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V nalogi smo ugotavljali, kakšne so lastnosti potresnega odziva pravokotnih armiranobetonskih sten in učinek njihove povezanosti z gladkimi armiranobetonskimi etažnimi ploščami, brez gred. Tovrstne stene običajno projektiramo kot konzolne. Pri tem običajno predpostavimo, da plošče stene povezujejo le kot toge šipe na nivoju etaž, oziroma zanemarimo upogibno togost in nosilnost povezovalnih plošč, pod predpostavko, da je ta v primerjavi s stenami zanemarljivo majhna. V nalogi smo naredili parametrično študijo, s katero smo analizirali, ali je ta predpostavka upravičena in kako nanjo vplivajo različni geometrijski ter konstrukcijski parametri. V analizah smo upoštevali določila standardov Evrokod 8 in Evrokod 2. Stene smo najprej dimenzionirali na osnovi rezultatov linearne elastične modalne analize. Glede na to, da lahko s takšno analizo ugotovimo zgolj približek potresnega odziva obravnavanih konstrukcij, smo njihov potresni odziv ocenili tudi z nelinearno analizo, pri kateri smo uporabili N2 metodo. Obravnavane konstrukcije sten so predstavljale značilen izsek iz tipičnih stenastih stavb. Stene smo v enem primeru obravnavali kot konzolne, v drugem pa kot povezane. Upogibna armatura teh dveh sistemov se v obravnavanih primerih ni bistveno razlikovala, ker pri povezanih stenah znaten del prevrnitvenega momenta prevzamemo z momenti, ki jih v konstrukciji povzročajo osne sile v stenah. Zaradi različnega poteka upogibnih momentov vzdolž sten, pa so bile prečne sile dokaj različne. Posledično je bila potrebna prečna armatura v povezanih stenah pri večini primerov bistveno večja kot v konzolnih. V ploščah so bili v primeru povezanih sten upogibni momenti večinoma zelo veliki in posledično je bila potrebna razmeroma velika količina upogibne armature. Ugotovili smo tudi, da je lahko stopnja povezanosti sten le s ploščami zelo velika. Ključno vlogo pri tem ima sodelujoča širina plošče, ki se aktivira ob močnem potresnem odzivu in je lahko bistveno večja od tiste, ki jo običajno upoštevamo pri projektiranju. Ta parameter pomembno vpliva tudi na vrsto mehanizma odziva, ki se aktivira v nelinearnem območju. In the task, we determined the characteristics of the seismic response of rectangular reinforced concrete walls and the effect of their connection with reinforced concrete slabs, without beams. These types of walls are usually designed as cantilever walls. In such cases, we usually assume that the only »connection« between the walls are constraints in the horizontal direction at floor level (rigid diaphragms). In other words, we ignore the bending stiffness and load-bearing capacity of the connecting slabs, assuming that it is negligibly small compared to that of the walls. In the assignment, we made a parametric study, where we analyzed whether this assumption is justified and how it is affected by various geometric and structural parameters. In the analyses, we took into account the provisions of the standards Eurocode 8 and Eurocode 2. The walls were first dimensioned based on the results of the linear elastic modal analysis. Considering that with such an analysis we can only determine the approximation of the seismic response of the considered structures, we also evaluated their seismic response with a non-linear analysis, in which we used the N2 method. The considered wall constructions represented a characteristic part of typical wall buildings. In one case, we treated the walls as cantilever walls, and in the other as connected walls. The logitudinal reinforcement of these two systems did not differ significantly in the cases considered, because in the case of connected walls, a significant part of the overturning moment is absorbed by the moments caused in the construction by the axial forces in the walls. Due to the different redistribution of bending moments along the walls, the transverse forces were quite different. As a result, the required transverse reinforcement in connected walls were in most cases significantly greater than in cantilever walls. In the slabs, in the case of connected walls, the bending moments were mostly very large and, as a result, a relatively large amount of longitudinal reinforcement was required. We also found out that the degree of connection of walls only with the slabs can be very high. A key role in this is played by the participating width of the slab, which is activated in the case of a strong seismic response and can be significantly larger than what is usually taken into account in the design. This parameter also significantly affects the type of response mechanism that is activated in the nonlinear region.

Una de las estructuras ligeras más empleadas en la construcción de cubiertas metálicas es el arco de acero conformado en frio. Se trata de un elemento auto-portante que se puede colocar de forma relativamente sencilla y sin necesidad de incorporar ningún sistema de refuerzo. El diseño de esta tipología puede llegar a constituir un importante reto ya que no existe un consenso definitivo sobre su comportamiento mecánico bajo diferentes fenómenos de inestabilidad. Es por ello que en el presente trabajo académico se ha decidido abordar el análisis del pandeo local del perfil del arco utilizando el Método de los Elementos Finitos para estudiar su comportamiento bajo solicitaciones de compresión pura. El objetivo principal ha consistido en analizar la influencia de la profundidad del rigidizador en el patrón de colapso y en la capacidad resistente. Se han estudiado con detalle los modos de pandeo con rigidizador completo, rigidizador rebajado y sin rigidizador y se han analizado los diversos mecanismos de fallo con objeto de conocer el comportamiento no lineal del sistema. Para validar las simulaciones se han realizado en el laboratorio de resistencia de materiales de la EPSEVG unos ensayos experimentales aplicando la técnica de la extensometría eléctrica en una muestra de chapa nervada. Como conclusión final del estudio se han establecido unas orientaciones sobre la resistencia local del perfil del arco y se han elaborado algunas recomendaciones que pueden llegar a ser de utilidad en el diseño de esta tipología estructural. SUMMARY One of the light structures most widely used to construct metal roofs is the cold-formed steel arch. This is due to the fact that it is a self-supporting element that can be easily placed without the need of including any reinforcement system. The design of this constructive typology can become an important challenge since there is no definitive consensus on its mechanical behavior under different phenomena of instability. This is the reason why in the present work we have decided to analyze the local buckling of the arch profile by using the Finite Element Method to study its behavior when compression internal forces are applied. The main goal has been to know the influence of the depth of the stiffener on the collapse patterns and on the bearing load capacity. We have studied in detail the buckling modes with full stiffener, lowered stiffener and without stiffener and we have analyzed the failure mechanisms to know the nonlinear behavior of the system. In order to validate the simulations, experimental tests were carried out in the strength of materials laboratory of the EPSEVG applying electrical extensometry on a sample of steel sheet. As a final conclusion of the study, guidelines are established on the local strength of the arch profile and some recommendations are made that might be useful to design this structural typology.

Cellulose acetate (CA) is a bio-sourced polymer available on an industrial scale. Plasticizers are commonly used to help transformation in the molten state of CA. However, over time, the migration out of the polymer matrix is observed. This will limit the use of cellulose acetate for applications such as agri-food and cosmetics. The objective of this thesis is to functionalize cellulose acetate in the melt state by reactive extrusion. Molecules that can act as external plasticizers, and react with different functions present on the polymer chain, have been selected. In a first step, the behaviour of polymer/plasticizer systems were studied and compared to usual blends with triacetin. The reactions between these plasticizers and hydroxyl or acetyl functions have been analyzed at different temperatures and with different catalysts using model reactions. This led to the development of a new material, cellulose acetate octanoate, with interesting thermal and mechanical properties.; L’acétate de cellulose (CA) est un polymère bio-sourcé disponible à l’échelle industrielle. Il est courant d’utiliser des plastifiants afin de faciliter sa transformation par des techniques de plasturgie en voie fondue. Cependant, avec le temps, ces derniers peuvent migrer hors de la matrice polymère. Cela va limiter l’utilisation de l’acétate de cellulose dans certains domaines d’application tel que l’agroalimentaire et la cosmétique. C’est pourquoi ces travaux de thèse proposent fonctionnaliser l’acétate de cellulose en voie fondue par extrusion réactive. Pour cela des molécules pouvant jouer le rôle de plastifiant externe, mais également susceptibles de réagir avec les différentes fonctions présentes sur le polymère, ont été sélectionnées. Dans un premier temps, le comportement des mélanges polymère/plastifiants a été étudié et comparé à celui de plastifiants usuels tel que la triacétine. Les possibilités de réactions entre ces plastifiants et les fonctions hydroxyles et acétyles présentent sur le CA ont été analysé, à différentes températures et avec différents catalyseurs, à l’aide de réactions modèles. Cela a permis d’aboutir au développement d’un nouveau matériau, l’acétate octanoate de cellulose, présentant des propriétés thermiques et mécaniques intéressantes.

