Les apiaceae peuvent être définies en tant qu' Aroma-Tincto-Oleo-Crop (ATOC), plantes qui contiennent à la fois une huile végétale et une huile essentielle. Appliquer le concept d'agroraffinage aux ATOC revient à proposer un procédé séquentiel alliant une co-extraction huile végétale et huile essentielle à une valorisation des résidus en tant que source de molécules biosourcées et de susbtrat pour la formulation d'agromatériaux . Les objectifs de cette thèse seront donc d'étudier la faisabilité biologique et technologique d'application du concept d'ATOC-raffinage à la coriandre (Coriandrum sativum L.). Le chapitre I présente l'état de l'art bibliographique sur l'extraction et l'analyse des huiles végétales et huiles essentielles de coriandre tandis que dans le chapitre II sont décrits les matériels et méthodes mis en oeuvre au cours de la thèse tant au niveau échantillonnage, extraction, analyse que traitement des données. Le chapitre III est centré sur l'étude des différents paramètres biologiques pouvant influencer la bioaccumulation des huiles végétales et huiles essentielles dans la coriandre (différentes variétés, différents organes de la plante, différents stades de développement biologique) et leur impact sur l'activité anti-oxydante des extraits obtenus à partir des résidus d'extraction. Dans le chapitre IV, la technologie d'extrusion (mono-vis et bi-vis) a été appliquée aux graines de coriandre dans le but d’évaluer la faisabilité du pressage mécanique du fruit de la coriandre pour l’extraction d'une huile végétale aromatisée. L’influence des conditions expérimentales sur le rendement d'extraction en huile végétale (diamètre de buse et distance buse-vis (extrudeur mono-vis) ou configuration de vis, coefficient de remplissage et température de pressage (extrudeur bi-vis)) a été étudiée tandis que la faisabilité de la valorisation du résidu solide d'extraction en agromatériaux (thermo-pressage) a été montrée. / Apiaceae could be defined as Aroma Tincto Oleo Crops (ATOC), e.g. plants containing both vegetable oil and essential oil. Applying agroreffinery concept to ATOC led to propose a sequential fractionation process coupling co-extraction of vegetal oil and essential oil to a valorization of by-product residues as biosourced active molecules and substrates for designing agromaterials. The aim of this thesis is to determine the biological and technological feasability of application of the ATOC-refinery concept to coriander (Coriandrum sativum L.) Chapter I reports a bibliographic state of the art study on extraction and characterisation of coriander vegetal oil and essential oil while chapter II describes materials and methods setting up during the thesis for sampling, extraction, analysis and data processing. Chapter III focus on the study of major various biological parameters influencing bioaccumulation of vegetal oil and essential oil in coriander (different plant varieties, different plant organs, different biological stages) and their impact on anti-oxidant activity of extracts obtained from extraction residues. In chapter IV, coriander fruits are processed by extrusion technology (mono screw and twin-screw extruder) in order to evaluate the feasability of mechanical pressing for extracting a flavored vegetal oil. Influence of operating parameters on vegetal oil extraction yields (nozzle diameter and nozzle/screw distance (single-screw extruder) or screw configuration, device’s filling coefficient and pressing temperature (twin-screw extruder)) is studied while the feasability of valorization of extraction cake as agromaterial (thermopressing) was stated.

Solvent-free extrusion emulsification (SFEE) is a recently developed process for producing submicron particles with high viscosity polymers inside a twin-screw extruder without the use of hazardous solvents. Its dependency on a catastrophic phase inversion makes the process knowingly sensitive to a variety of formulation and operational variables, causing a narrow window of production. The purpose of this thesis was to investigate and improve process stability as well as widening operational window. Transient effects of the start-up procedure was investigated by considering the process stability and particle size distribution. The transient sensitivity corresponded to the residency of material in the dispersion zone. When a sub-optimal water/surfactant fraction was allowed to produce an undesired polymer-water (thick lamella) morphology, this morphology continued to persist until the critical first half of the dispersion zone was purged of existing mass. Lot to lot variability of polyester resin was used to investigate the sensitivities of the SFEE process more deeply to better understand the mechanism involved. In this case, acid number was shown to have a significant effect on the initial amount of water needed in the dispersion zone for phase inversion, resulting in an emulsification boundary dependent on the resin acid number. In fact, a significant correlation was found between the acidic end groups of the resin and the maximum amount of water content that could be used in the dispersion zone. The effect of feed rate, screw speed, dispersion length, and surfactant concentration were studied for their individual influence on widening the emulsification boundary. The most significant improvement was observed by applying a longer dispersion length or lower feed rate because both significantly increase the residence time. The effect of residence time on the emulsification boundary was attributed to the total strain imposed on the polymer/water mixture which was related to interfacial growth in the dispersion zone. / Dissertation / Doctor of Philosophy (PhD)

No description available.

