O aumento da produção pela agroindústria, ao mesmo tempo em que proporciona benefícios, gera uma grande quantidade de resíduos que, se não tratados de forma adequada, trazem malefícios à sociedade e ao ambiente. A utilização destes subprodutos diminui custos da produção, aumenta o aproveitamento total do alimento e reduz o impacto ambiental. Dessa forma, alguns subprodutos como cascas, sementes e bagaços podem ser transformados em ingredientes alimentícios. Este trabalho teve como objetivo caracterizar as polpas e os resíduos do processamento de açaí, buriti e cupuaçu, bem como avaliar a melhor fonte de fibras para a elaboração de pães integrais. Os resíduos foram separados em: torta desengordurada de açaí, de buriti e cupuaçu; açaí integral; semente do açaí; endocarpo esclerificado do buriti; casca do buriti; buriti integral; semente do buriti; casca do cupuaçu; cupuaçu integral e semente do cupuaçu. Foram realizadas análises de composição centesimal e coloração nas polpas e resíduos, onde a casca de cupuaçu apresentou melhores características para elaboração de uma farinha para desenvolvimento dos pães. Os pães foram desenvolvidos substituindo parcialmente a farinha de trigo pela farinha de casca de cupuaçu (FCC) em 0%, 3%, 6% e 9% e analisados quanto à composição centesimal, fatores antinutricionais, propriedades físicas e aceitabilidade pelos consumidores. Para elaboração da FCC, as cascas foram lavadas, sanitizadas com hipoclorito de sódio, liofilizadas e trituradas em moinho de facas. Como resultados, os pães integrais tiveram sua composição centesimal quase inalterada em função da substituição da farinha de trigo pela farinha de casca de cupuaçu, exceto pelo aumento gradativo no teor de fibras alimentares em detrimento do teor de carboidrato. Assim, os pães com 6% de FCC, segundo a legislação brasileira, podem ser considerados como fonte de fibras e os pães com 9% com alto teor de fibras alimentares. O aumento do teor de FCC proporcionou diminuição no valor calórico dos pães em relação ao padrão, assim como melhor digestibilidade protéica in vitro; aumento não significativo nos teores de taninos; leve aumento no teor de fitatos e fenólicos totais, porém próximos aos encontrados na literatura. O valor de pH pouco variou nos pães. A farinha de casca de cupuaçu contribuiu para aumentar a diferença de cor dos miolos dos pães do que da crosta dos mesmos, onde maiores quantidades de farinhas de casca adicionadas promovem colorações mais escuras. O volume dos pães diminuiu proporcionalmente em relação ao aumento da substituição da farinha branca pela de casca, quando comparados ao pão padrão. Todos os pães encontram-se dentro da legislação em relação aos microrganismos. Para o teste de aceitação aplicado, constatou-se que 72,5% consumiam pães diariamente; 67,5% consideraram pães importantes na alimentação e 65,0% declararam importante o consumo de fibras para a saúde. Quanto à avaliação da qualidade, os pães com 0%, 3% e 6% de farinha de casca de cupuaçu obtiveram ótima aceitação e seriam adquiridos/consumidos por 92,5% dos provadores. / The increasing agribusiness production where as providing benefits, generates a large amount of waste that if not treated properly, may harm society and the environment. The use of these by products reduces production costs, increase the total utilization of food and reduce environmental impact. Thus, some byproducts such as hulls, seeds and meals can be processed into food ingredients. This study aimed to characterize the pulps and waste processing of assai, buriti and cupuassu as well as evaluate the best source of fiber for the production of whole grain breads. The residues were separated into: assai, buriti, cupuassu hulls, seeds and whole fruits as well as buriti sclerified endocarp and were analyzed for bromatological composition and pulp and waste coloR. Cupuassu hulls presented better characteristics for the preparation of a meal for the development of the loaves. The breads were developed by partially replacing wheat flour by ground cupuassu hulls (FCC) at 0%, 3%, 6% and 9% levels and analyzed for proximate composition, antinutritional factors, physical properties and consumer S acceptability. For preparation of the FCC, the shells were washed, sanitized with sodium hypochlorite, dried and crushed in a grinder of knives. As a result, the breads had their composition almost unchanged due to the substitution of wheat flour by cupuassu hull flour, except for a gradual increase in dietary fiber content at the expense of carbohydrate content. Hence, the breads with 6% of FCC, according to brazilian laws, can be considered as source of fiber and breads with 9% with high-fiber food. The increased content of FCC provideS a decrease in the caloric value of bread in relation to the pattern, as well as better protein digestibility in vitro, no significant increase in the levels of tannins, a slight increase in the content of phytate and total phenolics, but close to those found in the literature. The pH varied little in the breads. The cupuassu hull flour helped increase the difference in color between bread crumbs and crust, where larger quantities of hull flour promoted the darker hues. The loaf volume decreased proportionally to the increase of hull flour, when compared to standard bread. All breads are within the law in relation to microbiological patterns. For the acceptance test applied, it was found that 72.5% ate bread daily, 67.5% considered important in the diet breads and 65.0% reported significant fiber intake for health. Regarding the evaluation of quality, the bread containing 0%, 3% and 6% of cupuassu hull flour had great acceptance and would be bought or consumed by 92.5% of the panelists.