Ovaj završni rad opisati će uvođenje robotizacije u industrijski proces za potrebe tehnološke operacije površinske zaštite. U prvom dijelu će se objasniti procesi i sustavi površinske zaštite (bojanje, plastifikacija i sve rijeđe bitumenizacija), te priprema površina (sačmarenje) prije samog postupka zaštite. Primjeri postrojenja u realnom sektoru proizvodnje kao što su linija za plastifikaciju u fluidiziranom sloju i linija za bitumeniziranje vodenim postupkom. Približno sličnu liniju za lakiranje prikazati će se pomoću programskog alata V- REP. U programu će biti odabrani robot za bojanje KUKA koji raspršivanjem nanosi boju na radni komad kojeg će rotirati pozicioner. Stalak „Viktorija zdenac“ poslužiti će kao model radnog komada koji će se okretati dok robot na njega nanosi slojeve boje. Budući da je V- REP najnapredniji i vrlo prilagodljiv simulator, moguće ga je koristiti i u području virtualne stvarnosti (VR) za potrebe programiranja pokreta preko VR naočala i kontrolera. Drugi dio i glavna tema ovog rada je izrađivanje i simuliacija ćelije za bojanje robotom u programskome alatu V- REP. Opisati će se postavljanje kinematike robota KUKA i senzora za prihvat raspršivača te postupak umetanja modela stalka iz Solid Edge-a u V- REP i njegove putanje koja će služiti za upravljanje robotom iz skripti preko funkcija programskog jezika Lua. Pozicioner koji će okretati radni komad dok robot preko putanje vrši bojanje upravljan je također iz skripte sa svojim funkcijama i parametrima. Na kraju će se prikazati dijelovi ostalih proizvodnih procesa prije i poslije samog postupka bojanja, te zaštitni uvjeti kako za ljude tako i za okoliš. Nakon što se izradi robotska ćelija za bojanje, simulacijom se pregledava sami postupak nanosa boje na radni komad. This final paper will describe the introduction of robotization into the industrial process for the purposes of a technological surface protection operation. The first part will explain the processes and systems of surface protection (painting, plastification and less frequently bitumenisation), and the preparation of surfaces (shot blasting) before the protection process itself. Examples of installations in the real manufacturing sector include fluidized bed plastification line and water bitumenisation line. A roughly similar painting line will be displayed using the V-REP software tool. The program will select the KUKA painting robot that will spray paint onto a workpiece that will be rotated by the positioner. The stand „Viktorija zdenac“ will serve as a workpiece model that will rotate as the robot applies layers of paint on it. Because V-REP is the most advanced and highly customizable simulator, it can also be used in virtual reality (VR) for motion programming via VR glasses and controllers. The second part and mainly the main theme of this final paper is to design and simulate a robot painting cell in the V-REP software tool. It will describe the setting of the kinematics of the KUKA robot and the spray sensor. The process of inserting a stand model from Solid Edge into V-REP and its path will be used to control the robot from scripts via the functions of the Lua programming language. The positioner who will rotate the workpiece while the robot is painting the path is also controlled from the script with its functions and parameters. Finally, parts of other manufacturing processes will be presented before and after the painting process itself, as well as the protective conditions for both humans and the environment. After the robotic painting cell is created, the simulation examines the process of applying the paint to the workpiece itself.

In order to meet growing environmental concerns, there has been a considerable interest in generating bio-based polymers with a view to replacing the traditional oil-based chemistries. This thesis focuses on polyester thermosetting resins derived from renewable feedstock. Product optimization is however currently impeded by the limited knowledge about the mechanical properties of these new polymers. Indeed, the material foamability coupled to fast polymerization during processing prevents the fabrication and characterization of macroscopic polymer samples under technologically relevant conditions.To overcome this limitation, we prepare samples with micrometric sizes (typically in the 10 textmu m range) and controlled geometries from a model bio-based polyester resin. The mechanical behaviour of these micro samples is investigated experimentally using various micro mechanical characterization techniques. Because of its large hydrophilicity, the model polymer exhibits a large change in its mechanical properties upon exposure to humidity. For increasing humidity, pristine specimens undergo a water-triggered glass transition from a glassy to a water-swollen gel state which is attributed to the dramatic plasticization of the material by water. We also evidence the influence of hygric history on the mechanical, structural and sorption properties of the polymer and show that this dependence bears close similarities with the effect of thermo-mechanical physical ageing on polymer glasses. Finally, when subjected to long-term hygrothermal ageing conditions, the polymer exhibits an irreversible degradation of its mechanical properties which may be ascribed to the existence of hydrolysis process.; Dans un contexte de transition énergétique induite par la raréfaction des ressources énergétiques fossiles et le changement climatique, les polymères traditionnels dérivés de ressources pétrochimiques tendent à être remplacés par des chimies bio-sourcées. Cette thèse a pour objet de nouvelles résines polymères thermodurcissables de type polyester élaborées à partir de matières premières renouvelables. L'optimisation de leur formulation nécessite une meilleure connaissance de leur comportement mécanique en vue de leur application dans un contexte industriel. La caractérisation mécanique de ces matériaux est cependant limitée par l'impossibilité de réaliser des échantillons massifs dans des conditions représentatives des procédés industriels.Pour surmonter ces difficultés, nous préparons des échantillons d'une taille caractéristique de l'ordre d'une dizaine de microns et de géométrie contrôlée à partir d’un polyester bio-sourcé modèle. Nous étudions ensuite expérimentalement le comportement mécanique de ces échantillons grâce à des outils de caractérisation micro-mécanique adaptés. En raison de son hydrophilie élevée, le comportement mécanique du polymère se révèle fortement dépendant de l'humidité. Dans le cas d'échantillons non vieillis, cette dépendance se traduit par une transition du polymère d'un état vitreux vers un état gel que nous attribuons à un phénomène réversible de plastification par l'eau. Nous montrons dans un second temps que l’histoire thermohydrique agit sur les propriétés mécaniques, diffusives et microstructurales du matériau de manière similaire à l'impact de l’histoire thermomécanique sur les polymères vitreux. Enfin, le vieillissement thermohydrique prolongé du polymère entraine une dégradation irréversible de ses propriétés mécaniques qui pourrait révéler un phénomène d'hydrolyse.

Methods of introducing a water-soluble biocide modifier, oligohexamethyleneguanidine hydrochloride, into epoxy-amine systems were studied. The obvious way is the introduction of the modifier in the waterborne epoxy-amine systems. However, this leads to cured systems with reduced mechanical properties. Introduction of oligohexamethyleneguanidine hydrochloride solutions in organic solvents into epoxy-amine systems allows obtaining a homogeneous system, but their application is limited by the presence of a volatile solvent. Finally, introduction of oligohexamethyleneguanidine hydrochloride solutions in a water-soluble amine curing agent into epoxy-amine systems has good prospects. It is shown that the analyzed modifier has good solubility in ethylenediamine, but poor solubility in oligooxypropylenediamine. It was found that the modifier is capable of interacting chemically with epoxy resins at 22°C to form an elastic insoluble material. In an epoxy-amine system with a more active hardener (ethylenediamine) oligohexamethyleneguanidine hydrochloride acts as a plastifier (flexibilizer). This significantly reduces the glass transition temperature of the matrix (from 53 to 37ºC).

Plasticizers are additives used to soften polymers, but most of them are oily or waxy and are difficult to process in a continuous hot-melt process. The plasticizing effect of four functionalized ferulic acid derivatives designed with controlled solubility parameters was investigated upon the study of both the thermal stability and the mechanical properties of polylactic acid (PLA) blends. The synthesized powders were incorporated into PLA through a continuous hot-melt process (extrusion) allowing the derivatives to turn from crystalline to an amorphous state. Such phase transition permitted the derivatives to act as plasticizers, reaching a reduction of the Young's modulus of PLA by 40% for one of the derivatives blended at 20 wt%. Another derivative decreased the glass transition of the PLA from 56.6 °C to 26.3 °C at the same content. These works demonstrate the interest of using phase transition additives to ease the mixing of efficient plasticizers by hot-melt processing.

Increasing the carrying capacity of structures without increasing the weight is a constant focus of research and contemporary technology developments. Tubular structural members under tension loading are sensitive to bending and bucking. Inserting lightweight cellular filler in tubular structural member significantly increases loading and energy absorption capacity. Presented work is an overview of the collaboration between the University of Maribor (Slovenia), University of Aveiro (Portugal) and University of Split (Croatia), where numerical and experimental research has been performed. Evaluation of structural response under dynamic mechanical loading conditions has been performed by means of infrared thermography used as a passive method for tracing plastification occurrences in material. Such an approach based on infrared thermography enables better understanding of collapse mechanism and benefits of using cellular fillers. It additionally provides information to standard load-displacement curves. Aluminium tubes, with and without cellular filler, have been subjected to compression and three-point bending dynamic tests. As filler material, Advanced Pore Morphology (APM) spheres [1] and closed cell aluminium foams have been used. Aluminium foam was formed in moulds and inserted in tubes (ex-situ) [2], or foamed directly in tubes (in-situ) [3]. In-situ approach causes better stress redistribution due to bonding between the tube and filler, while exposure to heat results in structural changes of heat treated aluminium tubes. It has been shown that three-point bending test is an appropriate method for evaluation of such structures and comparable with results of numerical simulations [4], what is often not the case for simple compression or tension tests.

