No description available.

Binderless fiberboard production from Cynara cardunculus and Vitis viniferaTwo lignocellulosic materials, Cynara cardunculus and Vitis vinifera, were pretreated and used to produce fiberboards without synthetic adhesives. The lignocellulosic materials were steam exploded through a thermo-mechanical vapor process in a batch reactor. After pretreatment the materials were dried, ground and pressed to produce the boards. The effects of pretreatment factors and pressing conditions on the chemical and physicomechanical properties of the fiberboards were evaluated and the conditions that optimize these properties were found. Response surface methodology based on a central composite design and multiple response optimization were used. The variables studied were: pretreatment temperature, pretreatment time, pressing temperature, pressing pressure, and pressing time. Binderless fiberboards produced from Cynara cardunculus stalks at the optimum conditions found fulfilled the European standards for boards of internal use. Nevertheless, binderless fiberboards produced from Vitis vinifera prunings at the optimum conditions found for this material did not completely met the European standards; modulus of rupture and internal bond values for these boards were lower than required minimums.Simultaneously, commercial Kraft lignin was reacted in an alkaline medium to enhance its adhesive properties. Chemical changes in reacted Kraft lignins that include ash content, Klason lignin, acid-soluble lignin and sugars were determined, as well as, structural characteristics of these lignins in terms of phenolic hydroxyl, aliphatic hydroxyl, methoxyl, carbonyl, Mw, Mn and polydispersity. The effects of reaction temperature and reaction time on lignin properties were studied using response surface methodology, and optimal reaction conditions were found.Two different types of Kraft lignin were used, alkali treated Kraft lignin and crude acid-washed Kraft lignin, as additives to enhance the physicomechanical properties of binderless fiberboards produced from Vitis vinifera to reach and overcome the European standards completely. At the end fiberboards produced with 20% of Vitis vinifera fibers replaced by crude acid-washed Kraft lignin were able to meet the European standards completely.This research work was an effort to reduce our dependency upon petroleum derivates, to diminish deforestation and to increase the use of renewable and biodegradable materials with the intention of preserving the environment and to encourage a sustainable development of our society. / Producción de Tableros de Fibras a partir de Cynara cardunculus y Vitis viniferaEn el presente estudio trozos Cynara cardunculus y Vitis vinifera fueron pretratados, y usados para producir tableros de fibras sin adhesivos sintéticos. Estos materiales lignocelulósicos se explotaron con vapor a través de un proceso termomecánico de vapor en un reactor por lotes. Después del pretratamiento el material fue secado, molido y prensado en caliente para producir los tableros. Se evaluaron los efectos de los factores del pretratamiento (temperatura de reacción y tiempo de reacción) y las condiciones de prensado (presión de prensado, temperatura y tiempo) sobre las propiedades químicas y físico-mecánicas de los tableros de fibras y se establecieron las condiciones que optimizan dichas propiedades. Las propiedades físico-mecánicas de los tableros de fibras que fueron estudiadas son: densidad, módulo de elasticidad (MOE), módulo de ruptura (MOR), enlace interno (IB), absorción de agua (WA) y hinchazón en hinchazón (TS) y las propiedades químicas estudiadas de la materia prima y el material pretratado fueron las siguientes: Cenizas, contenido de lignina Klason, contenido de celulosa y contenido de hemicelulosas. Se uso una metodología de superficie de respuesta basada en un diseño de experimentos del tipo central compuesto y una metodología de optimización de respuesta múltiple.Los tableros de fibras sin adhesivos sintéticos producidos a partir de tallos de Cynara cardunculus a las condiciones óptimas encontradas cumplieron con las normas europeas para los tableros de uso interno. Sin embargo, los tableros de fibras sin adhesivos sintéticos producidos a partir de podas de Vitis vinifera a las condiciones óptimas encontradas para este material no cumplieron totalmente las normas europeas; los valores del módulo de ruptura y del enlace interno para estos tableros fueron inferiores a los mínimos requeridos. Una lignina Kraft comercial fue sometida a reacción en un medio alcalino para mejorar sus propiedades adhesivas. Se determinaron los cambios químicos en las ligninas Kraft tratadas, las propiedades medidas fueron: contenido en cenizas, lignina Klason, lignina soluble en ácido y azúcares, también se determinaron las características estructurales de estas ligninas en términos de hidroxilos fenólicos, hidroxilos alifáticos, metóxilos, carbonilos, Mw, Mn y polidispersidad. Se estudiaron los efectos de la temperatura de reacción y el tiempo de reacción sobre las propiedades de la lignina con una metodología de superficie de respuesta, y se encontraron la condiciones óptimas de reacción.Se usaron dos tipos diferentes de lignina Kraft, lignina Kraft tratada en medio alcalino y lignina Kraft cruda lavada con ácido, como aditivos para mejorar las propiedades físico-mecánicas de los tableros de fibras sin adhesivos sintéticos producidos a partir de Vitis vinifera, para alcanzar y superar las normas europeas completamente. Al final los tableros de fibras producidos con una substitución del 20% de fibras de Vitis vinifera por lignina Kraft cruda lavada con ácido fueron capaces de satisfacer las normas europeas por completo.Este trabajo de investigación fue un esfuerzo para reducir nuestra dependencia de los derivados del petróleo, para disminuir la deforestación y para aumentar el uso de materiales renovables y biodegradables con la intención de preservar el medio ambiente y fomentar un desarrollo sostenible de nuestra sociedad.

