Les matériaux composites ont connu ces dernières années une forte croissance, croissance aujourd'hui renforcée par les nouvelles normes européenne visant à diminuer les émissions CO2 d'ici 2020. La réalisation de pièces complexes peut poser de nombreuses problématiques de fabrication comme la formation de zones sèches, ou la création de distorsions géométriques. Les origines de ces problématiques sont souvent liées à un manque de connaissance et de maîtrise des phases d'imprégnation des renforts et de cuisson du matériau. L'amélioration de la robustesse des procédés nécessite d'avoir une connaissance fine des phénomènes physiques qui ont lieu lors de l'élaboration. Dans cette perspective, les procédés d'élaboration de matériaux composites ont été étudiés à travers la mise en place d'un démonstrateur de laboratoire dans le cadre du projet LCM Smart. Ce pilote d'injection a permis de valider des solutions d'instrumentation, à partir de capteurs innovants (OFS) développés en partenariat avec le laboratoire d'optique Hubert Curien.L'application de cette instrumentation dans le cadre du suivi du procédé RTM a démontré les capacités des OFS pour le suivi des caractéristiques physiques de la pièce (le front d'écoulement, la température, les déformations résiduelles et le degré de cuisson). La comparaison des caractéristiques mesurées avec des simulations numériques effectuées en collaboration avec ESI, a montré une bonne corrélation.Enfin, l'instrumentation a permis de mettre en évidence l'intérêt d'un outillage composite en HexTool pour la réduction des contraintes résiduelles liées à l'interaction outil/pièce.

Micro-Powder Injection Moulding (Micro-PIM) technology is one of the key technologies that permit to fit with the increasing demands for smaller parts associated to miniaturization and functionalization in different application fields. The thesis focuses first on the elaboration and characterization of polymer-powder mixtures based on 316L stainless steel powders, and then on the identification of physical and material parameters related to the sintering stage and to the numerical simulations of the sintering process. Mixtures formulation with new binder systems based on different polymeric components have been developed for 316L stainless steel powders (5 µm and 16 µm). The characterization of the resulting mixtures for each group is carried out using mixing torque tests and viscosity tests. The mixture associated to the formulation comprising polypropylene + paraffin wax + stearic acid is well adapted for both powders and has been retained in the subsequent tests, due to the low value of the mixing torque and shear viscosity. The critical powder volume loading with 316L stainless steel powder (5 µm) according to the retained formulation has been established to 68% using four different methods. Micro mono-material injection (with 316L stainless steel mélange) and bi-material injection (with 316L stainless steel mélange and Cu mélange) are properly investigated. Homogeneity tests are observed for mixtures before and after injection. A physical model well suited for sintering stage is proposed for the simulation of sintering stage. The identification of physical parameters associated to proposed model are defined from the sintering stages in considering 316L stainless steel (5 µm)mixtures with various powder volume loadings (62%, 64% and 66%). Beam-bending tests and free sintering tests and thermo-Mechanical-Analyses (TMA) have also investigated. Three sintering stages corresponding to heating rates at 5 °C/min, 10 °C/min and 15 °C/min are used during both beam-bending tests and free sintering tests. On basis of the results obtained from dilatometry measurements, the shear viscosity module G, the bulk viscosity module K and the sintering stress σs are identified using Matlab® software. Afterwards, the sintering model is implemented in the Abaqus® finite element code, and appropriate finite elements have been used for the support and micro-specimens, respectively. The physical material parameters resulting from the identification experiments are used to establish the proper 316L stainless steel mixture, in combination with G, K and σs parameters. Finally, the sintering stages up to 1200 °C with three heating rates (5 °C/min, 10 °C/min and 15 °C/min) are also simulated corresponding to the four micro-specimen types (powder volume loading of 62%, 64% and 66%). The simulated shrinkages and relative densities of the sintered micro-specimens are compared to the experimental results indicating a proper agreement

