La synthèse contrôlée de nanoparticules constitue toujours un enjeu majeur en science des matériaux (pour des applications telles que la catalyse par exemple) et la voie «fluides supercritiques» permet de répondre en partie à ce challenge. Dans ce contexte, ce travail de thèse a été consacré à l’élaboration de nanostructures d’oxyde de cérium aux caractéristiques contrôlées (tailles, morphologies, propriétés de surface,…) par synthèse solvothermale supercritique. A partir de l’étude de l’influence des paramètres opératoires du procédé sur les caractéristiques physico-chimiques des nanomatériaux obtenus, des mécanismes de formation et de fonctionnalisation de surface ont été proposés. D’un point de vue applicatif, ces poudres ont été caractérisées qualitativement et quantitativement vis-à-vis de la capture réversible du CO2. / The controlled synthesis of nanoparticles remains of key importance in materials science (for applications such as catalysis for instance) and “supercritical fluids” processes allow partially addressing this challenge. In this context, this PhD work has been dedicated to the synthesis of cerium oxide nanostructures with controlled characteristics (size, morphology, surface property,…) by supercritical solvothermal approaches. Through the study of the influence of process operating parameters on physicochemical characteristics of the synthesized materials, formation and surface modification mechanisms have been proposed. From an applicative point of view, powders have been submitted to qualitative and quantitative characterization towards CO2 capture.

Le développement de nouveaux catalyseurs pour l’hydrogénation sélective du propyne et du propadiène (MAPD) est un processus complexe, puisqu’il s’agit d’une réaction rapide effectuée en gaz-liquide-solide. Dans ces conditions, le flux d'hydrogène transporté aux sites actifs du catalyseur contrôle la vitesse de la réaction, particulièrement à l’échelle pilote. Cela rend difficile la comparaison des performances des différents catalyseurs (conversion et sélectivité). Afin d’améliorer la discrimination des solides, l’hydrogénation sélective du MAPD a été étudiée en monophasique (fluide/solide) dans un réacteur filaire à haute pression et en supercritique.La première partie de la thèse a eu pour objectif de déterminer les conditions de fonctionnement adéquates : un dispositif expérimental microfluidique et une méthodologie associée ont été développés et validés pour obtenir les diagrammes P-T de miscibilité et les coordonnées critiques des systèmes réactionnels mis en jeu. En parallèle, le réacteur a été caractérisé en utilisant des outils numériques (CFD) appliqués à l’hydrodynamique et au transfert de masse. Les tests expérimentaux ont alors pu être menés, dans la seconde partie de la thèse, afin d’étudier l'hydrogénation du MAPD à 303 K entre 20 et 120 bar. Dans ces conditions, plusieurs paramètres ont été étudiés, tels que la PPH (vitesse spatiale horaire, ou WHSV en anglais), la pression et la fraction de solvant. Les résultats montrent un gain important de conversion du MAPD à haute pression et en conditions supercritiques par rapport aux conditions classiques (>5 fois plus). Cela peut s’expliquer par la suppression de l’interface gaz-liquide et l’amélioration des diffusivités. Les variations de sélectivité observées en parallèle montre sa dépendance au flux d’hydrogène amené. Ces résultats prometteurs permettent une meilleure discrimination des catalyseurs ainsi qu’une meilleure compréhension du système réactif. Ainsi, pour la première fois, en utilisant ces données non classiques, il a au final été possible d'estimer des paramètres cinétiques intrinsèques pour l’hydrogénation sélective des coupes C3. / The development of new catalysts for propyne and propadiene (MAPD) hydrogenation is a complex process, because it is a fast reaction performed in gas-liquid-solid. Indeed, in these conditions, the hydrogen flux (G/L and L/S) transported to the reaction sites controls the overall reaction rate, particularly at pilot scale. To avoid this limitation, the MAPD selective hydrogenation was performed in single-phase, using a single pellet string reactor (SPSR) at high-pressure and supercritical conditions. For both conditions, the literature is scarce. Thus, the first step was to develop and validate a microfluidic experimental