The aim of this thesis is the investigation of modeling and optimization particularities of tubular polymerization reactors. The original work is divided in two sections, the first treating a modeling and optimization study of tubular reactors for methyl methacrylate polymerization in solution, and the second, an experimental and theoretical study of L-lactide reactive extrusion. In the first section, reactor simulations in similar operating conditions were performed in order to select a representative kinetic model among the published kinetic models for MMA solution polymerization. Two widely used numerical algorithms, one based on Pontryagin's Minimum Principle and the other a Genetic Algorithm, were compared for an average-complexity optimization problem. The results showed a superior robustness of the Genetic Algorithm for this category of problems. The second part of the thesis deals with the modeling and optimization of L-lactide reactive extrusion. A kinetic model is proposed and its parameters estimated using nonlinear estimation numerical procedures based on experimentally measured data. Reactive extrusion experiments were performed in representative operating conditions. The Llactide/ polylactide flow in the extruder was characterized by simulation using the commercial software LUDOVIC®. The simulated residence time distributions characteristics are used to model the reactive extrusion process of two approaches, an axial dispersion model and a compartment model, based on compartments whose characteristics are deduced from the simulations using LUDOVIC®. The modeling results are in good agreement with the measured data in the same operating conditions.

Submitted by Aelson Maciera (aelsoncm@terra.com.br) on 2017-05-25T19:49:56Z No. of bitstreams: 1 DissBDQ.pdf: 27222907 bytes, checksum: eb17b232bd0096bfa1e0fb1dd7f4bf74 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-05-30T13:44:57Z (GMT) No. of bitstreams: 1 DissBDQ.pdf: 27222907 bytes, checksum: eb17b232bd0096bfa1e0fb1dd7f4bf74 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-05-30T13:45:05Z (GMT) No. of bitstreams: 1 DissBDQ.pdf: 27222907 bytes, checksum: eb17b232bd0096bfa1e0fb1dd7f4bf74 (MD5) / Made available in DSpace on 2017-05-30T13:50:33Z (GMT). No. of bitstreams: 1 DissBDQ.pdf: 27222907 bytes, checksum: eb17b232bd0096bfa1e0fb1dd7f4bf74 (MD5) Previous issue date: 2015-10-06 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / In this study nanocomposites of polyamide-6 (PA-6) reinforced with silica nanoparticles (SiO2) were prepared in order to promote improved mechanical properties for engineering applications. The nanoparticles’ surfaces were chemically modified with the silane agent 3-aminopropyltrimethoxysilane (3- APTMS) to improve the chemical and physical interactions between them and the PA-6 matrix. Nuclear magnetic resonance analysis (NMR) and Fourier transform infrared absorption spectroscopy (FT-IR) showed that 3-APTMS grafting on nanoparticles surface was accomplished. The nanocomposites mixing process was studied in two forms: by torque rheometry, using a torque rheometer internal mixer; and in a co-rotating and intermeshing twin-screw extruder. A preliminary study of the influence of processing variables at the torque rheometer on the degradation of polyamide-6 matrix was performed. The results showed that the greater the filling volume of the mixture in the chamber and the rotational speed of the rheometer’s rotors, the lower the degradation of the polyamide-6. Based on this preliminary study, compositions with 1, 2, and 4 % weight of SiO2 nanoparticles, both unmodified and chemically modified with 3-APTMS were prepared in the torque rheometer. The nanocomposites were compression molded and it was observed that nanocomposites reinforced with 1 wt.