As fibras vegetais podem ser utilizadas nao somente para tecidos, mas tambem para fabricacao de fios, cordames, naotecidos, compositos em substituicao aos fabricados em madeira ou materiais sinteticos, sendo que o Brasil possui uma grande variedade de fibras naturais. O presente estudo teve como principal objetivo a caracterizacao fisico-quimica de seis fibras texteis vegetais de especies da familia Malvaceae: Sida rhombifolia L.; Sida carpinifolia L. f.; Sida cordifolia L.; Sidastrum paniculatum (L.) Fryxell; Malvastrum coromandelianum (L.) Gurck e Wissadula subpeltata (Kuntze) R. E. Fries. Foram realizados testes fisicos tenseis (resistencia e alongamento); microscopia optica (sem e com solucao de iodo); teores de regain e umidade; testes quimicos de combustao, determinacao do pH do extrato aquoso, efeitos de solvente organico, alcali e acido. Em adicao, foram feitos testes de DSC, TGA, SEM, FTIR, microscopia de luz polarizada, grau de polimerizacao e densidade. Os valores de tenacidade (21-33 cN/tex), alongamento (2-3%) e modulo de Young (10-20 N/tex) sao compativeis com as de fibras naturais de reconhecida empregabilidade textil, com excecao de Sida rhombifolia L. (12 cN/tex). Os resultados obtidos de microscopias opticas e SEM, combustao e regain (10-18%) sao compativeis com os de outras fibras celulosicas. Os testes de FTIR confirmaram presenca de celulose, hemicelulose e lignina, sendo que os testes de DSC e TGA indicaram as temperaturas de picos endotermicos e composicao de hemicelulose (285-337oC; 10-15%), -celulose (360- 365oC; 55-60%) e lignina (420-425oC, 11-27%), valores esses coerentes com os reportados em literatura para outras fibras lignocelulosicas. Em funcao dessas temperaturas, a possibilidade de emprego das fibras estudadas em compositos termoplasticos e bastante restrita. No entanto, por nao haver alteracao significativa de massa apos tratamento com solvente organico, ha indicacao que as fibras do presente estudo poderiam ser empregadas em compositos plasticos termorrigidos. / Vegetal fibers can be employed not only for fabrics, but also for the production of yarns, ropes, nonwovens and composites substituting those ones manufactured from wood or synthetic materials whereas Brazil has a great variety of natural fibers. The present study had as main objective the physicochemical characterization of six textile vegetal fibers of species from Malvaceae family: Sida rhombifolia L.; Sida carpinifolia L. f.; Sida cordifolia L.; Sidastrum paniculatum (L.) Fryxell; Malvastrum coromandelianum (L.) Gurck and Wissadula subpeltata (Kuntze) R. E. Fries. Tensile physical tests (resistance and elongation); optical microscopy (with and without iodine solution); moisture and regain contents; chemical combustion tests; aqueous extract pH; the effects of organic solvent, alkali, acid were carried out. In addition DSC, TGA, SEM, FTIR tests, polarized light microscopy, density and degree of polymerization tests were performed. The values of tenacity (21-33 cN/tex), elongation (2-3%) and Young s modulus (10-20 N/tex) are compatible with those ones from natural fibers of recognized textile employability, exception Sida rhombifolia L. (12 cN/tex). The results of optical and SEM microscopies, combustion and regain (10-18 %) are consistent with those of other cellulosic fibers. The FTIR tests confirmed the presence of cellulose, hemicellulose and lignin, whereas DSC and TGA tests showed endothermic peak temperatures and composition values of hemicellulose (285-337oC ; 10-15%) , -cellulose (360-365oC ; 55-60%) and lignin (420-425oC , 11- 27%), which are consistent with those reported in the literature for other lignocellulosic fibers. Taking in account these temperatures, the possibility of employing the studied fibers in thermoplastic composites is very limited. However, because no significant mass change after treatment with organic solvent, there is indication that the fibers of the present study could be employed in thermoset plastic composites.

