Made available in DSpace on 2014-06-11T19:27:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-29Bitstream added on 2014-06-13T20:35:16Z : No. of bitstreams: 1 oishi_ss_me_guara.pdf: 1972224 bytes, checksum: 3c999656c713b895ba43f4e61fdba9fd (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Em função da crescente importância do material carbono vítreo em áreas estratégicas, devido às suas características intrínsecas, tais como menor massa específica e bons valores de condutividades térmica e elétrica, tem se observado vários estudos na busca de novos precursores poliméricos, assim como no ajuste mais sistemático de seu processamento. Nesse sentido, este trabalho tem como objetivo o estabelecimento de rotas de síntese de resinas furfurílica e fenol-furfurílica e suas dopagens com partículas de cobre, visando o processamento de eletrodos de carbono vítreo reticulado (CVR). Neste contexto foram sintetizadas diferentes formulações de resinas furfurílica e fenol-furfurílica a partir da variação dos monômeros – álcool furfurílico, fenol e formaldeído, respectivamente. A confirmação do sucesso das sínteses foi realizada por análises de espectroscopia de infravermelho com transformada de Fourier, cromatografia gasosa, análises térmicas por calorimetria exploratória diferencial e medidas dos teores de carbono fixo, que mostram resultados entre 27 e 45% em carbono. Em seguida, estas amostras foram dopadas com um colóide contendo as partículas de cobre. As resinas, com e sem dopagem, foram catalisadas, impregnadas em espumas de poliuretano (PU) e carbonizadas, obtendo-se assim, o CVR. Análises por microscopias óptica e eletrônica de varredura mostram a homogeneidade na impregnação das espumas de PU e a textura uniforme das amostras de CVR. Os resultados de resistência à compressão apresentam os melhores valores para o CVR resultante da carbonização com a resina furfurílica ácida (0,55 MPa). / Due to the growing importance of glassy carbon material in strategic areas, due to its intrinsic characteristics, such as lower density and good thermal and electrical conductivities values, has been observed several studies looking for new polymeric precursors and tighter processing parameters. In this way, this study aims on the establishment of synthesis routes of furfuryl and phenol-furfuryl alcohol resins and their doping with cupper particles, in order to produce reticulated glassy carbon (RGC) electrodes. Inside of this context were synthesized different formulations of furfuryl and phenol-furfuryl alcohol resins by the monomers variation – furfuryl alcohol, phenol and formaldehyde, respectively. The success confirmation of the synthesis has been done by using FT-IR spectroscopy, gas chromatography, thermal analyses by differential scanning calorimetry (DSC) and carbon yield content measurements that present results between 27 and 45% of carbon. After this, the specimens were doped with a colloid contend the copper particles. The doped and non doped resins were catalyzed, impregnated in polyuretane (PU) foams and carbonized, in order to obtain the reticulated glassy carbon. Optical and Scanning Electron Microscopy analysis show the homogeneity of PU foams impregnation and uniform texture of RGC specimens. Compression results present the best values for RGC resulting from the carbonization with furfuryl alcohol acid resin (0,55 MPa).