% SiO2, both unmodified and surface-modified, presented the best tensile properties. For the nanocomposite samples processed in the twin-screw extruder, the influence of relevant variables – nanoparticle content, chemical surface modification, physical form of the fed PA-6 (granule and powder), rotational speed of screws and extruder feed rate – on mechanical, thermal, and dynamic-mechanical properties were studied. The samples were afterwards injection molded and it was observed that the samples produced using 1 wt.% surface-modified and 100% finely ground PA-6 showed the higher tensile modulus and yield strength values. / Neste estudo foram preparados nanocompósitos de poliamida 6 (PA6) reforçados com nanopartículas de sílica (SiO2), com o objetivo de promover melhoria de propriedades mecânicas para aplicações de engenharia. A superfície das nanopartículas foi modificada quimicamente com o agente silano 3-aminopropiltrimetoxisilano (3-APTMS) para melhorar as interações químicas e físicas entre elas e a matriz de PA6. Análises de ressonância magnética nuclear (RMN) e espectroscopia de absorção no infravermelho por transformada de Fourier (FT-IR) mostraram que houve sucesso na funcionalização das nanopartículas com o agente silano. O processo de mistura dos nanocompósitos foi estudado de duas formas: por meio de reometria de torque em um misturador interno; e em extrusora com rosca dupla co-rotacional e interpenetrante. Um estudo preliminar da influência das variáveis de processamento no reômetro de torque sobre a degradação da poliamida 6, mostrou que quanto maior o volume de preenchimento da câmara de mistura e a velocidade de rotação dos rotores do reômetro, menor foi a degradação da poliamida 6. Com base neste estudo preliminar, foram preparadas no reômetro de torque composições com 1, 2 e 4% em massa de nanopartículas de SiO2 não modificadas e modificadas quimicamente com 3- APTMS. Os nanocompósitos obtidos foram moldados por compressão, tendo sido observado que os nanocompósitos reforçados com 1 %m. de SiO2 não modificada apresentaram as melhores propriedades mecânicas de resistência à tração e deformação na ruptura em ensaio de tração, enquanto os nanocompósitos com 1 %m. de nanosílica modificada apresentaram as melhores propriedades mecânicas de módulo elástico também no ensaio de tração. Para as amostras de nanocompósitos processadas na extrusora de rosca dupla, foram estudadas as influências do teor de nanopartículas, da modificação química superficial, da forma física da PA6 alimentada (grânulo e pó), da velocidade de rotação das roscas e da taxa de alimentação da extrusora sobre as propriedades mecânicas, térmicas e dinâmico-mecânicas. Posteriormente, os corpos de prova foram moldados por injeção e observou-se que a amostra cuja composição polimérica foi de 100% de PA6 fina e reforçada com 1 %m. de nanosílica modificada superficialmente pelo agente silano 3- APTMS apresentou os maiores valores de módulo de elasticidade e de tensão no escoamento no ensaio mecânico sob tração.