A presente pesquisa teve como objetivo avaliar o uso de compósitos de fibras e resina epóxi no reforço de emendas dentadas em peças de madeira. Inicialmente, foi avaliada a influência da trama das fibras de sisal e de curauá sem tratamento nenhum nas propriedades mecânicas à tração dos compósitos com resina epóxi. Igualmente, foram caracterizados na tração compósitos de fibras de vidro e tecidos de sisal. Posteriormente, foi avaliada a resistência à tração paralela às fibras de peças de madeira Pinus sp em tamanho estrutural para três tipos de tratamentos: (1) peças sem emendas e sem reforço, (2) peças com emendas e sem reforço e (3) peças com emendas reforçadas por compósitos de fibras de vidro e resina epóxi. Também foram realizados testes de tração em corpos de prova isentos de defeitos com emendas dentadas usando madeira Lyptus® para três casos: (1) sem reforço na emenda, (2) reforço na emenda com fibra de vidro e (3) reforço na emenda com tecido de sisal. Os resultados da influência da trama das fibras de sisal e curauá com a resina epóxi nos testes de tração mostraram que o tipo de trama não influenciou significativamente na resistência e no módulo de elasticidade. Na caracterização dos compósitos poliméricos, a resistência do tecido de sisal foi cerca de 44% da resistência da fibra de vidro. Nas peças estruturais, devido à baixa resistência da madeira de Pinus sp utilizada, não se justificou a utilização do reforço. Nos corpos de prova isentos de defeitos de madeira Lyptus® com emendas dentadas, a eficácia do reforço foi evidenciado, com aumento de 37% na resistência à tração com reforço de fibra de vidro e de 40% com reforço de tecido de sisal, em relação aos corpos de prova isentos de defeitos sem reforço. / The present research evaluate the reinforcing of finger joints in timber pieces with composite fiber and epoxy. Initially, the influence of the weft in the tensile mechanical properties of composites using sisal fibers and curaua without any treatment was evaluated. The characterization of composites made with sisal fibers and glass fibers were also carried out. Additionally, the tensile strength parallel to the grain for pieces of Pinus sp in structural sizes for three types of treatments: (1) pieces without finger joints, (2) pieces unreinforced finger joints and (3) pieces reinforced finger joints with composite fiberglass and epoxy resin, was evaluated. Also, was evaluated the tensile strength of the finger joint test specimens Lyptus® wood for three cases: (1) unreinforced finger joint, (2) reinforced finger jointed with fiberglass and (3) reinforced finger jointed with fabric sisal. The results of influence of the weft sisal fibers and curaua with epoxy resin of tensile test showed that the weft did not significantly influence the strength and the modulus of elasticity. The characterization of polymeric composites, the strength of sisal fabric was about 44% of the fiber glass strength. The structural size pieces, the use of reinforcement it is not justified due to the low strength of the Pinus sp wood used. The test specimens of Lyptus® wood with finger joints, the efficacy of the reinforcement was evident, with 37% increase in tensile strength with glass fiber reinforcement and 40% with reinforcement sisal fabric, compared to specimens without reinforcement.

