The work reported in this dissertation is intended to propose, analyze and demonstrate a technology for a high temperature integrated power electronics module, for high temperature (e.g those over 200oC) applications involving high density and low stress. To achieve this goal, this study has examined some existing packaging approaches, such as wire-bond interconnects and solder die-attach, flip-chip and pressure contacts. Based on the survey, a high temperature, multilayer 3-D packaging technology in the form of an Embedded Chip Module (ECM) is proposed to realize a lower stress distribution in a mechanically balanced structure with double-sided metallization layers and material CTE match in the structure. Thermal and thermo-mechanical analysis on an ECM is then used to demonstrate the benefits on the cooling system, and to study the material and structure for reducing the thermally induced mechanical stress. In the thermal analysis, the high temperature ECM shows the ability to handle a power density up to 284 W/in3 with a heat spreader only 2.1x2.1x0.2cm under forced convection. The study proves that the cooling system can be reduced by 76% by using a high temperature module in a room temperature environment. Furthermore, six proposed structures are compared using thermo-mechanical analysis, in order to obtain an optimal structure with a uniform low stress distribution. Since pure Mo cannot be electroplated, the low CTE metal Cr is proposed as the stress buffering material to be used in the flat metallization layers for a fully symmetrical ECM structure. Therefore, a chip area stress as low as 126MPa is attained. In the fabrication process, the high temperature material glass and a ceramic adhesive are applied as the insulating and sealing layers. Particularly, the Cr stress buffering layer is successfully electroplated in the high temperature ECM by means of the hard chrome plating process. The flat metallization layer is accomplished by using a combined structure with Cr and Cu metallization layers. The experimental evaluations, including the electrical and thermal characteristics of the ECM, have been part of in the study. The forward and reverse characteristics of the ECM are presented up to 250oC, indicating proper device functionality. The study on the reverse characteristics of the ECM indicates that the large leakage current at high temperature is not due to the package surrounding the chip, but chiefly caused by the Schottky junction and the chip passivation layer. Finally, steady-state and transient measurements are conducted in terms of the thermal measurements. The steady-state thermal measurement is used to demonstrate the cooling system reduction. To obtain the thermal parameters of the different layers in the high temperature ECM, the transient thermal measurement is applied to a single chip ECM based on the temperature cooling-down curve measurement. / Ph. D.

Despite the many attractive features of carbon fiber reinforced polymers (FRPs) composites, they are prone to failure due to delamination. The ability to tailor the fiber/matrix interface FRPs is crucial to the development of composite materials with enhanced structural performance. In this dissertation, ZnO nanowires (NWs) were grown on the surface of carbon fibers utilizing low temperature hydrothermal synthesis technique prior to the hybrid composite fabrication. The scanning electron microscopy revealed that the ZnO nanowires were grown uniformly on the surface of the carbon fabric. The surface grown ZnO NWs functionally-graded the composite material properties and ensured effective load transfer across the interface. To assess the influence of the ZnO NWs growth, reference samples were also prepared by exposing the carbon fabric to the hydrothermal conditions. The damping properties of the hybrid ZnO NWs-CFRP composite were examined using the dynamic mechanical analysis (DMA) technique. The results showed enhanced energy dissipation within the hybrid composite. Quasi-static tensile testing revealed that the in-plane and out-of-plane strengths and moduli of the hybrid FRP composite were also boosted. The interlaminar shear strength (ILSS) measurements suggested the improvement in the mechanical properties of the composite to the enhanced adhesion between the ZnO nanowires and the other constituents (carbon fiber and epoxy). It was necessary thus, to utilize the molecular dynamics simulations (MD) to investigate the adhesion within the CFRP structure upon growing the ZnO nanowires on the surface of the carbon fibers. Molecular models of the carbon fibers, the epoxy matrix and the ZnO nanowires were built. The resulting molecular structures were minimized and placed within a simulation box with periodic boundary conditions. The MD simulations were performed using the force field COMPASS to account for the empirical energy interactions between the different toms in the simulation box. Proper statistical thermodynamics were employed to relate the dynamics of the molecular model to the macroscale thermodynamic states (pressure, temperature and volume). Per the computed potential