Neste trabalho, compósitos de PET sob a forma de flake e pós-condensado foram preparados com teores diferenciados de fibra de vidro (0, 20, 30 e 40%). Dois tipos de fibra foram utilizados: uma fibra com tratamento superficial a base de amino-silano e outra com tratamento a base de epóxi-silano. Os compósitos foram extrusados em extrusora mono-rosca, utilizando uma rosca de filete duplo com barreira, e em extrusora dupla-rosca interpenetrante co-rotacional. Após extrusão, os compósitos foram injetados a 120 ºC que, após várias temperaturas testadas, foi a temperatura que conferiu maior grau de cristalinidade do artefato final (acima de 30%). Os compósitos foram caracterizados quanto às propriedades mecânicas, térmicas e morfológicas. Os resultados mostraram que com a utilização de uma mono-rosca apropriada ao processamento de PET com fibra de vidro foi possível produzir compósitos com boas propriedades, comparáveis aos obtidos em extrusora dupla-rosca. Em relação aos tipos de PET utilizados, verificou-se que a massa molar da matriz polimérica, maior para o PET pós-condensado, teve uma pequena influência no desempenho das propriedades analisadas. Porém foi observado que os resultados foram indiferentes ao tratamento superficial das fibras testadas. Através da determinação do comprimento das fibras por análise óptica, e dos resultados experimentais do módulo de tração dos compósitos, pode-se constatar que nos compósitos injetados as fibras estão orientadas no sentido longitudinal à deformação. Com a microscopia eletrônica de varredura verificou-se que há sempre uma melhor distribuição e dispersão das fibras, com menores vazios à medida que aumenta o teor de fibras, corroborando os resultados mecânicos, sempre crescentes com o teor incorporado. A cristalinidade obtida nos corpos de prova moldados por injeção com o molde a uma temperatura de 120 ºC, aliada à presença da fibra de vidro, leva a um aumento na temperatura de distorção térmica (HDT). As análises de raios-X mostraram que com o aumento da quantidade da fibra, os picos cristalinos característicos do PET perdem definição, o que está associado à característica amorfa da fibra. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-05-15T17:17:43Z No. of bitstreams: 1 Dissertacao Nilcea Mondadori.pdf: 5475607 bytes, checksum: 3b5580025f75099d47502055cd80fde5 (MD5) / Made available in DSpace on 2014-05-15T17:17:43Z (GMT). No. of bitstreams: 1 Dissertacao Nilcea Mondadori.pdf: 5475607 bytes, checksum: 3b5580025f75099d47502055cd80fde5 (MD5) / In this work, flake and post-condensed PET composites of different glass fiber contents (0, 20, 30 and 40%) were prepared. Tow kinds of fibers were employed: one fiber having an amino silane-based surface treatment and another one having an epoxi silane-based surface treatment. The composites were extruded in a single-screw extruder with a barrier double-flight screw, and in a co-rotating interpenetrating twin-screw extruder. After extrusion the composites were injected at 120°C, this temperature being chosen after several tests indicating that it could promote the highest possible degree of crystallinity of the final product (higher than 30%). The composites were characterized as for mechanical, thermal and morphological features. Data indicate that by using a single-screw extruder proper to the processing of PET and fiber glass the properties of the obtained composites are fairly good, being comparable to those obtained from a twin-screw extruder. As for the types of PET utilized, it could be found that the molar mass of the polymeric matrix, larger for the post-condensed PET had some influence on the performance of the tested properties. On the other hand it could be observed that the surface treatment of the fibers does not influence the obtained data. Based on the optical analysis of the fiber length and the elastic modulus data it is possible to determine that the fibers of the injected composites are oriented longitudinally to the strain direction. With the aid of scanning electron microscopy (SEM), improvements in the distribution and dispersion of the fibers were always observed, with smaller voids as the fiber content increases, backing higher mechanical data as the incorporated fiber content is increased. Crystallinity resulting from injection-molded test specimens processed at 120°C, together with the presence of the glass fiber leads to a synergism in the heat distortion temperature (HDT). X-rays analyses indicate that at higher fiber content the composites show lower definition of the crystalline peaks, this being associated to the amorphous feature of the fiber.