This dissertation is focus¡qCuo Zhan CuiNing¡r¡mShuang Xiong Meng¡n¡qPoXiaoShief¡rThose three story¡¦s text are used¡uShi Wu Guan¡v for subject matter, differentiate narrate model, personage molding and idea of theme three parts for base to discuss.And use a method of ¡§conclusion to collect¡¨ compare to analyse. In the same time, By way of this theme¡¦s to compare, let us to clarify some question in tradition and evolve. In the narrate model,¡qCuo Zhan CuiNing¡r¡mShuang Xiong Meng¡nuse overtop for outside field of vision in this story, but¡qPoXiaoShief¡rjust use Lao San¡¦s observe for this point of view. Besides¡qCuo Zhan CuiNing¡ruse different to mess in a narrator, let this theme pervade dense deliver a sermon implication. But ¡mShuang Xiong Meng¡nand¡qPoXiaoShief¡rare use the same narrator give rise sympathetic emotions, let two texts full more sympathetic.¡qPoXiaoShief¡r use flashback statement technique let story copious. Unique statement and slow statement step is the characteristic of this story. In the main from ¡qCuo Zhan CuiNing¡rto¡qPoXiaoShief¡r,the narrate model also from single to various. In the personage model,¡qCuo Zhan CuiNing¡rin personage model is major match the story plot, belong E.M. Forster mean¡uflat character¡v. Zhu Su Chen form looks and character to describe, mold role to different style, but he ignore the personage character, let¡mShuang Xiong Meng¡nthis story¡¦s personage describe to perfection, can not call perfect¡uround character¡v. Zhu Xi Ning major inherent to describe personage character. From E.M. Forster theory to view, ¡qPoXiaoShief¡r we can say almost ¡uround character¡v. Make a comprehensive to those three stories we can found from exterior describe change to inherent describe. In the subject thinking, ¡qCuo Zhan CuiNing¡r most clear to see is¡uspeak and act cautiously life philosophy¡v and¡utradition of retribution for sin¡v. Except an official related topic are three texts highlight.¡qPoXiaoShief¡rexcept had ¡uShi Wu Guan¡vstory, and enter into Lao San¡¦s plot, open another topic for concerned humanity, and the same time confer center of gravity from people face on environment to people this topic. This series of¡qCuo Zhan CuiNing¡r is the prototype of statement works, in the change course the theme thinking from reflect live actual state to concerned humanity and people.

L'objectif des travaux est de démontrer que la lithographie douce, quelquefois baptisée " Micro-Contcat Printing (µCP)", constitue une méthode de dépôt de biomolécules présentant de nombreux avantages pour des applications de type Biopuces. Pour la fabrication de puces à ADN, nous démontrons que le µCP est une technique compétitive par rapport au dépôt robotisé de gouttes traditionnellement utilisé. Le coût est inférieur, la densité des puces est augmentée et la qualité et la définition des motifs biomoléculaires sont supérieures. Une étude complète des mécanismes d'encrage des timbres élastomères d'impression ainsi que des mécanismes de transfert par contact des molécules vers le substrat est présentée. Le rôle prépondérant des fragments de polymère non réticulés présents à la surface des timbres est mis en évidence. Dans un second volet nous étudions la possibilité de générer par la même méthode des puces à biomolécules uniques. Nous montrons comment le µCP peut être poussé jusqu'à une résolution sub-micrométrique proche de 50 nm. Deux voies technologiques originales impliquant la lithographie douce sont proposées : l'une pour peigner individuellement en des sites organisés précisément sur la surface des longs brins d'ADN pour des études de génétique, l'autre pour fixer des molécules individuelles d'ADN par une extrémité rendant possible l'étude dynamique de molécules uniques (ADN) sur de larges populations.

M. Tech. Polymer Technology / Determines the mechanical and thermal properties of polypropylene-based (PP) composites containing locally produced Sisal and Kenaf fibres.

