A úlcera de pressão é um ferimento que acomete grande número de pessoas hospitalizadas, incapacitadas de movimentação e os idosos. As alterações fisiológicas do envelhecimento seja no sistema cardiocirculatório, respiratório, renal ou no próprio sistema nervoso central, são as responsáveis pela maior predisposição dos idosos a complicações durante a hospitalização. A idade avançada é um dos fatores importantes no desenvolvimento da úlcera de pressão, pois ocorrem muitas mudanças, como o achatamento da junção entre a derme e a epiderme, menor troca de nutrientes, menor resistência à força de cisalhamento, diminuição da capacidade de redistribuir a carga mecânica da pressão. A úlcera de pressão pode ser definida como uma área localizada de necrose celular que tende a se desenvolver quando o tecido mole é comprimido entre uma proeminência óssea e uma superfície dura por um período prolongado de tempo. O tratamento para esse problema é difícil devido ao custo, ao tempo necessário para a cicatrização, aos constantes cuidados e deve proteger a ferida, ser biocompatível e fornecer uma hidratação ideal. Os biomaterias, entre eles, a quitosana apresenta características próprias para um curativo numa lesão grave. O objetivo desse trabalho foi preparar um curativo à base de quitosana que apresente propriedades adequadas ao tratamento de ferimentos relacionados à lesão de pele. O curativo foi obtido a partir da solução de quitosana, um polímero proveniente da quitina, que é encontrada principalmente em cascas de camarões, lagostas e insetos, sendo seco em estufa ou liofilizado, com ou sem suporte mecânico, em diferentes concentrações (1,2,3 e 6%), e em associação com outras substâncias. As membranas com melhores características mecânicas foram aquelas secas por liofilização, com suporte mecânico. Dessas, a que teve uma maior absorção de solução fisiológica 0,9% foi a membrana de quitosana a 1%, liofilizada com poliéster, que apresentou também, a melhor característica física sensorial e melhor preço. A fotomicrografia mostrou que as membranas com maior retenção de líquido apresentaram os maiores poros. Foi obtido, assim, curativos com as qualidades propostas no presente trabalho. / The pressure ulcer is a wound that commits a great number of hospitalized people, people disabled of movement and the elders. The main important factorsthat contribute to the elder\'s predisposition to clinical complications are physiological alterations in the aging process involving the cardiovascular system, respiratory, renal ou even in the central nervous system. The advanced age is one of the important factors in the development of the pressure ulcer therefore many changes may occur such as dermis and epidermis junction f1attening, nutrients decrease exchange, shear force decrease resistance and reduction of the capacity to redistribute the pressure mechanical load. The pressure ulcer may be defined as a cellular necrosis area that tends to develop when the soft skin tissue is compressed over a bony proeminence over a long period of time. The main reasons the treatment is so difficult are as follows: time necessary for scarifying process, constant care and wound protection, must be biocompatible and must provide ideal moisturizing. Biomaterials such as chitosan, presents optimal characteristics for a curative in acute lesions. In this present work the objective was the development of a chitosan made of curative that had adequate properties for treatmente of skin lesion related wounds. The curative was obtained from a chitosan solution which is a polymer obtained from chitin (which is commonly found in shrimp, lobsters and insect shells) and can be both heat-dried or lyophilized, with ou without mechanical support structure, in different solutions concentrations (1, 2, 3 and 6%) and also in association with other substances. The membranes with the best mechanical characteristics where those dried by lyophilization and with mechanical support structure. In this group the one that had the best physiological solution 0,9% absorption was the chitosan 1% lyophilized with polyester that also presented the best physical-sensorial characteristics and best price. The photomicrography showed that membranes with greater liquid retention presented the best pore size. This way, curatives where then obtained with the qualities proposed by this presente work.