O trabalho visou realizar um estudo sobre o comportamento mecânico e de inflamabilidade de estruturas aeronáuticas de interior fabricadas a partir de compósitos reforçados por fibras naturais, especificamente compósitos de resina fenólica com fibras de algodão e de sisal, verificando assim, a possibilidade de substituir compósitos sintéticos. Num primeiro momento, análises experimentais foram executadas para determinar as propriedades mecânicas dos materiais. Em seguida, análises computacionais foram realizadas, empregando as propriedades referentes aos compósitos sintéticos e reforçados por fibras naturais, utilizando critérios de falha e tendo como referência o desempenho do compósito sintético para uma dada estrutura aeronáutica de interior. Além disso, foram efetuadas análises do seu comportamento quanto à inflamabilidade. A incorporação de retardantes de chama foi necessária para que os compósitos reforçados por fibras naturais atendessem aos requisitos de certificação aeronáutica. Após o processo de aditivação, observou-se um aumento do módulo de elasticidade à flexão (55% para o compósito de algodão, 16% para o compósito de sisal) e a diminuição da tensão de ruptura à flexão dos compósitos reforçados por fibras naturais analisados (45% para o compósito de algodão, 55% para o compósito de sisal). No entanto, com o aumento da espessura da estrutura aeronáutica adotada (5,2% para o compósito de algodão, 10,7% para o compósito de sisal), conclui-se que a substituição do compósito sintético pelo natural seria viável. Isto acarretaria em um aumento de massa em 6,2%, caso a estrutura fosse fabricada em compósito reforçado por fibra de sisal. Finalmente, constatou-se que a fração mássica de aditivo utilizada tem grande potencial de otimização e, que a eficiência dos compósitos reforçados por fibras naturais ainda pode ser melhorada. / This dissertation has aimed to study the mechanical behavior and the flammability of aeronautical interior structures manufactured from composites reinforced by natural fibers, specifically phenolic resin and cotton and sisal fibers composites, verifying the possibility of synthetic composites replacement. Firstly, experimental analyses were performed to determine the mechanical properties of the materials. Then, computational analyses were carried out, using properties of synthetic composites and composites reinforced by natural fibers. Also, failure criteria were applied, considering the synthetic composite performance of an interior aeronautical structure as reference. Furthermore, the behavior regarding flammability was analyzed. The addition of flame retardants was necessary for the composites reinforced by natural fibers in order to attend the aeronautical certification requirements. After the addition of flame retardants, an increase in the flexural modulus of elasticity (55% for the cotton composite, 16% for the sisal composite) and a decrease in the flexural stress at break (45% for the cotton composite, 55% for the sisal composite) were observed. However, with an increase of the thickness of the aeronautical structure (5.2% for the cotton composite, 10.7% for the sisal composite), it was concluded that the replacement would be feasible, which would lead to a increase of the mass equal 6.2% for the sisal fiber composite. Finally, it was evidenced that the used flame retardant mass fraction has a great potential for optimization and that the natural composites efficiency can be improved.

Les fibres végétales peuvent être considérées comme une alternative intéressante aux fibres de verre pour la fabrication de matériaux composites. En effet, elles présentent des caractéristiques physiques intéressantes, telles que leur faible densité et leurs bonnes propriétés mécaniques spécifiques, qui peuvent rivaliser avec les composites renforcés de fibres de verre. En outre, les fibres végétales sont obtenues à partir de ressources renouvelables, et présentent généralement moins d'impacts environnementaux lors de leurs phases de production, d’utilisation et en fin de vie. Contrairement aux fibres de verre, les fibres végétales, telles que des fibres de lin, présentent des structures hiérarchiques complexes composées essentiellement de cellulose, hémicellulose, lignine, ciments peptiques et extractibles lipophiliques (cires, acides gras, etc.). Cette composition varie selon les espèces, le lieu et les conditions de croissance, la maturité de la plante, etc. De la même façon, la composition biochimique et la structure des produits et des sous-produits issus du lin sont soumis à de grandes variations selon les étapes successives de transformation réalisées à partir des tiges de lin jusqu’aux fils et tissus. Cela influence fortement les propriétés finales des fibres de lin et de leurs biocomposites. La première partie de cette étude se concentre sur la caractérisation de fibres de lin au cours de leurs étapes successives de transformation. Une homogénéisation de la composition chimique est observée dans les étapes finales de transformation, ainsi qu’une augmentation des propriétés en traction longitudinale des mèches de fibres de lin. La deuxième partie traite de l'utilisation de différents traitements de lavage appliqués sur des tissus d’étoupes de lin et leur influence sur l'extraction des composants de la paroi cellulaire des fibres, ainsi