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Orientador: Ana Maria Frattini Fileti / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-27T02:40:23Z (GMT). No. of bitstreams: 1 Camargo_StellaForganesdeGodoy_M.pdf: 2742507 bytes, checksum: a2cd6bf18b9859966ac846d9d5939a21 (MD5) Previous issue date: 2015 / Resumo: O processo de polimerização em emulsão é um processo industrialmente importante para a produção de polímeros com diversos tipos de aplicações. Existe um grande interesse industrial para a obtenção de teor de sólidos mais altos, pois assim otimiza-se o volume do reator para o mesmo tempo de reação, reduz-se espaço de armazenagem do produto acabado bem como custos com transporte ao consumidor final. Porém, para obtenção de polímeros com alta concentração de sólidos, a dificuldade de estabilização da emulsão, viscosidade mais alta e formação de resíduos (coágulos) geram limitações no processo, interferindo na segurança da reação. Para este trabalho foi escolhida a copolimerização em emulsão de estireno-butadieno devido à sua importância industrial bem como às propriedades relevantes para aspectos de segurança industrial. O objetivo foi estudar as influências do aumento de teor de sólidos nas propriedades da emulsão estireno-butadieno em processo semi-contínuo que afetam a segurança da reação. Primeiramente foi encontrado na literatura um modelo já validado para a copolimerização em emulsão estireno-butadieno em processo semi-contínuo como base para realizar as simulações nos software Aspen Polymers® para as análises das propriedades e comportamento exotérmico da emulsão. O teor de sólidos na emulsão estireno-butadieno foi aumentado, reduzindo gradativamente a água da formulação e mantendo a proporcionalidade entre as demais matérias-primas variando dos originais 48,4 % para 65,1 % em que toda a água da pré-emulsão foi eliminada. As propriedades finais da emulsão apresentaram resultados esperados conforme embasamento teórico abordado: a massa específica, a viscosidade, massa molar média e diâmetro de partícula aumentaram com o aumento do teor de sólidos e a polidispersidade, a temperatura de transição vítrea, o calor específico e a condutividade térmica diminuíram. A taxa de remoção de calor da reação e a temperatura da reação sob condições adiabáticas em possíveis cenários de descontrole de reação foram consideradas para a segurança do processo aumentando significativamente com o aumento do teor de sólidos e indicando presença de monômeros não reagidos ao final do tempo de reação de 10 horas. A análise de sensibilidade do modelo foi realizada variando a temperatura do processo em diferentes concentrações de produto final com o intuito de aumentar o rendimento da reação. Para cada alteração realizada, as variações das propriedades do produto foram analisadas em detalhe para verificar modificações no produto final. O melhor ponto de trabalho encontrado no estudo foi à concentração de 60 % à temperatura de reação de 78°C em que os resultados demonstraram que pequenas alterações no processo podem ser suficientes para garantir a segurança do processo, a qualidade do produto final com altos rendimentos / Abstract: The emulsion polymerization process is a very important process to the industry in the production of polymers with a wide range of applications. There is a large industrial interest to obtain higher solid content polymers in order to optimize the reactor capacity with the same time of reaction, reducing the storage area and transportation to the final costumer. However, to obtain polymers with high solid contents, the difficulties with the stabilization of the emulsion, the higher viscosity and formation of residues (clots) generate limitations in the process, interfering in the safety of reaction. To this paperwork was chosen the styrene-butadiene emulsion copolymerization because of their industrial importance as well as the relevant properties for industrial safety aspects. The objective was to study the influences of the increased solids content in the properties of the styrene butadiene emulsion in a semi-continuous process that affect the safety of the emulsion copolymerization reaction. First of all, was found in the literature a model already validated to the styrene butadiene emulsion copolymerization in a semi-continuous process. This model was used as a base to perform simulations in the Aspen Polymers® software in order to examine the exothermic properties and the behavior of the emulsion. The solid content in the styrene-butadiene emulsion was increased gradually reducing the water of the formulation and maintaining proportionality between the other raw materials ranged from the original 48.4 % to 65.1 % where all water from the pre-emulsion was removed. The final properties of the emulsion had expected results as discussed on theoretical basis: the specific mass, viscosity, molecular weight and particle diameter enlarged with the increasing of solid content and polidispersity, the glass transition temperature, the specific heat and the thermal conductivity decreased. The reaction heat removal rate and the reaction temperature under adiabatic conditions in scenarios of possible runaway reaction were considered for the safety of the process, increasing significantly with the rise of solid content and indicating the presence of unreacted monomers at the end of the reaction time of 10 hours. The analysis of the sensitivity of the model was performed by changing the processing temperature of the final product in different concentrations in order to increase the reaction yield. For each change made, variations of product properties were analyzed in detail to verify changes in the final product. The best working point found in this study was 60 % of solids content at 78°C reaction temperature. The results demonstrated that small changes in process may be sufficient to ensure the safety of the process and the quality of the final product with high yields / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestra em Engenharia Química

