Es wurde ein hydrostatischer Verbundstrangpressprozess analysiert, bei dem das Kernmaterial aus Magnesium und das Mantelmaterial aus Aluminium besteht. Ausgehend von der Problematik, dass die Verbunde eine starke Vorschädigung in Form von Rissen im Bereich der Grenzschicht zwischen den Verbundpartner aufwiesen, wurde der Prozess analysiert. Mit Hilfe der numerischen FEM-Simulation wurde ein Berechnungsmodell aufgebaut, anhand dessen der Prozess detailliert und maßgeblich hinsichtlich der wirkenden Spannungen und auftretenden Dehnungen untersucht wurde. Es wurden die Größen Kontaktschubspannung und axiale Umformgraddifferenz identifiziert, die einen Zusammenhang aufzeigten zwischen ihrer Änderung und der aufgetretenen Qualität im Strang. Für eine verbesserte Aussagequalität und bedingt durch die vielen Wechselwirkungen der beeinflussenden Parameter im Prozess wurde die Methode der statistischen Versuchsplanung (DoE) hinzugezogen. Auf Basis dieser Ergebnisse wurde der Prozess optimiert, in dem die Matrizengeometrie als ein beeinflussender Parameter angepasst worden ist, so dass ein gleichmäßigerer Werkstofffluss gewährleistet und die Strangqualität verbessert werden konnte. Im Folgenden wurde ein integratives, empirisches Verbundstrangpressmodell entwickelt, das es ermöglicht, die Verbundqualität, die Verbundfestigkeit und die Dicke der sich ausbildenden Grenzschicht zu berechnen. / A compound made of aluminum (sleeve material) and magnesium (core material) was analyzed. The compound was built up in a hydrostatic co-extrusion process. First investigations showed damage (cracks) in the interface between the aluminum and the magnesium. Regarding the damage an optimization of the process was necessary. The FEM simulation was used to analyze the process. The focus of the analysis was the stresses and strains in the forming zone. A first result was that high contact shear stresses occurred in the interface. These stresses damaged the interface. Further investigations showed big strain differences between both of the materials. These differences caused in the different flow behaviour (yield stresses) of both materials. A better understanding was reached by a design of experiment (doe). This analysis showed the interactions between the different parameters and the influence of the parameters itself. Parameters with a big influence on the compound quality are the yield stresses, the die design, the friction and the billet design. The first result was an improvement of the compound quality by changing the die design. Therefore, an impeccable compound quality could be reached. Furthermore the results of analysis lead to an embracing empirical compound extrusion model. This consists of three single models. The first model was the quality model. This model allows to predict the compound quality with respect to the big influencing parameters. The second model was a bond strength model. This model gives the possibility to compute the strength of the interface. And at last the third model was the diffusion model. The embracing compound extrusion model allows to make a statement about the compound quality and strength before any real trials are carried out.

Es wurde ein hydrostatischer Verbundstrangpressprozess analysiert, bei dem das Kernmaterial aus Magnesium und das Mantelmaterial aus Aluminium besteht. Ausgehend von der Problematik, dass die Verbunde eine starke Vorschädigung in Form von Rissen im Bereich der Grenzschicht zwischen den Verbundpartner aufwiesen, wurde der Prozess analysiert. Mit Hilfe der numerischen FEM-Simulation wurde ein Berechnungsmodell aufgebaut, anhand dessen der Prozess detailliert und maßgeblich hinsichtlich der wirkenden Spannungen und auftretenden Dehnungen untersucht wurde. Es wurden die Größen Kontaktschubspannung und axiale Umformgraddifferenz identifiziert, die einen Zusammenhang aufzeigten zwischen ihrer Änderung und der aufgetretenen Qualität im Strang. Für eine verbesserte Aussagequalität und bedingt durch die vielen Wechselwirkungen der beeinflussenden Parameter im Prozess wurde die