Glass fiber reinforced poly(ethylene terephthalate), GF/PET has excellent potential for future structural applications of composite materials. PET as a semi-crystalline thermoplastic polyester has high wear resistance, low coefficient of friction, high flexural modulus and superior dimensional stability make it a versatile material for designing mechanical and electromechanical parts. Glass fibers are currently used as strength giving material in structural composites because of their high strength and high performance capabilities. In order to obtain high interfacial adhesion between glass fiber and polymer, glass fibers are treated with silane coupling agents. The objective of this study is to produce GF/PET composites with varying glass fiber concentration at constant process parameters in a twin screw extruder. Also, by keeping GF content constant, it is aimed to observe the effects of process parameters such as screw speed and feed rate on structural properties of the composites. Another objective of the study is to investigate the influence of different coupling agents on the morphological, thermal and mechanical properties and on fiber length distributions of the composites. Tensile strength and tensile moduli of the GF/PET composites increased with increasing GF loading. There was not a direct relation between strain at break values and GF content. The interfacial adhesion between glass fiber received from the manufacturer and PET was good as observed in the SEM photograps. Degree of crystallinity values increased with the addition of GF. Increasing the screw speed did not affect the tensile strength of the material significantly. While increasing the feed rate the tensile strength decreased. The coupling agent, 3-APME which has less effective functional groups than the others showed poor adhesion between glass fiber and PET. Therefore, lower tensile properties were obtained for the composite with 3-APME than those of other silane coupling agents treated composites. Number average fiber length values were reduced to approximately 300&amp / #61549 / m for almost all composites prepared in this study.

Submitted by Milena Rubi (milenarubi@ufscar.br) on 2017-08-16T14:17:38Z No. of bitstreams: 1 TEIXEIRA_Andre_2017.pdf: 23449389 bytes, checksum: c2eafb920ec024ab4ae56b9b0007cff3 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-16T14:17:46Z (GMT) No. of bitstreams: 1 TEIXEIRA_Andre_2017.pdf: 23449389 bytes, checksum: c2eafb920ec024ab4ae56b9b0007cff3 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-16T14:17:53Z (GMT) No. of bitstreams: 1 TEIXEIRA_Andre_2017.pdf: 23449389 bytes, checksum: c2eafb920ec024ab4ae56b9b0007cff3 (MD5) / Made available in DSpace on 2017-08-16T14:17:59Z (GMT). No. of bitstreams: 1 TEIXEIRA_Andre_2017.pdf: 23449389 bytes, checksum: c2eafb920ec024ab4ae56b9b0007cff3 (MD5) Previous issue date: 2017-04-03 / Não recebi financiamento / For a few years now polymeric materials have been ever present around the whole globe. Polyurethane (PU) for example is the sixth most produced polymer globally, generating with that a considerable amount of scrap due to industrialization processes, usage or end of its life cycle. About this, the present dissertation proposes to reprocess industrially discarded PU through mechanical recycling and injection molding to validate reusing this waste, reducing the amount sent to landfill. In order to do that PU scrap was physically mixed with high density polyethylene (HDPE), a commodity polymer, in pellets. PU was obtained from industrial waste of an earplug production process and HPE was bought in local market. PU scrap was obtained as a polymeric blanket that was later milled and micronized. Three different mixtures were manually prepared and placed into an industrial scale injection molding machine which resulted in the production of test specimens of 2%, 5% and 7% in mass of micronized PU into a HDPE matrix. Test specimens were submitted to flexural, tension and impact testing and the results were compared to the properties of 100% virgin specimens and with literature data. The samples indicated that adding PU decreased impact resistance but kept the performance on flexural and tension strengths, even increasing maximum deformation. Regarding thermal properties, the studied material presented the same melt and crystallization temperatures results for Differential Scanning Calorimetry (DSC) as well as loss and storage modulus for Dynamic Mechanical Thermal Analysis (DMTA). Thermogravimetric analysis (TGA) showed a decreased to the mass loss peak temperature when PU percentage increased. Nonetheless, considering all