energies of the different components of the composite, it was found that the polar surfaces in the ZnO structures facilitates good adhesion properties in the graphite-epoxy composite. Besides the attractive mechanical properties of the ZnO nanowires, their piezoelectric and semiconductor properties were sought to design an energy harvesting device. To ensure sufficient charges collection from the mechanically stressed individual ZnO nanowires, a copper layer was sputtered on top of the ZnO nanowires which introduced also a Schottky effect. The mechanical excitation was provided by exposing the device to different vibration environment. The output voltage and currents were measured at the conditions (in terms of frequency and resistive load). It was demonstrated that the electrical output could be enhanced by stacking up similar devices in series or in parallel. Finally, in an attempt to exploit the reversibility of the electromechanical coupling of the energy harvesting device, the constitutive properties of the hybrid ZnO nanowires-CFRP composite were estimated using the Mori-Tanaka approach. This approach was validated by a finite element model (FEM). The FEM simulations were performed on a representative volume element (RVE) to reduce the computational time. The results demonstrated that the mechanical properties of the hybrid ZnO NWs-CFRP composite were better than those for the baseline CFRP composite with identical carbon fiber volume fraction (but with no ZnO NWs) which confirmed the experimental findings. Furthermore, the electro-elastic properties of the hybrid composite were determined by applying proper boundary conditions to the FE RVE. The work outlined in this dissertation will enable significant advancement in the next generation of hybrid composites with improved structural and energy harvesting multifunctionalties. / Ph. D.

Crystal Engineering is the design of crystalline material using non-covalent synthesis. Co-crystals are multi-component crystals which are constructed from complementary intermolecular interactions, they are also known as supramolecular complexes. Design of such materials utilises the synthon approach, this involves the understanding of common intermolecular interactions which occur in the crystal packing and is used to design new solids with desired physical properties and chemical properties. Primary amides form supramolecular heterosynthons, these synthons represent an opportunity for a design of multi-component crystals in which one molecule contains a primary amide and a second molecule which is complimentary to the primary amide, usually carboxylic acids. The progress with regards to the screening process for the determination of co-crystals is evident in the literature, In particular, high throughput solution growth methods and solvent drop grinding. The comparison of Isonicotinamide and Benzamide as a co-crystal component has been presented. This study was motivated by the observation that the CSD contains 24 Isonicotinamide and 1 Benzamide co-crystal. The interaction with carboxylic acids is the focus of the work, in particular those which form Isonicotinamide co-crystal are being screened with Benzamide. Our work utilises a ReactArray Microvate to carry out the low throughput solution growth on a matrix of carboxylic acid with Benzamide, this study has been coupled with the Kofler hot stage microscope method which visually aids to screen and view co-crystal phase formation. Crystallisation screens have resulted in the identification of known co-crystal phases of Isonicotinamide and Benzamide, additionally new co-crystal phases have also been identified with Fumaric, 3-hydroxybenzoic acid, Mandelic Acid, 4-Nitrobenzoic Acid and Tartaric Acid. Single crystal structures of the Fumaric and 4-Nitrobenzoic acid have been obtained. In order to develop an understanding of co-crystal formation in Isonicotinamide and Benzamide with our supramolecular library, packing landscape analysis is being undertaken using both the CSD and crystal structures we have obtained. This is undertaken as collaboration with Dr Andy Parkin and Professor Gilmore (University of Glasgow), we have identified that the dSNAP analysis is a way forward for the analysis of how co-crystals pack. The analysis highlighted the subtleties that were present in the packing motifs of the Isonicotinamide co-crystals. In particular the cis and trans orientation of the amide and acid carbonyl to each other and the planar and off planar layer assemblies. All of which are required to maximise the hydrogen bond usage of the components comprising the co-crystals. Further investigations have led to the collaborative project with Syngenta Ltd in the design of a co-crystal screen using a high through-put robot, Crissy® -Automation Platform by Zinsser Analytical, using an extended screen of 16 acid coformers with Isonicotinamide, Benzamide and Nicotinamide the sample have been characterised using a reflectance diffraction method, GADDS. Further analysis of this data involves the use of polySNAP, which has led to further collaboration with Professor Gilmore's group.

