Este trabalho tem como objetivos a preparação e a caracterização de blendas de amido termoplástico e borracha natural, obtidos a partir dos amidos de mandioca e milho e do látex de borracha natural utilizado diretamente como extraído da seringueira, sem nenhum tipo de tratamento prévio. Os amidos termoplásticos (TPS) foram processados em misturador intensivo em duas temperaturas diferentes (120oC e 150oC), utilizando como plasticizantes a glicerina, o etilenoglicol e o propilenoglicol na proporção de 30 % em massa na matriz, e teores de látex de borracha natural (NRL) variando na proporção de 2,5 a 10 % em massa na blenda. As propriedades das blendas foram avaliadas por difração de Raios-X, por termogravimetria (TG), ensaios mecânicos de resistência à tração, por ensaios de absorção de água e por microscopia eletrônica de varredura (SEM). O cisalhamento desenvolvido durante o processamento em misturador intensivo levou à perda da estrutura cristalina e à desestruturação dos grânulos de amido. A adição de látex diminuiu os valores de índice de cristalinidade dos TPS, não alterando, entretanto, o comportamento cristalográfico com relação ao tipo de padrão de cristalinidade apresentado pelos TPS. Com relação à estabilidade térmica, os TPS mostraram-se dependentes da fonte de amido utilizado, do tipo de plasticizante, da temperatura de processamento e do teor de látex presente. Quanto à resistência mecânica, o TPS de milho se mostrou mais resistente que o de mandioca, principalmente quando plasticizado com glicerina, tendo a temperatura de processamento pouca influência sobre os resultados. Com relação aos teores de látex adicionados, não foi observada nenhuma melhora significativa sobre a resistência mecânica dos TPS, exceto um pequeno aumento nos valores de alongamento à ruptura. A adição de látex proporcionou uma diminuição linear na absorção máxima de água no equilíbrio, assim como uma redução nos valores de coeficiente de difusão de água apresentado pelos TPS. Uma vez que o processo de mistura desempenha uma função importante na morfologia destas blendas, na maioria dos TPS plasticizados com glicerina, entretanto, para os TPS plasticizados com etilenoglicol e com propilenoglicol não houve uma boa dispersão dos componentes das misturas. Os TPS de milho plasticizados com glicerina à 150oC foram os que apresentaram uma melhor dispersão das partículas de látex quando comparado com os demais. A qualidade destas dispersões foi uma conseqüência da utilização do látex ao invés da borracha sólida, uma vez que o primeiro apresenta a presença de proteínas e lipídeos na superfície das partículas de borracha presentes no látex, atuando como um compatibilizante entre o amido, uma matriz polar, e a borracha, um material não-polar. / The aim of the study reported here was to prepare and characterize blends of thermoplastic starch and natural rubber, based on manioc starch (tapioca), corn starch and natural rubber latex used directly as extracted from Hevea brasiliensis (Brazilian rubber tree), without prior treatment. The thermoplastic starch (TPS) matrices were prepared in a high-intensity mixer at two temperatures (120°C and 150°C), with 30% (w/w) glycerol, ethylene glycol or propylene glycol as plasticizer, and from 2.5% to 10% (w/w) natural rubber latex (NRL) was added to form the blends. The properties of the composite blends were assessed by XRD, TGA, tensile strength tests, water absorption tests and SEM. The shearing forces developed during mixing resulted in a loss of crystallinity and breakdown of the starch granule structure. The addition of NRL reduced the crystallinity index of the TPS, but did not change the type of crystal structure exhibited by this phase. The thermal stability of the TPS matrix was found to depend on the origin of the starch, the type of plasticizer, the processing temperature and the latex content. In the mechanical strength tests, the cornstarch TPS proved stronger than the manioc product, especially when plasticized with glycerol, while the mixing temperature had little influence. With the addition of NRL, no significant was observed in the mechanical properties, except for a small increase in the elongation of the material at breakpoint. As latex was added there was a linear decrease in the maximum absorption of water at equilibrium, as well as a reduction in the diffusion coefficient of water in the matrix. While the mixing process played an important part in producing an adequate blend morphology in most of the mixtures containing glycerol, the components of blends in which the TPS was plasticized with ethylene or propylene glycol were not well-dispersed. The TPS that afforded the best dispersion of latex particles was composed of cornstarch and glycerol and plasticized at 150°C. The highquality dispersion achieved was a consequence of using raw latex instead of solid rubber, since in the latex the rubber particles are coated with surface proteins and lipids that help to compatibilize the starch, a polar matrix, with the nonpolar rubber.