For wood products such as flooring and worktop, only one surface is normally exposed in their use, and the mechanical properties like hardness and wearing resistance of that surface is then important. Since mechanical properties are strongly related to the density, surface densification, i.e. transverse compression of the wood cells beneath the surface of a piece of wood with the aim to increase the density of that region, may be a method for improving hardness and wearing resistance when low-density species are used for such products. The set-recovery, i.e. the moisture-induced swelling of the densified wood cells back to their original shape, is the main obstacle in the use of densified wood products. Although there are several methods reported in literature, such as post heat-treatment, that can almost eliminate the set-recovery, but such methods are either time consuming or difficult to implement into an industrial continuous process which may do densification competitive to techniques or materials that can achieve at least the same hardness.     In the present study, furfuryl alcohol was used as pre-treatment to fix the set-recovery of surface-densified Scots pine sapwood. The main effect and interactive influence of four process parameter (impregnation time, press temperature, press time and compression ratio) on set-recovery and Brinell hardness after two wet-dry cycles were studied by a two-level full factorial design of experiments. The characterizing variables of the density profile after the surface densification and set-recovery test were carried out as a supplementary tool to learn the mechanism of this two-step modification process. According to the result, the surface densified wood with furfuryl alcohol pre-treatment can retain their dimension and keep hardness at a very high level after two wet-dry cycles. The set-recovery and hardens after two wet-dry cycles were about 20 % and 30 N/mm2, respectively. The Pearson correlation analysis shows that the correlation coefficients between set-recovery with impregnation time, press temperature, press temperature, compression ratio were -0.35, -0.52, -0.37, and 0.16, respectively. That means that for the specimens with furfuryl alcohol pre-treatment, the higher press temperature can reduce the set-recovery significantly. The longer press time and impregnation time can also reduce the set-recovery in some extent, but the influence was  low. As expected, the hardness improvement was retained with low set-recovery. The lowest set-recovery value was 14% with the corresponding hardness of 41 N/mm2 was achieved by specimens processed with 120 minutes of impregnation, 10% compression ratio, 210℃ pressing temperature, and 15 minutes of pressing time. With 20 minutes of impregnation time, 10% compression ratio, 210℃ pressing temperature, and 5 minutes of pressing time, the sample still owns twofold hardness after the set-recovery test.

Resumo: Em função da crescente importância do material carbono vítreo em áreas estratégicas, devido às suas características intrínsecas, tais como menor massa específica e bons valores de condutividades térmica e elétrica, tem se observado vários estudos na busca de novos precursores poliméricos, assim como no ajuste mais sistemático de seu processamento. Nesse sentido, este trabalho tem como objetivo o estabelecimento de rotas de síntese de resinas furfurílica e fenol-furfurílica e suas dopagens com partículas de cobre, visando o processamento de eletrodos de carbono vítreo reticulado (CVR). Neste contexto foram sintetizadas diferentes formulações de resinas furfurílica e fenol-furfurílica a partir da variação dos monômeros - álcool furfurílico, fenol e formaldeído, respectivamente. A confirmação do sucesso das sínteses foi realizada por análises de espectroscopia de infravermelho com transformada de Fourier, cromatografia gasosa, análises térmicas por calorimetria exploratória diferencial e medidas dos teores de carbono fixo, que mostram resultados entre 27 e 45% em carbono. Em seguida, estas amostras foram dopadas com um colóide contendo as partículas de cobre. As resinas, com e sem dopagem, foram catalisadas, impregnadas em espumas de poliuretano (PU) e carbonizadas, obtendo-se assim, o CVR. Análises por microscopias óptica e eletrônica de varredura mostram a homogeneidade na impregnação das espumas de PU