A úlcera de pressão é um ferimento que acomete grande número de pessoas hospitalizadas, incapacitadas de movimentação e os idosos. As alterações fisiológicas do envelhecimento seja no sistema cardiocirculatório, respiratório, renal ou no próprio sistema nervoso central, são as responsáveis pela maior predisposição dos idosos a complicações durante a hospitalização. A idade avançada é um dos fatores importantes no desenvolvimento da úlcera de pressão, pois ocorrem muitas mudanças, como o achatamento da junção entre a derme e a epiderme, menor troca de nutrientes, menor resistência à força de cisalhamento, diminuição da capacidade de redistribuir a carga mecânica da pressão. A úlcera de pressão pode ser definida como uma área localizada de necrose celular que tende a se desenvolver quando o tecido mole é comprimido entre uma proeminência óssea e uma superfície dura por um período prolongado de tempo. O tratamento para esse problema é difícil devido ao custo, ao tempo necessário para a cicatrização, aos constantes cuidados e deve proteger a ferida, ser biocompatível e fornecer uma hidratação ideal. Os biomaterias, entre eles, a quitosana apresenta características próprias para um curativo numa lesão grave. O objetivo desse trabalho foi preparar um curativo à base de quitosana que apresente propriedades adequadas ao tratamento de ferimentos relacionados à lesão de pele. O curativo foi obtido a partir da solução de quitosana, um polímero proveniente da quitina, que é encontrada principalmente em cascas de camarões, lagostas e insetos, sendo seco em estufa ou liofilizado, com ou sem suporte mecânico, em diferentes concentrações (1,2,3 e 6%), e em associação com outras substâncias. As membranas com melhores características mecânicas foram aquelas secas por liofilização, com suporte mecânico. Dessas, a que teve uma maior absorção de solução fisiológica 0,9% foi a membrana de quitosana a 1%, liofilizada com poliéster, que apresentou também, a melhor característica física sensorial e melhor preço. A fotomicrografia mostrou que as membranas com maior retenção de líquido apresentaram os maiores poros. Foi obtido, assim, curativos com as qualidades propostas no presente trabalho. / The pressure ulcer is a wound that commits a great number of hospitalized people, people disabled of movement and the elders. The main important factorsthat contribute to the elder\'s predisposition to clinical complications are physiological alterations in the aging process involving the cardiovascular system, respiratory, renal ou even in the central nervous system. The advanced age is one of the important factors in the development of the pressure ulcer therefore many changes may occur such as dermis and epidermis junction f1attening, nutrients decrease exchange, shear force decrease resistance and reduction of the capacity to redistribute the pressure mechanical load. The pressure ulcer may be defined as a cellular necrosis area that tends to develop when the soft skin tissue is compressed over a bony proeminence over a long period of time. The main reasons the treatment is so difficult are as follows: time necessary for scarifying process, constant care and wound protection, must be biocompatible and must provide ideal moisturizing. Biomaterials such as chitosan, presents optimal characteristics for a curative in acute lesions. In this present work the objective was the development of a chitosan made of curative that had adequate properties for treatmente of skin lesion related wounds. The curative was obtained from a chitosan solution which is a polymer obtained from chitin (which is commonly found in shrimp, lobsters and insect shells) and can be both heat-dried or lyophilized, with ou without mechanical support structure, in different solutions concentrations (1, 2, 3 and 6%) and also in association with other substances. The membranes with the best mechanical characteristics where those dried by lyophilization and with mechanical support structure. In this group the one that had the best physiological solution 0,9% absorption was the chitosan 1% lyophilized with polyester that also presented the best physical-sensorial characteristics and best price. The photomicrography showed that membranes with greater liquid retention presented the best pore size. This way, curatives where then obtained with the qualities proposed by this presente work.