Neste trabalho, compósitos de PET sob a forma de flake e pós-condensado foram preparados com teores diferenciados de fibra de vidro (0, 20, 30 e 40%). Dois tipos de fibra foram utilizados: uma fibra com tratamento superficial a base de amino-silano e outra com tratamento a base de epóxi-silano. Os compósitos foram extrusados em extrusora mono-rosca, utilizando uma rosca de filete duplo com barreira, e em extrusora dupla-rosca interpenetrante co-rotacional. Após extrusão, os compósitos foram injetados a 120 ºC que, após várias temperaturas testadas, foi a temperatura que conferiu maior grau de cristalinidade do artefato final (acima de 30%). Os compósitos foram caracterizados quanto às propriedades mecânicas, térmicas e morfológicas. Os resultados mostraram que com a utilização de uma mono-rosca apropriada ao processamento de PET com fibra de vidro foi possível produzir compósitos com boas propriedades, comparáveis aos obtidos em extrusora dupla-rosca. Em relação aos tipos de PET utilizados, verificou-se que a massa molar da matriz polimérica, maior para o PET pós-condensado, teve uma pequena influência no desempenho das propriedades analisadas. Porém foi observado que os resultados foram indiferentes ao tratamento superficial das fibras testadas. Através da determinação do comprimento das fibras por análise óptica, e dos resultados experimentais do módulo de tração dos compósitos, pode-se constatar que nos compósitos injetados as fibras estão orientadas no sentido longitudinal à deformação. Com a microscopia eletrônica de varredura verificou-se que há sempre uma melhor distribuição e dispersão das fibras, com menores vazios à medida que aumenta o teor de fibras, corroborando os resultados mecânicos, sempre crescentes com o teor incorporado. A cristalinidade obtida nos corpos de prova moldados por injeção com o molde a uma temperatura de 120 ºC, aliada à presença da fibra de vidro, leva a um aumento na temperatura de distorção térmica (HDT). As análises de raios-X mostraram que com o aumento da quantidade da fibra, os picos cristalinos característicos do PET perdem definição, o que está associado à característica amorfa da fibra. / In this work, flake and post-condensed PET composites of different glass fiber contents (0, 20, 30 and 40%) were prepared. Tow kinds of fibers were employed: one fiber having an amino silane-based surface treatment and another one having an epoxi silane-based surface treatment. The composites were extruded in a single-screw extruder with a barrier double-flight screw, and in a co-rotating interpenetrating twin-screw extruder. After extrusion the composites were injected at 120°C, this temperature being chosen after several tests indicating that it could promote the highest possible degree of crystallinity of the final product (higher than 30%). The composites were characterized as for mechanical, thermal and morphological features. Data indicate that by using a single-screw extruder proper to the processing of PET and fiber glass the properties of the obtained composites are fairly good, being comparable to those obtained from a twin-screw extruder. As for the types of PET utilized, it could be found that the molar mass of the polymeric matrix, larger for the post-condensed PET had some influence on the performance of the tested properties. On the other hand it could be observed that the surface treatment of the fibers does not influence the obtained data. Based on the optical analysis of the fiber length and the elastic modulus data it is possible to determine that the fibers of the injected composites are oriented longitudinally to the strain direction. With the aid of scanning electron microscopy (SEM), improvements in the distribution and dispersion of the fibers were always observed, with smaller voids as the fiber content increases, backing higher mechanical data as the incorporated fiber content is increased. Crystallinity resulting from injection-molded test specimens processed at 120°C, together with the presence of the glass fiber leads to a synergism in the heat distortion temperature (HDT). X-rays analyses indicate that at higher fiber content the composites show lower definition of the crystalline peaks, this being associated to the amorphous feature of the fiber.

Le but de cette thèse est l’investigation des particularités des problèmes d’optimisation et modélisation des réacteurs tubulaires de polymérisation. La partie originale du travail est divisé en deux sections : la première traitant de l'étude théorique de la modélisation et de l’optimisation des réacteurs tubulaires de polymérisation du méthacrylate de méthyle en solution, et la deuxième, une étude expérimentale et théorique de l'extrusion réactive de L-lactide. Dans la première partie, afin de sélectionner un modèle cinétique représentatif, parmi les modèles publiés pour le processus de polymérisation de MMA, des simulations ont été effectuées en conditions identiques de fonctionnement. Deux algorithmes numériques, l’un basé sur le Principe du Minimum de Pontriaguine et l’autre de type Génétique, ont été comparés pour un problème d'optimisation de complexité moyenne. Les résultats ont montré une robustesse supérieure de l’Algorithme Génétique pour cette catégorie de problèmes. La deuxième partie de