apparatus and a methodology based on “design of experiments”, in order to obtain PT miscibility diagrams and critical coordinates. These methods combined allowed a fast PT screening compared to conventional phase behavior cells, being around 5 times higher. In parallel, the SPSR was characterized by computational fluid dynamics (CFD) for flow and mass transfer. It was shown that the hydrodynamic inside the reactor can be modeled as a plug flow reactor with low axial dispersion, and a LS mass transfer correlation was proposed. After the fluid and reactor characterization, the MAPD hydrogenation was performed at 303 K and from 20 to 120 bar. At these conditions, several parameters were tested, such as WHSV (weight hourly space velocity), pressure and solvent fraction. The results showed that high-pressure and supercritical conditions offer better reaction performance, which is due to the suppression of the gas-liquid limitation and to the diffusivity enhancements (more than 5 times faster than conventional conditions). With this thesis, it was possible, for the first time, to estimate the intrinsic kinetics parameters of a dense C3 cut mixture hydrogenation, allowing a deeper understanding of the involved mechanism. Thus, the use of unconventional conditions has opened a door to new forms of catalyst screening and new ways to study kinetics.

Orientador: Prof. Dr. Adriano Viana Ensinas / Coorientador: Prof. Dr. Reynaldo Palacios Bereche / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Energia, Santo André, 2018. / A indústria brasileira de bioetanol estima uma produção de vinhaça de 339,5 bilhões de litros na safra de 2017/2018. Devido a presença de compostos orgânicos e inorgânicos, há grande interesse em seu reaproveitamento como fertilizante nas lavouras de cana-de-açúcar. Porém, é observado que ao utilizá-la em grande quantidade, sem respeitar a saturação do solo pela Capacidade de Troca Catiônica (CTC), este efluente é lixiviado poluindo o lençol freático. De maneira a aproveitar a água em excesso contida nesse efluente, diferente dos processos termoquímicos convencionais os quais necessitam uma etapa de concentração, este trabalho propõe uma rota que aplica a tecnologia da Gaseificação Hidrotérmica Supercrítica (SCWG) para beneficiamento da vinhaça com o objetivo de produzir gás de síntese com alto teor de CH4 ou H2, o qual pode ser comercializado para produção de outros compostos com maior valor agregado, como a amônia ou o metanol, ou ainda, utilizado como combustível para conversão a energia elétrica. Para isso foi elaborado um diagrama de processo e desenvolvida uma metodologia para representação das propriedades físico-químicas da vinhaça visando sua modelagem/simulação por meio do software Aspen Plus®. Além disso, foi realizado um estudo para otimização do consumo de energia do processo utilizando técnicas de integração energética pelo Método Pinch. A modelagem do efluente indicou que a equação de estado de SoaveRedlich-Kulong (SRK) é a que melhor se adequa a definição das propriedades físicas e químicas em condição de equilíbrio Vapor-Liquido-Liquido (VLL) ao serem comparadas com dados experimentais. Ao tratar 582.75 m³/h de vinhaça, a rota possui uma capacidade de produção equivalente a 17 kg de CH4 ou 8,6 kg de H2 por kg de cana-de-açúcar. O gás de síntese produzido apresenta poder calorífico inferior (PCI) igual a 49 MJ/kg para o gás rico em CH4 e 64 MJ/kg para o H2. Além disso, ao ser utilizado na conversão em energia elétrica em uma turbina a gás foi capaz de produzir excedentes de eletricidade de 19 e 31 MW para o CH4 e o H2 respectivamente. A conversão total da vinhaça produzida no Brasil por meio desta tecnologia tem um potencial para atender a demanda de eletricidade de 7,5 milhões de residências. As eficiências energéticas do processo independente dos compostos produzidos são equivalentes, o que não estabelece um critério para favorecimento da produção. Este direcionamento deve considerar o valor agregado e o comportamento do mercado para sua comercialização, desta maneira, o emprego da SCWG seja em alta ou baixa escala, pode afetar positivamente a receita da usina além de contribuir na diversificação da matriz energética nacional e diminuição dos impactos ambientais locais proporcionados pelo uso inapropriado da vinhaça. / The Brazilian bioethanol industry