e a textura uniforme das amostras de CVR. Os resultados de resistência à compressão apresentam os melhores valores para o CVR resultante da carbonização com a resina furfurílica ácida (0,55 MPa). / Abstract: Due to the growing importance of glassy carbon material in strategic areas, due to its intrinsic characteristics, such as lower density and good thermal and electrical conductivities values, has been observed several studies looking for new polymeric precursors and tighter processing parameters. In this way, this study aims on the establishment of synthesis routes of furfuryl and phenol-furfuryl alcohol resins and their doping with cupper particles, in order to produce reticulated glassy carbon (RGC) electrodes. Inside of this context were synthesized different formulations of furfuryl and phenol-furfuryl alcohol resins by the monomers variation - furfuryl alcohol, phenol and formaldehyde, respectively. The success confirmation of the synthesis has been done by using FT-IR spectroscopy, gas chromatography, thermal analyses by differential scanning calorimetry (DSC) and carbon yield content measurements that present results between 27 and 45% of carbon. After this, the specimens were doped with a colloid contend the copper particles. The doped and non doped resins were catalyzed, impregnated in polyuretane (PU) foams and carbonized, in order to obtain the reticulated glassy carbon. Optical and Scanning Electron Microscopy analysis show the homogeneity of PU foams impregnation and uniform texture of RGC specimens. Compression results present the best values for RGC resulting from the carbonization with furfuryl alcohol acid resin (0,55 MPa). / Orientador: Edson Cochieri Botelho / Coorientadora: Mirabel Cerqueira Rezende / Banca: Choyu Otani / Banca: Pedro Carlos de Oliveira / Mestre

In this study southern pine scrim was treated with low molecular weight melamine formaldehyde (MF), phenolic formaldehyde (PF), and furfuryl alcohol (FA) at different loadings and formed into 25-mm thick panels. Mechanical, dimensional and biological properties were evaluated. Results showed that samples treated with 5 percent MF had the highest MOE, MOR and work to maximum load values (15.3 GPa, 54.2 MPa and 25.4 KJ/m3, respectively), while those treated with 10 percent MF had the highest internal bond and edgewise toughness values of 390 kPa and 12 N•m, respectively. With respect to dimensional stability, samples treated with 20 percent FA had the lowest swelling value (ASE = 36.8 percent), and the lowest water absorption value (27.5 percent). Dynamic swelling test revealed much higher ASE value (> 45 percent) for furfurylated samples. As for termite resistance, both untreated and treated samples had little weight loss (1.10-1.56 percent), high visual rating (8-9.3/10), and 100 percent mortality in laboratory test.

Wood is a natural and renewable resource and, moreover, a most decorative and beautiful material. Most valuable logs are used for veneer production for optimum exploitation and utilization. Attractive wood veneers adorn any surface and is primarily used for furniture, yacht and automotive interior works. However, such application of wood veneer is limited to rather simply shaped carrier components due to the veneer’s mechanical restrictions. Previously, several approaches have been discussed to flexibilize wood allowing a greater deformation, but none approach has been entirely satisfactory. On that score, another veneer modification process has been suggested comprising a furfuryl alcohol impregnation to plasticize the wood veneer realizing enhanced veneer flexibility and mouldability (Pfriem and Buchelt 2011b). In the presence of a suitable initiator and promoted by elevated temperatures, furfuryl alcohol forms a very hard, insoluble polymer inside the wood cell walls. If polymerization is initiated as the impregnated veneer is moulded, the polymer is assumed to fix the gained shape. This thesis summarizes experimental work investigating the effect of furfuryl alcohol modification on maple veneer plasticization, shape fixation, and shape stability and the impact of various process parameters on material characteristics. Veneer samples impregnated with furfuryl alcohol exhibited an increased cell wall swelling, were notably softer than dry reference veneer, and showed an enhanced mouldability