que sur la microstructure et les propriétés mécaniques de biocomposites époxy/lin. Il est montré que les composants de la paroi cellulaire jouent un rôle clé dans la dispersion des mèches et des fibres élémentaires de lin et sur le comportement mécanique transversal de leurs biocomposites. Enfin, l'application de différents traitements de fonctionnalisation sur des tissus de fibre de lin est étudiée afin d'améliorer l'adhérence interfaciale entre les fibres et la matrice. L'utilisation de molécules de type organosilanes (aminosilane, époxysilanes) et de molécules biosourcés (acides aminés et polysaccharides) est étudiée. Une augmentation de la rigidité en traction longitudinale et de la rigidité et de la contrainte maximale en traction transverse est observée en raison de l'amélioration de l'adhésion interfaciale par la fonctionnalisation de surface des fibres avec des molécules d'origine biosourcé et non-biosourcé. / Natural fibres can be considered as a relevant alternative to glass fibres in the manufacture of composite materials. Indeed, they present interesting physical characteristics, such as low density and good specific mechanical properties, which can compete with glass fibre reinforced composites. Moreover, natural fibres are obtained from renewable resources, and generally present lower environmental impacts during their production and use phases and their end of life. Unlike glass fibres, natural fibres, such as flax fibres, are complex hierarchical materials composed essentially of cellulose, hemicellulose, lignin, peptics cements and lipophilic extractives (waxes, fatty acids, etc.). This composition varies among species, collection site, plant maturity, batches, etc. Besides, the biochemical composition and structure of flax products and sub-products undergo wide variations according to the transformation steps from stems to yarns and fabrics. This influences greatly the final properties of flax fibres and their biocomposites. The first part of this study is focused on the characterization of flax fibres during their successive transformation steps. A homogenization of the chemical composition is observed at the final transformation steps, as well as an increment of the longitudinal tensile properties of flax yarns. The second part deals with the use of different washing treatments applied on flax tow fabrics and their influence on the extraction of flax cell wall components and the resulting microstructure and mechanical properties of epoxy/flax fibres reinforced biocomposites. It is shown that cell wall components play a key role in the flax yarns and elementary fibres dispersion and transverse mechanical behaviour of biocomposites. Finally, the application of different functionalization treatments onto flax fibres fabrics is investigated in order to improve the interfacial adhesion between fibres and matrix. The use of non-bio-based organosilane molecules (aminosilane, epoxysilane) and bio-based molecules (amino-acids and polysaccharides) is studied. Improvedstiffness in longitudinal tension test and stiffness and tensile strength in transverse tension test are observed due to the improvement of interfacial adhesion by surface functionalization of the fibres with both bio-based and non-bio-based molecules.

A presente pesquisa teve como objetivo avaliar o uso de compósitos de fibras e resina epóxi no reforço de emendas dentadas em peças de madeira. Inicialmente, foi avaliada a influência da trama das fibras de sisal e de curauá sem tratamento nenhum nas propriedades mecânicas à tração dos compósitos com resina epóxi. Igualmente, foram caracterizados na tração compósitos de fibras de vidro e tecidos de sisal. Posteriormente, foi avaliada a resistência à tração paralela às fibras de peças de madeira Pinus sp em tamanho estrutural para três tipos de tratamentos: (1) peças sem emendas e sem reforço, (2) peças com emendas e sem reforço e (3) peças com emendas reforçadas por compósitos de fibras de vidro e resina epóxi. Também foram realizados testes de tração em corpos de prova isentos de defeitos com emendas dentadas usando madeira Lyptus® para três casos: (1) sem reforço na emenda, (2) reforço na emenda com fibra de vidro e (3) reforço na emenda com tecido de sisal. Os resultados da influência da trama das fibras de sisal e curauá com a resina epóxi nos testes de tração mostraram que o tipo de trama não influenciou significativamente na resistência e no módulo de elasticidade. Na caracterização dos compósitos poliméricos, a resistência do tecido de sisal foi cerca de 44% da resistência da fibra de vidro. Nas peças estruturais, devido à baixa resistência da madeira de Pinus sp utilizada, não se justificou a utilização do reforço. Nos corpos de prova isentos de defeitos de madeira Lyptus® com emendas dentadas, a eficácia do reforço foi evidenciado, com aumento de 37% na resistência à tração com reforço de fibra de vidro e de 40% com reforço de tecido de sisal, em relação aos corpos de prova isentos de defeitos sem reforço. / The present research evaluate the reinforcing of finger joints in timber pieces with composite fiber and epoxy. Initially, the influence of the weft in the tensile mechanical properties of composites using sisal fibers and curaua without any treatment was evaluated. The characterization of composites made with sisal