The vibration damping property of plant fibres composites is of practical interest for commercial applications of biobased and eco-composites. Damping behaviour has been observed by experimentation and exploited in the marketing of sporting equipment but the origins of this behaviour have so far been only based on conjectures. In this thesis, the damping capacity of plant fibre composites was attributed to their chemical composition and the reversible interactions enabled by the breaking and reforming of hydrogen bonds under stress. The approach to explaining the mechanisms started with the characterisation of different plant fibre types to search for correlations between their physical and chemical structure. The investigation continued with quantifying the effect of hydrogen bonding compounds such as water, glycerol and polyglycerol on the damping coefficient of fibres and reinforced composites. The results of the polyol impregnation indicated that applying a pretreatment enhanced the vibration damping performance of flax reinforced composites, validating the hypothesis of the essential role played by hydrogen bonds in the fibres. The improvement in the damping coefficient of the composites was shown to be to the detriment of their stiffness. The compromised between the two properties was investigated in the final part of this thesis by using hybrid flax-carbon fibre reinforced composites.

Proposer des solutions permettant de concevoir et de fabriquer des pièces automobiles performantes mais également respectueuses de l’environnement est devenu un enjeu majeur pour les équipementiers automobiles. Ces travaux de thèse s’inscrivent donc dans ce contexte de compréhension et d’amélioration des matériaux composites non-tissés aiguilletées renforcés par des fibres végétales. À partir d’un même matériau de base, il est possible d’obtenir des structures et des propriétés différentes grâce au contrôle du taux de porosités dans le matériau. On peut ainsi conférer au composite de bonne propriétés d’absorption acoustique à des taux de porosités élevés (50%) ou au contrainte privilégier la tenue mécanique du produit en les limitant. La structure du matériau et la liaison fibre/matrice vont évoluer avec la fraction de porosités et en résulteront des comportements mécaniques bien différents. Suivant le taux de porosité, les performances mécaniques seront donc principalement gouvernées par des paramètres différents tels que la liaison interfaciale ou le renfort. Dans un environnement automobile, les conditions climatiques (humidité et température) jouent un rôle prépondérant dans les performances des biocomposites non-tissés. En effet, l’adhérence fibre/matrice est essentiellement liée aux contraintes radiales compressives, qui sont largement influencées par l’état hygrométrique du renfort. Enfin, la valorisation les chutes de fabrication issues de la thermocompression pour modifier la structure du composite non-tissé a permis de développer un produit présentant un gain en rigidité significatif. / Proposing solutions to produce more efficient and environmentally friendly automotive parts has become a major challenge for tier one suppliers. The work described in this thesis is about understanding and improving composite materials made with commingled plant fibre nonwovens. From the same initial nonwoven, it is possible to obtain very distinct material structures by controlling porosity content. One can then give to the material enhanced acoustic properties with high porosity content (50%) or in the contrary show good mechanical properties by limiting porosities. Material structure will evolve with porosity as well as its mechanical behavior. Thus, as function of porosity, interfacial adhesion of fibre mechanical properties will govern composite mechanical properties. Biocomposite automotive parts are exposed to a large range of climatic environments and their mechanical properties can vary significantly. Indeed, radial stresses are drastically influenced by the reinforcement hygroscopic state. Finally, the idea developing an innovative material structure from compression moulding wastes has helped enhancing material rigidity.

O presente estudo trata da descrição e análise da atividade artesanal com fibra de bananeira praticada pelas comunidades quilombolas de Ivaporunduva, André Lopes e Sapatu, município de Eldorado, região do Vale do Ribeira, tendo como referencial teórico o conceito de ecodesenvolvimento proposto por Sachs (1980). A atividade artesanal com fibra de bananeira foi iniciada no ano de 1997, através de um projeto de pesquisa executado pela Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ) - Universidade São Paulo (USP): "Projeto de Aproveitamento de Resíduos da Agroindústria da Banana no Vale do Ribeira, SP" cujo objetivo consistia em realizar estudos que resultassem em alternativas economicamente viáveis para o aproveitamento dos resíduos da bananicultura na região. Desde de então, a atividade artesanal com fibra de bananeira vêm sendo praticada por integrantes das comunidades referidas. Para coletas de dados foram utilizadas técnicas comumente trabalhadas pelas nas ciências sociais como: observação participante, entrevistas informais não-estruturadas e semi-estruturadas com os artesãos envolvidos e com representantes de Instituições governamentais e não governamentais atuantes no processo. Verificou-se neste trabalho a contribuição da atividade artesanal na valorização da mulher, a compatibilidade da tecnologia repassada com os contextos social e ambiental locais, o aproveitamento dos recursos locais disponíveis e o papel dessa atividade na economia familiar. Analisando o processo de geração, adoção e disseminação da atividade artesanal com fibra de bananeira e seus resultados nas comunidades conclui-se que esta atividade: (1) representa hoje um significativo complemento na renda familiar dos artesãos que a praticam; (2) é praticada em conformidade com a organização sócio-cultural local, (3) não gera impacto ambiental negativo e (4) dispõe, em quantidade significativa, da matéria prima necessária para realização da atividade. Portanto, sua prática é compatível com os preceitos do ecodensenvolvimento. / This study focuses on a description and analysis of activities in handcraft from banana plant fibre in practice among Quilombola communities in Ivaporunduva, André Lopes, and Sapatu, municipality of Eldorado, in the region of the Ribeira Valley, with the concept of ecodevelopment proposed by Sachs (1980) as theoretical reference. Activities in handcraft from banana plant fibre began in 1997 through a research project carried out by the Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ) - USP - the University of São Paulo: "Project for Use of Agroindustrial Residue from Banana in the Ribeira Valley, SP", the objective of which consisted in carrying out studies that would result in economically viable alternatives for the use of the residues of banana crops in the region. Activities in handcraft have been in practice by members of these same communities as from then. Data were collected by means of techniques in common use in social sciences such as: participant observation, non-structured and semi-structured informal interviews with the craftsmen involved and with representatives of government and non-government institutions active in the process. The study records the contribution of handcraft activities in enhancing the role played by women, in technological compatibility conveyed within local social and environmental contexts, in the use of local resources available, and in the role of these activities in terms of family economy. As a result of analyzing the process of generating, adopting, and disseminating handcraft activities from banana plant fibre and the results in the communities, it can be concluded that these same handcraft activities: (1) today, account for a significant supplement to the family income for the craftsmen who engage in handcraft; (2) are in practice in accordance with local socio-cultural organization; (3) do not generate a negative impact on the environment and (4) have resort to a significant quantity of the raw material necessary to carry out these same activities. This handcraft activity is, therefore, compatible with the precepts of ecodevelopment.