The work in this thesis relates to the preparation and structural and electrical characterisation of calcium and strontium hydrides, imides and nitride hydrides. Conventional solid state methods in controlled atmospheres were used to synthesise these materials. High temperature neutron diffraction, thermal analysis and conductivity studies performed on calcium and strontium hydride suggest an order – disorder transition in these materials at 350 – 450°C. Disordering is believed to involve rapid exchange of hydride ions across two crystallographic sites. This manifests itself in a lowering of the activation energy for bulk hydride ion conduction. The hydride ion conduction is good in these undoped materials: σ[total]subscript = 0.01 S/cm for CaH₂ at 1000K; for SrH₂, σ[total]subscript = 0.01 S/cm at 830K. Doping of SrH₂ with NaH causes a significant increase in the low temperature conductivity, due to presence of extrinsic defects. The high temperature conductivity is negatively affected by NaH doping. Calcium nitride hydride (Ca₂NH) was obtained as a single phase material by reacting either calcium metal or calcium hydride (CaH₂) in an argon atmosphere containing 5 – 7% H₂ and 1 – 7% N₂. Imide ions substituting for hydride and nitride ions constitute a major chemical defect in this material. Long range ordering of the nitride and hydride ions occurs, giving rise to a double cubic crystal symmetry. This order breaks down at 600 – 650°C. Applying the same reaction conditions to strontium metal results in a mixed phase of strontium nitride hydride and imide. No long range order in the nitride hydride phase could be observed. Doping Ca₂NH with lithium hydride (LiH) causes the appearance of a second calcium imide phase, whereas doping with sodium hydride (NaH) increases the amount of imide ions as a defect in the nitride hydride structure, thereby decreasing the long range ordering of nitride and hydride ions.

Ce travail est consacré à l’étude du procédé de synthèse, d’extraction et de purification d’une hydrazine exocyclique à applications cosmétiques, la N-aminopyrrolidine (NAPY). Dans un premier temps, l’optimisation des conditions de synthèse par la voie Raschig e été conduite en étudiant l’influence de deux paramètres, rapport molaire des réactifs (NH2Cl, pyrrolidine) et la température, sur le rendement de la réaction. Les solutions brutes de synthèse étant très diluées (≈5%g en NAPY), l’extraction et la purification du produit utile sont souvent liées à des opérations successives de démixtion et de distillation. La détermination de ces conditions de séparation requière alors la connaissance des propriétés thermodynamiques des équilibres entre phases impliqués dans ces opérations unitaires. L’optimisation de la démixtion nécessite alors l’étude du système ternaire solide-liquide-liquide NaOH/Pyrrolidine/Eau. Trois coupes isothermes isobares ont été complètement déterminées, par ATI (Analyse Thermique Isopléthique) combinée à des dosages chimiques. La méthode du diamètre et des modules a été mise au point pour la détermination du point critique de la courbe de démixtion. Les opérations de distillation mettent en jeu le système ternaire NAPY/Pyrrolidine/Eau. Le binaire limite liquide-vapeur Eau/Pyrrolidine a été déterminé par ébulliométrie à la pression atmosphérique. Pour essayer de mieux comprendre les interactions hétéromoléculaires ayant lieu en phase liquide, deux autres binaire liquide-vapeur eau/amine ont été obtenus. L’étude su système ternaire liquide-vapeur nous a permis de déduire deux schémas de distillation possibles. Une fois les conditions de synthèse et d’extraction définies et un schéma de procédé a été proposé, la NAPY est obtenue conforme aux spécifications cosmétiques / This global work is related to the synthesis, extraction and purification of a new exocyclic hydrazine with cosmetic applications, the N-aminopyrrolidine (NAPY). Firstable, the optimization of the synthesis conditions by the Raschig way are carried out by studying the influence of two parameters, the reagents’ molar ratio and the temperature, on the yield of the reaction. Due to the very low hydrazine content in the reaction liquors (≈5%w of NAPY), the extraction and purification of the useful product are often linked to successive demixing and distillation operations. The determination of these separation conditions requires then the knowledge of thermodynamics’ properties of the phase equilibria in these unitary steps. The optimization of the demixing needs then the study of the solid-liquid-liquid ternary solution NaOH/Pyrrolidine/Water. In this aim, three isothermal isobaric sections were studied, by combination of ATI (Isoplethic Thermal Analysis) and chemical analysis. The diameter and modulus method was developed in order to determine the composition of the critical point of the demixing curve. The distillation steps involve the liquid-vapor ternary system NAPY/Pyrrolidine/Water. The limit binary system Water/Pyrrolidine was determined by ebulliometry under atmospheric pressure. For a better understanding of the heteromolecular interactions in the liquid phase, two others liquid-vapor binary systems Water/Amine were obtained. The study of the ternary liquid-vapor system lad us to deduce two various distillation schemes. Once the synthesis and extraction conditions defined, a global process scheme was proposed, and NAPY was obtained in conformity with the cosmetical specifications