estimates a production of 339.5 billion litres of vinasse in the 2017/2018 harvest season. Due to the presence of organic and inorganic compounds, there is great interest in its reuse as fertilizer. However, is observed that when it is used in large quantity, without respecting the saturation of the soil by the Cation Exchange Capacity (CEC), this effluent is leached polluting the groundwater. In order to take advantage of the water excess contained in this effluent, different from conventional thermochemical processes which require a concentration step, this work proposes a route that applies Supercritical Water Gasification (SCWG) technology for the vinasse treatment in order to produce syngas with a high CH4 or H2 content, which can be commercialized to produce other compounds with higher added value, such as ammonia or methanol, or used as fuel for conversion to electric energy. For this, a process diagram and a methodology were developed to represent the physical-chemical properties of the vinasse to simulate the route using Aspen Plus® software. In addition, a study was carried out to optimize the process energy consumption using Pinch Method by energy integration techniques. The effluent modeling indicated that the most appropriate equation to the physical-chemical properties definition is the Soave-Redlich-Kulong (SRK) with VaporLiquid-Liquid equilibrium (VLL) when compared with experimental data. The treatment of 582.75 m³/h of the vinasse by the proposed route, has a production capacity equivalent to 17 kg of CH4 or 8.6 kg of H2 per kg of sugarcane. The syngas produced has a lower heat value (LHV) in dry basis equal to 49 MJ / kg for CH4 rich gas and 64 MJ / kg for the case with H2. Moreover, when used for conversion to electric energy in a gas turbine, it is being able to produce a surplus energy equal to 19 or 31 MW, respectively. The total conversion of vinasse produced in Brazil through this technology has the potential to meet the electricity demand of 7.5 million residences. The process energy efficiencies are equivalent independently of which compounds are produced, which does not establish a production criterion. This targeting should consider the value added and the market behavior for its commercialization, so that the SCWG's employment on a high or low scale, can positively affect the plant's revenue, besides contributing to the diversification of the national energy matrix and the reduction of local environmental impacts of the inappropriate use of vinasse.

Orientadores: Fernando Antonio Cabral, Luiz Ferreira de França / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T21:38:30Z (GMT). No. of bitstreams: 1 Peixoto_CamilaArantes_M.pdf: 600363 bytes, checksum: 95564747a5d85efcd82a01c07b415291 (MD5) Previous issue date: 2004 / Resumo: O óleo de palma e seus subprodutos são fontes de tocoferóis. Os tocoferóis, por sua vez , são compostos de grande importância para a indústria alimentícia, farmacêutica e cosmética. Eles agem no organismo como vitaminas lipossolúveis essenciais na nutrição humana por inibirem a formação de radicais livres e seus efeitos nocivos sobre o organismo. Além disso, possuem aplicação tecnológica em alimentos pois são antioxidantes naturais, prevenindo e retardando a rancidez oxidativa dos óleos e também de alimentos com alto teor de lipídios.No refino do óleo de palma, a etapa de desodorização é responsável pela perda em 33% dos tocoferóis totais presentes no óleo, e o destilado formado (DDOP), não tem aplicação tecnológica nem valor comercial. A extração com fluido supercrítico utilizando CO2 como solvente tem sido considerada como uma alternativa para substituir os tradicionais processos de separação que utilizam solvente orgânico. Com a finalidade de verificar a possibilidade de extração de tocoferóis do DDOP utilizando CO2 supercrítico, foram realizados neste trabalho experimentos em um sistema de extração na forma estática para obtenção de dados experimentais de equilíbrio de fases deste sistema multicomponente. Foram realizadas medidas de solubilidade nas condições operacionais de 60 a 90ºC; 20 a 35MPa e tempo de equilíbrio de 6h, de acordo com os testes preliminares realizados. Foi determinada a composição em tocoferóis individuais e totais dos extratos e feita análise da seletividade do CO2 supercrítico em separar os tocoferóis do