L'objectif principal de la thèse a été d'étudier le comportement triboélectrique des contacts glissants à sec entre matériaux polymères (ABS, PE, PP, PS et deux types de PVC), incluant la possibilité de contrôler et d'optimiser les résultats générés, en termes de charge électrique et d’usure. Un tribomètre linéaire a été conçu et construit, afin de permettre le réglage des principales variables de contrôle du processus de charge triboélectrique : force normale, vitesse de glissement, durée et course. Ce dispositif facilite la mesure de certaines grandeurs physiques caractérisant les conditions de frottement: les variations des forces normale et tangentielle, ainsi que le déplacement relatif entre les éprouvettes. De plus, la charge électrique générée et l’augmentation de la température à la surface du polymère ont été aussi été mesurées et mise en relation avec les propriétés tribologiques. Les expériences ont montré que le niveau et la distribution de la charge générée par le frottement sec dépendent de la force normale appliquée, du temps de frottement (le nombre de cycles), de la vitesse de glissement, des propriétés mécaniques des matériaux et de la rugosité ou de la texture des surfaces en contact. La décharge couronne peut être utilisée pour déposer une charge initiale sur les surfaces avant le glissement. La modélisation du processus de charge triboélectrique a été faite avec la méthodologie des plans d’expériences. Les résultats peuvent alors être utilisés pour prédire et optimiser la charge triboélectrique. Des cartes de contrôle peuvent assurer le monitoring du processus et la détection de variations non-maîtrisés de la charge générée par effet triboélectrique. / The main objective of the thesis was to study the triboelectric behavior of dry sliding contacts between polymeric materials (ABS, PE, PP, PS and two types of PVC), including the possibility to control and optimize the results in terms of either surface charge generated or wear. A linear tribometer with tribocharging capabilities was designed and built, to enable the study of the sliding contact between solids and to allow the adjustment of main tribocharging control variables: normal force, sliding speed, time and stroke. This device also provided measurement data to characterize the friction condition: the variations of the normal and tangential forces, as well as the relative displacement between the specimens. Furthermore, the electric charge generated and temperature raise due to rubbing on the surface of the polymer were measured, so that to investigate the relationship between the tribological properties. The experiments showed that the level and distribution of the charge generated by dry friction depends on the normal force applied, friction time (cycle), sliding speed, material mechanical properties and surface roughness or texture. Corona discharge may be used to provide initial charge on the surfaces before sliding. Modelling of tribocharging processes was done using the design of experiments methodology. The models can be used to predict and optimize the tribocharging. Control charts were used to monitor the process and detect the special causes of variation in the charge generated by triboelectric effect.

Additive manufacturing has grown considerably during the last couple of decades, whether it comes to the printing of metal structure or living cells. Additive manufacturing techniques relays on the successive addition of material to create the wanted structure. Among the diversity of these many printing techniques, electrohydrodynamic 3D-printing is of particular interest, as the technique has a promising outlook for high-resolution printing on the microscale. The technique is compatible with a myriad of thermoplastics, but its writing resolution is limited due to the inherent affect the manufacturing process has on the material. Electrostatic forces between already deposited fibres and the fibre in light affect the final position of printed fibre. This thesis evaluates the possibility to increase the writing resolution in melt electrohydrodynamic 3D printing by a closed-loop feedback system. Components were built and added to an already existing printing setup to implement in-situ measurements of the fibres position as well as active electrostatic guiding of the fibre. The setup consisted of a camera that determined the position of the fibre; the position was then used in a PID controller to calculate an appropriate potential. The potential was forwarded to a high voltage amplifier, connected to a steering electrode, mounted in the vicinity of the jet. The setup built for one-dimensional steering of the fibre improved the printing accuracy by ten times through suppressing the repulsive/attractive forces, where the process variable of the PID controller was measured. However, the precision decreased roughly four times as it was deposited on the substrate. The limitations of the system have been evaluated, and possible improvements for the two-dimensional control of the fibre are further discussed.

Organic electronics is a rapidly evolving field with vast number of applications having high potential for commercial success. Although a great progress has been made, many organic electronic applications: organic light-emitting diodes (OLEDs), organic fieldeffect transistors (OFETs), organic solar cells, etc; still require further optimization to fulfill the requirements for successful commercialization. For many applications, available at this time organic materials do not provide satisfactory performance and stability, which hinders the possibility of a large-scale production. Therefore, the key ingredient needed for a successful improvement in performance and stability of organic electronic devices is in-depth knowledge of physical and chemical properties of molecular and polymeric materials. Since many applications encompass several thin film layers made of organics, and often also inorganic materials, the understanding of both organic-organic and hybrid interfaces is yet another important issue necessary for the successful development of organic electronics. The research presented in this thesis is based mainly on photoelectron spectroscopy, which is an experimental technique especially suited to study both surfaces and interfaces of materials. In the thesis, the properties of one of the most successful polymeric materials, poly(3,4-ethylenedioxythiophene), often abbreviated as PEDOT, have been extensively studied. The research was done in close cooperation with an industrial partner – AGFA Gevaert, Belgium. The study was focused on the exploration of the intrinsic properties of the material, such as stability, morphology and conductivity. In addition, however, a possibility of alternation of these properties was also explored. This thesis reports also about investigations of the properties of various organic-organic and hybrid interfaces. The energy level alignment at such interfaces plays important role in charge injection and performance of the thin film organic-based devices. The conditions for different energy level alignment regimes at the various interfaces have been studied. The studies on interfaces were performed in close collaboration with the R&D division of DuPont Corporation, USA. This work led to the significant advances in understanding of the interface energetics and properties of industryrelevant organic materials, as represented not only by published scientific papers, but also patent applications.

