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Ce travail de recherche consiste à étudier les relations structure-propriétés de mélanges biopolymères à base de poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) et poly(butylène succinate) (PBS). Il est divisé en trois parties. La première partie est consacrée à l'étude des propriétés des mélanges PHBV/PBS préparés par voie fondue en fonction de la composition en termes de morphologie et de propriétés rhéologiques, mécaniques, thermiques et barrières. Les résultats obtenus ont été discutés par rapport aux polymères de base. La deuxième partie est consacrée à la compatibilisation des mélanges PHBV/PBS et l'amélioration des interactions à l'interface. Les effets de l'incorporation de la sépiolite à 5% en masse et du PHBV greffé par de l’anhydride maléique (PHBV-g-MA) à 5% en masse ont été étudiés en termes de changements morphologiques montrant un effet synergique entre le compatibilisant et la nanocharge sur les l’ensemble des propriétés des mélanges PHBV/PBS. Enfin, une étude sur le recyclage a été menée à travers une évaluation des effets du nombre de cycles d'extrusion sur les propriétés des matériaux. Elle révèle qu'après 6 cycles d'extrusion, la dégradation thermo-mécanique du PHBV est significativement réduite en présence du PBS. / The main objective of this work was to study the structure-properties relationships of biopolymerblends based on poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and polybutylene succinate (PBS). The work was devised into three parts. The first part was devoted to the study of the properties of PHBV/PBS blends prepared by melt compounding at different weight ratio in terms of morphology and properties. The results obtained were discussed in terms of properties and compared with the neat polymers. The second part was devoted to the study of compatibility of PHBV/PBS blends aiming to improve the interactions at the interface between the two components. The effects of both sepiolite (5% wt.) and PHBV-g-MA (5% wt.) were studied in terms of properties. The results showed a synergistic effect between the compatibilizer PHBV-g-MA and the nanofiller sepiolite though an increase in thermal, mechanical and rheological properties. The last part dealing with the recyclability of PHBV/PBS through the study of the effects of repeated extrusion cycles on the properties of materials. The results showed that after 6 reprocessing cycles the thermo-mechanical degradation of PHBV is significantly reduced in the presence of PBS.

En ce début de XXIème siècle, l’époque où seul la technique transformait la société toute entière est clairement révolue. Certes, les révolutions techniques sont là : interconnexion des personnes, explosion de l’internet, apparition de nouvelles formes d’énergies, de nouveaux procédés de production, de nouveaux matériaux etc... mais l’homme n'est plus un simple consommateur sensible au prix et aux incitations de l’état. Il souhaite être acteur et participer à l’utilisation des nouvelles technologies mais de manière raisonnée et en intégrant les grands enjeux sociétaux tels que le partage et la sauvegarde des ressources et matières premières. Cette thèse s’inscrit dans cette problématique globale: en effet tout au long du manuscrit nous réfléchissons à comment une révolution technique tel que la fabrication additive (FA) est prise en main par des citoyens dans des lieux de partage de la connaissance que sont les FabLabs, et plus précisément, s’il est possible et de quelle manière introduire de la durabilité dans le contexte open-source. Nous voyons dans un premier temps, comment la problématique sociétale forte du recyclage des matériaux se développe dans le contexte de la FA en générale et plus particulièrement nous proposons une revue bibliographique systématique sur le sujet. Dans un second temps nous recentrons notre recherche sur la FA dans le contexte open source et nous montrons que les machines dans ce contexte, bien qu’à des coûts très faibles par rapport aux machines professionnelles, ont cependant des niveaux de reproductibilités suffisant pour que l’on les utilise dans le cadre d’une recherche poussée. Dans le troisième chapitre nous proposons une méthodologie générale fixant l’étude du recyclage de polymères thermoplastiques dans le contexte open-source. Dans le quatrième chapitre nous utilisons la méthodologie vu précédemment pour le recyclage de l’acide polylactique (PLA). Nous montrons le niveau de dégradation de la matière à travers l’ensemble du procédé et concluons qu’il est possible de recycler le PLA pour l’impression 3D mais dans une moindre mesure que pour les procédés d’injection. Enfin nous concluons et proposons en perspective d’étudier le recyclage en circuit court d’autres polymères thermoplastique / Since the beginning of the XXI century, we can recognize that several technical (r)evolutions have changed the way we conceived our world. New realities have appeared thanks to the information and communication technologies (e.g. Internet), peer-to-peer dynamics (e.g. open software/hardware, collaborative economy), new means of production (fablabs, hackerspaces), among others. One of the impacts of this technical ecosystem is the individual's empowerment that changes the relationship between consumer and producer. For instance, we observe an evolution of role passing from a passive consumer towards an active prosumer, where this latter considers not only economic aspects, but also social and environmental issues.This thesis is integrated in this global issue; indeed, throughout the manuscript we analyze about the impact of open-source (OS) Additive Manufacturing (AM) (also as known as open-source 3D printing or just 3D printing) in the light of the sustainability issues. The democratization of OS AM and the creation of spaces for co-creation (e.g. FabLabs) proved the interest for changes in the established roles. Therefore, we are interested in how this OS technology could develop sustainable waste management