mechanical and thermal properties analyzed, present study shows that reusing the PU scrap is a viable option, given the appropriate process conditions. / Há alguns anos, os materiais poliméricos estão cada vez mais presentes nas indústrias, comércios, residências, enfim, no cotidiano de países do mundo inteiro. O poliuretano (PU), por exemplo, é o sexto tipo mais comum de polímero sintetizado mundialmente, gerando também uma quantidade considerável de resíduo, após o processamento industrial, uso ou fim de vida útil. Neste contexto, este trabalho aborda o reprocessamento, através da reciclagem mecânica e injeção, de poliuretano (PU) descartado industrialmente com a intenção de validar o reaproveitamento desse resíduo, diminuindo seu envio para aterros. Para isto, foram realizadas misturas físicas de resíduos de PU com o polietileno de alta densidade (PEAD), um polímero commodity, em forma de grânulos (pellets). O PU foi obtido de descartes primários do processo de fabricação de protetores auditivos e o PEAD foi comprado regularmente no mercado nacional. O PU de descarte estava no formato de uma manta polimérica que foi submetida à moagem e micronização. Posteriormente, as misturas foram realizadas manualmente e colocadas em injetora de porte industrial, o que permitiu a obtenção de corpos de prova nas proporções de 2%, 5% e 7% em massa de PU moído em relação ao polietileno de alta densidade (PEAD). Os corpos de prova injetados foram, então, submetidos aos ensaios de flexão, de tração e de impacto. Os resultados obtidos foram comparados aos das propriedades de corpos de prova 100% virgem (sem presença do PU) e com a literatura. As amostras indicaram que a adição do PU ocasionou decréscimo na propriedade de resistência ao impacto, mas manteve as propriedades testadas em flexão e tração, apresentando inclusive aumento na deformação máxima quando o PU foi adicionado. Quanto às propriedades térmicas, os materiais obtidos mantiveram os valores das temperaturas de fusão e de cristalização analisadas por DSC (Differential Scanning Calorimetry), bem como os valores de módulos de armazenamento e de perda analisados por DMTA (Dynamic Mechanical Thermal Analysis). De acordo com as análises realizadas por Termogravimetria (TG), foi observado decréscimo da temperatura de pico de perda de massa, quanto maior a presença de poliuretano. No entanto, considerando todas as propriedades mecânicas e térmicas analisadas, o trabalho indicou que é viável, diante de certas condições de processo, o reaproveitamento desse tipo de resíduo de PU.

Neste trabalho foi desenvolvido o projeto e fabricação de quatro componentes de uma pinça de biópsia (concha, garfo, oito e haste), através da micromoldagem de pós metálicos por injeção. A matéria prima utilizada neste trabalho é conhecida comercialmente como CATAMOLD® 316L A. Corpos de prova foram obtidos através da injeção em uma injetora de baixa pressão para determinação da quantidade de pó de aço inoxidável 316L e sistema aglutinante contida na matéria prima. Ensaios de injetabilidade foram realizados para análise do comportamento da matéria prima no processo de injeção. Foram avaliados os parâmetros de injeção (temperatura de injeção, temperatura do molde e velocidade de injeção) e as variáveis de saída (pressão de injeção, massa, segregação entre pó e sistema aglutinante e densidade). A influência dos parâmetros de injeção sobre as variáveis de injeção foi analisada através do delineamento estatístico via Redes Neurais Artificiais (RNA), com a utilização do programa Statgraphics® Centurion XV. Os corpos de prova obtidos na injetora de baixa pressão apresentaram alta quantidade de pó de aço inoxidável (92,2% em massa). Devido a esta alta concentração de pó, os ensaios de injetabilidade realizados na injetora de alta pressão apresentaram valores elevados para as pressões de injeção, variando de 1641 a 2115 bars para que houvesse o preenchimento total das cavidades. O molde microusinado para os componentes da pinça se mostrou eficiente na fabricação dos componentes, porém apresentou dificuldades na extração das peças. Mesmo com a obtenção de todos os componentes a montagem da pinça não foi realizada, visto que as furações de montagem foram retiradas no projeto, consequentemente não foram usinados. Depois de microinjetados, os componentes da pinça foram sinterizados e apresentaram variação dimensional de 0,01 a 0,29 mm em relação às dimensões de projeto e variação na contração de 7,05 a 13,33%, diferentes dos 14,30% citados no catálogo do CATAMOLD® 316L A. / In this work the design and manufacture of four components of the biopsy forceps (ladle, fork, eight