Methode der statistischen Versuchsplanung (DoE) hinzugezogen. Auf Basis dieser Ergebnisse wurde der Prozess optimiert, in dem die Matrizengeometrie als ein beeinflussender Parameter angepasst worden ist, so dass ein gleichmäßigerer Werkstofffluss gewährleistet und die Strangqualität verbessert werden konnte. Im Folgenden wurde ein integratives, empirisches Verbundstrangpressmodell entwickelt, das es ermöglicht, die Verbundqualität, die Verbundfestigkeit und die Dicke der sich ausbildenden Grenzschicht zu berechnen.:Inhaltsverzeichnis V Vorwort VII Einleitung 1 1 Stand der Technik 3 1.1 Allgemeines, Historische Entwicklung und Einteilung des Strangpressens 3 1.2 Wissenschaftliche Arbeiten auf dem Gebiet des Verbundstrangpressens, der Schädigung und der Haftfestigkeit 9 1.2.1 Prozess - Verbundstrangpressen 11 1.2.2 Schädigung 21 1.2.3 Haftfestigkeitsmodelle 28 1.3 Schlussfolgerung aus dem Stand der Technik 33 1.4 Zielsetzung und Struktur der Arbeit 35 2 Experimentelle Untersuchungen- Strangpressversuche 38 2.1 Ergebnisse der Pressversuche - Projektphase I 43 2.2 Ergebnisse der Projektphase II 52 2.3 Ergebnisse der Projektphase III 54 2.4 Besonderheiten, Oberflächenqualität, Verfahrenscharakteristika 56 3 Numerische Untersuchungen 64 3.1 Numerische Modellbildung 64 3.1.1 Materialbeschreibung/Fließkurven 66 3.1.2 Thermische Modellbildung 70 3.2 Ergebnisse der numerischen Analyse für das hydrostatische Strangpressen 81 3.2.1 Ermittlung einer indikativen Schädigungsgröße innerhalb der Simulation 91 3.2.2 Einfaktorielle Variationsrechnungen 95 3.3 Statistische Versuchsplanung und Analyse 103 3.3.1 Allgemeines und Versuchsplanung 103 3.3.2 Auswertung Versuchskern und erweiterter Versuchsplan 107 3.3.3 Fehleranalyse zu Versuchsplanergebnissen 113 3.4 Axiale Umformgraddifferenz als Indikatorgröße für die Schädigung 120 3.4.1 Volumenstromanalyse 128 3.4.2 Statistische Analyse hinsichtlich der Zielgröße axiale Dehnungsdifferenz 133 4 Integrativer Modellansatz zur Bestimmung qualitativer und quantitativer Merkmale des Verbundes 138 4.1 Allgemeines 138 4.2 Qualitätsmodell 139 4.2.1 Diskussion 139 4.2.2 Qualitätsmodell - Modellformulierung 145 4.3 Haftfestigkeitsmodell 155 4.4 Diffusionsmodell 163 5 Zusammenfassung 170 6 Ausblick 172 7 Quellen 174 Abbildungsverzeichnis IX Tabellenverzeichnis XV Kurzzeichenverzeichnis XVI Abkürzungsverzeichnis XIX / A compound made of aluminum (sleeve material) and magnesium (core material) was analyzed. The compound was built up in a hydrostatic co-extrusion process. First investigations showed damage (cracks) in the interface between the aluminum and the magnesium. Regarding the damage an optimization of the process was necessary. The FEM simulation was used to analyze the process. The focus of the analysis was the stresses and strains in the forming zone. A first result was that high contact shear stresses occurred in the interface. These stresses damaged the interface. Further investigations showed big strain differences between both of the materials. These differences caused in the different flow behaviour (yield stresses) of both materials. A better understanding was reached by a design of experiment (doe). This analysis showed the interactions between the different parameters and the influence of the parameters itself. Parameters with a big influence on the compound quality are the yield stresses, the die design, the friction and the billet design. The first result was an improvement of the compound quality by changing the die design. Therefore, an impeccable compound quality could be reached. Furthermore the results of analysis lead to an embracing empirical compound extrusion model. This consists of three single models. The first model was the quality model. This model allows to predict the compound quality with respect to the big influencing parameters. The second model was a bond strength model. This model gives the possibility to compute the strength of the interface. And at last the third model was the diffusion model. The embracing compound extrusion model allows to make a