DDOP em função da temperatura e da pressão.A solubilidade do DDOP em CO2 supercrítico mostrou forte dependência de acréscimos na pressão para cada temperatura estudada. As maiores solubilidades obtidas para o sistema multicomponente foram de 144,85 e 172,19 g/KgCO2 para as condições operacionais de 80ºC e 35MPa e 90ºC e 35MPa; respectivamente. O dióxido de carbono comprovou ser efetivo no fracionamento do DDOP. Observou-se que a seletividade do CO2 supercrítico apresentou valores muito abaixo da unidade, e diminuiu com incrementos nas condições operacionais de temperatura e pressão, o que evidencia que é possível concentrar os tocoferóis na fase pesada mas não recuperá-los do DDOP. Os melhores resultados de seletividade foram obtidos nas condições mais drásticas de temperatura e pressão adotadas, ou seja, para as temperaturas de 80 e 90ºC e para as pressões de 30 e 35MPa, tanto para os tocoferóis totais quanto para os individuais. Os compostos d-Tocotrienol e g-Tocotrienol foram os menos solúveis e o composto a-Tocotrienol foi o mais solúvel em CO2 supercrítico / Abstract: The palm oil and its by-products are source of tocopherols. The tocopherols, in turn, are compounds of great importance for food, pharmaceutical, cosmetic industries. They act in the organism as essential lipossoluble vitamins in human nutrition inhibiting the formation of free radicals and its harmful effect in the organism. Moreover, in food, tocopherols have technological application because of their action as natural antioxidant, preventing and delaying the oxidation of oils and food with high content of lipids. In the refining of palm oil, the stage of desodorization is responsible for the loss in 33% of the total tocopherols present in the oil, and the formed distilled (PFAD) do not have technological application, nor commercial value. The extration with supercritical fluid using CO2 as solvent has been considered as an alternative to substitute the traditional processes of separation that use organic solvent. With the purpose to verify the possibility of extraction of tocopherols of PFAD using supercritical CO2, the experiments were carried out in a static analytical apparatus for the attainment of experimental data of phase equilibria of this multicomponent system. Measures of solubility were carried out in the operational conditions of 60 to 90°C; 20 to 35MPa, and 6 hours of equilibrium time, in accordance with the preliminary tests realized. The composition of the extracts in individual and total tocopherols was determinated and it was analyzed the selectivity of supercritical CO2 in separate the tocopherols of PFAD in function of the temperature and pressure. The solubility of PFAD in supercritical CO2 showed high dependence of additions in the pressure for each studied temperature. The higher solubilities gotten for the multicomponent system were 144,85 and 172,19g/Kg CO2 for the operational conditions of 80ºC and 35MPa and 90ºC and 35MPa, respectively. The supercritical carbon dioxide proved to be effective in the fractionization of PFAD. It was observed that the values of selectivity of supercritical CO2 were below the unit and diminished with the increments in operational conditions of temperature and pressure, what evidenced that is possible to concentrate the tocopherols in heavy phase, but not to recover them of PFAD. The best results of selectivity were gotten in the most drastic conditions of temperature and pressure studded, or either, for the temperatures of 80 and 90ºC and of pressure of 30 and 35MPa, as much for the total tocopherols, how much for the individuals ones. The compounds d-Tocotrienol and g-Tocotrienol were the less soluble, and the compound d-Tocopherol was the most soluble in supercritical CO2 / Mestrado / Mestre em Engenharia de Alimentos