Cette étude porte sur des films composites à base d'amidon de manioc plastifié au glycérol et d'une argile kaolinique, comme charge minérale. L'origine et les mécanismes des interactions argile-amidon et leur rôle sur les propriétés des films ont été examinés. Pour vaincre le caractère non-expansible de la kaolinite, l'analyse du mécanisme de son exfoliation a été effectuée par insertion du diméthylsulfoxyde suivi d'un échange en milieux acétate d'éthyle et acétate d'ammonium. Une forte déstructuration de l'édifice cristallin de la kaolinite suite à l'échange est observée. La réassociation des feuillets après échange est désordonnée et permet d'escompter une meilleure dispersion de la kaolinite intercalée au sein d'un polymère. Ceci est confirmé par les analyses comparées de microscopies et de diffraction des rayons X sur des films incorporant diverses doses d'argile brute ou intercalée. L'abaissement de la température de transition vitreuse et du module élastique, ainsi que l'accroissement des effets de barrières à la décomposition thermique, à la diffusion de vapeur d'eau et à la transmission des UV visibles confirme la dispersion meilleure de la kaolinite intercalée. L'orientation des chaînes d'amidon et la diffusion du plastifiant transporté à l'interface par l'argile sont les mécanismes qui justifient l'effet plastifiant apporté par l'argile. L'interférence des interactions amidon-argile sur les interactions chaîne-chaîne au sein de l'amidon participe à la plasticité des films en diminuant la cristallinité. Les interactions amidon-argile se sont avérées faibles du fait des répulsions électrostatiques associées à des interactions associatives de type pont hydrogène / In this study, composites films made from glycerol plasticized cassava starch and a kaolinite clay, as mineral filler, were studied. The origin and mechanisms of clay-starch interactions and their role on films properties are examined. To deal with the unexpandable nature of kaolinite, an analysis of its exfoliation mechanism was done through dimethylsulfoxide (DMSO) intercalation followed by DMSO displacement using ethyl acetate and ammonium acetate. The crystalline structure of kaolinite is deeply disordered upon DMSO displacement because of a random reassociation of the clay layers. A better dispersion of the intercalated kaolinite within a polymer matrix is then expected. This expectation was confirmed by the comparison of microscopes and X-ray diffraction analyses on films charged with various dosages of raw or DMSO intercalated kaolinite. The lowering of the glass transition temperature and the elastic modulus together with the increase of barrier effects to thermal decomposition, water vapour diffusion and visible UV transmission, confirmed that the intercalated kaolinite is better dispersed. The starch chain orientation coupled to increase starch/glycerol miscibility due to the transportation of glycerol at the interface by clay particles are the two mechanisms that better explained plasticization effect induced by the filler. The interference of starch-kaolinite interactions on starch chain-chain interactions caused a decrease of starch matrix cristallinity that contribute to increase plasticization. The starch-kaolinite interactions are found to be weak due electrostatic repulsion associated to some weak associative forces due to hydrogen bonds

Ce travail porte sur l’étude des transformations induites par les procédés industriels (TIPI) dans le domaine de l’industrie pharmaceutique. Il se focalise sur le procédé de compression directe et sur deux principes actifs modèles qui sont la caféine et la carbamazépine. Des méthodes de caractérisations expérimentales des transitions de phases dans les comprimés ont été développées. La densité des comprimés a été mesurée par tomographie à rayons X et évaluée en surface par micro-indentation. Des méthodes thermiques telles que l’ACD et l’ATG ont été utilisées pour estimer les transformations dans tout le volume des comprimés. La spectroscopie Raman à basses fréquences a été appliquée pour la première fois pour cartographier la surface des comprimés. La spectroscopie Raman à hautes