La mutation de nos activités industrielles vers le développement durable est l’un des plus gros enjeux humains du 21ème siècle. L’utilisation de la biomasse dans divers domaines tels que l’énergie, la construction et les matériaux est une réponse face à la raréfaction des ressources fossiles et face aux risques écologiques. Les objectifs de cette thèse sont de créer de nouveaux matériaux les plus bio-sourcés possibles et d’optimiser les propriétés de ces matériaux en vue d’une éventuelle utilisation industrielle. Les travaux présentés ici traitent de la fabrication de matériaux composites à renforts de fibres naturelles, ayant pour matrice des résines bio-sourcées. Les ressources végétales principalement étudiées ici sont les tannins, utilisés pour la réalisation de : - Composites à matrice tannin – hexamine - Composites à matrice tannin – résorcine – aldéhyde Les tannins végétaux ont également été étudiés pour la conception de bio-plastiques tannin – alcool furfurylique pouvant être appliqués à la fabrication de composites. Les panneaux composites ont été réalisés en laboratoire et analysés mécaniquement en se basant sur des méthodes normatives européennes. Les résines ont également été caractérisées à l’aide de diverses techniques telles que l’analyse thermomécanique (TMA) ou la spectroscopie de masse MALDI-ToF. Au final, ces travaux ont permis de réaliser des matériaux composites hautement bio-sourcés, aux propriétés homogènes et reproductibles satisfaisant en outre les exigences d’emploi de plusieurs normes européennes / Changing our industrial activities towards sustainable development is one of the major human concerns of the 21th century. The use of biomass in various areas like energy, construction and materials is an answer to the future scarcity of fossil resources and to the ecological risks. The objectives of this thesis are to create new materials with the highest bio-based content possible and then to optimize these materials properties for a potential industrial use. The work presented here is about the fabrication of composite materials reinforced with natural fibers, using bio-based resins as a matrix. The main vegetable resources studied here are tannins, used to make: - Tannin – hexamine matrix composites - Tannin – resorcinol – aldehyde matrix composites Vegetable tannins were also studied to prepare tannin – furfuryl alcohol bio-plastics that may be used in the composites fabrication. The composites boards were made in laboratory and mechanically analyzed based on European norms methods. Resins were also characterized using various techniques such as thermomechanical analysis (TMA) or MALDI-ToF mass spectrometry. The end results of this work is the fabrication of highly bio-based composite materials, with homogenous and repeatable properties that furthermore satisfy several European norms requirements.

[pt] Visando adequar a sociedade do consumo a uma existência menos impactante ao meio ambiente, a busca por materiais oriundos de fontes renováveis e passíveis de biodegradação é crescente. No entanto, para que esta transição seja mais eficiente, se faz necessário mudar não só os materiais que são produzidos, mas também a logística da produção e os processos produtivos utilizados. Com base nisto, o objetivo deste trabalho é desenvolver e caracterizar uma chapa de fibras, desenvolvida a partir de resíduos da agro indústria do palmito de pupunha (Bactris Gasipaes), a ser produzida por meio da capacitação dos agricultores locais, com processos de baixa complexidade tecnológica, baixo custo de implementação e mínimo impacto ambiental associado à sua produção. Os ensaios foram realizados de acordo a norma ABNT 15316 - 2:2009, que determina parâmetros de amostragem e métodos de ensaio das chapas de fibras de média densidade (MDF). Como adesivo, aglomerante, foi utilizada a resina poliuretana, de base vegetal, em diferentes proporções fibra/matriz. Os resultados foram analisados seguindo a norma ABNT 15316 – 3: 2009, que estabelece os requisitos para chapas de densidades diferentes, produzidas para os mais diversos fins (estrutural, geral, forro, parede, dentre outros). Dessa forma, foi possível atestar a viabilidade de produção da chapa em pequena escala, garantindo a parcial substituição das chapas MDF disponíveis no mercado, o que comprova a real oportunidade de crescimento sustentável, através da geração de renda e desenvolvimento sócio ambiental. / [en] Aiming to adapt the consumer society to a life less harmful to the environment, the research for materials produced from renewable sources and subject to biodegradation is increasing. However, for this transition to be more efficient, it is necessary to change not only the materials that are being produced but also the production logistics and production processes used. On this basis, the objective of this work is to develop and characterize a fiberboard, developed from the agro-industry waste of Pupunha`s palm heart (Bactris gasipaes), to be produced through the training of local farmers, processes with low complexity technology, low cost of implementation and minimal environmental impact associated with its production. The tests were performed according to the ABNT 15316 - 2:2009, which determines the parameters of sampling and test methods for medium density fiberboard (MDF). The vegetal based polyurethane was used as adhesive/ binder. The samples were produced in different proportions fiber / matrix. The results were analyzed following the ABNT 15316-3: 2009, which establish the requirements for plates of different densities, produced for different purposes (structural, general, lining, wall, among others). Thus it was possible to demonstrate the feasibility of a small scale production of the alternative fiberboard, ensuring the partial replacement of the medium density fiberboards usually available on the market. This points out to the growth opportunity of the rural comunitys through income generation and socio-environmental development.

No description available.