L’objectif de cette thèse est d’étudier le comportement d’un mélange de fluide supercritique(diazote ou dioxyde de carbone) et de polyuréthane thermoplastique àl’état fondu lors de la mise en œuvre de butée d’attaques d’amortisseurs par le procédé d’injection Mucell®. Dans un premier temps, l’état de l’art a été développé dans une synthèse bibliographique qui a permis de décrire les principaux phénomènes intervenants lors de la transformation d’un mélange de fluide supercritique et de polymère en mousse micro-cellulaire. Puis, une étude à l’échelle laboratoire a permis de caractériser et de modéliser le comportement d’un polyuréthane thermoplastique mis en contact avec un fluide supercritique et de déduire les caractéristiques et les comportements essentiels à la compréhension des différents phénomènes rencontrés dans le procédé de mise en œuvre (diffusion, solubilité, nucléation...). Enfin, la dernière partie de ces travaux concerne la mise en application des connaissances précédemment acquise sur les moyens industriels dans le but de d’analyser et de stabiliser le moussage micro-cellulaire généré. / The aim of this thesis is to study the behavior of a supercritical fluid (nitrogen or carbon dioxide) and thermoplastic polyurethanemeltmix during the production of jounce bumpers by the MuCell® injection molding process. First of all, the state of the art was developed in a literature review which allowed to describe the main phenomena that occur during processing of a mixture of supercritical fluid and polymer in microcellular foam. Then, a study at the laboratory scale allowed to characterize and model the behavior of a thermoplastic polyurethane in contact with a supercritical fluid and deduct the characteristics and behaviors essential to the understanding of various phenomena encountered during the process(diffusion, solubility , nucleation...). Finally, the last part of this work concerns the implementation of previously acquired knowledge on industrial means in order to analyze and stabilize the generated microcellular foam.

Les pommes sont considérées comme bénéfiques pour la santé, de part leur teneur en polyphénols qui leur confèrent l’étiquette "d’aliment santé". Les procédés de transformation agroalimentaire des fruits et légumes génèrent des coproduits qui sont considérés comme sans valeur par les industriels. Or, au regard des volumes générés, ce sont des sources abondantes de nutriments.Une voie possible de valorisation de ces coproduits est la réintroduction dans des produits alimentaires en tant qu’ingrédient, de façon à proposer des aliments enrichis en molécules fonctionnelles. Pour ce faire, deux voies ont été explorées: l’utilisation de poudres d’épidermes de pommes pour stabiliser une émulsion et l’extraction des polyphénols au moyen de la technologie à base de CO2 supercritique. Ce travail examine également des solutions pour remédier au problème de brunissement enzymatique, comme le traitement thermique et l’addition de poudres de fruits naturellement riches en agents antibrunissement.Les phases de préparation des pommes sont de réelles étapes de transformation qu’il faut optimiser et maîtriser afin de préserver toutes les propriétés antioxydantes des coproduits végétaux. Nos travaux ont également permis de mettre en évidence des propriétés plus fonctionnelles des pelures de pommes, comme agent stabilisant d’émulsions. L’impact des paramètres d’extraction a été mis en évidence par l’exploration de plusieurs conditions telles que la masse chargée, le broyage, le protocole ainsi que la température et la composition du fluide extractant. / Apples are considered beneficial to health, because of their content of phenolic compounds that confer the label "health food". Fruits and vegetables food processes generate byproducts that are considered worthless by industrial. However, given the volumes generated, they are rich sources of nutrients.One possible way of valorization of these byproducts is the reintroduction of food as ingredient, to propose fortified foods with functional molecules. To do this, two approaches have been explored: the use of apple peels powders to stabilize an emulsion and the extraction of phenolic compounds by supercritical CO2+ethanol. This work also discusses solutions to remedy the enzymatic browning, such as heat treatment and the addition of naturally rich fruit powders as anti-browning agents.Apples preparation phases are real transformation steps which it’s necessary to optimize and master to preserve all the antioxidant properties of fruits and vegetables byproducts. Our works also highlight more functional properties of apple peels as a stabilizing emulsions agent. The impact of extraction parameters was demonstrated by the exploration of several conditions such as the loaded weight, the grinding, the protocol as well as the temperature and composition of supercritical fluids.