O presente trabalho teve por objetivo estudar o amido termoplástico (TPS) proveniente de batata e suas blendas com os polímeros biodegradáveis da classe dos poli (hidroxialcanoatos), como o homopolímero Poli (β-hidroxibutirato) (PHB) e o copolímero Poli (β-hidroxibutirato-co-valerato) (PHBV). Para tanto, foram desenvolvidas formulações de TPS, TPS/PHB, TPS/PHBV, TPS/PHBV, TPS/PHB/PHBV e dos próprios polímeros. Os teores de poli(hidroxialcanoatos) nas misturas foram iguais a 25, 50 e 75%. O TPS e as blendas foram preparados via mistura física dos polímeros base com água e glicerol. O estudo da plasticização do amido com 30 % de glicerol foi realizado em um misturador intensivo e os parâmetros de processo determinados (160°C, 10 min e 60 rpm) mostraram-se eficientes para a obtenção do termoplástico TPS. Os ensaios de absorção de água revelaram que o TPS pode apresentar ganho de massa de até 37%. As blendas preparadas com maiores teores do polímero (PHB e/ou PHBV) apresentaram maior resistência à absorção de água. A análise termogravimétrica (TG) das blendas revelou a existência de dois estágios de perda de massa, correspondentes à degradação do TPS e aos poliestéres. Dados de calorimetria demonstraram que o amido de batata possui teor de amilose de 23,6%. A curva DSC das blendas foram observados dois eventos térmicos endotérmicos, sendo o primeiro relacionado à saída de água e glicerol do TPS e o segundo correspondente à fusão do PHB e/ou PHBV. A análise por microscopia eletrônica de varredura evidenciou a presença de grãos de amido residuais nas formulações contendo maiores conteúdos de PHB e/ou PHBV. A análise térmica dinâmico-mecânica do TPS revelou a ocorrência de dois picos em tan δ, sendo o primeiro correspondente a transições na fase rica do plasticizante glicerol e um segundo pico definido como Tg do amido plasticizado. Os Ensaios Mecânicos de Tração mostraram para a amostra TPS o maior valor de deformação máxima, menor valor de módulo de elasticidade e baixo valor de tensão máxima, quando comparado às blendas TPS/PHB, TPS/PHBV e TPS/PHB/PHBV. O comportamento do TPS mostrou-se fortemente influenciado pelo teor de água presente na amostra. / The aim of this work was the study of thermoplastic starch (TPS) prepared from potato and its blends with biodegradable polyhydroxyalcanoates as homopolymer - Poly (β-hydroxibutirate) (PHB) and/or copolymer - Poly (β-hydroxybutirate-co-valerate) (PHBV). To reach the objectives of this study, there were developed formulations of TPS, TPS/PHB, TPS/PHBV, TPS/PHBV, TPS/PHB/PHBV and of the polymers themselves. The content of polyhydroxyalcanoates in the mixtures were 25, 50 and 75 %. The TPS and the blends were prepared by physical mixture of the polymers with water and glycerol. The study of starch\'plasticization, performed with 30 % of glycerol, was carried out in an intensive mixer and the determined parameters of the process (160°C, 10 min and 60 rpm ) were effective for the production of the parent thermoplastic starch. The water absorption tests showed that the TPS can present gain of mass up to 37 %. The blends prepared with higher amounts of the polymer (PHB and/or PHBV) presented higher resistance to the absorption of water. Thermogravimetric analysis (TG) of the blends revealed the existence of two mass loss stages, correspondents to the degradation of TPS and the polyesters. Data from calorimetry (DSC) demonstrated that the potato starch present 23.6% of amylose. The traces of DSC from TPS revealed only events related to the elimination of water and glycerol. For the blends two thermal endothermic events were observed. The first one corresponds to the elimination of water and glycerol from TPS and the second to the melting of the PHB and/or PHBV. The analysis performed by using scanning electron microscopy showed the presence of residual grains of starch in the formulations containing 50% or higher amounts of PHB and/or PHBV. The Dynamic Mechanical Thermal Analysis of TPS revealed the occurence of two tan δ peaks, being the first one correspondent to transitions in the glycerol rich phase and a second peak described as Tg of the plasticized starch. The Mechanical Tests showed for the TPS sample the highest value of elongation, the lower value of tensile strength and a low value of Young\'s modulus, when compared to the blends TPS/PHB, TPS/PHBV and TPS/PHB/PHBV. The behaviour of the TPS appeared strongly influenced by the content of water in the samples.

