de α,ω-diènes bio-sourcés a permis de mimer le polyéthylène basse densité linéaire, couramment employé pour le renfort au choc du PLLA. / The objective of this thesis work, is to promote the use of fatty acid-based aliphatic polyesters as impact modifiers for poly(L-lactide) (PLLA).Firstly, poly(ester-amide)s (PEAs) have been synthesized from castor oil derivatives. The structure-properties relationship of the PEAs so-formed was clearly established. The PEAs were then melt-blended with PLLA by extrusion, yielding blends with improved impact strength compared to neat PLLA.A series of polyesters covering a wide range of thermo-mechanical properties was then employed to evaluate the influence of the polyester morphology on the properties of the blends with PLLA. A strong dependence of the impact strength of the blends was noticed with the crystallinity degree of the polyester additive.An improvement of the mechanical properties of PLLA was also obtained by ring-opening polymerization of lactide initiated by a di-hydroxy telechelic poly(ricinoleic acid). The so-formed triblock copolymers were fully characterized in terms of morphology and mechanical properties.Finally, an exploratory investigation related to the synthesis of PLLA impact modifiers by ADMET was carried out. Particularly, the copolymerization of two bio-based α,ω-dienes yielded a series of “LLDPE like” polyesters, LLDPE being a commonly used impact modifier for PLLA.

Le poly(acide lactique) (PLA), un polyester bio-ressourcé et biodégradable, est un candidat majeur pour la substitution des polymères issus de ressources fossiles. Le contrôle méticuleux de sa microstructure permet de modifier ses propriétés physiques. Dans ce contexte, ce manuscrit rapporte le design de complexes originaux de métaux trivalents et leur utilisation pour la polymérisation par ouverture de cycle (ROP) stéréosélective du lactide racémique (rac-LA). Ainsi, (i) les complexes M-Salen chiraux (M = Al, Ga, In, Salen = (1,2-diphényléthane)bis(phénoxyimine)) ont permis de confirmer l’aptitude des précatalyseurs aluminiques à être isosélectifs (Pm = 0.90) pour la ROP du rac-LA dénotant toutefois de leur faible activité. L’utilisation du gallium et de l’indium dans le but d’augmenter l’activité des systèmes catalytiques correspondants n’a pas permis de conserver la stéréosélectivité. Des études cinétiques et microstructurales ont permis d’établir les mécanismes de ROP et de stéréocontrôle ; (ii) les nouveaux ligands Salan rigidifiés par un cœur hydropyrimidine ((hydropyrimidine)bis(méthylène))diphénol), ont révélé une activation Csp3-H intramoléculaire inattendue avec le gallium et l’indium menant à des entités zwitterioniques originales. Les études mécanistiques par RMN, GC et calculs DFT ont permis de décrire le mécanisme alors mis en œuvre ; (iii) un précatalyseur hétéro-bimétallique yttrium/lithium et basé sur un ligand chiral dérivé de la binaphthylamine, a permis d’engendrer un PLA quasiment parfaitement hétérotactique (Pr = 0.99) ; (iv) finalement, de nouveaux ligands chiraux à base de proline pourront permettre de s’orienter vers l’utilisation de métaux divalents (Zn, SnII…), dans le but d’accéder à des systèmes stéréosélectifs faisant preuve d’une meilleure activité catalytique. / Poly(lactic acid) (PLA) is one of the most promising bio-resourced and biodegradable polymers and may constitute a viable alternative to petroleum-based materials. Its physical properties can be tuned by an accurate control of his microstructure. In this context, this manuscript relates the design of original complexes of trivalent metals and their further use for the stereoselective ring-opening polymerisation (ROP) of racemic lactide (rac-LA). Hence, (i) the chiral M-Salen complexes (M = Al, Ga, In, Salen = (1,2-diphenyl-ethane)bis(phenoxyimine)) have confirmed the isoselectivity exhibited by aluminium precatalysts for the ROP of rac-LA (Pm = 0.90) but also their limited activity. The gallium and indium congeners were prepared to enhance the catalytic activity, but resulted on substantial loss of stereoselectivity. The ROP and stereocontrol mechanisms were both investigated by kinetic monitoring and by microstructural analysis of the polymer; (ii) novel Salan ligands rigidified by a hydropyrimidine core ((hydropyrimidine)bis(methylene))-diphenol) have led to unexpected intramolecular Csp3–H activation with gallium and indium, affording unusual zwitterionic complexes. NMR and GC studies as DFT computations have been implemented to understand the mechanism for this process; (iii) a hetero-bimetallic yttrium/lithium precatalysts based on a chiral binaphthylamine backbone has led to highly heterotactic PLA (Pr = 0.99); (iv) finally, new chiral ligands should afford complexes of divalent metals (Zn, SnII…) that should yield access to stereoselective catalytic systems featuring increased activity.