A state-of-art research facility has been built at the University of Ottawa, which is suitable for thermalhydraulic experiments in support of the development of the Canadian Supercritical-Water-Cooled Reactor (SCWR). The facility is a recirculating flow loop, using carbon dioxide as a medium and having three different test sections, two tubes with inner diameters of 8 and 22 mm, respectively, and a three-rod bundle. The loop can operate within ranges of pressure, temperature, heat flux and mass flux, which are of interest to the current SCWR design. The present thesis includes a comprehensive description of the facility. It also documents the procedure and results of its commissioning, as well as some preliminary measurements that have been collected so far. It is intended to provide an insight to the design of the facility and its functionality and to serve as a reference for future research activities. A number of tests performed by previous researchers in other facilities were replicated and nearly identical results were obtained. It was demonstrated that the design of the facility is sound and its performance is adequate within the intended ranges of operation conditions. It is expected that the results obtained in this facility will make a significant contribution to the understanding of supercritical heat transfer and pressure losses in the SCWR context.

Les propriétés spécifiques des milieux fluides supercritiques sont exploitées depuis denombreuses années dans les domaines de la séparation, de la chimie et des matériaux.Aujourd’hui, les activités de recherche se focalisent vers une meilleure compréhension et unmeilleur contrôle des processus thermodynamiques, physiques et chimiques mis en jeu, ce quinous a naturellement amené à développer la microfluidique supercritique. C’est dans cecontexte que s’inscrivent ces travaux de thèse ayant pour objet le développement et l’utilisationde l’outil microfluidique pour l’étude de la réactivité chimique et de la germination-croissance enmilieux fluides supercritiques.Notre premier objectif a concerné le développement de l’outil microfluidique supercritique etde microsystèmes résistants aux conditions de température et de pression. Quelquescaractéristiques physiques associées à ces dispositifs sont proposées de manière à observerclairement les avantages attendus du couplage de la microfluidique et des fluides supercritiques.Nous avons ensuite validé l’apport de la microfluidique supercritique sur la réactivité chimiqueet la chimie des matériaux via, d’une part, l’étude de l’oxydation hydrothermale du méthanol et,d’autre part, l’élaboration de nanocristaux de ZnO. Les propriétés de photoluminescence de cesnanocristaux de ZnO ont été caractérisées; nous avons montré que l’outil microfluidiquesupercritique permet de synthétiser des nanocristaux de ZnO avec une luminescenceexcitonique. / The unique properties of supercritical fluids (SCFs) have been widely used since the 1980’sin a wide range of applications including separation, chemistry and materials synthesis.Currently, the research activities are focused toward a better understanding and tailoring ofthermodynamical, physical and chemical phenomena involved in SCFs processes. In thiscontext, this is why we have chosen to develop supercritical microfluidics in the frame of thisPhD work, which aims at developing and using microfluidic tools in order to study the chemicalreactivity and the nucleation-growth in supercritical fluids.First of all, our strategy aimed at fabricating microsystems which could handle to the SCFsoperating conditions (high pressure and high temperature). Then, we have studied somephysical characteristics of these devices and in particular we determined the expectedadvantages associated with the combination of microfluidic tools and supercritical fluids.Afterwards, we have demonstrated the benefits of the supercritical microfluidics to materialssynthesis and chemical reactivity through the hydrothermal oxidation of methanol and thesynthesis of ZnO nanocrystals. This last point was also the subject of a photoluminescencestudy, demonstrating that supercritical microfluidics tools can be used as “precision synthesis”reactors.