la thèse est consacrée à la modélisation et à l’optimisation de l'extrusion réactive du Llactide. Nous avons proposé un modèle cinétique et ses paramètres ont été estimés en utilisant des procédures numériques basées sur les données cinétiques expérimentales. Les expériences d'extrusion réactives ont été exécutées dans les conditions de fonctionnement représentatives. L'écoulement de L-lactide/polylactide dans l'extrudeuse a été caractérisé par la simulation en utilisant un logiciel commercial, LUDOVIC®. Les caractéristiques de la distribution des temps de séjour simulées sont utilisées pour modéliser le processus d'extrusion réactive en utilisant deux approches, un modèle à dispersion axiale et un modèle à base de compartiments, dont les caractéristiques sont déduites des simulations effectuées avec LUDOVIC®. Les résultats de la modélisation du processus sont en bon accord avec des données mesurées en mêmes conditions opératoires. / The aim of this thesis is the investigation of modeling and optimization particularities of tubular polymerization reactors. The original work is divided in two sections, the first treating a modeling and optimization study of tubular reactors for methyl methacrylate polymerization in solution, and the second, an experimental and theoretical study of L-lactide reactive extrusion. In the first section, reactor simulations in similar operating conditions were performed in order to select a representative kinetic model among the published kinetic models for MMA solution polymerization. Two widely used numerical algorithms, one based on Pontryagin’s Minimum Principle and the other a Genetic Algorithm, were compared for an average-complexity optimization problem. The results showed a superior robustness of the Genetic Algorithm for this category of problems. The second part of the thesis deals with the modeling and optimization of L-lactide reactive extrusion. A kinetic model is proposed and its parameters estimated using nonlinear estimation numerical procedures based on experimentally measured data. Reactive extrusion experiments were performed in representative operating conditions. The Llactide/ polylactide flow in the extruder was characterized by simulation using the commercial software LUDOVIC®. The simulated residence time distributions characteristics are used to model the reactive extrusion process of two approaches, an axial dispersion model and a compartment model, based on compartments whose characteristics are deduced from the simulations using LUDOVIC®. The modeling results are in good agreement with the measured data in the same operating conditions.

No description available.

Le son et la paille de blé, riches en hémicelluloses, sont deux co-produits de la récolte de blé, abondants et renouvelables, mais qui restent à mieux valoriser. Dans le but d'extraire ces hémicelluloses, possédant plusieurs propriétés intéressantes (filmogènes, épaississantes, émulsifiantes, stabilisantes…), un procédé de fractionnement a été élaboré. Ce procédé consiste, après extraction alcaline, en la purification des extraits hémicellulosiques obtenus. Deux techniques ont été appliquées : l'ultrafiltration et la chromatographie sur résine échangeuse d'anions. L'ultrafiltration a permis de concentrer les extraits d'hémicelluloses et de les purifier en éliminant dans le perméat la plupart des molécules contaminantes, essentiellement les sucres libres et les sels minéraux. Les principales limitations de cette étape étaient la viscosité des extraits et les phénomènes de polarisation de concentration et de colmatage des membranes. La percolation sur résine, quant à elle, a permis de décolorer les extraits et de produire des poudres d'hémicelluloses plus claires en fixant certaines molécules colorées telles que les molécules possédant des groupements phénoliques. La combinaison des deux techniques a permis de produire des hémicelluloses pures à 60%. L'extrapolation du procédé à l'échelle pilote par l'utilisation d'un extrudeur bi-vis a permis d'obtenir des poudres d'hémicelluloses pures à 40%. / Wheat bran and wheat straw are two by-products abundant and renewable, rich in hemicelluloses, but still not well valued. In order to extract these hemicelluloses characterized by their several interesting properties (film-forming, thickening, emulsifying, stabilizing…), a fractionation process was developed. This process consisted, after alkaline extraction, to purify the hemicellulosic extracts obtained. Two techniques were used: ultrafiltration and chromatography on anion exchange resin. The ultrafiltration allowed to concentrate the extracts and to purify them by removing in the permeate, the contaminating molecules, mostly free sugars and minerals. The main limiting factors of this stage were the extracts viscosity and the fouling of the membranes. The percolation on the resin discoloured the extracts and allowed to produce hemicellulosic powders with lighter colours and that by capturing the coloured compounds such as molecules with phenolic groups. The combination of the two techniques allowed the production of purified hemicelluloses; the purity was about 60%. The extrapolation of the process at a pilot scale using a twin-screw extruder allowed to obtain hemicelluloses with a purity of 40%.