statement about the compound quality and strength before any real trials are carried out.:Inhaltsverzeichnis V Vorwort VII Einleitung 1 1 Stand der Technik 3 1.1 Allgemeines, Historische Entwicklung und Einteilung des Strangpressens 3 1.2 Wissenschaftliche Arbeiten auf dem Gebiet des Verbundstrangpressens, der Schädigung und der Haftfestigkeit 9 1.2.1 Prozess - Verbundstrangpressen 11 1.2.2 Schädigung 21 1.2.3 Haftfestigkeitsmodelle 28 1.3 Schlussfolgerung aus dem Stand der Technik 33 1.4 Zielsetzung und Struktur der Arbeit 35 2 Experimentelle Untersuchungen- Strangpressversuche 38 2.1 Ergebnisse der Pressversuche - Projektphase I 43 2.2 Ergebnisse der Projektphase II 52 2.3 Ergebnisse der Projektphase III 54 2.4 Besonderheiten, Oberflächenqualität, Verfahrenscharakteristika 56 3 Numerische Untersuchungen 64 3.1 Numerische Modellbildung 64 3.1.1 Materialbeschreibung/Fließkurven 66 3.1.2 Thermische Modellbildung 70 3.2 Ergebnisse der numerischen Analyse für das hydrostatische Strangpressen 81 3.2.1 Ermittlung einer indikativen Schädigungsgröße innerhalb der Simulation 91 3.2.2 Einfaktorielle Variationsrechnungen 95 3.3 Statistische Versuchsplanung und Analyse 103 3.3.1 Allgemeines und Versuchsplanung 103 3.3.2 Auswertung Versuchskern und erweiterter Versuchsplan 107 3.3.3 Fehleranalyse zu Versuchsplanergebnissen 113 3.4 Axiale Umformgraddifferenz als Indikatorgröße für die Schädigung 120 3.4.1 Volumenstromanalyse 128 3.4.2 Statistische Analyse hinsichtlich der Zielgröße axiale Dehnungsdifferenz 133 4 Integrativer Modellansatz zur Bestimmung qualitativer und quantitativer Merkmale des Verbundes 138 4.1 Allgemeines 138 4.2 Qualitätsmodell 139 4.2.1 Diskussion 139 4.2.2 Qualitätsmodell - Modellformulierung 145 4.3 Haftfestigkeitsmodell 155 4.4 Diffusionsmodell 163 5 Zusammenfassung 170 6 Ausblick 172 7 Quellen 174 Abbildungsverzeichnis IX Tabellenverzeichnis XV Kurzzeichenverzeichnis XVI Abkürzungsverzeichnis XIX

A novel on-line capillary rheometer (OLR) was used to examine the shear and extensional characteristics of polyolefin melts during twin screw extrusion (TSE). Comparisons with off-line rheometry were made using a twin-bore capillary rheometer and a modular in-line slit die rheometer (ILR) provided in-line rheometry comparisons. Both capillary rheometers were controlled via PCs running dedicated software, and the extrusion line and ELR were fully instrumented allowing real-time process monitoring to be carried out by IBM compatible PCs via data acquisition hardware and software. The prototype OLR was developed by the re-design of several key features including an instrumented transfer section and capillary die block which facilitated the use of various die geometries. Shear and extensional on-line rheometry of three polyethylenes (linear and branched), and four molecular weight grades of polypropylene were examined, and a direct comparison with off-line capillary rheometry showed a good correlation. The effect of a high loading of filler on two of the polyethylenes was investigated. In-line shear stress and entry pressure measurements showed a reasonable correlation with on-line rheometry. A study of entry flows in the OLR using capillary dies approaching orifice showed non-linearities occurred at very low capillary length to diameter(L:D) ratios, and this was repeatable using off-line rheometry. Predicted zero length entry pressures (Po) were used to estimate apparent extensional viscosity using a number of standard models. Melt instability and capillary wall slip were also investigated using on-line rheometry. Melt pressure and temperature in the twin screw extruder and OLR were monitored at various process conditions to examine the ability of the OLR to condition melt during testing, and the effect of OLR testing on extrusion conditions. Pressure variation in the extruder, OLR and off-line rheometer were compared in order to quantify process noise. The effect of OLR testing on melt rheology and polymer molecular weight were examined using off-line rheometry and gel permeation chromatography(GPC).