comparable to water impregnated veneer samples. Each characteristic is indicative for an increased plasticization. DSC studies were carried out to assess the influence of various initiator contents and ethanol dilutions of the impregnation liquid on the curing reactions and the retained polymer yield. Thereby, high initiator contents promoted a more rapid curing at lower temperatures with higher polymer yields, whereas higher dilution shifted the curing towards higher temperatures and possibly retard the curing resulting in lower polymer yields. The furfuryl alcohol polymer retaining inside the cell walls was proved to fix the achieved shape of veneer providing moreover enhanced shape stability at elevated temperatures and increasing moisture compared to unmodified reference veneer samples. According to these findings, furfuryl alcohol modification can be used for wood veneer plasticization and improved mouldability, shape fixation, and stabilization. However, material properties vary notably with changing process parameters. / Holz ist nicht nur eine natürlicher und nachwachsender Rohstoff, sondern vielmehr auch ein sehr dekoratives und schönes Material. Die wertvollsten Baumstämme werden daher häufig zur Furnierproduktion genutzt, um diese raren Stämme bestmöglich auszunutzen und zu verwerten. Besonders schöne Furniere schmücken jegliche Oberfläche und werden vorallem in der Möbelindustrie, sowie beim Yacht- und Autoinnenausbau verwendet. Jedoch ist die Anwendung aufgrund mechanischer Restriktionen auf eher einfach geformte Oberflächen und Trägerteile begrenzt. In der Vergangenheit wurden unterschiedliche Methoden entwickelt, um den Einsatzbereich von Furnieren durch eine erhöhte Flexibilität und Verformbarkeit auszuweiten, jedoch ist keiner dieser Prozesse in allen Aspekten zufriedenstellend. Aus diesem Grund wurde von Pfriem und Buchelt (2011b) eine neue Methode vorgeschlagen. Hierbei sollen Furniere mit Furfurylalkohol imprägniert werden, um einerseits die Furniere zu plastifizieren und eine erhöhte Flexibilität und Umformbarkeit zu ermöglichen. Andererseits härtet Furfurylalkohol in Gegenwart eines geeigneten Initiators und durch erhöhte Temperaturen begünstigt aus und bildet in den Zellwänden ein hartes, weitestgehend unlösliches Polymer aus. Hierbei wird angestrebt, die Polymerisation zu initiieren, wenn das imprägnierte Furnier bereits umgeformt ist, so dass das entstehende Polymer das Furnier im umgeformten Zustand fixiert. Die vorliegende Dissertation fasst die erzielten Ergebnisse von Experimenten zusammen, die durchgeführt wurden, um die plastifizierende Wirkung von Furfurylalkohol auf Ahornfurniere sowie die formfixierende und stabilisierende Eigenschaft des ausgehärteten Polymers zu untersuchen und den Einfluss unterschiedlicher Prozessparameter auf erzielte Materialeigenschaften zu bestimmen. Es konnte nachgewiesen werden, dass durch die Imprägnierung mit Furfurylalkohol ein Quellen der Zellwände verursacht wird und dass die getränkten Proben deutlich weicher sind als die Referenzproben und eine erhöhte Umformung aufwiesen. Diese erzielten Änderungen weisen auf eine deutliche Plastifizierung der Holzsubstanz hin. DSC-Analysen von Furnieren, die mit unterschiedlich zusammengesetzten Imprägnierflüssigkeiten auf Basis von Furfurylalkohol imprägniert wurden, belegen den Einfluss unterschiedlicher Initiatoranteile und Verdünnungen mit Ethanol auf die Polymerisation. Während höhere Anteile an Initiator eine rasche Reaktion bei niedrigeren Temperaturen und einen hohen Beladungsgrad hervorrufen, bewirken starke Verdünnungen des Furfurylalkohols mit Ethanol eine Verzögerung der Polymerisation und eine Verschiebung dieser zu höheren Temperaturen bei gleichzeitigen vergleichsweise geringen Beladungsgraden. Mit weiteren Versuchen konnte bestätigt werden, dass das Polymer des Furfurylalkohols in den Zellwänden die erzielte Umformung der Furniere fixiert und auch bei höheren Temperaturen und Luftfeuchten eine erhöhte Formstabilität bewirkt. Die Versuche haben gezeigt, dass Furfurylalkohol zur Plastifizierung und verbesserten Umformbarkeit von Furnieren sowie zu deren Formfixierung und Formstabilisierung genutzt werden kann, allerdings variieren die Materialeigenschaften mit unterschiedlichen Prozessparametern insbesondere mit unterschiedlichen Initiatoranteilen in der Imprägnierflüssigkeit.