options through a polymer recycling process. In a first phase, we present the concept of additive manufacturing (AM) and its importance on sustainability issues. A systematic literature review related to the material recycling advances in the commercial and open-source (OS) AM is developed with a focus on thermoplastic polymer recycling.In a second phase, our aim is to validate open-source AM systems as a reliable manufacturing tool. We develop and test an experimental protocol in order to evaluate the dimensional performance using as case study a representative OS 3D printer: called FoldaRap. It was found that the International Standard Tolerance Grade of this machine is situated between IT14 and IT16. We conclude that the dimensional performance of this case study is comparable to the commercial AM systems, taking into account the important different in terms of machine cost. In a third phase, we center our attention on the recycling process and we propose a systematic methodology to evaluate the feasibility of the use of recycled thermoplastic polymer in OS 3D printers. A case study is developed with the evaluation of the recycling process using polylactid acid (PLA). The results allow us to conclude that the use of recycled PLA is technically feasible. Nevertheless, the degradation of the material is more important than in other traditional manufacturing systems (e.g. injection). Finally, we concludes and propose as perspectives, the study of a distributed recycling process for other type of polymers

[pt] Esta pesquisa examina as potencialidades e limitações da manufatura aditiva na produção de dispositivos médicos em resposta à crescente demanda global durante a pandemia da COVID-19. A pesquisa busca entender as implicações da adaptação de projetos, da conformidade com regulamentações e da criação de uma cadeia de produção resiliente e sustentável, utilizando impressoras 3D de baixo custo. Além disso, a pesquisa incita reflexões sobre a intersecção entre medicina e design, instigando novas pesquisas neste campo interdisciplinar. O estudo se aprofunda na análise de adaptações de design e na exploração de uma cadeia produtiva alternativa mais resiliente e com menor impacto ambiental. A pesquisa considera a possibilidade de utilizar resíduos hospitalares como matériaprima para a produção de componentes médicos, uma prática que pode reduzir custos de descarte e a pegada de carbono. Além disso, discute a implementação do DRAM (Design, Reciclagem e Manufatura Aditiva Distribuídos) em ambientes hospitalares para responder às demandas de saúde em cenários de interrupção da cadeia de suprimentos. A pesquisa levanta questões importantes sobre a fronteira entre medicina e tecnologia, destacando a importância da responsabilidade ética e social na evolução científica e tecnológica. Argumenta a importância da manutenção adequada dos equipamentos médicos e o papel vital que a manufatura aditiva pode desempenhar na produção rápida de peças de reposição, especialmente em situações de emergência, como a pandemia da COVID-19. Com uma análise detalhada do joelho, um projeto prático desenvolvido durante o mestrado, a pesquisa identifica a necessidade de reestruturação dos processos de fabricação, considerando fatores econômicos e geográficos. A experiência do projeto instigou discussões enriquecedoras sobre o papel do designer, a potência da tecnologia de fabricação digital e a relevância dessa atividade em situações de emergência. Finalmente, a pesquisa conclui que a Reciclagem Distribuída e a Manufatura Aditiva (DRAM) podem se apresentar como uma solução sustentável e descentralizada para a produção de itens críticos em hospitais. Sugere a possibilidade de implementação de um ciclo fechado de produção e consumo de materiais através da fabricação de filamentos a partir de resíduos no próprio local de cuidados de saúde. Isso não só reduziria a dependência de fornecedores externos e a pegada ambiental da produção, mas também poderia melhorar a eficiência e agilidade dos sistemas de saúde em situações de emergência. / [en] This Master s dissertation examines the potentialities and limitations of additive manufacturing in the production of medical devices in response to the growing global demand during the COVID-19 pandemic. The research seeks to understand the implications of project adaptations, compliance with regulations, and the creation of a resilient and sustainable production chain, using low-cost 3D printers. Furthermore, the research instigates reflections on the intersection between medicine and design, stimulating new research in this interdisciplinary field. The study delves into the analysis of design adaptations and explores an alternative production chain that is more resilient and has less environmental impact. The research considers the possibility of using hospital waste as raw material for the production of medical components, a practice that can reduce disposal costs and the carbon footprint. In addition, it discusses the implementation of DRAM (Distributed Recycling and Additive Manufacturing) in hospital environments to respond to health demands in scenarios of supply chain disruption. The research raises important questions about the frontier between medicine and technology, highlighting the importance of ethical and social responsibility in scientific and technological evolution. It argues the importance of proper maintenance of medical equipment and the vital role that additive manufacturing can play in the quick production of replacement parts, especially in emergency situations, such as the COVID-19 pandemic. With a detailed analysis of the elbow, a practical project developed during the master s program, the research identifies the need for restructuring manufacturing processes, taking into account economic and geographic factors. The project s experience instigated enriching discussions about the role of the designer, the power of digital manufacturing technology, and the relevance of this activity in emergency situations.