Deep water oil production imposes several challenges to the oil companies. One of the greatest difficulties is related to the damages that the flexible riser pipes are subjected. These pipes conduct the produced oil to the platform. They are also used to inject water in the well in order to recover its production capacity. Among the damages mentioned, its worth to mention the abrasive wear that takes place at the touchdown point (TDP). In order to reduce this tribological degradation, PU coats have been used at the TDP region. Considering the diversity of PU that can be used in this application, it is highly desired that the PU plaques quality are controlled before its installation. Based on this demand, a portable apparatus was designed and constructed in the Laboratory for Friction and Wear at the Federal University of Uberlândia to simulate the tribological interactions between the riser pipe and the sea bed. So this work aims to produce WC-Co indenter for this test apparatus. To accomplish that, the following steps were proposed: a) equipment preparation for wear tests; b) determination of test parameters (cycle number and load) through a full factorial design; c) geometric and dimensional control of the indenters before and after machining processes; d) realization of wear tests before and after machining the indenters; e) machining of indenters using honing and lapping and f) analysis of the improvements achieved on the wear results. The results obtained allowed the following conclusions: 1) the proposed machining processes and parameters for are appropriate to manufacture the indenter In accordance with their selected dimensional and geometric tolerances. Roughness values of about 2.0 μm has been reduced by at least 60%, while for values lower than 2.0 μm this reduction was at least 33%, and 2) abrasion tests using the new indenters provide more precise and reliable results. / A extração de petróleo em águas profundas impõe diversos desafios às empresas petrolíferas. Um dos principais são os danos que os dutos flexíveis, as tubulações que levam o petróleo do poço de extração até a plataforma flutuante, sofrem ao serem expostos ao hostil ambiente subaquático. Dentre estes danos, destaca-se o desgaste abrasivo na região onde o duto toca o solo marinho, chamada de touchdown point (TDP). Para prolongar a vida útil do duto e evitar vazamentos de óleo no mar, são empregados revestimentos protetores poliméricos, usualmente chamados de calhas. A partir de uma necessidade da indústria petrolífera de testar e controlar o recebimento destes revestimentos foi projetado e construído um equipamento denominado de Simulador de Interações Marítimo-Mecânicas em Calhas (SIMMC) no Laboratório de Tecnologia em Atrito e Desgaste UFU que visa à realização de testes em campo. Assim sendo, o objetivo deste trabalho foi fabricar, controlar e testar penetradores de metal duro visando à realização de ensaios de desgaste por abrasão que permitam avaliar a resistência ao desgaste abrasivo de materiais poliméricos usados na proteção de risers. Para tanto, foram propostas as seguintes etapas: a) preparação do SIMMC Portátil para realização dos ensaios de desgaste; b) determinação dos parâmetros de teste ideais para o SIMMC Portátil (número de ciclos, carga externa e velocidade de rotação) por meio de um planejamento fatorial completo; c) controle dimensional e geométrico dos penetradores antes e após a usinagem; d) realização de testes de desgaste antes e após a retífica; e) usinagem dos penetradores utilizando afiação e lapidação e f) análise da influência das melhorias trazidas por esses processos para os resultados dos testes de desgaste. Os resultados obtidos permitem concluir que: 1) os processos de usinagem propostos são adequados para fabricação dos penetradores dentro das tolerâncias dimensionais e geométricas definidas no projeto. Valores de rugosidade da ordem de 2,0 μm foram reduzidos em pelo menos 60%, enquanto que para valores menores que 2,0 μm esta redução foi pelo menos de 33% e 2) os ensaios de abrasão utilizando os penetradores fabricados fornecem resultados mais precisos e confiáveis. / Mestre em Engenharia Mecânica

ABSTRACT This thesis work consists of a case study, where August Lund AB assigned the further development of an ergonomically designed plastic serving pitcher. The purpose of the assignment was to further develop the serving pitcher, to adapt it for hot beverages and the manufacturing method injection molding, and to serve as a basis for decision making regarding how further investments in the previously produced ergonomic design solution was to be made. To achieve this, the following thesis question was formulated: Which are the leading factors that dictates the product development of plastic products that will be injection molded? To be able to answer the thesis question and complete the development of the pitcher a literature study about