Introdução: O amaranto apresenta potencial funcional devido ao seu efeito hipocolesterolemizante e alto valor nutritivo. Sua aplicação na alimentação humana pode ser ampliada pela sua utilização como uma farinha instantânea obtida a partir da extrusão termoplástica e o seu consumo poderá ter impacto na saúde pública, prevenindo doenças cardiovasculares e melhorando o estado nutricional da população. Objetivo: Avaliar os efeitos da extrusão termoplástica nas características tecnológicas da farinha de amaranto. Métodos: O amaranto foi moído, preparado e extrusado em extrusora de rosca única de acordo com um planejamento fatorial fracionário. As variáveis independentes em estudo foram: tipo de farinha (integral e desengordurada), umidade (15 por cento e 25 por cento ), temperatura na terceira zona da extrusora (120°C e 180°C) e rotação da rosca (60 por cento e 90 por cento ). Resultados: Nas condições do experimento, a variável tipo de farinha apresentou efeitos superiores aos efeitos das variáveis consideradas clássicas da extrusão como temperatura, umidade e rotação da rosca. Obteve-se farinha extrusada com alta solubilidade em água, alto grau de gelatinização, baixa viscosidade e baixa tendência à retrogradação, apresentando potencial para aplicação como um produto instantâneo e não sendo sua qualidade nutricional afetada pela extrusão. O planejamento experimental realizado pode servir como um caminho para a otimização das respostas estudadas / Introduction. Amaranth presents great potential as a functional food due to its cholesterol-lowering effect and its high nutritive value. The use of amaranth can be increased through its use as an instant flour produced by the thermoplastic extrusion process. Amaranth consumption can benefit public health by preventing cardiovascular disease and by improving the nutritional status of the population. Objective. The aim of this work was to evaluate the effect of thermoplastic extrusion on the technological characteristics of amaranth flour. Methodology. Amaranth was milled, prepared and extruded in a single-screw laboratory extruder following a fractionated factorial design. The independent variables were: type of flour (whole and defatted), moisture (15 per cent and 25 per cent ), third zone barrel temperature (120°C and 180°C) and screw speed (60 per cent and 90 per cent ). Results. The variable type of flour presented a greater effect than classic extrusion variables such as temperature, moisture and screw speed. Extruded flour with high solubility in water, high degree of gelatinization, low viscosity and low retrogradation tendency was obtained by extrusion and could be used as an instant food product. The nutritive quality of the flour was not affected by extrusion. The factorial experiment conducted in this work can be employed as a way for optimization of the dependent variables studied

Orientadores: Fernanda Paula Collares Queiroz, Lucia Helena Innocentini Mei / Tese (doutorado) - Universidade Estadual dse Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-12T14:25:27Z (GMT). No. of bitstreams: 1 Fakhouri_FaraydeMatta_D.pdf: 8442121 bytes, checksum: 0c402098c4f41a7575fbfc8ec41dc913 (MD5) Previous issue date: 2009 / Resumo: O objetivo deste trabalho foi desenvolver um bioplástico flexível, biodegradável e comestível, à base de polímeros naturais de fontes renováveis (amido e gelatina) por processo de extrusão termoplástica seguido de sopro. Inicialmente, foi realizada a caracterização física e funcional de biofilmes à base de amido e gelatina elaborados pela técnica de solução (casting), visando a escolha das melhores formulações para serem utilizadas na produção destes bioplásticos por processo de extrusão e sopro. As soluções filmogênicas de amido de mandioca (nativo e modificado) e milho (nativo, ceroso, ceroso modificado e lipofílico) foram preparadas nas concentrações de 3 e 5% e a de gelatina, na concentração de 10%. Os biofilmes compostos de gelatina e amido (de mandioca ou de milho) foram elaborados nas proporções 4:1, 1:1 e 1:4, plastificadas