Les travaux de cette thèse proposent le développement d’un procédé de fabrication de composants micro-structurés à base d’unmatériau magnétocalorique. A plus long terme, ces composants de type lame mince seront intégrés à des dispositifs deréfrigération magnétique. Leur réalisation par les procédés conventionnels tels que l’usinage n’est pas envisageable dansl’optique d’une industrialisation. La solution envisagée est basée sur la mise en forme de composants par réplication d’uncomposite magnétocalorique. Ce micro-composite est défini par le mélange des poudres magnétocaloriques hydrogénées detype La(Fe,Si)13 dans une matrice thermoplastique (PP, LDPE). Cette technique permet de bénéficier des avantages desprocédés de mise en forme des polymères comme l’extrusion ou le moulage par injection. Le développement d’un tel procédéest divisé en deux parties. La première partie concerne l’élaboration et la caractérisation du micro-compositemagnétocalorique. Les tests réalisés en mélangeur ont permis de proposer plusieurs formulations micro-compositesmagnétocaloriques selon différents taux de charge. Cette première partie du développement étudie les différents aspects dumatériau micro-composite comme la rhéologie et les propriétés magnétocaloriques des mélanges. La caractérisationrhéologique basée sur les tests au rhéomètre capillaire est réalisé afin d’évaluer la capacité de mise en forme des mélangesassociée au procédé d’extrusion-conformage. Les propriétés propres aux matériaux magnétocaloriques telles que la variationde température adiabatique (ΔT) et la température de Curie (Tc) sont investiguées. Le contrôle de la Tc par mesure DSC a misen évidence des problématiques de déshydrogénation des poudres liées à la température d’élaboration. L’impact du taux decharge en poudre est étudié par la mesure des ΔT permettant d’estimer les performances finales du micro-composite. Ladeuxième partie traite du développement du procédé de mise en forme par extrusion-conformage. Une ligne d’outillages dédiéeà l’extrusion-conformage des lames micro-structurées a été réalisée et validée à l’échelle du laboratoire. La stabilité de latempérature de Curie a été vérifiée tout au long du processus d’élaboration des composants micro-structurés. Les paramètresd’extrusion tels que la température d’extrusion ont pu être définis afin d’éviter la déshydrogénation des poudresmagnétocaloriques. Les composants extrudés sont caractérisés en termes d’homogénéité du taux de charge en poudre et detolérances géométriques aboutissant à la / This thesis proposes the development of a method of manufacturing micro-structured components made of a magnetocaloricmaterial. In the long term, these blade-type components will be integrated in magnetic refrigeration devices. On an industrialscale, their production by the conventional process, machining, is not possible. The solution proposed is based on shaping thecomponent by a replication process via a magnetocaloric composite material. This micro-composite is defined by the mixtureof hydrogenated magnetocaloric powders of La(Fe,Si)13 in a thermoplastic matrix (PP, LDPE). This technique allowsutilization of the polymer shaping process, extrusion. The development of this process is divided into two parts. The first partconcerns the development and characterization of the magnetocaloric micro-composite. Results from tests performed with themixer allow the proposal of several micro-composite formulations under different loading rates. These formulations are thenstudied for various aspects of micro-composite material. The rheological characterization based on capillary rheometer tests istaken to evaluate the shaping ability of the mixtures associated with the extrusion process. Specific properties ofmagnetocaloric materials such as the adiabatic temperature variation (ΔT) and the Curie temperature (Tc) are also investigated.The control of the Tc by DSC measurement highlighted problematic dehydrogenation of the powders as a result of theelaboration temperature. The impact of loading rate is studied by measuring the ΔT in order to estimate the final performanceof the micro-composite. The second part deals with the development of the shaping process by extrusion. A tooling linededicated to extrusion of the micro-structured blades is carried out and validated at the laboratory scale. The stability of Tc ischecked throughout the elaboration process of the micro-structured components. The extrusion parameters are defined to avoidthe dehydrogenation of magnetocaloric powders. The extruded components are characterized in terms of homogeneity of thepowder loading rate and geometric tolerances resulting in the validation of the developed process. The industrial transfer isnow possible to a large scale production.