and rod), by metal powder injection molding was developed. The feedstock used in this work is known commercially as CATAMOLD® 316L A. Specimens were obtained by injection into a low-pressure injection molding machine for determining the amount of 316L stainless steel powder and binder system contained in the feedstock. Mouldability tests were performed to analyze the behavior of the feedstock in the injection process. The injection parameters (injection temperature, mold temperature and injection speed) and output variables (injection pressure, mass segregation between powder and binder system and density) were evaluated. The influence of injection parameters on the variables of injection was analyzed using the statistical design via Artificial Neural Networks (ANN), using the software Statgraphics® Centurion XV. The specimens obtained at low pressure injection showed high amount of stainless steel powder (92.2 wt%). Due to this high concentration of power, mouldability tests were performed in high-pressure injection showed high values for injection pressures ranging from 1641 to 2115 bars so that there was the complete filling of cavities. The micromachined mold for the components of the forceps proved efficient in the manufacture of components, but presented difficulties in the extraction of parts. Even with the obtaining of the all the components the biopsy forceps was not assembled, since the mounting holes were taken in the project, and therefore were not machined. After injected , the components of the forceps were sintered and showed dimensional variation from 0.01 to 0.29 mm in relation to project dimensions and variation in contraction from 7.05 to 13.33% , different from those 14.30% cited in the catalog of CATAMOLD® 316L A

O processo tradicional de fabricação de ímãs de terras raras – TR – é a metalurgia do pó convencional. Este processo inclui etapas de preparação da liga, moagem, compactação sob campo e sinterização. Atualmente, ímãs obtidos pelo processo de injeção tem como resultado os ímãs conhecidos como bonded, que são compósitos de resina e ligas magnéticas. O processo de obtenção proposto neste trabalho é a moldagem de pós por injeção – MPI, o que implica novos desafios uma vez que ligas de terras raras são altamente reativas. A obtenção de ímãs de Nd-Fe-B por esse processo fornece a oportunidade de diversificar ainda mais os setores, potencialmente lucrativos, que trabalham com materiais magnéticos. As dificuldades desse processo foram encontradas em cada etapa, desde a mistura da liga com os polímeros à eliminação destes polímeros depois de as peças serem injetadas, essa etapa se tornou crítica dado que está diretamente relacionada às propriedades finais do material. Assim, propuseram-se novos ciclos de extração dos polímeros com solventes orgânicos e degradação térmica. Além disso, modelou-se ferramental para o processo de injeção, uma vez que o material deve ser orientado magneticamente durante a injeção. Finalmente usou-se o MAXWELL 14® (software para análises por elementos finitos para resolução em 3D) para incluir propriedades no banco de dados do software e assim predizer o comportamento do material quando aplicado nas máquinas elétricas de núcleos com de formato complexo. / The typical magnets production process of Rare Earths – RE is the conventional powder metallurgy. This process includes preparation stages of alloys, grind, pressing under field and sintering. Nowadays, magnet obtained by the injection process has as result the magnets known as bonded, that is a resin composite and magnetic alloys. The proposed process to obtainment, in this work, is the Metal Injection Molding- MIM, what involve new challenges once alloys of RE are highly reactive. The magnets obtainment of ND-Fe-B for this process supplies even opportunity of diversifying the sectors, potentially lucrative, that work with magnetic materials. The difficulties of this process were found in each stage, since the alloy mixture with the polymers to the elimination of these polymers after the pieces are injected, this stage became criticizes given it is directly related to final properties of the material. This way if it propose to polymers extraction new cycles with organic solvents and thermal degradation. Moreover, it modeled die for the injection process, once the material should be guided magnetically during the injection. It finally used MAXWELL 14 ® (Software for analyses by finite elements for resolution in 3D) to include properties on the bench of data of the software and thus predict the material behavior when applied in cores of electrical machines with complex shape.