Les papiers imprégnés de résine ont été largement utilisés dans la fabrication de stratifiés pour des panneaux de bois. Généralement, l'imprégnation du papier implique l’utilisation de resins mélamine-formaldéhyde, urée-formaldéhyde et melamine-formaldéhyde-urée. Cependant, ces matériaux sont coûteux lorsqu'ils sont utilisés en grande quantité et ils proviennent de ressources non renouvelables. Par conséquent, dans ce travail, nous avons préparé des papiers imprégnés de résines tannins furanique pour remplacer les résines mélamine-formaldéhyde et d'urée-formaldéhyde lors de l'imprégnation des papiers. Les résines tannins furaniques sont composées de deux matières naturelles principales: a) le tannin de mimosa qui est non-toxique, respectueux de l'environnement et relativement peu coûteux qui remplace la résine synthétique et b) de l'alcool furfurylique obtenu par réduction catalytique du furfural, un composé naturel obtenu par l'hydrolyse des sucres dérivés des déchets agricoles. Les tannins sont des composés phénoliques naturels extraits des écorces des arbres et qui ont été utilisés dans l'industrie depuis de nombreuses années comme adhésifs pour la production de panneaux de bois. Mais il n’y a pas jamais eu jusqu’à présent des recherches sur leurs utilisations dans la fabrication des stratifiés. Dans ce travail, nous avons étudié : 1) Le temps de gel entre des tannins de mimosa et des tannins de pin avec de l'alcool furfurylique, sans ajout de formaldéhyde de pH 1 à pH 11 2) L’analyse MALDI-TOF et RMN des tannins de mimosa avec de l'alcool furfurylique 3) La qualité de la surface du contreplaqué recouvert d’un papier imprégné de résine tannins de mimosa-alcool furfurylique 4) Les stratifiés de 10 plis à haute pression (HPL) ont été préparés avec de la résine tannins de mimosa-alcool furfurylique. La qualité de surface des HPL et les propriétés mécaniques du contreplaqué recouvert avec ces HPL ont été examinées. 5) Les stratifiés de 10 plis à haute pression ont été préparés avec de la résine de tannins de mimosa - alcool furfurylique en milieu acide. Les qualités de surface des HPL ont été comparées avec celles des HPL preparés avec une résine phénol-formaldéhyde / Resin impregnated papers have been widely used in manufacturing laminates for wood panels. Generally, paper impregnation involves melamine formaldehyde, melamine urea formaldehyde and urea formaldehyde resin. However, these materials are expensive when used in high quantity and derived from non renewable resources. Therefore, in this work we prepared tannin furanic resin impregnated paper to replace melamine formaldehyde and urea formaldehyde in the paper impregnation. Tannin furanic resin composed of two main natural materials: a) mimosa tannins which is non-toxic, environmentally friendly and relatively inexpensive to substitute the synthetic resin and b) furfuryl alcohol obtained by catalytic reduction of furfural, a natural compound obtained by the hydrolysis of sugars derived from agricultural waste. Tannins are naturally occurring phenolic compounds extracted from the bark trees that have been used industrially for many years as wood panel adhesives but no distance work have been done to study their potential in paper laminates. In this work, we studied: 1) The gel time between mimosa and pine tannin with furfuryl alcohol without the addition of formaldehyde from pH 1 to pH 11 2) The MALDI-TOF and NMR of mimosa tannin with furfuryl alcohol 3) The surface quality of the plywood overlaid with mimosa tannin- furfuryl alcohol resin 4) 10-ply high pressure laminates (HPL) were prepared with mimosa tannin- furfuryl alcohol resin. The surface quality of the HPL and the mechanical properties of plywood overlaid with this HPL were examined. 5) 10-ply high pressure laminates were prepared with mimosa tannin- furfuryl alcohol resin in the acid condition. The surface quality of the prepared HPL were compared with PF

Wood is a natural and renewable resource and, moreover, a most decorative and beautiful material. Most valuable logs are used for veneer production for optimum exploitation and utilization. Attractive wood veneers adorn any surface and is primarily used for furniture, yacht and automotive interior works. However, such application of wood veneer is limited to rather simply shaped carrier components due to the veneer’s mechanical restrictions. Previously, several approaches have been discussed to flexibilize wood allowing a greater deformation, but none approach has been entirely satisfactory. On that score, another veneer modification process has been suggested comprising a furfuryl alcohol impregnation to plasticize the wood veneer realizing enhanced veneer flexibility and mouldability (Pfriem and Buchelt 2011b). In the presence of a suitable initiator and promoted by elevated temperatures, furfuryl alcohol forms a very hard, insoluble polymer inside the wood