Cette thèse porte sur l’étude des systèmes de lois de conservation couplés par une interface mobile. Un modèle dynamique d’un procédé d’extrusion obtenu à partir des bilans de masse, de taux d’humidité et d’énergie est proposé. Ce modèle exprime le transport de la matière et de la chaleur dans une extrudeuse par des systèmes d’équations hyperboliques définis sur deux domaines complémentaires variant dans le temps. L’évolution des domaines est dictée par une Equation aux Dérivées Ordinaires (EDO) issue du bilan de masse total dans une extrudeuse. Par le principe des applications contractantes l’existence et l’unicité de la solution pour cette classe de système sont prouvées. Le problème de stabilisation de l’interface mobile est aussi abordé en utilisation le formalisme des systèmes à retard. La méthode des caractéristiques permet de représenter le système composé des équations issues du bilan de masse par un système à retard sur l’entrée. Au moyen d’un contrôleur prédictif la position de l’interface est stabilisée autour d’un point équilibre. La dernière partie de ce travail est dédiée à l’étude des systèmes Hamiltoniens à ports frontière couplés par une interface mobile. Ces systèmes augmentés de variables couleur qui sont des fonctions caractéristiques du domaine peuvent s’exprimer comme des systèmes Hamiltoniens à ports frontière / This thesis is devoted to the analysis of Partial Differential Equations (PDEs) which are coupled through a moving interface. The motion of the interface obeys to an Ordinary Differential Equation (ODE) which arises from a conservation law. The first part of this thesis concerns the modelling of an extrusion process based on mass, moisture content and energy balances. These balances laws express heat and homogeneous material transport in an extruder by hyperbolic PDEs which are defined in complementary time-varying domains. The evolution of the coupled domains is given by an ODE which is derived from the conservation of mass in an extruder. In the second part of the manuscript, a mathematical analysis has been performed in order to prove the existence and the uniqueness of solution for such class of systems by mean of contraction mapping principle. The third part of the thesis concerns the transformation of an extrusion process mass balance equations into a particular input delay system framework using characteristics method. Then, the stabilization of the moving interface by a predictor-based controller has been proposed. Finally, an extension of the analysis of moving interface problems to a particular class of systems of conservations laws has been developed. Port-Hamiltonian formulation of systems of two conservation laws defined on two complementary time-varying intervals has been studied. It has been shown that the coupled system is a port-Hamiltonian system augmented with two variables being the characteristic functions of the two spatial domains

Le remplacement des systèmes de distribution d’énergie actuels dans les avions (pneumatiques, hydrauliques, mécaniques et électriques) par des systèmes 100% électriques est un enjeu majeur dans le cadre du projet de l’avion « plus électrique ». Le processus d’électrification de l’avion conduit à une augmentation de la puissance embarquée à bord des aéronefs, et par conséquent à une augmentation de la masse du réseau filaire. Afin de pallier à cette augmentation, un nouveau matériau composite possédant des propriétés électriques supérieures à celle du cuivre a été développé dans le but d’augmenter la capacité de courant admissible dans le conducteur à section constante. Ce travail de thèse présente le procédé d’élaboration du matériau composite cuivre-nanotubes de carbone développé ainsi que les techniques de caractérisation utilisées et les résultats associés. Différents paramètres tels que la qualité de la dispersion des renforts dans la matrice, le type de nanotubes de carbone utilisés (multi-parois vs mono-paroi), la nature de l’interface créée entre le cuivre et les renforts (mécanique vs chimique) ainsi que les techniques de mise en forme du matériau (pressage uni-axial à chaud, extrusion à chaud) et de post-traitements (recuit, laminage à chaud) ont été étudiés afin d’obtenir des propriétés physiques optimales. Il en résulte une augmentation des propriétés thermiques (+6,8% pour la conductivité thermique), mécaniques (+32% pour la dureté Vickers) et également électriques - pour la première fois observée- (+3,4 % pour la conductivité électrique) et ce en comparaison avec à une matrice de cuivre pur. / The substitution of the current energy chains in aircrafts (pneumatic, hydraulic, mechanical and electrical) by a 100% electrical chain is a major issue in the field of the “more electric” aircraft. The electrification process leads to an increase of the inboard power of aircrafts, and therefore to an increase of the wired network weight. To counterbalance this increase of mass, a new composite material with higher electrical properties that copper should be considered, in order to increase the current density in the conductor at constant cross section. Several parameters have been studied such as the quality of the carbon nanotubes dispersion, the type of CNTs used (single-walled vs. multi walled), the interface between the matrix and the reinforcements (mechanical vs. chemical), the shaping of material (uni-axial hot pressing, hot extrusion process) and the post treatments processes (heat treatment, hot lamination process). An enhancement of the thermal properties (+ 6.8% of thermal conductivity), the mechanical properties (+32% of Vickers hardness) and for the first time an increase of the electrical properties (+3.4 % for the electrical conductivity) have been observed in comparison with pure copper.