O presente estudo trata da descrição e análise da atividade artesanal com fibra de bananeira praticada pelas comunidades quilombolas de Ivaporunduva, André Lopes e Sapatu, município de Eldorado, região do Vale do Ribeira, tendo como referencial teórico o conceito de ecodesenvolvimento proposto por Sachs (1980). A atividade artesanal com fibra de bananeira foi iniciada no ano de 1997, através de um projeto de pesquisa executado pela Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ) - Universidade São Paulo (USP): "Projeto de Aproveitamento de Resíduos da Agroindústria da Banana no Vale do Ribeira, SP" cujo objetivo consistia em realizar estudos que resultassem em alternativas economicamente viáveis para o aproveitamento dos resíduos da bananicultura na região. Desde de então, a atividade artesanal com fibra de bananeira vêm sendo praticada por integrantes das comunidades referidas. Para coletas de dados foram utilizadas técnicas comumente trabalhadas pelas nas ciências sociais como: observação participante, entrevistas informais não-estruturadas e semi-estruturadas com os artesãos envolvidos e com representantes de Instituições governamentais e não governamentais atuantes no processo. Verificou-se neste trabalho a contribuição da atividade artesanal na valorização da mulher, a compatibilidade da tecnologia repassada com os contextos social e ambiental locais, o aproveitamento dos recursos locais disponíveis e o papel dessa atividade na economia familiar. Analisando o processo de geração, adoção e disseminação da atividade artesanal com fibra de bananeira e seus resultados nas comunidades conclui-se que esta atividade: (1) representa hoje um significativo complemento na renda familiar dos artesãos que a praticam; (2) é praticada em conformidade com a organização sócio-cultural local, (3) não gera impacto ambiental negativo e (4) dispõe, em quantidade significativa, da matéria prima necessária para realização da atividade. Portanto, sua prática é compatível com os preceitos do ecodensenvolvimento. / This study focuses on a description and analysis of activities in handcraft from banana plant fibre in practice among Quilombola communities in Ivaporunduva, André Lopes, and Sapatu, municipality of Eldorado, in the region of the Ribeira Valley, with the concept of ecodevelopment proposed by Sachs (1980) as theoretical reference. Activities in handcraft from banana plant fibre began in 1997 through a research project carried out by the Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ) - USP - the University of São Paulo: "Project for Use of Agroindustrial Residue from Banana in the Ribeira Valley, SP", the objective of which consisted in carrying out studies that would result in economically viable alternatives for the use of the residues of banana crops in the region. Activities in handcraft have been in practice by members of these same communities as from then. Data were collected by means of techniques in common use in social sciences such as: participant observation, non-structured and semi-structured informal interviews with the craftsmen involved and with representatives of government and non-government institutions active in the process. The study records the contribution of handcraft activities in enhancing the role played by women, in technological compatibility conveyed within local social and environmental contexts, in the use of local resources available, and in the role of these activities in terms of family economy. As a result of analyzing the process of generating, adopting, and disseminating handcraft activities from banana plant fibre and the results in the communities, it can be concluded that these same handcraft activities: (1) today, account for a significant supplement to the family income for the craftsmen who engage in handcraft; (2) are in practice in accordance with local socio-cultural organization; (3) do not generate a negative impact on the environment and (4) have resort to a significant quantity of the raw material necessary to carry out these same activities. This handcraft activity is, therefore, compatible with the precepts of ecodevelopment.