com sorbitol ou glicerol, sendo 5% para as soluções de gelatina e 10% para as soluções de amido. Todos os biofilmes formados foram visualmente transparentes. A adição de gelatina provocou um aumento na espessura, na permeabilidade ao vapor de água (PVA) e na resistência à tração (RT), provocando também uma diminuição na opacidade dos mesmos. Posteriormente, diferentes ácidos graxos (palmítico, mirístico, cáprico, capróico e caprílico), nas concentrações de 5, 15, 25 e 50%, foram adicionados à mistura de amido lipofílico e gelatina. Esta adição causou, em geral, um aumento da opacidade, da espessura e da elongação, no entanto, ocorreu uma diminuição na RT e da PVA dos biofilmes formados. A melhor formulação de amido lipofílico, gelatina e plastificante (glicerol, sorbitol e ácido mirístico) foi utilizada para a produção de filmes por diferentes técnicas (prensados, prensados e soprados e extrudados). Bioplásticos prensados apresentaram menores valores de RT e maiores valores de solubilidade em água. Os filmes extrudados, obtidos nas mesmas concentrações de amido, gelatina e plastificante, apresentaram-se semi-rígidos, característica não desejável para o objetivo em questão. Com base nestes resultados, foram alteradas as concentrações dos componentes da mistura para permitir a obtenção de bioplásticos com propriedades adequadas pelo processo de extrusão termoplástica. Estes bioplásticos foram caracterizados quanto às propriedades físicas, fisico-químicas, morfológicas, mecânicas, de barreira e térmicas. Os bioplásticos elaborados foram flexíveis, apresentaram expansão durante o sopro e foram visualmente homogêneos, porém, os elaborados com sorbitol apresentaram-se quebradiços após o condicionamento. A adição de gelatina causou uma diminuição no valor de PVA, mas não influenciou a solubilidade em água nem a opacidade dos bioplásticos. A adição de lipídios ocasionou uma diminuição na RT dos bioplásticos, tanto no sentido transversal como no longitudinal em relação ao sentido de produção. Filmes compostos com 10 e 20% de gelatina, sem adição de ácido graxo apresentaram os menores valores de PVA e maiores valores de RT / Abstract: The goal of this research was to develop a flexible, biodegradable and edible film using natural polymers (starch and gelatin) from renewable sources through a process of thermoplastic extrusion followed by blowing. The first step of the research consisted on a physical and functional characterization of starch and gelatin based biofilms produced using the casting technique. The purpose was to select the solutions to be used on the production of these biofilms by extrusion and blowing. The filmogenic solutions of manioc starch (native and modified) and corn (native, waxy, waxy modified and lipofilic) were prepared at concentrations of 3 and 5%. The filmogenic solution of gelatin was prepared at a concentration of 10%. The gelatin and (manioc and corn) starch based biofilms were prepared at ratios of 4:1; 1:1 and 1:4. They were plasticized with sorbitol or glycerol at 5% for the the gelatin solutions and 10% for the starch solutions. All the biofilms obtained were visually transparent. The addition of gelatin resulted in an increase of the film thickness, an increase of the water vapour permeability (WVP), an increase of the tensile strength (TS) and a decrease in the opacity. Different fatty acids (palmitic, miristic, capric, caproic and caprilic) were added to the lipofilic starch and gelatin solution at concentrations of 5, 15, 25 and 50%. These additions resulted in an increase on opacity, thickness and elongation. However, there was a decrease on WVP and TS. The best solution of lipofilic starch, gelatin and plasticizer (glycerol, sorbitol and miristic acid) was used in the production of films by different techniques (pressed, pressed and blowed and extruded). Pressed biofilms showed lower values of strain at break and higher values of water solubility. The extruded films, obtained at the same concentrations of starch, gelatin and plasticizer were found to be