As linhas flexíveis, estruturas compostas por um determinado número de camadas plásticas e de aço, possibilitam o escoamento de fluidos em operações de exploração e produção de hidrocarbonetos entre plataformas marítimas de petróleo e o leito marinho e/ou a costa. E, atualmente, têm sido utilizadas na exploração de hidrocarbonetos em lâminas dágua cada vez maiores. O presente estudo visa modificar quimicamente o LLDPE através de processos de extrusão reativa envolvendo a graftização de VTMS na presença de peróxidos orgânicos, e posterior formação de ligações cruzadas promovida pela água. Visa analisar também o efeito da introdução de ligações cruzadas nas propriedades térmicas e mecânicas do LLDPE. De forma a atingir os objetivos propostos, um planejamento experimental foi realizado para analisar o efeito de variáveis como velocidade de rotação do parafuso da extrusora, tipo e teor de peróxido nos índices de fluidez dos produtos da reação do LLDPE com peróxido de dicumila (DCP) e 2,5-dimetil-peróxi-hexano (Trigonox 101). Essa metodologia também foi utilizada para avaliar o efeito da concentração de silano, da velocidade de rotação do parafuso da extrusora e do procedimento de imersão nos índices de fluidez dos produtos da reação do LLDPE com 0,02% p/p de DCP e concentrações variáveis de silano. As amostras foram caracterizadas através dos ensaios para determinação de índice de fluidez (MFI) e teor de gel, ensaios convencionais de tração e técnicas de análise térmica, TGA e DSC. A técnica de FTIR foi utilizada para verificar a ocorrência das reações de graftização e formação de ligações cruzadas no LLDPE. As amostras reagidas com teores de 0,07% de DCP e 1,0 e 1,5% de silano, respectivamente, apresentaram valores significativos para os teores de gel em ambas as velocidades de rotação (10 e 50rpm). A amostra reagida com 0,07% de DCP e 1,5% de silano, a 10rpm, apresentou um teor de gel de 74,77%. A análise termogravimétrica (TGA) realizada evidenciou que houve um aumento da estabilidade térmica do polímero devido à formação de ligações cruzadas. Não se observou um aumento significativo para o limite de resistência para o LLDPE modificado devido à heterogeneidade dos corpos de prova. As análises de FTIR mostraram que houve a graftização e a formação de ligações cruzadas no LLDPE. / The flexible lines are flexible structures manufactured through plastic and steel layers that allows its use in order to permit fluid flow in exploration and production of hydrocarbon between offshore oil units and sea bed and/or coast. Nowadays these pipes are one of the main ways to permit the exploration of hydrocarbon in deepwater. The present study aims to analyze the LLDPE (Low Density Polyethylene) chemical changing through a reactive extrusion process involving VTMS grafting in presence of organic peroxides. After a crosslinking due to water, an analysis will be carried out in order to assess the PEX (crosslinked polyethylene) application in flexible pipe structures. The crosslinking effect at thermal and mechanical properties will also be studied. An experimental planning was carried out in order to evaluate the effect of variable variations such as the rotational velocity of the single-screw extruder, type and concentration of peroxides at melt flow index of the products originated from the LLDPE-peroxides (DCP and Trigonox 101) reaction, and in order to analyze the silane concentration effect, rotational velocity and immersion procedure at melt flow index in products with LLDPE and contents with DCP variable concentrations of silane. The samples were characterized through tests such as MFI (Melt Flow Index), gel content determination, tensile testing and thermal analyses, DSC (Differential Scanning Calorimetry) and TGA (Thermal Gravimetric Analysis). The Fourier Transformed Infrared Spectroscopy (FTIR) was also used to characterize the samples. The samples content 0,07% of DCP and 1,0 and 1,5% of silane, respectively, showed considerable value for gel contents in both rotational velocities (10 and 50rpm). The sample with 0,07% of DCP and 1,5% of silane, at 10rpm, a value of 74,77% of gel content could be noticed. The thermal analyses carried out showed that an increase of thermal stability for the polymer due to crosslinking generation happened. After tensile testing, a considerable changing in mechanical proprieties of the changed LLDPE was not seen due to the specimens heterogeneity. However through FTIR, silane linking was noticed demonstrating the LLDPE reticulation.