fibers and glass fibers were also carried out. Additionally, the tensile strength parallel to the grain for pieces of Pinus sp in structural sizes for three types of treatments: (1) pieces without finger joints, (2) pieces unreinforced finger joints and (3) pieces reinforced finger joints with composite fiberglass and epoxy resin, was evaluated. Also, was evaluated the tensile strength of the finger joint test specimens Lyptus® wood for three cases: (1) unreinforced finger joint, (2) reinforced finger jointed with fiberglass and (3) reinforced finger jointed with fabric sisal. The results of influence of the weft sisal fibers and curaua with epoxy resin of tensile test showed that the weft did not significantly influence the strength and the modulus of elasticity. The characterization of polymeric composites, the strength of sisal fabric was about 44% of the fiber glass strength. The structural size pieces, the use of reinforcement it is not justified due to the low strength of the Pinus sp wood used. The test specimens of Lyptus® wood with finger joints, the efficacy of the reinforcement was evident, with 37% increase in tensile strength with glass fiber reinforcement and 40% with reinforcement sisal fabric, compared to specimens without reinforcement.

Palm oil production create a number of solid biomass waste products, in particular empty fruit bunches and mesocarp fiber; two cellulosic plant materials that are under-utilized and a source of environmental pollution today. Their fibred structure are interesting from an industrial design perspective as similar waste products from industrialized crops are used to create composite materials. This bachelor thesis is based on an initial research phase of the palm oil industry in Thailand, where literary studies, case-studies and interviews were used to gain understanding of how the palm oil industry in Thailand operates. This laid the foundation to a material driven design process; an exploratory phase where samples of waste products collected during the research phase were tinkered with, to create composite materials of natural fibers and starch-based plastics. The materials created were characterized by their technical properties, and evaluated through a focus group of Thai students to define their experiential characteristics. The insights learned from the evaluation were used to create a demonstrative concept of how the material can be put to future use. The experiential characterization showed that the material have valuable sensorial, performative, emotional and interpretive properties, such as strength, flexibility and translucency, while being perceived as elegant, amusing, strange and natural. This leads to the conclusion that there is possible added value in the waste products that are seen as a nuisance today. Parallel to the material driven design process, samples of empty fruit bunches and mesocarp fiber were used to develop a 3D-printing filament. While only simple test prints have been tried at the time of writing, it provides proof of concept.

Les matériaux composites à matrice polymère sont couramment utilisés dans des structures dont la durée de vie peut dépasser la dizaine d’années. En conditions de service, ils peuvent être soumis à des sollicitations thermiques, mécaniques et hydriques, couplées ou non, et subissent également un vieillissement, c’est-à-dire une évolution de leur structure induisant une modification, et souvent une dégradation de leurs performances via divers mécanismes. Ceci est particulièrement vrai pour les propriétés ignifuges et thermomécaniques. Si de nombreuses études traitent de l’impact du vieillissement sur les propriétés mécaniques, peu de travaux mettent en évidence une perte partielle ou totale de résistance au feu de matériaux ignifugés après vieillissement. Par ailleurs, une tendance forte aujourd’hui est le développement de matériaux composites renforcés par des fibres naturelles, susceptibles de remplacer les fibres de verre. Cependant, les fibres naturelles sont sujettes à dégradation en conditions hygrothermiques ou hydrothermiques. De même, les systèmes retardateurs de flamme les plus étudiés aujourd’hui, à base de phosphore, sont sensibles à ce type de vieillissement.Ces travaux de thèses rapportent l’évolution du comportement au feu et thermomécanique d’un composite à matrice époxy renforcé par des fibres de lin et contenant un retardateur de flamme phosphoré face à divers scénarios de vieillissement. Afin de comprendre l’influence des paramètres de vieillissement, des environnements hygrothermiques à 70°C et humidité relative variable mais également hydrothermique ont été imposés aux composites ignifugés avec deux retardateurs de flammes phosphorés différents. L’influence de la température, ainsi que celle d’un séchage, ont également été étudiées. L’évolution des propriétés du biocomposite ignifugé, que ce soit les propriétés mécaniques ou la réaction au feu, a été mise en relation avec la quantité d’eau absorbée par celui-ci lors du vieillissement. Enfin, puisque les composites étudiés peuvent être utilisés pour des applications exigeant un maintien des performances mécaniques en cas d’incendie, ces travaux de thèse ont porté également sur l’évolution des propriétés mécaniques des différents matériaux étudiés vieillis hydrothermiquement après une exposition