fréquences a été développée dans le but d’augmenter le nombre de données et d’automatiser le traitement des spectres. La transformation de la caféine forme I (métastable) en forme II (stable) nécessite plusieurs années dans les conditions ambiantes. Les investigations menées sur la caféine I ont révélé que la transition est induite par la compression directe car une transformation partielle en forme II est mesurée dans tout le volume du comprimé. La transformation continue au sein du comprimé lors de son stockage et le taux de transformation reste supérieur à celui de la poudre de caféine forme I non comprimée. Les quantifications misent en place par ACD et spectroscopie Raman à basses fréquences ont montré des transformations de la forme I dans tout le volume des comprimés et leur valeur est indépendante de l’intensité de la pression de compression. De plus, les deux formes de la caféine coexistent à l’échelle micrométrique, ce qui tend à prouver que des cristallites de forme II apparaissent dans tous les grains de caféine. La caféine formulée avec de la cellulose microcristalline présente un comportement plastique lors de la compression. La tomographie à rayons X révèle l’existence d’une zone locale de densité plus élevée au niveau des parois latérales, sans que ceci influe localement sur le taux de transition de la caféine. L’emploi d’une caféine calibrée entraine un comportement plus fragmentaire, qui semble réduire le taux de transformation mesuré. Aucune transformation de phase solide de la carbamazépine dihydrate n’a été décelée par ATG et spectroscopie Raman dans les comprimés fabriqués. Il semble que ce principe actif soit stable en compression directe / The purpose of this study was to improve the understanding of process induced transformations (PITs) in the field of the pharmaceutical industry. This present study is focused on the direct compression process applied to two model active molecules named caffeine and carbamazepine. Experimental characterization methods of phase transitions in the tablets were developed. Densities inside the tablets were measured by X-ray computed micro-tomography and by micro-indentation at the surface. Thermal methods for DSC and TGA were applied in order to estimate transformation degrees of tablet parts. Low frequencies micro-Raman Spectroscopy (MRS) was used for the first time as a way for polymorphs mapping. Raman spectroscopy was also developed in the high frequencies range to increase the analyzed part area and to computerize the spectra treatment. Caffeine form I is transformed naturally toward caffeine form II but this transition can take many years at room temperature. Our investigations have shown that the direct compression process induced a partial transition of caffeine I toward caffeine II. Phase transition degree stayed higher in the tablet than in the non-compressed powder during two years. Quantification process was set up for DSC and low frequencies MRS. It was found that the pressure level did not influenced the transition degree. Moreover, both polymorphs coexist at the micrometer scale in all caffeine particles. Caffeine formulated with micro-crystalline cellulose exhibits a plastic behavior under compaction. X-ray tomography revealed higher densities zones next to the tablet slides but any impact on the transition degree was detected. The use of calibrated caffeine particles led to a more brittle behavior and seemed to decrease the transition degree. The investigations on carbamazepine dihydrate did not show any phase transformation of this active molecule induced by direct compression

A preparação de formulações contendo o princípio ativo 17-valerato de betametasona (VB) é amplamente difundida entre as indústrias farmacêuticas, por se tratar de fármaco antiinflamatório de escolha, no tratamento de condições em que a terapia com corticoesteróides é indicada. Muito empregado no tratamento tópico de condições alérgicas e inflamatórias dos olhos, orelhas e nariz, inalação para a profilaxia da asma e também em veterinária. Isto devido ao seu alto poder antiinflamatório, quando comparado a outros corticoesteróides, e sua falta virtual de propriedades mineralocorticóides, causando baixa retenção de sódio e, subsequentemente, de água. Conforme descrita na Farmacopéia Americana USP 32 NF 27, o princípio ativo 17-valerato de betametasona hidrolisa-se em seu isômero 21-valerato de betametasona, seu principal produto de degradação, que possui baixo poder antiinflamatório. Adicionalmente, a norma brasileira em vigência para estudos de estabilidade de medicamentos, RE n°1, de 29 de Julho de 2005, propõe condições estressantes para estudo de estabilidade de longa duração (30°C/75%UR), o que acelera a reação de hidrólise (degradação) do princípio ativo. Conhecidamente, estudos prévios mostram