As linhas flexíveis, estruturas compostas por um determinado número de camadas plásticas e de aço, possibilitam o escoamento de fluidos em operações de exploração e produção de hidrocarbonetos entre plataformas marítimas de petróleo e o leito marinho e/ou a costa. E, atualmente, têm sido utilizadas na exploração de hidrocarbonetos em lâminas dágua cada vez maiores. O presente estudo visa modificar quimicamente o LLDPE através de processos de extrusão reativa envolvendo a graftização de VTMS na presença de peróxidos orgânicos, e posterior formação de ligações cruzadas promovida pela água. Visa analisar também o efeito da introdução de ligações cruzadas nas propriedades térmicas e mecânicas do LLDPE. De forma a atingir os objetivos propostos, um planejamento experimental foi realizado para analisar o efeito de variáveis como velocidade de rotação do parafuso da extrusora, tipo e teor de peróxido nos índices de fluidez dos produtos da reação do LLDPE com peróxido de dicumila (DCP) e 2,5-dimetil-peróxi-hexano (Trigonox 101). Essa metodologia também foi utilizada para avaliar o efeito da concentração de silano, da velocidade de rotação do parafuso da extrusora e do procedimento de imersão nos índices de fluidez dos produtos da reação do LLDPE com 0,02% p/p de DCP e concentrações variáveis de silano. As amostras foram caracterizadas através dos ensaios para determinação de índice de fluidez (MFI) e teor de gel, ensaios convencionais de tração e técnicas de análise térmica, TGA e DSC. A técnica de FTIR foi utilizada para verificar a ocorrência das reações de graftização e formação de ligações cruzadas no LLDPE. As amostras reagidas com teores de 0,07% de DCP e 1,0 e 1,5% de silano, respectivamente, apresentaram valores significativos para os teores de gel em ambas as velocidades de rotação (10 e 50rpm). A amostra reagida com 0,07% de DCP e 1,5% de silano, a 10rpm, apresentou um teor de gel de 74,77%. A análise termogravimétrica (TGA) realizada evidenciou que houve um aumento da estabilidade térmica do polímero devido à formação de ligações cruzadas. Não se observou um aumento significativo para o limite de resistência para o LLDPE modificado devido à heterogeneidade dos corpos de prova. As análises de FTIR mostraram que houve a graftização e a formação de ligações cruzadas no LLDPE. / The flexible lines are flexible structures manufactured through plastic and steel layers that allows its use in order to permit fluid flow in exploration and production of hydrocarbon between offshore oil units and sea bed and/or coast. Nowadays these pipes are one of the main ways to permit the exploration of hydrocarbon in deepwater. The present study aims to analyze the LLDPE (Low Density Polyethylene) chemical changing through a reactive extrusion process involving VTMS grafting in presence of organic peroxides. After a crosslinking due to water, an analysis will be carried out in order to assess the PEX (crosslinked polyethylene) application in flexible pipe structures. The crosslinking effect at thermal and mechanical properties will also be studied. An experimental planning was carried out in order to evaluate the effect of variable variations such as the rotational velocity of the single-screw extruder, type and concentration of peroxides at melt flow index of the products originated from the LLDPE-peroxides (DCP and Trigonox 101) reaction, and in order to analyze the silane concentration effect, rotational velocity and immersion procedure at melt flow index in products with LLDPE and contents with DCP variable concentrations of silane. The samples were characterized through tests such as MFI (Melt Flow Index), gel content determination, tensile testing and thermal analyses, DSC (Differential Scanning Calorimetry) and TGA (Thermal Gravimetric Analysis). The Fourier Transformed Infrared Spectroscopy (FTIR) was also used to characterize the samples. The samples content 0,07% of DCP and 1,0 and 1,5% of silane, respectively, showed considerable value for gel contents in both rotational velocities (10 and 50rpm). The sample with 0,07% of DCP and 1,5% of silane, at 10rpm, a value of 74,77% of gel content could be noticed. The thermal analyses carried out showed that an increase of thermal stability for the polymer due to crosslinking generation happened. After tensile testing, a considerable changing in mechanical proprieties of the changed LLDPE was not seen due to the specimens heterogeneity. However through FTIR, silane linking was noticed demonstrating the LLDPE reticulation.