Wide bandgap (WBG) devices and power electronic converters (PEC) that enable the dynamic control of energy and high-power density designs inevitably contain defects including sharp edges, triple points, and cavities, which result in local electric field enhancements. The intensified local electric stresses cause either immediate dielectric breakdown or partial discharge (PD) that erodes electrical insulators and accelerates device aging. With the goal of addressing these dielectric challenges emerging in power-dense applications, this dissertation focuses on 1) modeling the dielectric characteristics of supercritical fluids (SCFs), which is a new dielectric medium with high dielectric strength and high cooling capability; and 2) establishing the optimal fabrication conditions of electrets, which is a new dielectric solution that neutralizes locally enhanced electric fields. In this dissertation, the dielectric breakdown characteristics of SCFs are modeled as a function of pressure based on the electron scattering cross section data of clusters that vary in size as a function of temperature and pressure around the critical point. The modeled breakdown electric field is compared with the experimental breakdown measurements of supercritical fluids, which show close agreement. In addition, electrets are fabricated based on the triode-corona charging method and their PD mitigation performance is evaluated through a series of PD experiments. Electrets are fabricated under various charging conditions, including charging voltage, duration, polarity, and temperature with the goal of identifying the optimal condition that leads to effective PD mitigation. The PD mitigation performance of electrets fabricated based on these charging conditions is further assessed by investigating the impact of various power electronics voltage characteristics, including dv/dt, polarity, switching frequency, and duty cycle. Electret based electric field neutralization approach is further utilized in increasing the critical flashover voltage associated with the surface flashover voltage. Moreover, due to the high mechanical strength of epoxy composites at cryogenic temperatures, in this dissertation, epoxy-based electrets are fabricated as a solution to PD in high temperature superconducting cables. The experimental demonstrations conducted with electret in this dissertation is dedicated for the establishing the electret based electric field neutralization approach as a dielectric solution for the dielectric challenges in power electronics driven systems.

The development of structured macroporous hydrogels are of great interest in many industries due to their high permeabilities, large surface areas and large pore volumes. In drug delivery and wound healing applications, these macropores may theoretically be utilized as large drug reservoirs to deliver anti-inflammatory drugs to a wound site, while simultaneously absorbing exudate and maintaining a hydrated environment in which the wound may heal. However, current methods of generating macroporous structured hydrogels are low-throughput, expensive, and require the use of organic solvents, salts, and other additives that are difficult to remove from the crosslinked hydrogel scaffold. In contrast, the Pressurized Gas eXpanded liquid (PGX) processing technology, patented by the University of Alberta and licensed for all industrial applications by Ceapro Inc., has been shown to generate purified and exfoliated biopolymer scaffolds in a less expensive and more efficient way. Herein, the tunability of the PGX processing method was investigated in depth, varying solvent/anti-solvent ratios, nozzle mixing volume, polymer molecular weight, and polymer concentration to examine the resulting effects on produced polymer morphologies. PGX-processed chitosan and alginate scaffolds were stabilized as bulk hydrogels through post-processing crosslinking methods using anti-solvents, solid-state chemistries, and/or rapid gelation kinetics. The mechanical strength, swelling/degradation kinetics, affinity for protein uptake, and cytotoxicity of these stabilized scaffolds were subsequently examined and compared to hydrogels produced without the use of PGX processing. Furthermore, in situ crosslinking methods were explored, in which alginate and poly(oligoethylene glycol methacrylate) polymers were shown to form stable aerogels during the standard PGX processing method. Finally, the PGX apparatus was reconfigured to enable the impregnation of a model hydrophobic drug into pre-processed polymer scaffolds via circulation of supercritical CO2. The total loading was calculated and the release kinetics from loaded-scaffolds examined. In conclusion, this work outlines a novel method of creating structured macroporous hydrogels from PGX processed biopolymers with the potential to provide improved drug loadings and sustained release profiles. It is expected that this work will provide a basis for a great deal of research into the further stabilization of scaffolds for use in other applications, the investigation of a larger range of bioactive molecules for impregnation and release, and the exploration of PGX hydrogel scaffolds for in vivo wound healing. / Thesis / Master of Applied Science (MASc)