que formulações tópicas contendo o VB (loção, creme, solução e pomada) apresentam uma estabilidade curta. Assim, uma forma de estabilizar o VB é a complexação (inclusão), com compostos de ciclodextrina (CD). O objetivo deste projeto foi estabelecer procedimentos para a obtenção, caracterização físico-química e avaliação de estabilidade térmica do complexo sólido supracitado. Para atender este objetivo técnicas de análise térmica (calorimetria exploratória diferencial e termogravimetria), infravermelho médio com transformada de Fourier, ressonância magnética nuclear e cromatografia líquida de alta eficiência, fizeram-se necessárias. / Preparation of formulations containing the active ingredient betamethasone 17-valerate (VB) is widely defunded within pharmaceutical industry, once it concerns an anti-inflammatory drug and an option, in the treatment of conditions in which corticosteroids therapy is indicated. Often employed in topical treatment of eye, ear and nose allergic and inflammatory conditions, inhalation for asthma prophylaxes, and also in veterinary. This because its high anti-inflammatory activity, when compared to others corticosteroids, and its virtual lack of mineralocorticoids properties, causing a low sodium retention and, subsequently, of water. As described in the United States pharmacopeia USP 32 NF 27, the active ingredient betamethasone 17-valerate hydrolyses into its isomer betamethasone 21- valerate, its main degradation product, that has a low anti-inflammatory activity . Additionally, the Brazilian legislation for drug products stability study, RE n°1, July 29th 2005, introduce long therm stability study stressing conditions (30°C/75%RH), accelerating the reactive hydrolysis (degradation) for the active ingredient. Well known, previous studies show that topical formulations containing VB (lotion, cream, solution and ointment) presents a short stability. Complexation (inclusion) with cyclodextrin (CD) compounds shows a reasonable way to improve the VB stability. The project objective is to establish procedures for the obtainment, physicochemical characterization and solid complex (cited above) thermal stability evaluation. In order to achieve this objective thermal analysis techniques (differential scanning calorimetry and thermogravimetry), Fourier transformation middle infrared, nuclear magnetic resonance and high performance liquid chromatography, were needed.

O presente trabalho propôs-se a estudar o fenômeno de fosqueamento em filmes de tinta em pó feitos a partir de resinas poliésteres sólidas pelo sistema conhecido como Triglicidilisocianutato (TGIC). Este fenômeno é indesejado e ocorre na ocasião de mistura de lotes de tintas produzidos independentemente com resinas poliésteres sólidas que compartilham as mesmas fórmulas, especificações e processo industrial. Amostras de uma tríade de resinas poliéster, que apresenta uma particular relação de fosqueamento, foram estudadas por termogravimetria/ termogravimetria derivada (TG/DTG), calorimetria exploratória diferencial (DSC), espectroscopia de ressonância magnética nuclear de Hidrogênio (1H-RMN), cromatografia de permeação em gel (GPC), análise térmica diferencial (DTA) e espectroscopia de infravermelho com transformada de Fourier (FTIR). A partir da análise minuciosa dos resultados obtidos em cada técnica escolhida, não se notou diferenças significativas que pudessem vir a justificar o fosqueamento indesejado para os lotes estudados. Estas avaliações nos permitiram concluir que o fenômeno não ocorre por contaminação industrial dos materiais e que alguma relação latente de fosqueamento por blenda seca deve ainda ser revelada por estudo subsequente. / The present work endeavored to study the matting phenomenon of powder coatings films made of solid polyester resins through a system known as Triglycidyl isocyanurate (TGIC). This phenomenon is an undesired result and occurs when at the time of blending paint batches produced independently with polyester resins that share the same formula, specifications e industrial process. Samples of a polyester resin triad, that shared a particular matting relation, were studied by thermogravimetry/ thermogravimetry derivative (TG/DTG), differential scanning calorimetry nuclear magnetic resonance (1H-NMR), gel permeation chromatog r(aDpShCy), proton (GPC), differential thermal analysis (DTA) and Fourier transform infrared spectroscopy (FTIR). Through in-depth analyses of all results obtained from each chosen method, no accountable differences, that could justify the undesired matting phenomenon, were noticed. These evaluations paved us the way to conclude that the studied phenomenon was not occurring due to industrial contamination, and that some latent dry blend matting relation is still to be revealed by an ensuing study.