Cellulose acetate (CA) is a bio-sourced polymer available on an industrial scale. Plasticizers are commonly used to help transformation in the molten state of CA. However, over time, the migration out of the polymer matrix is observed. This will limit the use of cellulose acetate for applications such as agri-food and cosmetics. The objective of this thesis is to functionalize cellulose acetate in the melt state by reactive extrusion. Molecules that can act as external plasticizers, and react with different functions present on the polymer chain, have been selected. In a first step, the behaviour of polymer/plasticizer systems were studied and compared to usual blends with triacetin. The reactions between these plasticizers and hydroxyl or acetyl functions have been analyzed at different temperatures and with different catalysts using model reactions. This led to the development of a new material, cellulose acetate octanoate, with interesting thermal and mechanical properties., L’acétate de cellulose (CA) est un polymère bio-sourcé disponible à l’échelle industrielle. Il est courant d’utiliser des plastifiants afin de faciliter sa transformation par des techniques de plasturgie en voie fondue. Cependant, avec le temps, ces derniers peuvent migrer hors de la matrice polymère. Cela va limiter l’utilisation de l’acétate de cellulose dans certains domaines d’application tel que l’agroalimentaire et la cosmétique. C’est pourquoi ces travaux de thèse proposent fonctionnaliser l’acétate de cellulose en voie fondue par extrusion réactive. Pour cela des molécules pouvant jouer le rôle de plastifiant externe, mais également susceptibles de réagir avec les différentes fonctions présentes sur le polymère, ont été sélectionnées. Dans un premier temps, le comportement des mélanges polymère/plastifiants a été étudié et comparé à celui de plastifiants usuels tel que la triacétine. Les possibilités de réactions entre ces plastifiants et les fonctions hydroxyles et acétyles présentent sur le CA ont été analysé, à différentes températures et avec différents catalyseurs, à l’aide de réactions modèles. Cela a permis d’aboutir au développement d’un nouveau matériau, l’acétate octanoate de cellulose, présentant des propriétés thermiques et mécaniques intéressantes.

In order to meet growing environmental concerns, there has been a considerable interest in generating bio-based polymers with a view to replacing the traditional oil-based chemistries. This thesis focuses on polyester thermosetting resins derived from renewable feedstock. Product optimization is however currently impeded by the limited knowledge about the mechanical properties of these new polymers. Indeed, the material foamability coupled to fast polymerization during processing prevents the fabrication and characterization of macroscopic polymer samples under technologically relevant conditions.To overcome this limitation, we prepare samples with micrometric sizes (typically in the 10 textmu m range) and controlled geometries from a model bio-based polyester resin. The mechanical behaviour of these micro samples is investigated experimentally using various micro mechanical characterization techniques. Because of its large hydrophilicity, the model polymer exhibits a large change in its mechanical properties upon exposure to humidity. For increasing humidity, pristine specimens undergo a water-triggered glass transition from a glassy to a water-swollen gel state which is attributed to the dramatic plasticization of the material by water. We also evidence the influence of hygric history on the mechanical, structural and sorption properties of the polymer and show that this dependence bears close similarities with the effect of thermo-mechanical physical ageing on polymer glasses. Finally, when subjected to long-term hygrothermal ageing conditions, the polymer exhibits an irreversible degradation of its mechanical properties which may be ascribed to the existence of hydrolysis process., Dans un contexte de transition énergétique induite par la raréfaction des ressources énergétiques fossiles et le changement climatique, les polymères traditionnels dérivés de ressources pétrochimiques tendent à être remplacés par des chimies bio-sourcées. Cette thèse a pour objet de nouvelles résines polymères thermodurcissables de type polyester élaborées à partir de matières premières renouvelables. L'optimisation de leur formulation nécessite une meilleure connaissance de leur comportement mécanique en vue de leur application dans un contexte industriel. La caractérisation mécanique de ces matériaux est cependant limitée par l'impossibilité de réaliser des échantillons massifs dans des conditions représentatives des procédés industriels.Pour surmonter ces difficultés, nous préparons des échantillons d'une taille caractéristique de l'ordre d'une dizaine de microns et de géométrie contrôlée à partir d’un polyester bio-sourcé modèle. Nous étudions ensuite expérimentalement le comportement mécanique de ces échantillons grâce à des outils de caractérisation micro-mécanique adaptés. En raison de son hydrophilie élevée, le comportement mécanique du polymère se révèle fortement dépendant de l'humidité. Dans le cas d'échantillons non vieillis, cette dépendance se traduit par une transition du polymère d'un état vitreux vers un état gel que nous attribuons à un phénomène réversible de plastification par l'eau. Nous montrons dans un second temps que l’histoire thermohydrique agit sur les propriétés mécaniques, diffusives et microstructurales du matériau de manière similaire à l'impact de l’histoire thermomécanique sur les polymères vitreux. Enfin, le vieillissement thermohydrique prolongé du polymère entraine une dégradation irréversible de ses propriétés mécaniques qui pourrait révéler un phénomène d'hydrolyse.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Densification is relevant in the timber industry. Since it makes it possible to increase the use of wood less valued by the market. However, densified wood shows high dimensional instability. In order to minimize this problem, a post-treatment using the oil heat treatment (OHT®) was performed. In view of the above, the present research aims to evaluate the technological properties of densified wood of the eucalipto submitted to treatment in vegetable oil. The methodology consisted in the use of wood of E. grandis, E. dunnii, E. cloeziana and E. tereticornis that were submitted to the process of densification and post-treatment in vegetable oil. Twenty-four treatments were performed, consisting of different species, densification temperatures and post-treatment. For the characterization of the produced wood based material, physical, mechanical, chemical and superficial tests were carried out. For the statistical analysis, the 4 x 6 qualitative factorial arrangement was used, with four species and six treatments, compared by the Tukey test. The main results showed that densification increases distinctly in the basic density (ρb) among the evaluated species, which shows that the increase of ρb by densification is conditioned to its initial value. In the case of wood dimensional stability it was observed that the densification caused a reduction in this property in relation to the control. However, in the treatments in which the post-treatment in oil was applied, there was a decrease of more than 30% in the dimensional instability, caused by the relaxation of the stresses stored during the compression, through the partial hydrolysis of the hemicelluloses. As for the hygroscopicity of the wood, it was observed that the densification using the temperature of 140 °C showed an increase in the water absorption after 24 hours of immersion, caused by the reopening of the flattened vessels. However, when the wood was submitted to the post-treatment, there was a reduction of the hygroscopicity caused by the thermal degradation and the presence of oil in the cell lumens. In wettability it was identified that the only densified wood presented a hydrophilic character. However, when submitted to post-treatment it has become hydrophobic. Mechanical strength showed the most satisfactory results in densified wood at 140 °C without post-treatment, obtaining increases in all properties and species evaluated. However, with the post-treatment application there was an average decrease of 20% in the mechanical strength of the treated wood. In the analysis of Infrared Spectrometry it was verified that there was a greater chemical alteration after the application of the post-treatment, obtaining degradation of hemicelluloses and amorphous cellulose, which provided proportional increase of crystalline cellulose and lignin. For the colorimetric parameters, it was identified that the post-treatment presented the greatest changes in the color of the wood, causing the wood of the four species to gain a tropical tone (dark brown), which is feasible for the application of aesthetic purposes. A densificação apresenta relevante importância na indústria madeireira. Uma vez que possibilita ampliar a utilização de madeiras menos valorizadas pelo mercado. Entretanto, a madeira densificada apresenta elevada instabilidade dimensional. Visando minimizar esse problema foi realizado um pós-tratamento, utilizando a termorretificação em óleo pelo processo OHT® (Oil heat treatment). Diante do exposto, a presente pesquisa tem por objetivo avaliar as propriedades tecnológicas da madeira densificada de eucalipto submetida ao tratamento em óleo vegetal. A metodologia consistiu na utilização da madeira de E. grandis, E. dunnii, E. cloeziana e E. tereticornis que foram submetidas ao processo de densificação e pós-tratamento em óleo vegetal. Foram realizados 24 tratamentos, compondo-se de diferentes espécies, temperaturas de densificação e pós-tratamento. Para a caracterização do material gerado, foram realizados ensaios físicos, mecânicos, químicos e superficiais na madeira. Para a análise estatística foi utilizado o arranjo fatorial qualitativo 4 x 6, com quatro espécies e seis tratamentos, comparados pelo teste de Tukey. Os principais resultados demostraram que a densificação apresentou acréscimos distintos na densidade aparente (ρap) entre as espécies avaliadas, o que demonstra que o aumento da ρap por meio da densificação está condicionado ao seu valor inicial. No caso da estabilidade dimensional da madeira foi observado que a densificação provocou redução nessa propriedade em relação ao controle. Entretanto, nos tratamentos em que foi aplicado o pós-tratamento em óleo houve decréscimo de mais de 30% na instabilidade dimensional, ocasionado pelo relaxamento das tensões armazenadas durante a compressão, por meio da hidrólise parcial das hemiceluloses. Já para a higroscopicidade da madeira foi observado que a densificação utilizando a temperatura de 140 °C apresentou aumento na absorção de água após 24 horas de imersão, provocado pela reabertura dos vasos achatados. No entanto, quando a madeira foi submetida ao pós-tratamento houve redução da higroscopicidade ocasionada pela degradação térmica e presença de óleo nos lumens celulares. Na molhabilidade foi identificado que a madeira somente densificada apresentou caráter hidrofílico. Entretanto, quando submetida ao pós-tratamento tornou-se hidrofóbica. A resistência mecânica apresentou os resultados mais satisfatórios na madeira densificada a 140 °C sem aplicação de pós-tratamento, obtendo acréscimos em todas as propriedades e espécies avaliadas. No entanto, com a aplicação de pós-tratamento houve decréscimo médio de 20% na resistência mecânica da madeira tratada. Na análise de Espectrometria no Infravermelho foi verificado que houve maior alteração química após a aplicação do pós-tratamento, obtendo degradação de hemiceluloses e celulose amorfa, o que proporcionou acréscimo proporcional de celulose cristalina e lignina. Para os parâmetros colorimétricos, foi identificado que o pós-tratamento apresentou as maiores alterações na cor da madeira, fazendo com que a madeira das quatro as espécies ganhassem um tom tropical (marrom escuro), viável para aplicação de fins estéticos.