Orientador: Luiz Carlos Barbosa / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-08T19:58:45Z (GMT). No. of bitstreams: 1 Osorio_SergioPauloAmaral_D.pdf: 8946065 bytes, checksum: 9771cf8636d67bee8eb1b92d030d0d13 (MD5) Previous issue date: 2007 / Resumo: Neste trabalho três tipos de vidro telurito são estudados, fabricados e caracterizados, tendo em vista a fabricação de fibras ópticas de cristal fotônico. Basicamente, dois processos de fabricação de fibras de cristal fotônico foram considerados: 1) Empilhamento e puxamento, e 2) Extrusão. Os vidros teluritos fabricados são: 0,77TeO2¿0,23WO3; 0,75TeO2¿0,20Li2O¿0,05TiO2 e 0,68TeO2¿0,155ZnO¿0,05Li2CO3¿0,015Bi2O3¿0,095CsCl (mol%), dos tipos binário, ternário e quinqüenário, respectivamente, os quais foram dopados com Er2O3. As caracterizações efetuadas foram: a) Medida do índice de refração, 2) Fotoluminescência, 3) Absorbância, 4) Tempo de vida dos íons de Érbio, 5) Análise Térmica Diferencial, 6) Análise termogravimétrica e, 7) Viscosidade. Como dito anteriormente, pode-se fabricar fibras microestruturadas de telurito por extrusão, ou pelo método de empilhamento e puxamento. A extrusora disponível no laboratório de materiais vítreos foi feita para extrudar materiais polímeros. Nossa tentativa de utilizá-la para vidros telurito não foi bem sucedida. Porém, pudemos tirar algum proveito desta experiência para futuros projetos. Os tubos de vidro telurito utilizados no método de empilhamento e puxamento foram fabricados tanto por sucção vertical do vidro fundido, quanto por rotação horizontal dos tubos em chama. No primeiro método, o diâmetro interno dos tubos de revestimento diminuiu de baixo para cima, devido ao efeito da gravidade, fazendo com que o preenchimento dos mesmos com tubos capilares fosse inadequado, ou seja, a secção transversal da fibra apresentou espaços vazios não preenchidos pelos capilares. No segundo método, o diâmetro interno dos tubos de revestimento não apresentou variação significativa ao longo de seu comprimento, possibilitando, assim, um melhor preenchimento dos mesmos por tubos capilares. Embora as fibras fabricadas com tubos feitos por rotação horizontal em chama apresentem boa geometria de secção transversal, a contaminação do vidro pela chama acarreta um aumento nas perdas de potência óptica dos modos guiados. Este efeito foi eliminado pela utilização de centrifugação em um forno radiante. Verificamos, também, que as fibras microestruturadas com somente um anel de capilares ao redor do núcleo apresentam grandes perdas por confinamento. / Abstract: In this work, three types of tellurite glasses are synthesized and characterized, aiming the manufacturing of photonic crystal fibers or microstructured fibers. Basically, two types of manufacturing processes are considered: 1) Stacking and draw, and 2) Extrusion. The tellurite glasses are: 0,77TeO 2¿0,23WO3; 0,75TeO2¿0,20Li2O¿0,05TiO2 e 0,68TeO2¿ 0,155ZnO¿0,05Li2C3¿0,015Bi2O3¿0,095CsCl (mol%), composed by two, three and five types of oxides, respectively, and Erbium oxide. The glasses were characterized by: a) index of refraction, 2) photoluminescence, 3) absorbance, 4) Erbium ions lifetime, 5) Differential Thermal Analysis, 6) Thermo gravimetric Analysis, and 7) Viscosity. The extrusion machine of the laboratory was devised for polymers. Nevertheless, we tried with telluride glass but without success. The tellurite glass tubes used for the stack and draw process were manufactured by vertical suction of the melted glass as well as by horizontal rotation of the tubes in flame. For the vertical suction method, the tellurite tube inner diameter shows a taper feature from the bottom to the top of the tube, due to the gravity effect, that makes the jacket tube unsuitable for capillary filling, that is, the fiber transversal section shows empty spaces that could not be filled with capillaries. For the second method, the telluride jacket tube inner diameter do not shows a significant variation with length, so it was possible to better fill it with the capillaries. Although the fibers made with tubes manufactured by horizontal rotation in flame shows good transversal geometry, the contamination of the glass by the flame gases brought about great losses for optical guided modes. The burner was replaced by a radiant oven. We verified, also, that micro structured fibers with only one ring of capillaries around the nucleus shows great confinement loss arising from the leaky nature of the modes / Doutorado / Física da Matéria Condensada / Doutor em Física