O objetivo desse trabalho consiste na validação experimental e implementação de melhorias de projeto, de um cabeçote de extrusão com rosca de seção variável usada em uma impressora 3-D experimental. O primeiro estudo realizado envolveu a análise térmica por elementos finitos do sistema rosca-cilindro, com o intuito de se verificar a implantação de um sistema de refrigeração com suportes aletados ao longo do barril que têm como função a dissipação de calor gerado no processo de extrusão, por convecção forçada. O perfil de temperaturas ao longo do barril também é um resultado importante e uma validação experimental foi realizada com medições realizadas em termopar. Foram realizados testes de extrusão utilizando o polímero Nylon 12 PA e o polímero biodegradável PCL (Polycaprolactona), que permitiram a avaliação da estrutura do material extrudado, através da visualização de imagens de MEV (Microscopia Eletrônica de Varredura) e avaliação da forma dos filamentos. Scaffolds foram fabricados utilizando o sistema em estudo e submetidos à mesma avaliação com imagens de MEV. Por meio de um DOE (Design of Experiments) foram conduzidas medições de diâmetros dos filamentos extrudados, que revelaram o fenômeno de inchamento de extrudado, para o menor diâmetro de bico. Com o maior diâmetro do bico de deposição foram gerados scaffolds, com porosidade controlada e também foi demonstrada a capacidade de extrusão e deposição de materiais compósitos (polimérico/cerâmico). O cabeçote demonstrou, portanto, sua capacidade em aplicações de pesquisa, que envolvam geração de filamentos e protótipos poliméricos e cerâmicos. Esses materiais encontram aplicações desde a engenharia tecidual até aplicações industriais, com ou sem controle de porosidade. Um estudo preliminar sobre a melhoria do projeto mecânico do cabeçote incluiu a redução do seu peso, por meio da troca do sistema de redução, com a escolha de um redutor cicloidal ou harmônico e retirada de material da estrutura, o que deve reduzir o peso do sistema em aproximadamente 38%. / This work presents the experimental validation and design improvements of an extrusion head with variable section applied of an experimental 3-D printer. The first study was the thermal analysis by finite elements of the barrel-screw system. The aim is to verify the cooling capacity resulted from the implantation of a cooling system with finned supports along the extrusion barrel. This cooling system should dissipate the heat generated in extrusion process by forced convection. The temperature profile along the barrel is also an important result and an experimental validation was performed with measuring obtained by a thermo-coupling. Extrusion trials were performed processing Nylon 12 PA and a biodegradable polymer PCL (Polycaprolactone). In these trials, the structure of extruded material, in filament shape, was evaluated using SEM (Scanning Electron Microscopy) images. Scaffolds generation were performed and these were evaluated with the same method using SEM. A DOE (Design of Experiments) method, in which measurements of filaments diameters were conducted, have revealed the extrusion swelling in both nozzles tips used (0.4 and 0.8mm), but with more strong effects for the smaller one.Scaffolds with controlled porosity were generated using the large nozzle tip and the extrusion capacity could be demonstrated, not only with polymers, but also with composites of the type polymer/ceramic.Therefore, it can be indicated that the extrusion head in study can be applied in research fields in which the generation of filaments, polymer and polymer/ceramic prototypes, were necessary as tissue engineering or industrial applications, with or without porosity control. A preliminary study included the weight reduction by changing the reduction system and removing material from the head\'s structure. This study could indicate that these improvements could reduce the total weight of the extrusion head in 38%.