plastic design was conducted, that formed the foundation of the theoretical framework. Secondary data was collected using academic literature consisting of books and scientific papers. A product development process was formed for the case study, that was a derivative of the generic product development processes presented in the literature used. To complete the theoretical framework for the case study primary data was collected by conducting laboratory testing, simulations, tests and interviews. The main part of the work conducted in the case study consisted of finding a satisfactory insulation solution, that would prevent the user of the pitcher from getting burned by the heat from the hot beverage. This resulted in that the product development never reached beyond the conceptual phase. Two different methods of insulation were explored. The first method consisted of a thermoplastic elastomer overmolding that was located at the gripping area. It was concluded from the conducted laboratory testing and the simulations that the thickness of the grip had to be at least 10 mm. The thickness necessary was regarded as to thick because of the associated manufacturing costs and the proposed method was rejected. The second method explored was a pitcher containing an inner pitcher that formed an insulating air gap. The simulation result indicated that a 3.5 mm air gap was necessary to obtain adequate insulation. An insulation method using an air gap in combination with the ergonomic design solution brings several unsolved problems, that need further investigation to be solved if the combination is to be used. The employer had the request of investigating if a thermos effect could be achieved. The result showed that an air gap would insulate the pitcher so that a 10°C higher beverage temperature would be achieved during the 45 minutes than if an uninsulated pitcher was to be used. To attain a better thermos effect, the air gap could be filled with a foam to reduce the convective heat transfer in the air gap. Reaction Injection Molding could potentially be used to produce the insulating foam. It was concluded based upon the case study and the theoretical framework that the leading factors that dictates the product development of plastic products that will be injection molded was the structural constraints and the design guidelines of plastic design. Also, the cost of manufacturing in relation to the product performance, the products potential selling price and the production volume. In another word, to be able to asses which changes of the design that leads to increased manufacturing cost and if the increase is justifiable in relation to the obtained product performance. DFM turned out to be essential and have a central role in the product development of plastic products that will be injection molded. / SAMMANFATTNING Det här examensarbetet utgörs av en fallstudie, där på uppdrag av August Lundh AB en ergonomiskt designad serveringskanna i plast skulle vidareutvecklas. Arbetet syftade till att vidareutveckla kannan så att den anpassades för varm dryck och tillverkningsmetoden formsprutning, för att sedan utgöra ett underlag för huruvida företaget skulle vidareinvestera i den tidigare framtagna ergonomiska designlösningen. För att vidareutveckla kannan krävdes kunskaper om tillverkningsmetoden och vilka designmöjligheter som metoden medger. Därför formulerades följande frågeställning: Vilka är de styrande faktorerna vid produktutveckling av plastprodukter som ska formsprutas? För att kunna svara på frågeställningen och utföra uppdraget utfördes en litteraturstudie om plasttillverkning som utgjorde grunden för den teoretiska referensramen som arbetet utgick ifrån. Sekundärdata insamlades genom akademisk litteratur i form av böcker och vetenskapliga artiklar. En produktutvecklingsprocess som var anpassad för fallstudien togs fram, som var ett derivat av de generiska produktutvecklingsprocesserna som den använda litteraturen presenterade. I fallstudien insamlades primärdata genom laborationer, tester, simuleringar och intervjuer för att komplettera den teoretiska referensramen. Större delen utav arbetet i fallstudien utgjordes av att finna en tillfredsställande isoleringslösning, för att förhindra att användaren av kannan ska bränna sig på grund av värmen från den varma drycken. Detta medförde att arbetet aldrig passerade konceptstadiet i produktutvecklingsprocessen. Två olika isoleringslösningar undersöktes. Den första isoleringslösning utgjordes av en pågjutning av en termoplastisk elast på greppytan. Laborationer och simuleringar visade att tjockleken som skulle krävas för att uppnå tillräcklig isolering behövde vara minst 10 mm, vilket ansågs vara för tjockt på grund av tillverkningsekonomiska aspekter och förslaget förkastades. Den andra isoleringslösningen som utreddes utgjordes av en kanna innehållandes en innerkanna, för att på så sätt skapa en isolerande