à un flux de chaleur correspondant à un début d’incendie. / Polymeric materials, especially composites are used for long term applications. When used, those materials can be subjected, for example, to thermic, mechanical or hydric stresses but can also age. Indeed, with time, there will be an evolution of their structure leading, in most cases, to an alteration of their properties via several mechanisms. This is all the more true for their mechanical and fire performances. If many studies analyze the influence of ageing on the mechanical properties of a composite, few highlight a partial or total drop of fire performances of a fire-retarded composite. Moreover, the substitution of glass fibers by natural fibers is a trend in constant evolution but those natural fibers can be easily degraded during a hygrothermal or hydrothermal ageing. Similarly, flame retardant containing phosphorous are more and more studied while being sensitive to those types of ageing.This thesis reports the evolution of a thermoset composite (epoxy matrix) reinforced with natural fibers (UD flax fibers) and containing a phosphorous flame retardant through various ageing scenarios and the impact of ageing on their mechanical properties and their fire performances. In order to understand the influence of the various ageing parameters, hygrothermal and hydrothermal ageings were carried out on flame-retarded composites with two different phosphorous flame retardants. This allowed us to connect the alteration of properties and the amount of water absorbed during ageing. Finally, since sometimes the studied composites must maintain their mechanical properties even exposed to a fire, this thesis also reports the impact of a short exposition to a heat flux similar to small fire on the various studied composites that have been previously subjected to a hydrothermal ageing.

O trabalho visou realizar um estudo sobre o comportamento mecânico e de inflamabilidade de estruturas aeronáuticas de interior fabricadas a partir de compósitos reforçados por fibras naturais, especificamente compósitos de resina fenólica com fibras de algodão e de sisal, verificando assim, a possibilidade de substituir compósitos sintéticos. Num primeiro momento, análises experimentais foram executadas para determinar as propriedades mecânicas dos materiais. Em seguida, análises computacionais foram realizadas, empregando as propriedades referentes aos compósitos sintéticos e reforçados por fibras naturais, utilizando critérios de falha e tendo como referência o desempenho do compósito sintético para uma dada estrutura aeronáutica de interior. Além disso, foram efetuadas análises do seu comportamento quanto à inflamabilidade. A incorporação de retardantes de chama foi necessária para que os compósitos reforçados por fibras naturais atendessem aos requisitos de certificação aeronáutica. Após o processo de aditivação, observou-se um aumento do módulo de elasticidade à flexão (55% para o compósito de algodão, 16% para o compósito de sisal) e a diminuição da tensão de ruptura à flexão dos compósitos reforçados por fibras naturais analisados (45% para o compósito de algodão, 55% para o compósito de sisal). No entanto, com o aumento da espessura da estrutura aeronáutica adotada (5,2% para o compósito de algodão, 10,7% para o compósito de sisal), conclui-se que a substituição do compósito sintético pelo natural seria viável. Isto acarretaria em um aumento de massa em 6,2%, caso a estrutura fosse fabricada em compósito reforçado por fibra de sisal. Finalmente, constatou-se que a fração mássica de aditivo utilizada tem grande potencial de otimização e, que a eficiência dos compósitos reforçados por fibras naturais ainda pode ser melhorada. / This dissertation has aimed to study the mechanical behavior and the flammability of aeronautical interior structures manufactured from composites reinforced by natural fibers, specifically phenolic resin and cotton and sisal fibers composites, verifying the possibility of synthetic composites replacement. Firstly, experimental analyses were performed to determine the mechanical properties of the materials. Then, computational analyses were carried out, using properties of synthetic composites and composites reinforced by natural fibers. Also, failure criteria were applied, considering the synthetic composite performance of an interior aeronautical structure as reference. Furthermore, the behavior regarding flammability was analyzed. The addition of flame retardants was necessary for the composites reinforced by natural fibers in order to attend the aeronautical certification requirements. After the addition of flame retardants, an increase in the flexural modulus of elasticity (55% for the cotton composite, 16% for the sisal composite) and a decrease in the flexural stress at break (45% for the cotton composite, 55% for the sisal composite) were observed. However, with an increase of the thickness of the aeronautical structure (5.2% for the cotton composite, 10.7% for the sisal composite), it was concluded that the replacement would be feasible, which would lead to a increase of the mass equal 6.2% for the sisal fiber composite. Finally, it was evidenced that the used flame retardant mass fraction has a great potential for optimization and that the natural composites efficiency can be improved.