semi-rigid, a characteristic not aligned with the objective of theresearch. Based on the results of this first assessment, the concentrations of the components were adjusted with the purpose of obtaining extruded films with the desired properties. The resulting biofilms were characterized for their physical, physico-chemical, morphology, mechanical, barrier and thermical properties. Biofilms in general were flexible, showed expansion during blowing and were visually homogeneous. However, biofilms prepared with sorbitol were cracking very easily after storage. The addition of gelatin resulted in a reduction of the WVP but did not have any influence on the water solubility nor on the opacity of the biofilms. The addition of lipids resulted in a reduction of the TS of the biofilms both in longitudinal and transversal directions. Biofilms with 10 and 20% of gelatin and no fatty acid added showed lower values of WVP and higher values of TS / Doutorado / Doutor em Tecnologia de Alimentos

Le procédé de fabrication directe de pièces thermoplastiques est un procédé innovant qui permet de créer sans outillage, à partir d'une modélisation géométrique numérique, des pièces de géométrie complexe en quelques heures. La fabrication dite additive est réalisée par étalement successif de couches de poudre thermoplastique de quelques dizaines de micromètres, dont une partie est fondue sous rayonnement laser et refroidie lentement afin de permettre la densification de la poudre par diffusion de l'air emprisonné. La résistance mécanique finale du matériau dépend fortement de cette densification. Un grand nombre de paramètres procédé et matériau influencent les mécanismes physiques mis en jeu qui sont contrôlés par la thermique du procédé. La clé de la maîtrise de ce procédé réside dans la parfaite maîtrise de la thermique du lit de poudre. Cette étude a pour objectif de modéliser le procédé de fabrication directe de pièces thermoplastiques haute température de type PEEK. Dans un premier temps, une simulation microscopique de la fusion laser d'un lit de poudre préchauffé et de la coalescence des grains est développée à l'aide de la méthode C-NEM implémentée sur le logiciel Matlab. Les cycles thermiques, la densification et le soudage des grains sont étudiés en fonction des paramètres matériau et procédé. Dans un second temps, l'étude de la thermique d'une couche de poudre à l'état liquide refroidie par apport d'une nouvelle couche de poudre par-dessus est menée à l'aide d'un logiciel éléments finis commercial. L'objectif est de définir les conditions d'étalement permettant au polymère fondu de rester à l'état liquide. / Direct manufacturing technology using Selective Laser Sintering of thermoplastic powder allows obtaining final parts in a short time, with a high degree of geometry flexibility and evolution. Parts are built layer by layer, a specific area of each layer is melted by the laser radiation and the whole part is cooled down slowly to induce a good densification, permitting the gas diffusion through the melted material. The mechanical properties of parts made by this process highly depend on the final polymer density. A lot of process and material parameters control the parts properties. The key of the process master lies in its perfect thermal control. The aim of this work is to model the selective laser sintering process for high temperature polymers like PEEK at two scales. Firstly, a microscopic simulation of the melting and the grain coalescence of preheated polymer powder bed is performed using the C-NEM method implemented on Matlab. This tool allows to study the material thermal cycles, the powder densification and the welding quality of grains for different material and process parameters. Then, the thermal study of the additional powder layer spreading on the melted layer is performed on a commercial finite element software. This study aims to determine the good spreading conditions allowing the melted material not to decrease below its crystallization temperature to enhance material densification.