O processo de moldagem de pós por injeção (MPI) é uma tecnologia relativamente recente e permite a fabricação de peças e componentes de diversos materiais, com a possibilidade de fabricar peças em larga escala. O processo MPI é composto por quatro etapas: mistura do pó com o material orgânico (ligante), moldagem por injeção, extração do ligante e sinterização. O ligante é um veículo temporário composto por polímeros e/ou ceras e sua função é possibilitar o escoamento da carga injetável para o molde durante a moldagem por injeção e após a moldagem este deve ser totalmente removido da peça. A maioria dos polímeros utilizados no ligante é oriunda do petróleo, que é uma fonte não renovável que gera sérios impactos ambientais. Neste estudo foi proposto a utilização de ligante à base de borracha natural, que além de ser proveniente de fonte renovável, confere elasticidade à peça moldada, que possibilita a fácil desmoldagem de peças com geometria complexa e pequenas espessuras. Também se analisou a substituição da parafina, que estudada em trabalhos anteriores em ligante para injeção de alumina com a borracha natural, pela cera de carnaúba na moldagem por injeção de pó de ferro metálico. Foram avaliados três ligantes à base de borracha natural e as ceras: (i) parafina, (ii) cera de carnaúba e (iii) parafina + cera de carnaúba e estudou-se o efeito da composição do ligante em cada etapa do processo MPI. Investigou-se as propriedades químicas e térmicas dos ligantes, o teor de pó admissível nas cargas injetáveis, as rotas de remoção do ligante por via térmica e solvente e as propriedades finais como retração linear, porosidade, microestrutura e resistência à flexão. As composições de ligante a base de borracha natural e cera de carnaúba proporcionaram melhores propriedades ao processo MPI. Nestas composições foi possível a moldagem por injeção de cargas injetáveis com maior teor de pó, apresentaram maior estabilidade reológica, em que a viscosidade apresentou baixa variação em relação à temperatura e maior estabilidade com o aumento do teor de pó. Além disso, foram as únicas amostras que não apresentaram defeitos durante a extração por solvente e apresentaram propriedades finais satisfatórias para o processo MPI de ferro. / The Powder Injection Molding process (PIM) is a relatively new technology and allows the manufacturing of parts and components of various materials, with the possibility of fabricating parts in microscale. The PIM process is composed of four steps: mix the powder with the organic material (binder), injection molding, extraction of the binder and sintering. The binder is a temporary vehicle composed of polymers and/or waxes and its function is to allow the flow of the feedstock into the mold during injection molding, and after molding this should be completely removed from the sample. Most of the polymers used in the binder are derived from petroleum, which is a non-renewable source that generates serious environmental impacts. In this study, it was proposed the use of binder based on polymer and wax from renewable sources that reduce the environmental impact. It was analyzed the substitution of paraffin, which was studied in previous studies with natural rubber, by the carnauba wax in the injection molding of the iron carbonyl. Were evaluated three binders based on polymer and wax: (i) paraffin, (ii) carnauba wax and (iii) paraffin wax carnauba wax and we studied the binder composition effect in each step of PIM process. The chemical and thermal binder properties, the critical powder volume concentration, the solvent and thermal debinding and the sintered properties were analyzed. As results, we found that the natural rubber and carnauba wax binder have better PIM process properties. In this binder was possible an injection molding with higher powder content, showing higher rheological stability, which the viscosity was more stable under temperature and powder content variation. Furthermore, the samples with this binder shown no defects after solvent debinding and suitable sintered properties for the iron PIM process.