cell walls. If polymerization is initiated as the impregnated veneer is moulded, the polymer is assumed to fix the gained shape. This thesis summarizes experimental work investigating the effect of furfuryl alcohol modification on maple veneer plasticization, shape fixation, and shape stability and the impact of various process parameters on material characteristics. Veneer samples impregnated with furfuryl alcohol exhibited an increased cell wall swelling, were notably softer than dry reference veneer, and showed an enhanced mouldability comparable to water impregnated veneer samples. Each characteristic is indicative for an increased plasticization. DSC studies were carried out to assess the influence of various initiator contents and ethanol dilutions of the impregnation liquid on the curing reactions and the retained polymer yield. Thereby, high initiator contents promoted a more rapid curing at lower temperatures with higher polymer yields, whereas higher dilution shifted the curing towards higher temperatures and possibly retard the curing resulting in lower polymer yields. The furfuryl alcohol polymer retaining inside the cell walls was proved to fix the achieved shape of veneer providing moreover enhanced shape stability at elevated temperatures and increasing moisture compared to unmodified reference veneer samples. According to these findings, furfuryl alcohol modification can be used for wood veneer plasticization and improved mouldability, shape fixation, and stabilization. However, material properties vary notably with changing process parameters. / Holz ist nicht nur eine natürlicher und nachwachsender Rohstoff, sondern vielmehr auch ein sehr dekoratives und schönes Material. Die wertvollsten Baumstämme werden daher häufig zur Furnierproduktion genutzt, um diese raren Stämme bestmöglich auszunutzen und zu verwerten. Besonders schöne Furniere schmücken jegliche Oberfläche und werden vorallem in der Möbelindustrie, sowie beim Yacht- und Autoinnenausbau verwendet. Jedoch ist die Anwendung aufgrund mechanischer Restriktionen auf eher einfach geformte Oberflächen und Trägerteile begrenzt. In der Vergangenheit wurden unterschiedliche Methoden entwickelt, um den Einsatzbereich von Furnieren durch eine erhöhte Flexibilität und Verformbarkeit auszuweiten, jedoch ist keiner dieser Prozesse in allen Aspekten zufriedenstellend. Aus diesem Grund wurde von Pfriem und Buchelt (2011b) eine neue Methode vorgeschlagen. Hierbei sollen Furniere mit Furfurylalkohol imprägniert werden, um einerseits die Furniere zu plastifizieren und eine erhöhte Flexibilität und Umformbarkeit zu ermöglichen. Andererseits härtet Furfurylalkohol in Gegenwart eines geeigneten Initiators und durch erhöhte Temperaturen begünstigt aus und bildet in den Zellwänden ein hartes, weitestgehend unlösliches Polymer aus. Hierbei wird angestrebt, die Polymerisation zu initiieren, wenn das imprägnierte Furnier bereits umgeformt ist, so dass das entstehende Polymer das Furnier im umgeformten Zustand fixiert. Die vorliegende Dissertation fasst die erzielten Ergebnisse von Experimenten zusammen, die durchgeführt wurden, um die plastifizierende Wirkung von Furfurylalkohol auf Ahornfurniere sowie die formfixierende und stabilisierende Eigenschaft des ausgehärteten Polymers zu untersuchen und den Einfluss unterschiedlicher Prozessparameter auf erzielte Materialeigenschaften zu bestimmen. Es konnte nachgewiesen werden, dass durch die Imprägnierung mit Furfurylalkohol ein Quellen der Zellwände verursacht wird und dass die getränkten Proben deutlich weicher sind als die Referenzproben und eine erhöhte Umformung aufwiesen. Diese erzielten Änderungen weisen auf eine deutliche Plastifizierung der Holzsubstanz hin. DSC-Analysen von Furnieren, die mit unterschiedlich zusammengesetzten Imprägnierflüssigkeiten auf Basis von Furfurylalkohol imprägniert wurden, belegen den Einfluss unterschiedlicher Initiatoranteile und Verdünnungen mit Ethanol auf die Polymerisation. Während höhere Anteile an Initiator eine rasche Reaktion bei niedrigeren Temperaturen und einen hohen Beladungsgrad hervorrufen, bewirken starke Verdünnungen des Furfurylalkohols mit Ethanol eine Verzögerung der Polymerisation und eine Verschiebung dieser zu höheren Temperaturen bei gleichzeitigen vergleichsweise geringen Beladungsgraden. Mit weiteren Versuchen konnte bestätigt werden, dass das Polymer des Furfurylalkohols in den Zellwänden die erzielte Umformung der Furniere fixiert und auch bei höheren Temperaturen und Luftfeuchten eine erhöhte Formstabilität bewirkt. Die Versuche haben gezeigt, dass Furfurylalkohol zur Plastifizierung und verbesserten Umformbarkeit von Furnieren sowie zu deren Formfixierung und Formstabilisierung genutzt werden kann, allerdings variieren die Materialeigenschaften mit unterschiedlichen Prozessparametern insbesondere mit unterschiedlichen Initiatoranteilen in der Imprägnierflüssigkeit.