luftspalt. Simuleringsresultaten indikerade att en 3,5 mm luftspalt var nödvändig för att erhålla en tillräckligt god isolering. En luftspaltsisolering i kombination med den ergonomiska designlösningen medför en rad olösta problem, som kräver vidare utredning om kombinationen ska användas. En önskan från uppdragsgivaren var att utreda om en termoseffekt kunde uppnås. Resultatet visade att en luftspalt skulle bibehålla dryckens värme cirka 10°C högre under 45 minuter, än en kanna utan isolering. För att uppnå en bättre termoseffekt skulle luftspalten kunna fyllas med ett skummaterial, för att på så sätt reducera den konvektiva värmeledningen i luftspalten. En tillverkningsmetod som eventuellt skulle kunna användas för att producera en skumisolering är reaktionsformsprutning. Fallstudien och den teoretiska referensramen visade att de styrande faktorerna vid produktutveckling av plastprodukter som ska formsprutas var de konstruktionsmässiga begränsningarna och de design-riktlinjer som finns för plastdesign. Samt tillverkningskostnaden i relation till produktens prestanda, potentiella försäljningspris och tillverkningsvolym, det vill säga att avgöra vilken designändring som medför en ökad tillverkningskostnad och huruvida den är försvarbar eller inte, i relation till vilken ökad produktprestanda som fås. Att arbeta med DFM visade sig vara nödvändigt och vara en central del av produktutveckling av plastprodukter som ska formsprutas.

This thesis presents a multiscale investigation and characterization of additive manufactured Polyamide material using fused deposition modelling technique. Manufacturing was performed using Markforgeds – Mark one 3D printer.  A multiscale investigation dedicated to minimizing the effect of shape distortion during 3D printing are presented, focusing on both molecular alignment in microstructure and implementing internal structures in mesostructure. Characterization on samples investigating microstructure was performed with coefficient of linear thermal expansion measurement and 3-point bending experiment. Different samples with varying infill patterns are tested and results indicates an isotropic behaviour through the manufactured samples and implies no molecular alignment due to printing pattern. In meso-structure, an implemented internal pattern is investigated. All samples are measured with 3D scanning equipment to localize and measure the magnitude of shape distortion. Attempts to find relationships in shape distortion and porosity between the samples resulted in no observed trends. Compressive experiments where performed on samples in axial- and transverse directions resulting in anisotropic behaviour. The largest compressive stiffness is recorded in axial direction reaching 0,33 GPa. The study is done in collaboration with Swerea SICOMP and Luleå University of Technology.

Polyethylene is a widely-used material in package industries. The fracture behavior of this material has not been studied in the plastic region in many years. In this thesis work, the J-Integral which is one material property used to represent the plastic material strength is calculated through the numerical analysis. To build a correct numerical model, the material behavior is summarized from previous uniaxial tensile test. The result from the fracture experiment for variable initial crack length is used to validate the reliability of the numerical model. The numerical analysis is done by the software ABAQUS which has the function to get the value of J-Integral directly. The final result contains the comparison between experiments and numerical analysis and the value of J-Integral at the crack initiation.

We report on a new framework for preparing high-refractive index polymeric materials which combines the selective thiol radical mono-addition to phenyl-acetylene derivatives with hyperbranched architectures. Using this strategy we have synthesized a series of linear and hyperbranched polyvinyl sulfide (PVS) materials, employing different dithiol (A₂ and A'₂) and di- and trialkyne (B and B₃) monomers. The process requires only a simple radical initiator, such as AIBN, in lieu of expensive or toxic catalysts and this chemistry produces polymers in high yield (up to 96%) and high molecular weight (up to 123 000 g mol⁻¹). The polymers are optically transparent, thermally stable (up to 420 °C) and readily form highquality films. The end group composition of the hyperbranched materials can be easily adjusted by changing the A₂/B₃ feed ratio. The sulfur incorporation and conjugation resulting from thiol–yne coupling with selective mono-addition results in materials with high refractive indices in the visible and IR region (nD = 1.68–1.75) and optical dispersions as low as 0.004. Moreover, we demonstrate that the hyperbranched architecture produces materials with better performance in terms of light reflection and chromatic dispersion compared to linear structures.