La gestion durable des boues résiduaires est l'un des grands enjeux du 21ème siècle. Si toutes les eaux usées produites par la population urbaine mondiale étaient traitées, ce qui est l’objectif ultime de l’OMS, 83 millions de tonnes de matières sèches seraient produites annuellement à l’horizon 2017. Pour réduire les coûts du traitement et de la valorisation des boues qui représentent la moitié de la facture de l’assainissement collectif, l’optimisation des procédés est nécessaire. Les ingénieurs ont donc besoin d’outils permettant d’adapter le fonctionnement des technologies de traitement aux caractéristiques des matériaux. Concrètement, les technologues ont besoin de connaître ou d’estimer le comportement en écoulement des boues, c’est-à-dire leurs propriétés rhéologiques, à chaque étape du traitement. Celles-ci ne pouvant être déterminées en continu, l’objectif de cette thèse est de démontrer la faisabilité d’utilisation des propriétés électriques pour prédire les écoulements des boues. Au cours de ce travail de thèse, les comportements rhéologique et électrique d’une boue type ont été établis : ainsi les propriétés d’écoulement d’une boue résiduaire peuvent être décrites par un modèle d’Herschel-Bulkley modifié (de façon à prendre en compte les cisaillements très élevés) tandis que sa signature électrique pourra être représentée par un circuit équivalent de Maxwell. L’impact de paramètres majeurs comme la température et la teneur en matières sèches sur les propriétés rhéologiques et électriques des boues et sur leur corrélation a été étudié. Les résultats obtenus nous ont également permis de montrer comment la structure du matériau est liée à ces caractéristiques. Enfin, des outils spécifiques ont été mis au point, pour la mesure simultanée des propriétés électriques et rhéologiques des fluides organiques complexes. L’ensemble des résultats obtenus ouvre de nombreuses perspectives, opérationnelles et fondamentales. / Sludge management is one of the 21st century’s main issues. If the whole wastewater produced by worldwide urban population was treated, which is the ultimate goal of WHO, 83 million tons of dry matter could be annually produced until 2017. In order to reduce the costs of sludge treatment and reuse, which represent half of the collective sanitation bill, process optimization is needed. Engineers are in need of tools allowing them to adapt treatment technologies to material characteristics. More specifically, technologists need to know or to estimate sludge flow behavior, i.e. their rheological properties, at each step of the process. However, these properties can’t be continuously acquired. The purpose of this thesis is then to demonstrate the feasibility of the usage of sludge electrical properties to predict their flow. During this work, rheological and electrical behavior of one sludge type had been established: so flow properties of sludge can be described by means of a modified Herschel-Bulkley model (so that high shear rates are taken into account), whereas electrical properties can be represented by Maxwell’s equivalent circuit. Major parameters impacts, as temperature and dry matter content on sludge rheological and electrical properties and their correlation have been studied. The results we obtained allowed us to highlight the way the structure of the material is related to these properties. Finally, specific tools have been developed for simultaneous measurement of rheological and electrical properties of complex organic fluids. All the obtained results open many operational and fundamental prospects.

Le travail présenté porte sur l’étude de la résistance à la rayure d’un vernis acrylate liquide à 100% d’extrait sec et photo-réticulable, en fonction des conditions de réticulation et d’application. Ce vernis est destiné à être appliqué sur des substrats thermoplastiques. Une première étude réalisée sur support polycarbonate a permis de mettre en évidence l’interaction entre le supporte et les monomères du vernis. La photo-polymérisation nécessite une source de rayonnement UV afin de former le réseau 3D. L’évolution de l’énergie (dose UV) et de la puissance (pic d’irradiance UV) a été décrite en fonction des différents paramètres de réglages (vitesse de défilement et position de l’échantillon sous la lampe, distance entre ces deux derniers, focalisation du rayonnement,). La résistance à la rayure des revêtements a été caractérisée par le test de microscratch qui permet de mettre en évidence la transition ductile/fragile, ainsi que le comportement élastique du système feuil/substrat et donne une information sur le travail d’adhésion, selon le mode de rupture. Ces analyses ont été complétées par la mesure du taux de conversion. Le réglage du rayonnement UV permet de modifier les propriétés finales du revêtement. Il existe également un lien entre l’angle d’incidence du rayonnement, l’épaisseur de vernis, et un préchauffage des matériaux avant l’application ou la réticulation, sur le taux de conversion et la résistance mécanique du film. La rhéologie du vernis, en vue d’une application au bol rotatif avec effet électrostatique, a été étudiée. Nous avons montré l’influence du chauffage du vernis sur la viscosité. Les essais en conditions semi-industrielles ont permis de mettre en évidence les paramètres procédés impactant l’aspect et le tendu de la pièce. / This research aimed to study the impact of the application and the curing process conditions on the UV-cured coating properties. The UV formulation is a high solid content clear-coat, containing acrylates oligomer and monomers, and developed for thermoplastics substrate, to protect them against scratches. The characterization of the coating and the polycarbonate substrate showed the interaction between the two polymers. UV irradiation is the key to create the polymer network. Several parameters can affect the evolution of its energy and intensity: the conveyor speed, the position of the sample under the bulb, the distance between the last two, and the focalisation of the UV rays. The coating is then analysed in terms of scratch resistance, by the microscratch test. This test gives information about the ductile/brittle transition, the elastic behaviour and the adhesion work. It is completed by the reticulation rate measure. These properties can be modified by the UV radiation setting and the process conditions, like the angle of the support, the coating thickness, and the thermic pre-treatment of the materials before the application or the curing. The clear coat is aimed to be sprayed by electrostatic rotary deposition. The study of the rheological behaviour of the liquid coating showed an impact of the heating on its viscosity. Semi-industrials tests allowed highlighting the process parameters in order to improve the coating levelling and appearance.