Le développement d'une nouvelle voie de synthèse de poly(éther cétone cétone),polymères thermostables, a été étudiée pour des matériaux composites à matrice thermoplastique obtenus par le procédé de moulage par injection de résine RTM. Pour cela,nous nous sommes orientés vers une polymérisation par couplage réactif entre des monomères difonctionnels et des agents de couplage. Neuf monomères X-EKKE-X avec différentes extrémités réactives ont été synthétisés par acylation de Friedel-Crafts ou substitution nucléophile aromatique puis caractérisés structurellement et thermiquement.Des essais de couplage à partir de monomères à extrémités COOH sur des bisoxazoline sont permis la synthèse en masse de quatre polymères, semi-cristallins ou amorphes, de faibles masses molaires. A travers l'étude du comportement thermique de molécules modèles, une fragilité thermique à partir de 250°C a été mise en évidence pour ces polymères et attribuée au pont ester-amide entre deux unités EKKE. / A new synthetic route to poly(ether ketone ketone), thermostable and semi-crystalline polymers, has been studied towards composite materials with a thermoplastic matrix obtained by a resin transfer molding process (RTM). This original synthesis was conducted by coupling reactions between difunctionals monomers and coupling agents. Nine X-EKKE-X monomers with different reactive extremities have been synthesized by Friedel-Crafts acylation or nucleophilic aromatic substitution. Thermal and structural properties were thoroughly investigated. Four polymers with semi-crystalline or amorphous morphologies and low molecular weights were obtained by coupling reactions between monomers with COOH functional extremities and bisoxazolines. Through the study of the thermal behavior of models molecules, a thermal fragility was highlighted for these polymers from 250°C and assigned to the amide-ester bridge between two EKKE units.

Four novel high performance soft thermoplastic polyurethane elastomers utilizing methylene bis(4-cyclohexylisocyanate) as a hard segment, 1,4 butanediol as a chain extender and modified low crystallinity carbonate copolymer as a soft segment were synthesized. The samples were characterized by infrared spectroscopy (FTIR), tensile, elongation, hardness, abrasion resistance and atomic force microscopy (AFM). SAXS data shows evidence of an interdomain "center-to-center" distance of 45Å. DSC traces show evidence of one glass transition temperature and a weak melting region. DMA analysis reveals a low temperature secondary relaxation and the glass to rubber transition followed by a rubbery plateau. All samples demonstrated the ability to maintain excellent physical and mechanical properties in hardness below 70 Shore A. Thermoplastic polyurethanes in this study do not possess surface tackiness usually observed in soft polyurethanes. Biocompatability testing showed no toxicity of these samples as indicated by USP Class VI, MEM Elution Cytotoxicity and Hemolysis toxicology reports. This novel type of polyurethane material targets growing markets of biocompatible polymers and can be utilized as peristaltic pump tubing, balloon catheters, enteral feeding tubes and medical equipment gaskets and seals. Polyimides are a family of engineering polymers with temperature stability, high polarity and solvent resistance. These high-performance materials are used in aerospace applications, in the production of semi-dry battery binders, and in a host of other high temperature demanding situations. However, their glass transition and melt temperatures are characteristically very high and close to one another, making them difficult to melt process and limiting them to thin film formulations from their polyamic acid precursors. Here, a new series of thermoplastic polyether-polyimides (PE-PIs) are synthesized by incorporating a polyetherdiamine monomer to reduce rigidity and break up an otherwise fully aromatic backbone as seen with most conventional polyimides. It will be shown that control of the stoichiometric ratio between the aromatic 4,4'-methylenebis(2,6-dimethylaniline) and aliphatic polyetherdiamines relative to PMDA (pyromellitic dianhydride), along with the molecular weight of the polyetheramine, can be used to tune the Tg to best balance between temperature performance and processability.