Submitted by Adriely Bruce (adriely_bruce@hotmail.com) on 2016-12-02T14:22:37Z No. of bitstreams: 1 Dissertação - Gleicyanne O. S. Portela.pdf: 22271229 bytes, checksum: 080a862aceacc66dfad8d9ac34c508bf (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-12-02T19:19:50Z (GMT) No. of bitstreams: 1 Dissertação - Gleicyanne O. S. Portela.pdf: 22271229 bytes, checksum: 080a862aceacc66dfad8d9ac34c508bf (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-12-02T19:20:26Z (GMT) No. of bitstreams: 1 Dissertação - Gleicyanne O. S. Portela.pdf: 22271229 bytes, checksum: 080a862aceacc66dfad8d9ac34c508bf (MD5) / Made available in DSpace on 2016-12-02T19:20:26Z (GMT). No. of bitstreams: 1 Dissertação - Gleicyanne O. S. Portela.pdf: 22271229 bytes, checksum: 080a862aceacc66dfad8d9ac34c508bf (MD5) Previous issue date: 2016-04-01 / The usage of natural fibers as reinforcement in cementitious matrices has been an alternative to replacing the synthetic fibers. In this work jute fiber were characterized and added in composite. For the production of geopolymer, the activators were potassium hydroxide and potassium silicate hydroxide mixed with metakaolin, cement and sand. Characterization tests utilizing x-ray fluorescence techniques (XFR), X-ray diffractometry (XRD), chemical and physical tests, tensile and flexural tests and analyzis of the microstructu e by scanning electron microscopy (SEM) were performed for characterization of materials. Compressive strength tests on the matrix were performed at the ages of 7, 14 and 28 days, and the samples had a maximum performance of compressive strength at 58,29 MPa. The composites reinforced with three layers of jute fabric were submitted to mechanical tests after 14days and showed a flexural behavior with maximum stress of 21.4 MPa. The results indicated that the use of natural fibers increased mechanical performance of traction and flexion geopolymer composite. / O uso de fibras naturais como reforço em matrizes cimentícias tem sido uma alternativa para substituição das fibras sintéticas. Neste trabalho, as fibras de juta foram caracterizadas e adicionadas compósitos. Para a produção dos geopolímeros os ativadores foram o hidróxido de potássio e silicato de hidróxido de potássio, misturados a metacaulinita, cimento e areia. Ensaios de caracterização utilizando técnicas de Fluorescência de raio-x (FRX), Difratometria de raio-x (DRX), ensaios químicos e físicos, ensaios de tração e flexão e analise da microestrutura por microscopia eletrônica de varredura (MEV) foram realizados para a caracterização dos materiais. Os testes de resistência à compressão na matriz foram realizados nas idades de 7, 14 e 28 dias, amostras apresentaram desempenho máximo de resistência à compressão de 58,29 MPa. Os compósitos reforçados com três camadas de tecido de juta foram submetidos aos ensaios mecânicos após 14 dias e apresentaram comportamento à flexão com tensão máxima de 21,4 Mpa. Os resultados obtidos indicaram que o uso de fibras naturais aumentou o desempenho mecânico de tração e flexão do compósito geopolímero.