Le travail de recherche présenté dans cette thèse s’est orienté vers l’élaboration de matériaux avancés et la conception de polymères/composites biosourcés. Ce dernier sujet a été entrepris à travers la combinaison de différentes matières premières biosourcées qui sont connues comme ayant un grand potentiel de substitution des monomères pétrosourcés. Tout d’abord, un travail fondamental a été exécuté en combinant l’huile de lin epoxydée (ELO) avec des dérivés d’anhydrides d’acides comme agents de réticulation, afin de relier la réactivité chimique de polymérisation à la structure du réseau formé et aux propriétés thermomécaniques. Afin de devenir économiquement viable, les bio-raffineries doivent urgemment valoriser les sous-produits issus de la conversion de la biomasse. Fort de ce constat, une deuxième étude sur l’incorporation et la copolymérisation d’une quantité importante d’humins (résidu hétérogène obtenu durant la conversion des sucres en hydroxymethylfurfural (HMF)) avec de l’alcool furfurylique (FA) a été réalisée avec succès afin de créer de nouvelles résines thermodures. Une autre voie proposée consiste en la combinaison de ELO et de FA à travers une polymérisation cationique, dans l’idée de créer de nouvelles résines totalement biosourcées, générant ainsi une gamme de matériaux aux propriétés mécaniques modulables. / The research work presented in this thesis was oriented on advanced thermoset materials and also on the conception of bio-based polymers and composites. This last topic has been investigated by the combination of different bio-based raw materials which are well-known to have a great potential to substitute the petroleum monomers. Firstly, a fundamental work has been done on the combination of epoxidized linseed oil (ELO) and anhydrides as cross-linkers, which links the polymerization reactivity with the network structure and thermomechanical properties. For being economically realistic, the bio-refineries are urged to valorize the sidestream products issued from biomass conversion. In that respect, a second study investigated successfully the incorporation and copolymerization of an important amount of humins (heterogeneous residues obtained during the sugar conversion into hydroxymethylfurfural (HMF)) with furfuryl alcohol (FA) in order to create new resins. Another proposed combination, focused on ELO and FA cationic copolymerization with the purpose to create new fully bio-based resins with tailored mechanical properties. Concerning the elaboration of advanced polymers and composites, a reflection around the hierarchically organized natural materials has been achieved in order to adapt the self-organization and structuration concepts to polymeric network.