The high functionality epoxy resins tetraglycidyl-4,4’-diaminodiphenyl-methane(TGDDM) and triglycidyl-p-aminophenol (TGPAP) are the main components in most aerospace grade epoxy resin formulations. Owing to their high reactivity and high viscosity, TGDDM and TGPAP pose difficulties when used in wet layup composite manufacturing. As such, these resins are often modified to achieve the desired performance both in the liquid and cured states. The main objective of this thesis is to optimise a low viscosity multi-component epoxy resin formulation suitable for use as an aerospace grade composite matrix. The formulation will allow for the addition of high levels of thermoplastic to improve the fracture toughness of the resin whilst also maintaining resin processability. Through the use of thermal analytical techniques this thesis aims to study the effects of varying the TGDDM/TGPAP ratio, incorporation of a low viscosity bi-functional epoxy resin, the diglycidyl ether of bisphenol F (DGEBF) and changes to the stoichiometric ratio (r)between reactive groups of the epoxy resin and amine hardener (4,4’-diaminodiphenylsulphone, DDS) in multi-component epoxy resin formulations. Resin formulations were optimised using factorial experimental design (FED). Results from two FED’s showed curing multi-component resins at a low stoichiometric ratio significantly increased the processing window whilst also increasing the glass transition temperature (Tg) of the cured resin. No apparent benefit could be assigned to the inclusion of TGDDM owing to its poor processability and a Tg similar to TGPAP. Up to 60% DGEBF was incorporated in a multi-component resin formulation whilst still attaining a Tg greater than 220°C. Its inclusion at 60% had the additional benefit of increasing the processing window by 48 minutes over TGPAP, an increase of 62%. Two optimised resin formulations, 100% TGPAP (100T) and a binary mix of 60% DGEBF and 40% TGPAP (60D) were taken forward to study the effects of adding a thermoplastic toughener (polyethersulphone, PES) in incremental amounts up to 50wt%. SEM images showed all toughened 100T resins had a phase separated morphology whilst all 60D resins were homogenous. The phase separation seen in 100T did not improve the matrix fracture toughness when loaded at 10 wt% and 30 wt% PES. Only when 50 wt% PES was added did fracture toughness increase in comparison to the homogenous 60D resins. Through factorial experimental design two epoxy resin formulations which excluded TGDDM were optimised with a low stoichiometric ratio. The optimum aerospace formulation is dependent on the desired processability and fracture toughness of the resin. High DGEBF-containing formulations give the longest processing windows whilst the 100% TGPAP formulation toughened with 50% PES has the highest fracture toughness.

Ce travail s'inscrit dans la démarche générale de compréhension et d'amélioration des propriétés mécaniques des matériaux thermoplastiques amylacés, en proposant une nouvelle démarche originale de modification structurale de l'amidon thermoplastique s’appuyant sur la combinaison de deux techniques: la réticulation de l'amidon sous faisceau d’électrons et l'orientation macromoléculaire issue du procédé de transformation par extrusion. La première partie du manuscrit est consacrée aux propriétés thermomécaniques de l’amidon plastifié et propose notamment une mise à jour de la courbe maitresse contrainte-allongement mettant en évidence le phénomène d’antiplastification mais aussi de surplastification grâce notamment à l’étude des propriétés à Tg équivalentes. L’évolution des températures de transition β (Tβ) des matériaux a pu être reliée aux différentes étapes de la plastification et des analyses ATG ont mises en évidence les phénomènes de sorption et désorption du plastifiant. Les mécanismes d’endommagement de l’amidon plastifié ont également été explorés à l’aide de la technologie de vidéotraction. Le second chapitre du document est consacré à l’étude de la réticulation de l’amidon thermoplastique à l’état solide sous faisceau d’électrons. De nombreux facteurs ont été étudiés comme la dose absorbée, la teneur en eau, la teneur en plastifiant, le type et la teneur en réactif introduit, ainsi que l’impact du taux de réticulation sur le mécanisme de rétrogradation. Le troisième et dernier chapitre traite du mécanisme d’orientation moléculaire particulier de l’amidon thermoplastique, et de son impact sur les propriétés mécaniques. Le couplage de l’orientation et de l’irradiation sous faisceau d’électrons a également été appréhendé. / This work is part of the general approach aiming to understand and improving the mechanical properties of thermoplastics starch materials by proposing a new and original approach to the structural modification of thermoplastic starch through the combination of two techniques: radiation crosslinking and macromolecular orientation. The first part of the thesis focuses on the thermo-mechanical properties of plasticized starch and proposes an update to the master Stress-strain curve highlighting “antiplasticization” and “overplasticization” phenomena thanks to the study of properties at equivalent Tg. The evolution of materials β transition temperature (Tβ) could also be linked to the different plasticization stages and TGA results highlighted the sorption and desorption phenomenon of the plasticizer. The damage and fracture mechanisms of plasticized starch were also explored with videotraction technology. The second chapter of the document is devoted to the study of crosslinking of thermoplastic starch at solid state under an electron beam radiation. Many factors were explored like the absorbed dose, water content, plasticizer content, nature and amount of crosslinking agents introduced, and their impact on curing mechanisms and retrogradation of the plasticized starch. The third and final chapter deals with the specific mechanism of molecular orientation of the thermoplastic starch and its impact on mechanical properties. The coupling of orientation and irradiation under an electron beam was also investigated.

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