Vegetable isolated proteins are a renewable source of raw material, available in the large quantities. In spite of weak mechanical properties compared with the traditional polymers, they possess other important characteristics such as biodegradability, filmability and they are non-toxic. This study investigated the effect of processing type, compatibilization and addition of nanofillers on the properties of poly(butylene succinate-co-adipate)/plasticized isolated soy protein blends (PBSA/PISP). Initially, plasticizing and blending of soy protein with poly (butylene succinate-co-adipate) at various composition were carried out simultaneously in a single step extrusion. Then, the effect of adding poly(2-ethyl oxazoline) as compatibilizer has been studied. Addition of compatibilizer improves the interface and thermal properties of the blends. Besides, addition of halloysite nanotubes improves some mechanical and thermal properties. Finally, in the case of blend films prepared with equal PBSA/PISP composition (50/50), the compatibilizer increases the optical properties whereas addition of halloysite nanotubes improves the water vapour barrier properties and delay the degradation of blends as tested by soil buriel test. The overall results gives preliminary insights into potential usage of these films in packaging and possibly in biomedical sector.; Les protéines isolées végétales sont une source renouvelable de matière première, disponible en grande quantité. Malgré des propriétés mécaniques faibles par rapport aux polymères traditionnels, elles possèdent d’autres spécificités intéressantes comme leur biodégradabilité, leur filmabilité et leur absence de toxicité. Cette étude s’est focalisée sur l’influence du procédé d’élaboration, la compatibilité et l’ajout de nanocharges sur les propriétés de mélanges poly(butylène succinate - co - adipate)/protéines de soja isolées plastifiées (PBSA/PISP). Dans un premier temps, les protéines de soja sont plastifiées et mélangées au poly(butylène succinate - co - adipate), dans des proportions différentes et extrudées simultanément en une étape d’extrusion. Ensuite, l’effet de l’ajout du poly(2-éthyl-oxazoline) comme compatibilisant a été étudié. L’addition de ce compatibilisant permet d’améliorer l’interface et les propriétés thermiques. En outre, l’addition de nanotubes d’halloysite permet d’améliorer certaines propriétés mécaniques et thermiques. Enfin dans le cas de films préparés avec une composition PBSA/PISP égale (50/50), le compatibilisant améliore les propriétés optiques, tandis que l’ajout des nanotubes d’halloysite améliore les propriétés de barrière à la vapeur d’eau et retarde la dégradation du film enfoui dans un sol. L’ensemble des résultats donne de premières indications sur l’usage potentiel de ces films dans le domaine de l’emballage et éventuellement dans le biomédical.

Vegetable isolated proteins are a renewable source of raw material, available in the large quantities. In spite of weak mechanical properties compared with the traditional polymers, they possess other important characteristics such as biodegradability, filmability and they are non-toxic. This study investigated the effect of processing type, compatibilization and addition of nanofillers on the properties of poly(butylene succinate-co-adipate)/plasticized isolated soy protein blends (PBSA/PISP). Initially, plasticizing and blending of soy protein with poly (butylene succinate-co-adipate) at various composition were carried out simultaneously in a single step extrusion. Then, the effect of adding poly(2-ethyl oxazoline) as compatibilizer has been studied. Addition of compatibilizer improves the interface and thermal properties of the blends. Besides, addition of halloysite nanotubes improves some mechanical and thermal properties. Finally, in the case of blend films prepared with equal PBSA/PISP composition (50/50), the compatibilizer increases the optical properties whereas addition of halloysite nanotubes improves the water vapour barrier properties and delay the degradation of blends as tested by soil buriel test. The overall results gives preliminary insights into potential usage of these films in packaging and possibly in biomedical sector.; Les protéines isolées végétales sont une source renouvelable de matière première, disponible en grande quantité. Malgré des propriétés mécaniques faibles par rapport aux polymères traditionnels, elles possèdent d’autres spécificités intéressantes comme leur biodégradabilité, leur filmabilité et leur absence de toxicité. Cette étude s’est focalisée sur l’influence du procédé d’élaboration, la compatibilité et l’ajout de nanocharges sur les propriétés de mélanges poly(butylène succinate - co - adipate)/protéines de soja isolées plastifiées (PBSA/PISP). Dans un premier temps, les protéines de soja sont plastifiées et mélangées au poly(butylène succinate - co - adipate), dans des proportions différentes et extrudées simultanément en une étape d’extrusion. Ensuite, l’effet de l’ajout du poly(2-éthyl-oxazoline) comme compatibilisant a été étudié. L’addition de ce compatibilisant permet d’améliorer l’interface et les propriétés thermiques. En outre, l’addition de nanotubes d’halloysite permet d’améliorer certaines propriétés mécaniques et thermiques. Enfin dans le cas de films préparés avec une composition PBSA/PISP égale (50/50), le compatibilisant améliore les propriétés optiques, tandis que l’ajout des nanotubes d’halloysite améliore les propriétés de barrière à la vapeur d’eau et retarde la dégradation du film enfoui dans un sol. L’ensemble des résultats donne de premières indications sur l’usage potentiel de ces films dans le domaine de l’emballage et éventuellement dans le biomédical.

Densification parameters were investigated for the fast-growing pine and eucalyptus. Both woods showed optimal results in terms of apparent density and mechanical properties when milder treatments of 150 °C were applied. Pine showed mass loss and improved mechanical properties with a longer heating time of 60 min, while eucalypt performed better with shorter treatments of 30 min. Eucalypt has more highly acetylated hemicelluloses, mainly composed of xylose units, which degrade more quickly with consequent decrease in mass and mechanical properties. However, apparent densities close to 1.0 g·cm-3 were obtained, and greatly enhanced bending properties, hardness, and impact resistance were observed, especially when the optimal parameters were used. Treatments at 170 °C or greater, while resulting in well-densified specimens, yielded inferior mechanical properties. The densified woods also presented initial apparent contact angles greater than 85°, highlighting a considerable increase of hydrophobicity. The densification process therefore allows these less valuable timber species to be used in applications such as flooring and decking.

U ovom radu ispitana su toplinska svojstva mješavina različitog udjela polilaktida (PLA) i termoplastičnog škroba (TPS). TPS je pripremljen s različitim udjelima glicerola (30 i 40 mas. %) kao plastifikatora. Radi uvida u hidrofilni/hidrofobni karakter mješavina PLA/TPS praćena je apsorpcija vode. Rezultati toplinskih svojstava pokazali su da TPS ubrzava proces hladne kristalizacije polilaktida uslijed nukleacijskog učinka TPS-a. TPS povećava sposobnost kristalizacije PLA i omogućava pravilnije slaganje lanaca polilaktida u kristalnoj strukturi. Utjecaj glicerola kao plastifikatora TPS-a nema značajnu ulogu u ispitivanju toplinskih svojstava, dok je ispitivanje apsorpcije vode pokazalo da se uz veći udio glicerola kao plastifikatora TPS-a dobivaju niže vrijednosti apsorpcije vode mješavina PLA/TPS. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna., In this paper, thermal properties of polylactide (PLA) and thermoplastic starch (TPS) blends with different proportions of TPS were investigated. TPS at different ratios of glycerol (30 and 40 wt. %) as a plasticizer, were prepared. To gain an insight into the hydrophilic/hydrophobic character of the PLA/TPS blends, water absorption was performed. The results of thermal properties indicated that TPS enhanced the cold crystallization process of polylactide due to the nucleation effect of TPS. TPS increases the ability of the PLA crystallization and provides a more accurate alignment of polylactide chains in the crystal structure. The effect of glycerol as a TPS plasticizer has no significant role in the thermal properties, while water absorption testing has shown that with higher glycerol content as TPS plasticizers, lower water absorption values of PLA/TPS blend are obtained. This work is licensed under a Creative Commons Attribution 4.0 International License.

Por vezes o comportamento vinculado a fadiga é a principal fonte de dúvidas em projetos de engenharia. Aqui, o crescimento de trincas por fadiga é analisado numericamente utilizando uma plataforma de elementos finitos, onde o problema da fratura é modelado de forma discreta através do uso de elementos coesivos de interface. Os casos estudados abordam estruturas que apresentam uma trinca inicial de tamanho conhecido que propaga por um caminho condicionado. Os problemas são restritos ao estado plano de deformações e sujeitos em sua grande maioria a abertura normal entre as superfícies da trinca. O processo de separação das interfaces da trinca é descrito pelo uso de dois modelos de zona coesiva irreversível. Os modelos possuem relações de tensão-separação que não seguem um caminho pré-definido, sendo dependentes da evolução do dano ligado as propriedades da zona coesiva. Inicialmente são mostradas respostas básicas uniaxiais para os elementos coesivos, que provam a existência de curvas S-N e que o acumulo de dano ocorre de forma não linear. Em seguida, analisa-se crescimento de trincas por fadiga em uma viga do tipo double cantilever beam, onde a estrutura observada é formada pela união de duas chapas metálicas através de um adesivo coesivo que direciona o crescimento da trinca Casos com carga de amplitude única são computados, resultando na representatividade da propagação por uma lei de Paris. Além disso, uma análise de fadiga transiente é realizada através de respostas geradas pela aplicação de sequências de carregamentos em blocos, que mostram a dependência entre o formato do bloco e a maneira a qual ocorre a propagação da trinca. Na sequência, observa-se o efeito escala no crescimento de trincas por fadiga em uma placa submetida a tração com comportamento quase-frágil. Obtém-se uma conexão entre a altura da placa e o formato da ruptura. Por fim, o efeito da plastificação sobre a propagação de trincas, incluindo a captura do efeito crack closure, é comprovado em uma estrutura multicamada que emprega uma malha refinada na ponta da trinca. Os resultados mostram que o modelo computacional implementado reproduz comportamentos semelhantes atingidos nos trabalhos de referência para os problemas analisados. Sometimes fatigue-related behavior is the main source of doubt in engineering projects. Here, the fatigue crack growth is analyzed numerically using a finite element platform, where the fracture problem is discretely modeled through the use of cohesive interface elements. The cases studied deal with structures that present an initial crack of known size that propagates through a conditioned path. The problems are restricted to plane strain and are mostly subject to the normal opening between the surfaces of the crack. The process of separating the interfaces of the crack is described by the use of two models of irreversible cohesive zone. The models have stress-separation relationships that do not follow a predefined path, being dependent on the evolution of the damage linked to the properties of the cohesive zone. Initially basic uniaxial responses are shown for the cohesive elements, which prove the existence of S-N curves and that the accumulation of damage occurs non-linearly. Then, fatigue crack growth is analyzed in a double cantilever beam, where the observed structure is formed by the union of two metal plates through a cohesive adhesive that directs the growth of the crack Cases with single amplitude loading are computed, resulting in the representativeness of propagation by a Paris law. In addition, a transient fatigue analysis is performed through responses generated by the application of block loading sequences, which show the dependence between the block shape and the manner in which crack propagation occurs. In the sequence, the scale effect on the growth of fatigue cracks in a plate subjected to traction with quasi-fragile behavior is observed. A connection is obtained between the height of the plate and the rupture format. Finally, the plastification effect on crack propagation, including crack closure capture, is demonstrated in a multilayer structure that employs a refined mesh at the crack tip. The results show that the computational model implemented reproduces similar behaviors reached in the reference works for the analyzed problems.

International audience; Native starch containing 12% water was melt processed in presence of 23% of various plasticizers at 120 °C, either by simple compression molding or by extrusion using a laboratory scale microcompounder. Glycerol, a typical starch plasticizer, was used as a reference and compared to three choline salts: raw choline chloride (which is a solid in dry state with a melting point above 300 °C), and two ionic liquids synthesized from this precursor (choline acetate and choline lactate, liquids below 100 °C). These ionic plasticizers were shown to allow a more efficient melting of native starch in both processes. The investigation of macromolecular structure changes during processing shows that this efficiency can be ascribed to a starch chain scission mechanism, resulting in lower specific mechanical energy input need for starch thermoplasticization compared to glycerol plasticized starch. Compared to the synthesized ionic liquids, raw commercial choline chloride leads to a good compromise between limited chain scission, and final water uptake and thermomechanical properties.

Most of the adhesives used in the marine industry are polymers with a mechanical behaviour which is strongly influenced by environmental conditions (water activity or temperature). Therefore, it is important for engineers and designers to be able to consider these effects during the different stages of development and manufacturing of a bonded structure.The present work presents a method for analyzing the influence of water ageing on the behaviour of an epoxy adhesive in an adhesively bonded assembly.First, a viscoelastic-viscoplastic model is developed to characterise the mechanical response of the adhesive at initial state in a bonded joint using the modified Arcan device. The model is identified using the inverse identification method and the considered samples are tested at an unaged stage (no water activity). The results obtained after the identification process are used to predict the bulk behaviour of the adhesive. A comparison between numerical results and experimental tests realised on bulk specimens is then made in order to validate this first approach.In a second phase, in order to decrease the times for samples saturation, the evolution of the mechanical properties of the adhesive in bulk form is tested under different water ageing conditions (immersion in seawater and different relative humidity). The obtained results allowed to identify the evolution of the model parameters as a function of water content. In parallel, a diffusion model was developed to characterise the water ingress in the bonded joint. These two approaches are then combined to model the water profiles and to consider the evolution of mechanical properties of a water aged adhesively bonded assembly, for different immersion times. Finally, to validate the framework, the prediction is compared with experimental tests performed on aged specimens., La majorité des adhésifs utilisés dans l’industrie marine sont des polymères avec un comportement mécanique qui est fortement influencé par les conditions environnementales (vieillissement hydrique ou température). Par conséquent, il est très important pour les ingénieurs travaillant dans des bureaux d’études d’être capable de prendre en compte ces effets lors des différentes étapes de développement et conception des assemblages collés.Le présent travail propose une méthode d’analyse de l’influence du vieillissement hydrique sur le comportement mécanique d’un adhésif structural époxy dans un assemblage collé. Tout d’abord, un modèle viscoélastique-viscoplastique a été développé pour caractériser la réponse mécanique de l’adhésif dans un joint de colle. Pour cela, le dispositif expérimentalArcan a été utilisé. Le modèle est identifié en utilisant la méthode d’identification inverse et les échantillons sont testés à l’état non-vieilli (pas de vieillissement hydrique). Les résultats obtenus après la démarche d’identification sont utilisés pour prédire le comportement mécanique d’éprouvettes massiques.Dans un deuxième temps, afin de diminuer les temps de saturation d’échantillons, l’évolution des propriétés mécaniques de l’adhésif est analysée sous différentes conditions de vieillissement hydrique (immersion dans l’eau de mer et en humidité relative contrôlée) grâce à des essais sur éprouvettes massiques.Les résultats obtenus seront utilisés pour identifier l’évolution de chaque paramètre du modèle proposé, en fonction de la quantité d’eau absorbée. En parallèle, un modèle de diffusion a été développé pour caractériser le gradient de teneur en eau des joints de colle. Les deux approches sont ensuite combinées pour modéliser les profils d’eau pour différents temps de vieillissement et prédire l’évolution des propriétés mécaniques du joint de colle après le vieillissement. Finalement, pour valider la méthode proposée, la prédiction du modèle est comparée avec des essais réalisés sur assemblages collés vieillis.

Summary. Properties of the latex coagulum formed during the manufacture of styrene-butadiene latices were investigated. Processing conditions coagulum for further use in the composition of the polymer base composites and rubber compounds were grown. Plasticizers latex coagulum system, improving its handling on the process equipment were developed. In the process of changing the structure of the plasticization of the polymer matrix: solid areas appear in images taken with a scanning probe microscope. Ability to manufacture polymer composites based on treated latex coagulum was shown. When creating the polymeric compositions of styrene-butadiene rubber SCS-30-15 ARKM plasticized coagulum optimum ratio of 70:30 has been selected. Influence the type and dosage of plasticizer viscosity compositions latex coagulum with rubber SKS-30-15 ARKM been established. Application consisting of plasticized polymer base coagulum provides physic-mechanical properties of rubber at the control rules of molded rubber products. It is noted that the best combination of properties of rubber and rubber blends possess samples based polymer compositions coagulum plasticized combination of petroleum oils. It has been established that the use of latex coagulum in the polymer base composition causes sufficiently high values of Mooney viscosity and short curing starts. The influence of active chemical additives (derivatives of saturated fatty acids, 2,2-azo-bis-isobutyronitrile) to change the properties of the latex coagulum during machining on a mill was studied. Two ways of handling coagulum in the presence of accelerators mastication was proposed. Found that mixing coagulum accelerators advisable to carry out before the stage of the plasticizing coagulum.

Polylactide (PLA), a biodegradable and bio-based polymer, raised researchers’ attention to replace conventional plastics. At room temperature, PLA is brittle and requires physical plasticization that increases its ductility but at the same time drastically decreases its stiffness. As an alternative, plasticization by reactive extrusion was recently developed. The reactive extrusion of PLA with acrylated poly(ethylene glycol) (acrylPEG) as plasticizer yields a plasticized PLA named pPLA. This thesis aims at identifying the structure of this pPLA and studying its evolution engendered by thermomechanical transformations as drawing and recycling. First, pPLA’s structural features are analyzed by a multi-scale and multi-disciplinary approach. pPLA is characterized by partially grafted and partially free inclusions of the polymerized plasticizer and a slightly crosslinked PLA matrix. These plasticizer inclusions lead to a material with a good stiffness-ductility balance. Second, the deformation mechanisms of pPLA upon drawing indicate that chain orientation mechanisms are predominant compared to damage, the latter dominating deformation in PLA. Third, the thermomechanical recycling of pPLA shows that degradation is dependent on the type of processing step. Compression-molding is detrimental to pPLA inducing after recycling a higher degradation compared to PLA. This thesis releases new characterization methodologies enabling a better identification of biopolymer structural features, Le polylactide (PLA) est un polymère à la fois biodégradable et biosourcé focalisant l'attention des chercheurs pour le remplacement des plastiques conventionnels. A la température ambiante, le PLA est fragile et nécessite d’être modifié par plastification physique afin d’augmenter sa ductilité, mais dans le même temps sa rigidité chute fortement. Une alternative à cette plastification physique est la plastification par extrusion réactive. L’extrusion réactive du PLA avec l’acrylate de poly(éthylène glycol) (acrylPEG) donne lieu à un PLA plastifié nommé pPLA. Cette thèse a pour objectifs l’identification de la structure du pPLA et l’étude de son évolution lors de transformations thermomécaniques d’étirage et de recyclage. La structure du pPLA a été analysée par une approche multi-échelles et multidisciplinaire. L’acrylPEG polymérisant et formant des inclusions, est partiellement greffé au PLA et partiellement libre. De plus, les réactions conduisent à une légère réticulation de la matrice. La présence de plastifiant conduit à un bon équilibre entre rigidité et ductilité. Les mécanismes de déformation du pPLA sous étirage ont montré que les mécanismes d’orientation moléculaire sont prépondérants par à l’endommagement, qui lui prédomine dans le PLA. L’analyse du recyclage thermomécanique du pPLA a mis en évidence une dégradation du matériau dépendant du type de procédé utilisé. L’utilisation de la compression à chaud est le procédé le plus défavorable, conduisant à une dégradation plus importante du pPLA par rapport au PLA. Ces travaux ont permis de développer des méthodologies de caractérisation permettant une meilleure identification structurale des biopolymères

Die vorliegende Masterarbeit beschäftigt sich mit der Validierung von zwei unterschiedlichen Methoden zur Optimierung der thermischen Schmelzehomogenität in einer Einschnecken-Plastifiziereinheit. Während eines konventionellen Spritzgießprozesses kommt es aufgrund der sich verkürzenden wirksamen Schneckenlänge zur Ausbildung eines Temperaturgefälles in der Schmelze im Schneckenvorraum. Durch Einflussnahme auf diesen Temperaturgradienten kann die Qualität des produzierten Spritzlings positiv beeinflusst werden. Bei den beiden Methoden handelt es sich um zwei gänzlich verschiedene Ansätze. Einerseits soll untersucht werden, welchen Einfluss eine Erhöhung des Energieeintrages während des Dosiervorganges auf die Kunststoffschmelze hat. Dies erfolgt durch lineare Steigerung des Staudruckes bzw. der Schneckenumfangsgeschwindigkeit in Bereichen des zu erwartenden Temperaturabfalles. Andererseits soll in dieser Arbeit untersucht werden, ob durch eine Unterfütterung des Spritzgießprozesses die Höhe der Temperaturdifferenz reduziert werden kann. Dies soll durch einen experimentellen Versuchsaufbau analysiert werden, indem ein Dosiergerät der Plastifizierschnecke vorgeschaltet wird. Die eben beschriebenen Versuche werden an einer Engel Emotion 100 durchgeführt. Die Temperaturaufzeichnung erfolgt mit zwei verschiedenen Methoden. Direkt im Schneckenvorraum wird mit Hilfe eines Ultraschallmesssystems die Temperaturverteilung im Inneren des Massezylinders vor der Düse gemessen. Anstatt die Schmelze in ein Werkzeug einzuspritzen wird diese ins Leere ausgebracht, um mittels Thermografie als Referenzmessung die Temperatur der Kunststoffmasse nach der Düse zu messen. This master thesis is dealing with the validation of two different methods to optimize the thermical homogeneity of the melt pool in a single screw plastification unit. During a conventional injection moulding process, a temperature gradient in the produced polymer melt occurs because of the shortening effective screw length. Due to manipulation of the temperature gradient, quality of the produced product can be influenced positively. These two methods are dealing with two completely different approaches. On the one side, the influence of an increasing energy input during the dosing sequence should be analysed. This occurs because of linear increase of backpressure respectively screw circumference speed in regions of an expected temperature gradient. Alternatively, the possibility of a reduction of the temperature gradient because of a starved feeding screw should be analysed in this work. This is achieved with an experimental setup by using a dosing unit in front of the plastification screw. The just described experiments are accomplish with an Engel Emotion 100. Temperature recording happens with two different methods. Directly in front of the screw tip, with the help of an ultrasonic measurement system, temperature distribution is measured inside the barrel in front of the nozzle. Instead of injecting the melt into a tool, the polymer ejects the barrel into free space and the temperature of the melt is measured again with an thermographic camera after the nozzle. eingereicht von Michael Hettrich-Keller Masterarbeit Universität Linz 2017

The aim of the thesis is to study the feasibility of replacing the fossil oils by vegetable oils in polymer matrices.The first section discusses the diffusion of oil in EPDM and PVC matrices. This study was carried out by confronting the theoretical model of the Hansen solubility parameters to experiment rheology tests. The results were analyzed to highlight the strengths and weaknesses of this model.In second part, we used an elastomer formulation based on vegetable oils plasticizers. The effectiveness of these plasticizers has been verified using different tests. The results showed the problems of incompatibility between the EPDM matrix and the bio-based oils. In situ modification method was therefore used on Tung oil to fix the vegetable oil into the matrix.Finally, in a last part we studied different properties of the crosslinked material. We have developed two crosslinking systems based on di-functional molecules, the 2-furanmethanethiol and 3-mercaptopropyltriethoxysilane, L'objectif de ces travaux de thèse consiste à étudier la faisabilité du remplacement des huiles issues des ressources fossiles par des huiles végétales dans des matrices polymères. La première partie étudie la diffusion des huiles dans les matrices EPDM et PVC, en confrontant le modèle théorique des paramètres de solubilités de Hansen à des tests de diffusions suivis par rhéologie. Les résultats ont été analysés afin de mettre en évidence les avantages et les faiblesses de ce type de modèle. Dans un second temps, nous avons formulé une matrice élastomère en utilisant des plastifiants à base d'huiles végétales et vérifié avec différents tests l'efficacité de ces plastifiants. Les résultats ont mis en évidence des problèmes d'incompatibilité entre la matrice EPDM et les huiles agrosourcées. Une méthode de modification in situ a donc été utilisée sur de l'huile de Tung afin de fixer l'huile végétale dans la matrice. Enfin dans une dernière partie nous avons apporté différentes propriétés de réticulations à l'huile de Tung. Nous avons développé deux systèmes de réticulations basés sur des molécules di-fonctionnelles, le 2-furanmethanethiol et le 3-mercaptopropyltriethoxysilane. Au cours d'un procédé continu de mélangeage, nous avons greffé le 2-furanmethanethiol sur la matrice et sur l'huile végétale grâce à une réaction thiol-ène et une réaction de Diels-Alder, ce qui nous a permis de réticuler le système. Nous avons également étudié une autre molécule capable de créer des noeuds siloxanes à partir de réactions d'hydrolyse-condensations de fonctions alkoxysilanes après greffage sur la matrice EPDM et sur l'huile par réaction thiolène. Les résultats obtenus ont montré des propriétés similaires à un système de réticulation classique avec du dicumyl peroxide (DCP)

In this paper, the durability of the adhesive bond between concrete and carbon fibre reinforced polymers (CFRP) strengthening systems has been investigated under accelerated ageing conditions, i.e. , at 40 °C and 95% relative humidity. Mechanical characterizations were carried-out on control and exposed CFRP strengthened concrete specimens, in order to assess the evolutions of the adhesive bond properties during hydrothermal ageing. Results from different experimental campaigns are presented and reveal significant evolutions (decrease in the adhesive bond strength and/or change in the failure mode) depending on various parameters, such as the surface preparation of concrete, the presence of a carbonated concrete layer, the nature of the CFRP overlay (carbon fibre sheets or pultruded CFRP plates), the ageing behaviour of the bulk epoxy adhesive itself, or the test configuration used to evaluate the adhesive bond strength (pull-off or shear loading test). Moisture diffusion from the superficial layer of concrete ( i.e. , diffusion of interstitial pore solution) towards the adhesive joint is suspected to be a key factor driving the degradation process during hydrothermal ageing.

The application of nonlinear dynamic results on Civil Engineering structures allows to imagine the control of their vibrations. An auxiliary structure coupled to principal structure enables this control. Using auxiliary structures with large masses is possible, for example by coupling two principal structures together, but the main solution is using weak masses coupled to the principal ones. Different kinds of coupling can be used, but it is interesting to separate active and passive couplings. If active couplings are very efficient, they require information and energy. In contrast, passive couplings require nothing. The passive system that is used the most is the Tuned Mass Damper (TMD), with a linear interaction between structures, principal and auxiliary. They require to be tuned in frequency, which is problematic in terms of durability. Recent research shows it is possible to use nonlinear couplings between structures, principal and auxiliary, for passive control, by using the localisation phenomena. This kind of absorbers is named Nonlinear Energy Sink (NES). The research in this thesis shows progress in two ways: Its furthers the development the role of the vibration absorber of the NES and explores new possible roles. This thesis presents two possible applications for NES, as absorbers for vibratory control or as sensors for state structure auscultation. In the case of vibratory control, the first step is to create a standardised analysis of coupled structure behaviour applicable to different kinds of coupling. The next step is to determine possible modifications of this analysis to use on other cases, for example to take in account gravity and/or complex rheology for principal structure. With these results of coupled structure behaviour analysis, the study of NES for state structure auscultation is made. The principle of NES as sensor is using properties of nonlinear coupling to suddenly change the kind of behaviour with a small variations of system parameters. Finally, this thesis presents the creation of a scale 1 prototype — cable of 21 m for 2,6 cm diameter — for control of horizontal vibrations of cable by a cubic NES and vertical vibrations of cable by piecewise linear NES., L’application des résultats de la dynamique des systèmes non linéaires aux structures du Génie Civil a permis d’imaginer un contrôle de leurs vibrations. Il s’agit d’utiliser une structure auxiliaire couplée à la structure principale à contrôler. S’il est possible d’imaginer des structures auxiliaires de fortes masses, en couplant deux structures principales entre elles par exemple, la plupart du temps il s’agit d’une faible masse qui leur est couplée. Ces couplages peuvent être de nature différente et il est intéressant de séparer les couplages actifs et passifs. Si les couplages actifs sont très efficaces, ils nécessitent un apport d’informations et d’énergie, contrairement au cas passif. Les systèmes passifs les plus utilisés sont les Tuned Mass Damper (TMD), qui reposent sur un couplage linéaire entre les structures, principale et auxiliaire. Ils nécessitent d’être accordés en fréquence, ce qui pose des problèmes de durabilité. De récents travaux ont montré qu’il est possible d’utiliser un couplage non linéaire entre les structures, principale et auxiliaire, pour le contrôle passif, grâce au phénomène de localisation. De tels absorbeurs non linéaires sont nommés puits d’énergie non linéaire, ou Nonlinear Energy Sink (NES). Les travaux présentés dans ce document proposent des avancées sur deux points : d’un côté continuer à développer le rôle d’absorbeur de vibrations des NES et d’un autre côté explorer s’ils peuvent remplir d’autres rôles. Ainsi ce manuscrit se consacre à deux applications possibles des NES, comme absorbeurs de vibrations pour le contrôle vibratoire ou comme capteurs pour l’auscultation de l’état des structures. Dans le cadre du contrôle vibratoire, il s’agit d’homogénéiser une démarche d’analyse de comportement des structures couplées applicable à différents types de couplages. Ensuite il convient de déterminer si cette démarche est modifiable pour être appliquée dans d’autres cas, ici la prise en compte de la gravité et/ou de rhéologies plus complexes pour la structure principale. En se fondant sur les mêmes résultats d’analyse du comportement des structures couplées, une étude des NES pour l’auscultation de l’état des structures est menée. Il s’agit d’utiliser les propriétés des couplages non linéaires à basculer entre des comportements fortement différents pour de faibles variations des paramètres du système. Le principe d’un capteur pour l’auscultation de l’endommagement est ainsi décrit sur ces bases. Enfin ce manuscrit s’intéresse à la création d’un démonstrateur en échelle 1 — câble de 21 m pour 2,6 cm de diamètre — sur la base du contrôle des vibrations horizontales d’un câble par NES cubique et des vibrations verticales d’un câble par NES linéaire par morceaux.

Darbe yra aprašomos plastifikuoto DAC, gautų plastifikavimui naudojant tris skirtingus bioskaidžius plastiklius, plėvelių mechaninės bei terminės savybės. Pasinaudojus gautais mechaninių bandymų rezultatais yra teikiamas galimas DAC plastifikavimo mechanizmas. Pasinaudojant tyrimo metu atliktais rezultatais sudaryta plastifikuoto celiuliozės acetato gamybos technologinė schema. Atsižvelgus į plastifikuoto DAC savybes yra sudaryta gamybos linija plėvelių ir vienetinių plastikinių detalių gamybai., Work provides mechanical and thermal properties of plasticized cellulose acetate films. All films were plasticized using three different, but biodegradable plasticizers. After evaluating data that was collected during mechanical experiments is given possible plasticizing mechanism. After analysis of the technology and to the properties of the plasticized cellulose acetate has been made a production line that allows to produce films or plastic articles

Presented research is based on comparing experimental methodology, based on the middle wave infrared thermography and the digital image correlation, with constitutive modeling and numerical simulation of aluminium alloy deformation process. Digital image correlation is used as a comparison tool to the novel infrared approach of tracing plastification and damage process in material. Knowledge obtained from dynamical experiments at lower velocities is used as a basis for evaluating impact where infrared approach enables acquisition of plastification and damage at higher frame rates. Examples include evaluation of tension and three point bending aluminum alloy specimens tested at different strain rates. Obtained strain and temperature distributions are used as input for the calibration of material parameters in constitutive relations. The computational model accuracy is verified by excellent agreement with experimental measurements.

National audience; PLA is a bio-based and biodegradable polymer with high tensile strength and rigidity. Nevertheless, its low impact toughness and its brittleness are obstacles for a use in highly loaded parts. To overcome these drawbacks, the influence of several additives is studied. First of all, PLA plasticization by TBC leads to a marked increase of ductility, however counterbalanced by a drop of tensile strength and rigidity. The formation of copolymers PLA-impact modifier (BS) allows to increase impact toughness but not ductility. Finally, quaternary compositions PLA-BS-TBC-clay nano-reinforcements have interesting tensile and impact properties compared to a mineral filled PP frequently used for automotive applications.; Le PLA est un polymère biosourcé, biodégradable et à hautes rigidité et résistance en traction. Toutefois, sa faible résilience et sa fragilité sont des obstacles à son utilisation pour des pièces fortement sollicitées. Pour y remédier, cette étude s'intéresse à l'enrichissement progressif de compositions à base de PLA. Dans un premier temps, l'ajout de plastifiant (TBC) permet une nette augmentation de la ductilité du matériau, mais dégrade les autres propriétés en traction. La formation de copolymères PLA-modificateur d'impact (BS) permet un fort accroissement de la résilience, mais pas de la ductilité. Enfin, les compositions quaternaires PLA-BS-TBC-nanocharges d'argile constituent une piste viable pour une utilisation sous fortes sollicitations, grâce à des propriétés mécaniques en traction et à l'impact prometteuses, comparées à celles d'un PP chargé, classiquement utilisé dans l'automobile.

Biopolymers are viable alternatives to the use of conventional plastics derived from fossil fuels resources. In this study, our objective, beyond doing the melt processing ionic liquids plasticized starch and cellulose acetate in laboratory scale microcoumpounder which simulate the performance of a co-rotating twin screw extruder, are to investigate the effects and influence of ionic liquids and water on the intrinsic properties of the materials which are prepared. In general ways, processing with ionic liquids compared with conventional plasticizers, presents: a better interaction with starch and cellulose acetate, a more efficient depressor of glass transition temperature and allows the production of processed materials with efficient crystallinity destruction and plasticization. In the second step, we investigate the effects of supercritical carbon dioxide on the processing of starch with ionic liquid and the effects of the processing pressure, temperature and duration of supercritical carbon dioxide (ScCO2), which is an environmentally-friendly component, on the properties of plasticized starch. The significant results show that ScCO2 is capable of interacting with starch chains and with ionic liquids, so that it may induce a decrease in the glass transition temperature of the plasticized starch; Les biopolymères constituent une alternative crédible à l’utilisation des plastiques issus de ressources pétrolières. Dans cette étude, la transformation de l’amidon et de l’acétate de cellulose en présence de liquides ioniques en voie fondue (par extrusion) a été réalisée. Les caractéristiques physico-chimiques des formulations obtenues ont montré une dépendance vis-à-vis du type et de la concentration de plastifiant utilisé, mais aussi de l’humidité relative appliquée. De manière générale, les liquides ioniques ont présenté comparativement à des plastifiants usuels: une interaction plus privilégiée avec les deux polymères, une réduction beaucoup plus importante de la cristallinité, une diminution significative de la température de transition vitreuse et une plastification efficace des deux matrices polymères étudiées. Dans un deuxième temps, on s’est intéressé à associer le pouvoir de solvatation et de plastification du dioxyde de carbone supercritique (CO2Sc) sur la mise en oeuvre de l’amidon par les liquides ioniques. Les résultats les plus importants ont montré que le CO2Sc est capable d’interagir sur l’amidon et sur les liquides ioniques, de sorte qu’il peut induire une diminution de la température de la transition vitreuse de l’amidon plastifié

The main objective of the thesis is modelling and visualization of the phenomena of polymer plastication in the injection-moulding process. In injection moulding or in extrusion, plastication is the step during which polymer pellets are melted by the means of mechanical dissipation provided by a rotating screw and by thermal conduction coming from a heated metallic barrel. This step is crucial for melt thermal homogeneity, charge dispersion and fibre length preservation. Although there have been a large number of theoretical and experimental studies of plastication during the past decades, mostly on extrusion and mostly using the screw extraction technique, extremely few of them have dealt with trying to visualise plastication, let alone measuring the plastication profile in real-time. As a matter of fact, designing such equipment is an arduous task. We designed an industry-sized metallic barrel, featuring 3 optical glass windows; each window possessing 3 plane faces itself to allow for visualisation and record by synchronised cameras and lightening by lasers. The mechanical behaviour of this assembly was analysed by numerical simulation under different thermal stresses, pressures and constraints. The heterogeneity of structural materials (steel - glass) showed potential leakage problems, or fragility problems, that have been taken into account in the design. We named it "transparent barrel" or "barrel with glass windows". This "transparent barrel" allows us to visualize and follow through scientific cameras, the different states of the polymer when introduced into the screw-barrel. The images recorded can be further analysed by digital image processing. Preliminary results confirm the plastication theory and show a compacted solid bed and a melt pool side by side. The total plastication length is a direct function of screw rotation frequency as it is obvious from results on the melt pool width, which increases when the screw rotation frequency decreases. However, some evidence of solid bed breakage has been recorded, whereby the solid bed does not diminish continuously along the screw but is fractured in the compression zone. Some others results need to be checked with others experiments. We also wish, through this system "transparent barrel", to study, modelling and visualize the aspects of dispersion and mixing charges (tracers, pigments, master batch) in the matrix polymer., L’objectif principal de la thèse est de modéliser et visualiser les phénomènes de plastification des polymères dans le procédé d’injection-moulage. Dans les procédés de transformation des polymères par un système vis-fourreau (extrusion, injection), la plastification est l’étape durant laquelle le polymère originellement à l’état solide est graduellement fondu et homogénéisé par le chauffage externe et l’action mécanique de la friction contre les parois de l’outillage et du cisaillement. Cette étape est capitale dans la maîtrise technique et économique du procédé, en termes d’homogénéité thermique, de mélange des charges et de temps de séjour du polymère. Nous envisageons de visualiser et modéliser l’ensemble du processus de plastification dans les monovis d’injection. Afin de comprendre et de mesurer cette étape, nous avons conçu, validé et réalisé un fourreau à fenêtres. Ce système se compose de trois fenêtres de visualisation, insérées dans un fourreau en acier usiné par électroérosion. Le comportement mécanique de cet assemblage a été analysé par simulation numérique, sous différentes sollicitations thermiques, pressions et contraintes. L’hétérogénéité des matériaux de structure (acier – verre) a fait apparaître des problèmes potentiels de fuites, de fragilité qui ont été pris en compte dans la conception. Ce fourreau à fenêtres nous permet de visualiser et de suivre à l'aide des caméras scientifiques, les différents états du polymère une fois introduit dans l’ensemble vis-fourreau. Les résultats confirment les hypothèses théoriques de la plastification. Certains sont mis en évidence, comme l’existence d’un lit solide adossé à l’arrière du filet de la vis, ainsi que son évolution par rapport à la vitesse de rotation de la vis, ou l’apparition des films fondus entre le filet de la vis et le lit solide, et entre la paroi du fourreau et le lit solide. Certains sont par contre à vérifier par d’autres expériences, comme par exemple : l’apparition de la rupture du lit solide quelle que soit la vitesse de rotation de la vis, la valeur de la vitesse du lit solide par rapport à la vitesse de rotation de la vis. Nous souhaitons aussi, grâce à ce système "fourreau transparent", pouvoir étudier, modéliser et visualiser les aspects de dispersion et de mélange des charges (traceurs, pigments, mélange maître) au sein de la matrice polymère à l’état solide ou fondu.

Thermography is becoming more and more relevant method in industry and as a research tool. It is accepted method in many fields where nondestructive testing is carried out. In this paper a focus was on evaluation of stress concentrations and fatigue of metal structures. Three thermographic methods ; Thermoelastic stress analysis, Risitano method and acquisition of plastification zone and fracture propagation, are addressed and compared with results of classical cyclic testing of Al2024 alloy specimens. Specimens with three types of stress concentrator are used ; 3 mm triangular notch, R3 mm circular notch, and a hole with 6 mm diameter. All themrographic methods showed high level of coincidence with classical fatigue tests. Thermoelastic stress analysis provides first stress invariant field for cyclic loaded sample, revealing stress concentrations near notches. Risitano method, from thermal dissipations at various levels of cyclic load, estimates dynamic strength of materials. Fast cooled middle-wave infrared cameras enable locating and tracing material plastification and fracture propagation. The outcomes of all evaluated methods are in accordance one with another.

Termografija, kao nerazorna metoda, ima sve veću primjenu u istraživanjima i industriji. U radu je prikazana primjena termografije u procjeni koncentracije naprezanja te zamora materijala i konstrukcija. Na primjerima uzoraka s koncentratorima naprezanja prikazana je primjena termografije u analizi metalnih materijala. U tu svrhu uspoređeni su rezultati klasičnih ispitivanja na umarlici s tri termografske metode: termoelastičnom analizom naprezanja, Risitanovom metodom te metodom praćenja širenja zone plastifikacije i loma. Termoelastičnom analizom naprezanja na ciklički opterećenim uzorcima dobiva se raspodjela naprezanja te koncentracije naprezanja na površini materijala. Risitanova metoda na temelju mjerenja porasta temperature ciklički opterećenog uzorka s porastom opterećenja predviđa dinamičku čvrstoću uzorka. Zbog velike disipacije topline u zoni plastifikacije i pukotine, brze srednjovalne kamere omogućuju praćenje tijeka plastifikacije i širenja pukotine. Opisane metode primjerene su za dinamička ispitivanja, nerazorne su i beskontaktne te ne utječu na rezultate ispitivanja., Thermography is becoming more and more relevant method in industry and as a research tool. It is an accepted method in many fields where non-destructive testing is carried out. In this paper focus was on evaluation of stress concentrations and fatigue of metal structures. Three thermographic methods: Thermoelastic stress analysis, Risitano method and acquisition of plastification zone and fracture propagation, are addressed and compared with results of classical cyclic testing of Al2024 alloy specimens. Specimens with three types of stress concentrator are used; 3 mm triangular notch, R3 mm circular notch, and a hole with 6 mm diameter. All thermographic methods showed high level of coincidence with classical fatigue tests. Thermoelastic stress analysis provides first stress invariant field for cyclic loaded sample, revealing stress concentrations near notches. Risitano method, from thermal dissipations at various levels of cyclic load, estimates dynamic strength of materials. Fast cooled middle-wave infrared cameras enable locating and tracing material plastification and fracture propagation. The outcomes of all evaluated methods are in accordance with each other.

It is essential for understanding biogeochemical processes in sediments to work with virtually undisturbed samples in scales as small as possible, ideally to those scales where the processes take place. To maintain spatial structure and study microorganisms and mineral constituents in high resolution sediment samples were plastified with Glycolmethacrylate (GMA), a water permeable polyester. Special efforts were paid to minimize changes in biological, chemical and physical disturbance during the preparation. Impregnating sediments and microbial mats with GMA enabled characterization of the sediment structure (2D arrangement of particles), and analysis of elemental composition of matrix background and individual particles. Insights in spatial distribution of microorganisms were derived by identifying microorganisms in embedded undisturbed sediment samples adopting staining and fluorescence in situ hybridization (FISH) protocols.