L’utilisation et la valorisation de ressources renouvelables dans le domaine de la chimie connait un intérêt grandissant pour remplacer les ressources fossiles. Le travail présenté dans ce manuscrit de thèse est axé sur deux ressources bio-sourcées utilisées pour la préparation de thermodurcissables bio-sourcés : huile végétale et biomasse lignocellulosique. La première partie concerne les polybenzoxazines. A partir d’un monomère à base de phénol, le caractère bio-sourcé est progressivement augmenté par substitution du phenol par du cardanol. Le cardanol est un dérivé phénolique bio-sourcé extrait de l’huile de coque de noix de cajou. Une première étude se concentre sur les effets apportés par cette chaine alkyle sur la réactivité et les propriétés finales du matériau. Par la suite, la réaction de polymérisation du composé de référence est évaluée par des études cinétiques, corrélées aux analyses thermo-mécaniques pour une meilleure compréhension de la réaction de polymérisation. La seconde partie de cette thèse se concentre sur la préparation de composites totalement bio-sourcés, avec des microfibrilles de cellulose (MFC) modifiées pour obtenir des dialdehyde cellulose (DAC). Le poly(alcool furfruylique) (PFA) est une matrice bio-sourcée polymérisée à partir d’alcool furfurylique (FA) et d’anhydride maléique, tous deux obtenus à partir du HMF. Les propriétés du PFA peuvent être modifiées en y incorporant un renfort, tel que la cellulose. La modification de MFC par oxydation génère des fonctions aldéhydes réactives qui améliorent la compatibilité avec la matrice. Cette étude compare différents composites préparés à partir de MFC oxydée à différents DO pour déterminer quel DO entraine une meilleure compatibilité. Pour finir, des matériaux préparés à partir d’une unique source de cellulose, les « all cellulose composites », ont fait l’objet de la dernière étude. Deux différents renforts furaniques ont été utilisés pour contrer les problèmes de sensibilité à l’humidité de la cellulose, et donc augmenter l’hydrophobicité. / To reduce the use of finite petroleum-based resources, interest has grown regarding the valorization of renewable resources in chemistry. The work presented in this thesis focused on two bio-based resources: plant oil and lignocellulosic biomass, for the preparation of greener thermoset materials. The first part discussed about polybenzoxazine thermosets. The bio-based content was gradually increased through substitution of petro-based phenol by bio-based cardanol. Cardanol is a natural phenolic derivative extracted from the cashew nutshell liquid. A first study focused on the effect of this aliphatic side chain and how it can tune the reactivity and the final thermo-mechanical properties of the materials. In the following study the reactivity of polymerization of di-phenol monomer was investigated using advanced isoconversional analyses and thermo-mechanical analyses for a better understanding of the polymerization reaction. The second part discussed about the preparation of fully bio-based composites using modified cellulose microfibrils (MFC). Poly(furfuryl alcohol) (PFA) is a bio-based matrix obtained after polymerization of furfruyl alcohol (FA) with maleic anhydride, both obtained from HMF. The PFA properties can be modified by the introduction of cellulose as a filler. MFC was modified by oxidation to lead to reactive dialdehyde functions. By varying the degree of oxidation (DO), the properties of different composites were studied to determine the most adequate DO for the better PFA/MFC compatibility and the most adequate PFA/MFC ratio. Finally, the last study of this thesis focused on the concept of “all cellulose composites” (ACC), and particularly how to reduce the moisture sensitivity of these materials. Two different furanic compounds were used as cross-linkers to increase the hydrophobicity: a first compound with one furan ring and a second with two furan rings.

Orientador: Edson Cocchieri Botelho / Resumo: Este trabalho de pesquisa consiste na obtenção e caracterizações térmica, mecânica, reológica e elétrica de compósitos multifuncionais obtidos a partir da utilização de fibras de carbono (FC), resina furfurílica (RF) e nanotubos de carbono (CNT) para aplicações aeroespaciais. O uso de uma bioresina como fonte alternativa ao petróleo em compósitos multifuncionais e a avaliação dos ganhos de propriedades na utilização de nanotubos de carbono (0, 1,3 e 2,5% em volume) associados a fibras contínuas de carbono (tecido plain weave) são os objetivos principais deste trabalho. O desenvolvimento deste trabalho de pesquisa estabelece os parâmetros de processo mais adequados para a obtenção de compósitos multifuncionais com propósitos estruturais, térmicos e/ou elétricos. Neste trabalho, os compósitos multifuncionais foram processados com a utilização de moldagem por compressão a quente, sendo esta uma das contribuições desta dissertação. Após processados, os laminados foram avaliados a partir de ensaios mecânicos (cisalhamento interlaminar por compression shear test (CST), impacto a baixas velocidades, DCB (Double Cantilever Beam test), ENF (End Notched Flexure) e fadiga); assim como, a partir de análises térmicas (DMA (Análise Dinâmico-Mecânica), DSC (Calorimetria Exploratória Diferencial), TGA (Análise Termogravimétrica) e TMA (Análise Termomecânica)), ensaios elétricos, análises morfológicas (MO (Microscopia Óptica), MEV (Microscopia Eletrônica de Varredura) e ultrassom) e análises ... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor