PPGCEM - Mestrado em Ciência e Engenharia de Materiais
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Master Thesis Desenvolvimento e avaliação de nanofluidos de alumina para recuperação avançada de petróleo em reservatórios areníticos(Universidade Federal do Rio Grande do Norte, 2026-02-24) Rocha, Camila Louyse Oliveira da; Martinelli, Antonio Eduardo; https://orcid.org/0000-0003-3885-9104; http://lattes.cnpq.br/0022988322449627; https://orcid.org/0000-0003-1531-4099; http://lattes.cnpq.br/7793908717511173; Alves, Annelise Kopp; http://lattes.cnpq.br/0064626732086273; http://lattes.cnpq.br/0064626732086273; Paskocimas, Carlos Alberto; https://orcid.org/0000-0002-1915-4291; http://lattes.cnpq.br/2365059843175411; Oliveira, Gregory Vinicius Bezerra de; https://orcid.org/0000-0002-8223-8199; http://lattes.cnpq.br/5656895709723231Enhanced Oil Recovery (EOR) comprises a set of techniques designed to increase oil extraction from reservoirs where primary and secondary recovery methods are limited. Among the strategies employed, nanofluids have gained significant attention, as they combine a base fluid, additives, and nanoparticles capable of modifying critical reservoir properties such as wettability, oil viscosity, and interfacial tension, thereby increasing the recovery factor. Among the nanomaterials applied in EOR, aluminum oxide (Al₂O₃) stands out due to its high stability, large surface area, and chemical versatility, which favor its interaction with fluids and rock surfaces. Coprecipitation is a widely used method for synthesizing Al₂O₃ nanoparticles because it produces homogeneous particles with high purity; however, their tendency to agglomerate in liquid media still limits their performance. To overcome this limitation, the use of anionic polymers such as sodium polyacrylate (PAS) has proven effective by enhancing electrosteric repulsion between particles and consequently improving colloidal stability. In this context, the present study aimed to synthesize γ-Al₂O₃ nanoparticles via coprecipitation, stabilize them through the addition of PAS, and evaluate the performance of the resulting nanofluids in enhanced oil recovery processes in sandstone reservoirs. The nanoparticles were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FEG-SEM), and Brunauer–Emmett– Teller (BET) surface area analysis, while the nanofluids were evaluated in terms of rheological behavior, zeta potential, sedimentation, UV–Vis spectroscopy, dynamic light scattering (DLS), interfacial tension, and wettability. EOR experiments were conducted through conventional recovery followed by the injection of nanofluids containing γ-Al₂O₃ nanoparticles and additive (enhanced recovery), as well as an additional test consisting of conventional recovery followed by polymer solution injection, both performed at a flow rate of 0.5 mL·min⁻¹, with the recovered oil volume determined from the collected effluent samples. The results indicated the initial formation of fibrillar pseudoboehmite with low crystallinity and a high degree of hydration, which was subsequently converted into high-purity nanometric γ-Al₂O₃ with crystallite sizes of approximately 3 nm, spherical morphology, and a specific surface area of 250–270 m²·g⁻¹. The nanofluids exhibited dilatant behavior both in the absence and presence of PAS, while the addition of the polymer increased colloidal stability, promoted a bimodal particle distribution, and caused a reversal of the surface charge. Wettability and interfacial tension measurements showed that the combination of γAl₂O₃ and PAS reduced interfacial tension and altered the rock surface from oleophilic to strongly hydrophilic, particularly at higher alumina concentrations, indicating a synergistic effect between the polymer and the nanoparticles. In the EOR tests, polymer solution injection resulted in a moderate increase in the recovery factor compared with the reference brine, whereas PAS-stabilized nanofluids promoted progressive and concentration-dependent increases in oil recovery, reaching the highest enhanced recovery factors, a performance associated with greater colloidal stability, lower sedimentation, and more effective nanoparticle transport through the porous medium, demonstrating the high potential of PAS-stabilized γ-Al₂O₃ nanofluids for enhanced oil recovery applications.Master Thesis Síntese e estudo do óxido de alta entropia (Fe0,2,Ni0,2Co0,2Al0,2Zn0,2)3O4 pelo método sol-gel assistido por polivinilpirrolidona (PVP) e sua aplicação como eletrocatalisador para a reação de evolução de oxigênio(Universidade Federal do Rio Grande do Norte, 2025-06-02) Vasconcelos, Gabriel dos Santos; Gomes, Uilame Umbelino; Torres, Marco Antonio Morales; http://lattes.cnpq.br/0091292234916055; http://lattes.cnpq.br/9858094266525225; http://lattes.cnpq.br/2806155952751330; Mashhadikarimi, Meysam; https://orcid.org/0000-0003-1449-3654; http://lattes.cnpq.br/9422624675887080; Silva, Ariadne de Souza; https://orcid.org/0009-0002-9675-0748; http://lattes.cnpq.br/5623381698478389; Raimundo, Rafael Alexandre; https://orcid.org/0000-0002-9943-9464; http://lattes.cnpq.br/9772819884310876High-entropy oxides (HEOs) have emerged as a promising class of functional materials due to their tunable electrochemical and magnetic properties, with potential applications in electrocatalysis, energy storage, and electronic devices. In this context, the present study aims to synthesize and thoroughly characterize the high-entropy oxide (Fe₀.₂Ni₀.₂Co₀.₂Al₀.₂Zn₀.₂)₃O₄, referred to as HEO-600, synthesized at 600 °C via the sol-gel method assisted by polyvinylpyrrolidone (PVP). Additional samples were produced at higher temperatures, revealing the formation of distinct crystalline phases, including spinel-type and rock-salt structures. Structural and compositional characterization was carried out using various techniques, including X-ray diffraction (XRD), field-emission scanning electron microscopy (FEG-SEM) with energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). XPS analysis confirmed the equimolar composition of the elements in the HEO-600 sample, whereas the EDS analysis revealed a homogeneous distribution of cations, corroborating the formation of a uniform solid solution. TEM micrographs showed well-dispersed, non-agglomerated particles with an average size of 9.2 nm. The magnetic properties of the HEO-600 sample were investigated using Mössbauer spectroscopy, direct current (DC) magnetometry, and alternating current (AC) magnetometry. The Mössbauer spectrum indicated that iron ions were distributed between tetrahedral (A) and octahedral (B) sites in a 43% and 57% ratio, respectively, confirming a partially inverted spinel structure. Magnetic susceptibility measurements (DC and AC) revealed superparamagnetic behavior at room temperature, as well as the presence of a spin glass-like phase, with a transition temperature at 206 K. This magnetic phase was suppressed under an external field of approximately 4300 Oe, highlighting the complexity of magnetic interactions in the system. In addition to structural characterization, spectroscopic and electrochemical analyses were performed to evaluate the catalytic potential of the HEO-600 sample for the oxygen evolution reaction (OER). Fourier-transform infrared (FTIR) spectroscopy provided additional information on the vibrational configuration of the system, and the chemical bonds present in the oxide. Electrochemical experiments demonstrated that the HEO-600 sample exhibits promising performance for OER, with an overpotential of 358 mV at a current density of 10 mA cm⁻². This value indicates competitive catalytic activity compared to other transition metal-based high-entropy oxides. Thus, this work significantly contributes to the advance in the understanding of the structural, magnetic, and electrochemical properties of high-entropy oxides. The results obtained not only expand the knowledge of the correlation between synthesis, structure, and properties of these materials but also highlight their potential for technological applications in electrochemical catalysis.Master Thesis Desenvolvimento de nanocompósitos cimentícios a base de nanoplacas de grafeno para aplicações em poços CCS(Universidade Federal do Rio Grande do Norte, 2025-12-12) Silva, Dayanne Gabriella da; Martinelli, Antonio Eduardo; https://orcid.org/0000-0003-3885-9104; http://lattes.cnpq.br/0022988322449627; http://lattes.cnpq.br/3415325334445679; Freitas, Júlio Cézar de Oliveira; https://orcid.org/0000-0003-1324-9705; http://lattes.cnpq.br/2357217530716519; Braga, Glauco Soares; http://lattes.cnpq.br/4514550024139119Carbon Capture and Storage (CCS) is a fundamental technology for reducing largescale greenhouse gas emissions. This technique enables the safe confinement of carbon dioxide (CO₂), one of the main contributors to global warming, in deep geological formations, thereby limiting its release into the atmosphere. To implement this technology, it is essential to construct wells that allow the injection of CO₂ captured from industrial sources, ensuring secure storage and preventing its return to the surface. In this context, the cementitious material responsible for zonal isolation and well structural integrity must exhibit high chemical and mechanical resistance, as its degradation by CO₂ can compromise the long-term durability of the system. Thus, the incorporation of nanomaterials such as graphene nanoplatelets (GNPs) into cement pastes emerges as a promising approach, since their two-dimensional lamellar structure and high aspect ratio can enhance the mechanical strength, conductivity, and chemical stability of the cementitious system. Additionally, GNPs offer high scalability and lower cost compared with other graphene-based derivatives. This study aimed to evaluate the effect of different GNP concentrations (0.03%, 0.06%, and 0.09% BWOC) on the mechanical strength, permeability, and chemical resistance of cement pastes. The formulations were subjected to carbonation tests under supercritical CO₂ conditions in an aqueous medium, with evaluations performed after 7, 14, and 28 days of exposure. Complementary analyses, including X-ray Diffraction (XRD), Thermogravimetry (TG), and Scanning Electron Microscopy (SEM), were conducted to identify and quantify hydration and carbonation products formed before and after chemical attack, as well as to assess GNP dispersion within the cement matrix and its influence on product formation. The results showed that GNP-containing pastes exhibited increased compressive strength and reduced permeability, particularly at early curing ages. Carbonation was also slowed by the addition of GNPs, with the 0.06% concentration demonstrating the best performance. Microstructural analysis revealed well-dispersed GNPs in the cement matrix and the presence of carbonation products, while thermal and crystallographic analyses indicated the effect of GNP addition on the formation of compounds before and after CO₂ exposure. Therefore, the results indicate that GNPs present strong potential for the development of cementitious nanocomposites designed for CCS well construction.Master Thesis Formulação de tintas nanométricas funcionais de TiNb2O7(Universidade Federal do Rio Grande do Norte, 2025-06-12) Rodrigues, Rayssa Ribeiro; Martinelli, Antonio Eduardo; https://orcid.org/0000-0003-3885-9104; http://lattes.cnpq.br/0022988322449627; http://lattes.cnpq.br/4144399849996058; Paskocimas, Carlos Alberto; https://orcid.org/0000-0002-1915-4291; http://lattes.cnpq.br/2365059843175411; Mendes, Armando Monte; https://orcid.org/0000-0002-3442-9927; http://lattes.cnpq.br/3173204192281049; Macedo, Daniel Araújo de; http://lattes.cnpq.br/1027496814443777The search for new battery materials has intensified with the aim of increasing efficiency, storage capacity, and device compactness. Among the promising anode materials, TiNb₂O₇ (NTO) stands out, as it exhibits a high theoretical capacity (~388 mAh g⁻¹), which corresponds to the maximum charge that can be stored per gram of material during charge and discharge cycles. In addition, NTO presents high cyclic stability, meaning it is capable of maintaining its performance over multiple cycles, which is essential for battery durability. However, material selection is not the only crucial factor for battery performance; manufacturing methods also play a fundamental role. Although significant advances have been achieved in recent decades, the modernization of manufacturing techniques remains underexplored due to limitations of conventional methods. In this context, 3D printing, or additive manufacturing especially through the Direct Ink Writing (DIW) technique emerges as an innovative approach for fabricating battery components, enabling the creation of miniaturized electrodes with complex geometries and high surface area, which directly contributes to the optimization of properties related to electrical conductivity and ion storage. In the DIW technique, ink formulation is a key factor in ensuring ideal printing characteristics. The lack of information about such formulations highlights the need for further research in this area. Therefore, the present work proposes the development of a functional nanometric ink for application in the DIW technique, aimed at fabricating miniaturized electrodes for lithium-ion batteries. The goal is to make the process measurable, ensure good printability, and preserve the structural properties of the printed parts after sintering. For this purpose, the resin incorporates TiNb₂O₇ (NTO) as one of its components, obtained through synthesis. A hydrothermal synthesis route was adopted to produce high-purity NTO nanoparticles, ensuring morphological control key requirements for developing good electrochemical properties. After this step, the material was calcined, and the resulting powder was used in the preparation of inks for 3D printing. The printed samples were initially evaluated dimensionally and then subjected to a sintering process. Subsequently, structural and morphological characterizations were carried out, including X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FEG-SEM). Thermal analyses such as Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) were also performed. In addition to these electrochemical analyses focused on the oxygen evolution reaction (OER) were carried out to evaluate the functional behavior of the electrodes. The results demonstrated that it was possible to obtain NTO through hydrothermal synthesis and to produce nanometric inks compatible with a modified bioprinter for electrode fabrication. The formulated resin, composed of a polyvinyl alcohol (PVA) solution and alcohol as the base, showed good printability and maintained dimensional stability of the structures after printing.Master Thesis Catalisador de níquel suportado em óxido de grafeno termicamente reduzido para produção de hidrogênio por reforma a seco do metano(Universidade Federal do Rio Grande do Norte, 2025-08-21) Farias, Willian Alber da Silva; Melo, Dulce Maria de Araújo; https://orcid.org/0000-0001-9845-2360; http://lattes.cnpq.br/3318871716111536; https://orcid.org/0000-0002-3596-0947; http://lattes.cnpq.br/0754692042581100; Martinelli, Antonio Eduardo; https://orcid.org/0000-0003-3885-9104; http://lattes.cnpq.br/0022988322449627; Medeiros, Rodolfo Luiz Bezerra de Araújo; http://lattes.cnpq.br/7274621195761563; Costa, Tiago Roberto da; http://lattes.cnpq.br/2101911477495720; Oliveira, Ângelo Anderson Silva de; http://lattes.cnpq.br/2636344590780366In recent decades, the significant increase in energy consumption, driven by population growth and intensified industrial activity, has greatly expanded the demand for fossil fuels, contributing to the rise in greenhouse gas (GHG) emissions. Among the main contributors to this climate crisis are methane and carbon dioxide, with natural gas combustion being a relevant source of these emissions. In this context, strategies such as carbon capture and storage (CCS) and the transition to renewable energy sources have become essential. Dry reforming of methane (DRM) has gained growing interest for combining the mitigation of two GHGs with the production of strategic industrial feedstocks. The success of DRM depends heavily on the choice and performance of the catalyst. Nickel has emerged as a cost-effective alternative to noble metals, due to its lower cost and good catalytic activity. However, its susceptibility to sintering and carbon deposition limits its operational stability, requiring the development of supports that promote metal dispersion and provide greater thermal and structural resistance. In this scenario, graphene oxide (GO) and its thermally reduced form (TrGO) emerge as promising supports, due to their high specific surface area, excellent thermal and electrical conductivity, and ability to form strong interactions with metal particles. This study aims to investigate the performance of nickel catalysts supported on reduced GO (Ni-TrGO), assessing how crystal structure, surface morphology, metal dispersion, and nickel content influence catalytic activity during DRM. For this purpose, two distinct formulations (5% and 20% wt Ni) were synthesized and characterized using various analytical techniques, aiming to correlate physicochemical properties with CH₄ and CO₂ conversion parameters, H₂ and CO yield, and post-reaction thermal stability. The results demonstrate that metal–support interactions improve catalytic performance as nickel content increases, aiding in the identification of more effective catalyst formulations for applications in energy valorization processes with lower environmental impact.Master Thesis Solidificação direcional, microestrutura e dureza de ligas ZnSb(Universidade Federal do Rio Grande do Norte, 2025-05-30) Silva, João Raffael Dias da; Silva, Bismarck Luiz; http://lattes.cnpq.br/4377238190630005; http://lattes.cnpq.br/5479594063168612; Rodrigues, Adilson Vitor; https://orcid.org/0000-0003-2647-6384; http://lattes.cnpq.br/4214705590567511; Peres, Maurício Mhirdaui; https://orcid.org/0000-0002-4229-4145; http://lattes.cnpq.br/3068024292581677High-temperature soldering alloys (270 °C to 350 °C) are used in sectors such as the automotive, aerospace and energy industries and are in increasing demand due to their higher performance and smaller size. The alloys used in these applications are based on lead (Pb), a potentially harmful metal due to its toxicity levels. Thus, Zn-Sb alloys are emerging as potential candidates to replace lead-based alloys, due to their low cost, mechanical properties and transformation temperatures close to these applications. This work investigates the effect of antimony (Sb) on macrostructural and microstructural evolution, thermal parameters (cooling rate - Ṫ, growth rate for liquidus isotherm - VL and eutectic front - VE), macrosegregation, and hardness in binary Zn-1.0wt.%Sb, Zn-2.0wt.%Sb and Zn-4.0wt.%Sb alloys solidified directionally non-equilibrium. The samples have been characterized by Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD), as well as mechanical Vickers hardness (HV) tests. Thermodynamic calculations have been carried out using the CALPHAD method via the Thermo-calc software, in order to obtain information such as transformation temperatures, solidification paths, phases and their fractions. The increase in Sb content from 1% to 2% did not cause changes in the macrostructures, which had a completely columnar growth, while the Zn-4.0wt.%Sb alloy exhibited a macrostructure with equiaxed growth due to the grain refining effect of Sb. The microstructure of the Zn-1.0wt.%Sb and Zn-2.0wt.%Sb alloys is composed of Zn-rich dendrites surrounded by a eutectic mixture composed of Zn + Zn4Sb3 (the latter with a fiber morphology, with Zn4Sb3 plates appearing for Ṫ<2.80 °C/s and 2.25 °C/s, respectively). The Zn-4.0%Sb alloy exhibited a microstructure composed of a eutectic Zn + Zn4Sb3 mixture (with mostly fibrous intermetallics, forming plates for Ṫ<2.90 °C/s) with primary Zn4Sb3 particles of idiomorphic morphology, indicating a hypereutectic composition. Increasing the Sb content led to changes in the macrossegregation profiles, following the inverse, constant and normal sequence for the Zn-1.0wt.%Sb, Zn-2.0wt.%Sb and Zn-4.0wt.%Sb alloys, respectively. The increase from 1% to 2%Sb did not lead to changes in the scale of the dendritic arrangement, but with the 4%Sb content, there was a refinement of the eutectic fibrous spacing compared to the other two compositions, as well as a decrease in the liquidus and solidus temperatures. The increase in Sb content caused an increase in Vickers hardness, associated with the mechanisms of solid solution hardening, microstructural refinement (eutectic arrangement) and the largest fraction of the hardening Zn4Sb3 phase in the eutectic. The literature indicates divergent compositions of eutectic concentration for the Zn-Sb system (1wt.%Sb to 2wt.%Sb), and this work indicates the Zn-4.0wt.%Sb alloy as quasi-eutectic due to the microstructure found appearing to be hypereutectic in contrast to the eutectic concentration of 4.0wt.%Sb found in the thermodynamic simulations obtained via Thermo-Calc.Master Thesis Influência de tratamentos superficiais em heteroestruturas TiNb2O7/Ni81Fe19(Universidade Federal do Rio Grande do Norte, 2025-04-22) Dantas Neto, João de Medeiros; Corrêa, Márcio Assolin; https://orcid.org/0000-0002-8904-4151; http://lattes.cnpq.br/2531075321550052; https://orcid.org/0000-0002-3882-1571; http://lattes.cnpq.br/5314977327695071; Oliveira, Danniel Ferreira de; Araújo, João Carlos Rocha de; Acchar, WilsonOver the past decades, the global shift towards clean energy sources has intensified, driven by the urgent need to reduce carbon emissions and our reliance on fossil fuels. Within this context, energy storage systems are crucial, and lithium-ion batteries (LIBs) are emerging as one of the most promising technologies. However, conventional graphite anodes, widely used in these batteries, face significant limitations, which has driven the search for alternative materials. Titanium niobate (TNO) emerges as a viable candidate, as it can be synthesized relatively simply through a solid-state reaction between TiO₂ and Nb₂O₅. Despite its advantages, TNO presents challenges that need to be overcome. A promising approach is the combination of this material with nickel-iron (NiFe) alloys, along with techniques such as tape casting for controlling electrode morphology and porosity. Additionally, surface treatments can be applied to reduce roughness and uniformize the surface, facilitating the deposition of ferromagnetic materials via magnetron sputtering and improving adhesion between the substrate and thin film. This study investigates a TNO/NiFe heterostructure, produced by combining tape casting and magnetron sputtering, with the objective of evaluating its potential for LIB applications. The developed materials were characterized regarding their structural, morphological, electrical, dielectric, and magnetic properties. The results of these samples indicated a reduction in surface roughness by approximately 80%, leading to a decrease of about 90% in electrical resistance, which was reduced from 4.38 kΩ to 0.27 kΩ after polishing. The magnetic properties were also influenced, with a notable decrease in saturation and coercive fields, which was reduced from 13 Oe to 4 Oe as polishing was intensified. The results demonstrate the success of polishing in improving the electrical and magnetic properties of the heterostructure. The combination of tape casting with polishing proved to be an effective approach for producing TNO substrates with potential applications in batteries. The integration of LIB components with ferromagnetic layers aligns with recent research on the use of magnetic fields in ionic dynamics, driving the development of advanced battery technologies.Master Thesis Estudo da síntese e caracterização do niobato de cobre via método sol-gel a partir da preparação do precursor de nióbio(Universidade Federal do Rio Grande do Norte, 2025-02-20) Souza, Vitor Manoel Silva Fernandes de; Gomes, Uilame Umbelino; http://lattes.cnpq.br/9858094266525225; http://lattes.cnpq.br/1501536898400376; Lourenço, Cleber da Silva; Souto, Maria Veronilda Macêdo; Pergher, Sibele Berenice CastellaCopper niobate (CuNb₂O₆) has garnered increasing scientific interest due to its properties and technological applications, ranging from solar cells to microwave devices and infrared lasers. Considering the need to develop simpler and more cost-effective methodologies for its production, this study investigated the synthesis of CuNb₂O₆ using the protein-based sol-gel method, a wet chemical route that remains relatively unexplored for the formulation of this material. The production of the niobium precursor constitutes the central focus of this study, as it represents a fundamental step toward the efficient synthesis of copper niobate. This approach stands out as a sustainable alternative, starting with the preparation of the ammonium oxalate niobium precursor, obtained through fusion and complexation processes, along with the use of commercial copper nitrate. Both precursors exhibit high solubility in water, and gelatin was employed as a chelating and polymerizing agent, providing greater control over material formation. The resulting gels underwent controlled thermal treatments, being calcined in a muffle furnace at temperatures of 600 °C, 700 °C, 800 °C, 900 °C, and 1000 °C for three hours, with a heating rate of 5 °C/min. The samples were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray Spectroscopy (EDS), in addition to Thermogravimetric Analysis (TGA) for assessing the niobium oxalate. The results revealed that at 600 °C, CuNb₂O₆ was fully formed in the monoclinic phase, whereas increasing the temperature to 1000 °C favored predominant crystallization in the orthorhombic phase, highlighting the structural transition of the material. In addition to the effectiveness in producing copper niobate, the adopted methodology proved to be efficient in significantly reducing both the temperature and synthesis time for both crystalline structures. The obtained samples exhibited high purity, absence of contamination, and characteristic morphologies consistent with data reported in the literature, reinforcing the potential of this method as a promising alternative for CuNb₂O₆ synthesis.Master Thesis Síntese verde da zeólita ZSM-5 assistida por micro-ondas e aplicação na rota de pirólise catalítica do óleo de fritura e sebo bovino(Universidade Federal do Rio Grande do Norte, 2024-12-09) Caldas, Amanda Menezes; Melo, Dulce Maria de Araújo; https://orcid.org/0000-0001-9845-2360; http://lattes.cnpq.br/3318871716111536; http://lattes.cnpq.br/3615366618228937; Gondim, Amanda Duarte; Araújo, Aruzza Mabel de Morais; Carvalho, Fabíola Correia deCatalysis plays a fundamental role in the current energy transition, enabling efficient biomass conversion. Zeolitic materials are among the heterogeneous catalysts widely explored in the industry, including petrochemicals, due to their high activity, selectivity, and thermal stability. In this class, zeolite ZSM-5 stands out, which has a porous structure, which gives it the characteristics of a molecular sieve, capable of selectively adsorbing molecules. The hydrothermal process is the most commonly used for the synthesis of this catalyst, where crystallization times of up to 72 hours are reported, in addition to the use of organic template and/or seeds to obtain the crystalline structure. Based on this, this work explored an innovative method without organic template and no seedless, assisted by microwaves, to obtain zeolite ZSM-5. The method allowed the formation of the crystalline structure in a period of up to 10 hours, depending on the conditions, and proved to be an efficient alternative by providing savings in time, reagents, energy, and total costs. The applicability of the catalyst was explored for the thermal conversion of residual biomass from frying oil (OF) and beef tallow (SB) from the catalytic pyrolysis process, in their protonated (HZSM-5) and nickel-impregnated (Ni/HZSM-5) forms. The samples were characterized, enabling confirmation of the formation of the stable orthorhombic structure and structural preservation. The OFW and KAS kinetic studies were proposed, which demonstrated the decrease in activation energies (Ea), provided by the catalysts. The results obtained from the catalytic pyrolysis tests confirmed the performance of the catalysts for the cracking of hydrocarbons, and selectivity for C10 to C14 fractions, with profiles that favor the production of biokerosene. The deoxygenation promoted by the catalysts was higher with Ni/HZSM-5, where oxygenated percentages of 7.8% were obtained for the frying oil and 1.3% for the beef tallow, demonstrating the influence of bifunctionality due to the addition of the metal. Pyrolysis-coupled chromatography analyses demonstrated a reduction in oxygenated products in the catalyzed processes, and the aromatization effect, especially for the frying oil biomass due to the unsaturations present in its chemical structure. Thus, the work is presented in order to contribute to sustainable development through two aspects: through the promising sustainable method of synthesis of the ZSM-5 zeolite, and through the waste stream.Master Thesis Investigação de diferentes organossilanos na funcionalização e grau de dispersão do óxido de grafeno reduzido (rGO) em nanocompósitos poliméricos(Universidade Federal do Rio Grande do Norte, 2025-01-31) Santos, Ana Letícia Fernandes dos; Nascimento, Maria Carolina Burgos Costa do; https://orcid.org/0000-0002-4261-1331; http://lattes.cnpq.br/4409025248163428; https://orcid.org/0000-0001-8592-4736; http://lattes.cnpq.br/2657989493886536; Delmonte, Mauricio Roberto Bomio; https://orcid.org/0000-0001-9016-4217; http://lattes.cnpq.br/9558299312183852; Santos, Amelia Severino Ferreira e; https://orcid.org/0000-0002-7655-120X; http://lattes.cnpq.br/5119417295487126Graphene is gaining more and more attention due to its unique properties, and is increasingly being applied in various sectors, including its application as a nanofiller in polymeric matrices. However, this nanomaterial finds challenges in this application due to factors that contribute to low dispersion in the matrix and, consequently, lower than desired properties. Thus, chemical modification of its surface can be a key alternative for enhancing different applications. This work aims to evaluate the degree of dispersion of reduced graphene oxide (rGO) functionalized with different organosilanes in an epoxy matrix. To this end, graphene oxide (GO) was first synthesized in the laboratory, functionalized with 3-aminopropyltriethoxysilane (APTES), 3- aminopropyltrimethoxysilane (APTMS), 3-glycidoxypropyltrimethoxysilane (GPTMS) and triethoxymethylsilane (MTES), and then thermally reduced to produce functionalized reduced graphene oxides. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman spectroscopy, thermogravimetry (TGA), solvent dispersion stability and scanning electron microscopy (SEM) analyses were carried out to prove the success of the synthesis of these materials and to help evaluate the functionalization efficiency. The results obtained confirmed the success of covalent functionalization with all the silanes used on the surface of GO, as well as the permanence of their molecules in the basal plane of reduced graphene oxide (rGO) carbons. To check the degree of dispersion in the polymer matrix, polymer nanocomposites were prepared with 0.5% by mass of each functionalized rGO. Analysis of the fracture surfaces of these materials by SEM showed that better distribution, dispersion and interfacial bonding were obtained for nanocomposites containing functionalized rGO rather than pure rGO. It was possible to observe that the dispersion of the nanoparticles improved for the nanocomposites containing rGO functionalized with the different organosilanes, and the most satisfactory results were obtained for the nanocomposites containing rGO/APTES.Master Thesis Microestrutura e propriedades dos compósitos WC-10%CrMnFeCoNi preparados por moagem de alta energia e sinterização SPS(Universidade Federal do Rio Grande do Norte, 2024-12-30) Vieira, Pâmala Samara; Mashhadikarimi, Meysam; Silva, Bismarck Luiz; http://lattes.cnpq.br/4377238190630005; http://lattes.cnpq.br/9422624675887080; https://orcid.org/0009-0009-6365-2691; http://lattes.cnpq.br/9791896377375104; Gomes, Uilame Umbelino; Filgueira, MarcelloMetal alloys traditionally have one main matrix, with additions of secondary elements to improve their properties. However, high entropy alloys (HAE) challenge this paradigm by using multiple main elements, creating a simple solid solution, which results in excellent characteristics and properties. Research has explored the potential of high entropy alloys as substitutes for the cobalt (Co) ligand in tungsten carbide (WC) carbide. With this in mind, the aim of this work was to study the high entropy alloy (CrMnFeCoNi) and its use as a substitute for the conventional binder in hard metal obtained by high-energy milling (HEM) and sintering via SPS. The analyses were carried out using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD). The mechanical properties were assessed using Vickers hardness. HEM, carried out for 10, 20 and 30 hours, proved to be effective in forming HAE, promoting deformation, fractures and cold welding of the particles. After 30 hours of milling, the FCC phase of the alloy was predominant, with amorphization of the secondary phases. In the WC-10%CrMnFeCoNi composite, HEM influenced the morphology and size of the particles, resulting in good dispersion of the phases and high incorporation of the alloy into the WC particles, even after only 10 minutes of mixing. XRD analysis revealed the WC and HAE phases, with no indication of chemical reactions or impurities. Sintering resulted in almost uniform microstructures, with good dispersion of the WC particles in the binder matrix and low porosity. The composite with HAE milled for 30 hours showed better homogenization and dispersion of the phases, which favoured sintering and reduced porosity compared to the other samples. EDS analysis confirmed these results. The hardness values of the samples varied, with 1786.9 HV1 (10 hours), 1643 HV1 (20 hours) and 1864 HV1 (30 hours). The best result was observed for the composite produced with HAE ground for 30 hours, as it showed greater homogenization and less porosity, resulting in an increase in hardness.Master Thesis Desenvolvimento de novos materiais a base de zeólita, mordenita e hidróxidos duplos lamelares para adsorção de CO2(Universidade Federal do Rio Grande do Norte, 2024-07-01) Silva, Geneyse Grazielle Cruz Monteiro da; Pergher, Sibele Berenice Castella; http://lattes.cnpq.br/5249001430287414; http://lattes.cnpq.br/3965793229969775; Nascimento, Rubens Maribondo do; https://orcid.org/0000-0001-9094-0044; http://lattes.cnpq.br/8671649752936793; Bieseki, Lindiane; Penha, Fábio GarciaResearch and development of new materials are fundamental to face contemporary technological and environmental challenges. In this dissertation, the development of new materials based on zeolite, Mordenite and Lamellar Double Hydroxides (HDL) was explored. These materials are recognized for their unique properties and potential in diverse applications, from catalysis to ion storage. Using a multidisciplinary approach, synthesis methods, characterization and potential applications of these materials were investigated. The synthesis was carried out using methodologies used in previous studies. Characterization encompassed a wide range of analytical techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and particle size analysis (PSA). The results obtained from the characterization techniques revealed materials with well-defined structures, controlled morphologies and specific properties, demonstrating their potential in various technological applications. Regarding CO2 adsorption analysis, the materials demonstrated potential for application in the area. This dissertation contributes to the advancement of scientific and technological knowledge in the area of materials, offering new perspectives for the development of more efficient and sustainable technologies.Master Thesis Obtenção de compósito híbrido PEAD/mAlgas/MMT-Ag/PE-g-MAH(Universidade Federal do Rio Grande do Norte, 2024-03-08) Lamas, Bruna Luz Carreras; Ito, Edson Noriyuki; https://orcid.org/0000-0001-7784-9035; http://lattes.cnpq.br/7249500407405478; http://lattes.cnpq.br/3708679379618398; Viana, Graco Aurélio Câmara de Melo; Gomes, Felipe Pedro da CostaPolymeric hybrid composites are formed by several phases of different compositions, in which the interfacial interaction between these materials is one of the factors that determine the final properties. The study of interfacial modifications is extremely important for the development of a material with technical quality for industrial application. The objective of this work was to obtain hybrid composites with a highdensity polyethylene (HDPE) matrix, varying the compositions and concentrations of fillers types, namely, microalgae (mAlgas), organophilic montmorillonite clay (MMT), montmorillonite clay treated with nanoparticles silver (MMT-Ag) and the use of polyethylene grafted with maleic anhydride (PE-g-MAH), as an interfacial compatibilization agent, aiming to study interfacial interactions correlated with the mechanical and rheological properties of polymer hybrid composites. Bulk formulations were varied from 2 and 4 wt% mAlgas, 2 and 4 wt% MMT, 3 wt% MMTAg and 3 wt% PE-g-MAH. The mixtures were compounded in a twin-screw extruder and test specimens were produced by injection molding. The characterizations of the fillers were carried out by measurements of fluidity index (MFI), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) and the characterizations of the compound formulations were MFI, XRD , XRF, SEM, EDS, uniaxial traction and Shore D hardness. The results showed that mAlgas contribute to an increase in fluidity, while MMT decreases fluidity during processing in the melt state. Hybrid composites using PE-g-MAH showed lower fluidity, whereas HDPE/MMT/PE-g-MAH composites showed lower fluidity, that is, the results showed the reactive interaction of maleic anhydride with mAlgas and MMT. The mechanical characterizations evaluated the influence of shape, types of fillers and interfacial interaction on the properties of HDPE/mAlgas/MMT-Ag/PE-g-MAH hybrid composites, elucidating the interactions between the components of this complex system of mixtures.Master Thesis Obtenção do carbeto de alta entropia (TiVTaNbW)C via moagem de alta energia(Universidade Federal do Rio Grande do Norte, 2024-11-07) Marques, Anderson Costa; Mashhadikarimi, Meysam; Nascimento, Rubens Maribondo do; https://orcid.org/0000-0001-9094-0044; http://lattes.cnpq.br/8671649752936793; http://lattes.cnpq.br/9422624675887080; https://orcid.org/0000-0002-8846-658X; http://lattes.cnpq.br/4372440881887239; Paskocimas, Carlos Alberto; Filgueira, Marcello; Gomes, Uilame UmbelinoHigh-entropy alloy-based ceramic carbides represent a new class of materials that has garnered significant interest within the scientific community and industries such as aerospace, thermal spray coatings, high-temperature molds and dies, cutting tools, and radiation-resistant shields. Various carbide compositions are produced using different processing methods. This study aims to obtain equimolar High-Entropy Carbide (HEC), (TiVTaNbW)C, by High-Energy Ball Milling (HEBM), using metallic precursor powders. HEBM occurs in two stages: the first involves the formation of the high-entropy alloy (TiVTaNbW), with milling cycles of 6, 12, and 18 hours; the second focuses on obtaining the HEC, analyzed at 6 and 12 hours, both at 500 RPM. The carbide’s properties were analyzed using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Spark Plasma Sintering (SPS), Vickers Hardness, Confocal Microscopy, and Pin-on-Disk tribological tests. XRD revealed characteristic carbide peaks, while SEM showed carbide regions and the surface element distribution. FTIR indicated typical metal-carbon bonding bands, and SPS improved the material’s properties, reaching a Vickers hardness of 16.24 ± 2.01 GPa and a KIC value of 6.83 ± 0.73 MPa√m, as obtained by confocal analysis. The Pin-on-Disk test recorded a wear rate of 285.17 μm and a friction coefficient of 0.46. The results confirm that obtaining (TiVTaNbW)C via High-Energy Ball Milling is a promising process with potential applications in industries requiring high wear resistance, corrosion resistance, high hardness, thermal stability, and fracture toughness.Master Thesis Síntese de nanoplaquetas de óxido de grafeno reduzido (rGO) por diferentes rotas para aplicação em tintas condutoras(Universidade Federal do Rio Grande do Norte, 2024-10-14) Paula, Ygor Matheus Pereira de; Nascimento, Maria Carolina Burgos Costa do; https://orcid.org/0000-0002-4261-1331; http://lattes.cnpq.br/4409025248163428; http://lattes.cnpq.br/1914368867081510; Leite, Amanda Melissa Damião; Silva, Kesia Karina de Oliveira Souto; Fangueiro, RaulGraphene, a two-dimensional material with excellent properties, is one of the allotropic forms of carbon. Graphite, the precursor that gives rise to graphene, is made up of several layers of hexagonally bonded carbons, each of which characterizes a graphene sheet. Separating these layers would ensure that graphene is obtained and, to this end, chemical exfoliation followed by reduction has emerged as a large-scale synthesis method. Obtaining graphene oxide (GO) involves inserting oxygenated functional groups between the graphite chains, and its reduction partially removes these groups, making it possible to improve its properties. Reduced graphene oxide (rGO), the product of the reduction of the material, has properties similar to graphene and, among them, high electrical conductivity. The excellent properties of graphene guarantee this material and its derivatives wide applicability, especially in the field of electronic equipment and in the production of conductive inks. The main difficulty for this application is related to the difficulty of producing these materials on a large scale and with a morphology that favors their electrical properties. Another difficulty lies in choosing the ideal formulation for a possible conductive ink, evaluating aspects such as the quality of the dispersion of the material in the chosen base, the properties obtained and the related cost-benefit ratio. In this work, the synthesis of GO and nanoplatelets of rGO was addressed, and two reduction methods were chosen, thermal reduction and chemical reduction using ascorbic acid as a reducing agent. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy analyses were carried out, confirming the quality of the materials synthesized using different routes. Satisfactory results were obtained by evaluating the hydrophilic behavior, the adhesion of the different ink compositions to the substrate, and the electrical conductivity analyses of the inks produced with GO and nanoplatelets of rGO.Master Thesis Estudo do efeito do teor de diferentes reforços (WC E NbC) e da moagem de alta energia nas propriedades mecânicas e elétricas dos compósitos com matriz metálica de cobre(Universidade Federal do Rio Grande do Norte, 2024-09-18) Silva, Thalita Queiroz e; Mashhadikarimi, Meysam; Gomes, Uilame Umbelino; http://lattes.cnpq.br/9858094266525225; http://lattes.cnpq.br/9422624675887080; http://lattes.cnpq.br/5763433926920164; Paskocimas, Carlos Alberto; Filgueira, MarcelloComposites designed with a copper matrix reinforced with ceramic and refractory materials are promising for use as electrical conductors due to their combination of excellent thermal and electrical properties, and the high mechanical resistance to wear. Several researchers have explored the addition of different reinforcements in manufacturing composites to enhance these properties. This study aimed to investigate the applicability of two types of reinforcements (WC and NbC) in copper metal matrix composites fabricated using powder metallurgy and Spark Plasma Sintering (SPS) in electrical contact application. The study evaluated variables such as composition (type of reinforcement and concentrations of 5% and 20% by mass) and processing (with milling times of 5, 10, and 20 hours). Analyses were conducted using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Fluorescence (XRF), and X-ray Diffraction (XRD) with Rietveld refinement. Mechanical properties were assessed through Vickers microhardness testing. The microscopy analysis of the composite powders revealed that the Cu particles were severely deformed, forming plates, while the ceramic particles (WC and NbC) were fragmented and incorporated into the Cu phase due to high-energy milling. XRD analysis showed characteristic peaks of the composites, with increased Full Width at Half Maximum (FWHM) values, reduced crystallite sizes, and increased microdeformation of the phases. XRF analysis indicated potential contamination of the composite powders due to the milling conditions. The microstructural analysis indicates increased composite porosity as the reinforcement content and milling time increase. A significant increase in average Vickers microhardness values was noted for nearly all the composites compared to pure Cu. Notably, the composite with 20% by mass of NbC, milled for 20 hours, exhibited the highest microhardness, with 189.7 HV on the surface and 178.4 HV in the cross-section, surpassing the values of the other composites. The electrical conductivity of the composites obtained decreases mainly with the increase in the addition of carbides.Master Thesis Optimização da degradação fotocatalítica do levofloxacino através da heteroestrutura de Bi2WO6/CuO(Universidade Federal do Rio Grande do Norte, 2024-07-31) Wilson, Rebecca Roberta Ysraelle Oliveira Verde; Motta, Fabiana Villela da; Delmonte, Mauricio Roberto Bomio; https://orcid.org/0000-0002-3523-737X; http://lattes.cnpq.br/9918299069511517; http://lattes.cnpq.br/5053372623203630; Bohn, Felipe; Lovisa, Laura XimenaThe improper disposal of pharmaceutical waste containing antibiotics contaminates aquatic systems, promoting the emergence of antibiotic-resistant superbugs. Heterogeneous photocatalysis (HP) and binary heterostructures emerge as promising strategies to efficiently degrade these contaminants. In this study, a CuO nanosheets structure was decorated with Bi2WO6 nanoflower to form Bi2WO6/CuO n-p heterostructures through a simple two-step process using a microwave-assisted hydrothermal approach (MWHA). The synthesized photocatalysts were evaluated through the degradation of the antibiotic levofloxacin as the target pollutant under solar irradiation. The optical properties and structural morphology of the BWO/CuO photocatalysts were demonstrated. The XRD and FT-IR results corroborate, indicating the crystallinity and purity of the samples obtained by MWHA. The X-ray diffractograms showed the presence of crystalline phases of orthorhombic β-Bi2WO6 and monoclinic β-CuO, with no secondary phases. The FEG-SEM images of the heterostructures revealed a morphology resembling a three-dimensional flower with aggregated nanosheets, which are derived from the pure samples. BET analyses indicated that the BW/Cu-10 sample has the largest surface area among the heterostructures, which explains its superior photocatalytic performance. The degradation of levofloxacin by BW/Cu-10 achieved 95% efficiency in 120 minutes. The enhanced photocatalytic abilities of the BWO/CuO heterostructures were attributed to the construction of an np heterojunction, effective charge separation according to the n-p type mechanism, and prolonged carrier lifetime, which efficiently suppressed the recombination of photoinduced electron/hole pairs. The obtained BWO/CuO heterostructures were stable over four consecutive cycles with almost constant degradation capacity. Therefore, due to their promising photocatalytic abilities, BWO/CuO are suitable photocatalysts for environmental treatment applications.Master Thesis Avaliação do desempenho anticorrosivo de revestimentos de epóxi contendo microcápsulas poliméricas de poli(ureiaformaldeído) (PUF) preenchidas com 5-etilideno-2-norboneno (ENB)(Universidade Federal do Rio Grande do Norte, 2024-05-17) Moreira, Vandicleya Alves; Nascimento, Maria Carolina Burgos Costa do; Castro, Nicolau Apoena; http://lattes.cnpq.br/3740711945494961; https://orcid.org/0000-0002-4261-1331; http://lattes.cnpq.br/4409025248163428; https://orcid.org/0009-0009-1395-4253; http://lattes.cnpq.br/2826911178541780; Schiavon, Maria Ingrid Rocha BarbosaCorrosion of metals is one of the main challenges faced by the industry, which can cause serious structural failures and great economic losses. One of the most commonly used corrosion prevention methods is anticorrosive coatings, which can be inorganic, organic or hybrid. Organic coatings have advantages such as easy application and good cost-benefit, however, these coatings are susceptible to damage caused by mechanical or environmental factors, which can compromise barrier protection against corrosion. To overcome this problem, anticorrosive coatings containing self-healing materials, such as polymeric microcapsules, have been developed in recent years. In this work, poly(urea-formaldehyde) (PUF) microcapsules filled with 5-ethylidene-2-norbonene (ENB) previously synthesized by in situ polymerization, in 11 synthesis conditions resulting from a complete factorial design, were applied in coatings to epoxy base for evaluating anticorrosive efficiency on metallic substrates. The coatings containing the microcapsules were applied to steel substrates, previously cleaned and prepared, using the dip coating method. The anticorrosive properties of the coatings and the performance of the microcapsules were evaluated using a corrosion test by immersion in a saline solution, after simulating damage through scratches. The results of the corrosion test showed better performance for the coatings containing the microcapsules obtained under the PUF/ENB 1 and PUF/ENB 9 synthesis conditions. Analyzes by stereoscopy and optical microscopy showed good dispersion of these microcapsules in the scratch regions, which contributed to the best performance of coatings. Scanning electron microscopy analyzes showed greater details of the interface between coating and metallic substrate and reinforced what had been observed in the corrosion test results.Master Thesis Avaliação microestrutural e mecânica de pastas de cimento contendo cinza da casca do arroz e silica flour para poços geotérmicos(Universidade Federal do Rio Grande do Norte, 2024-01-15) Lins, Eduardo Jorge da Cunha; Martinelli, Antônio Eduardo; https://orcid.org/0000-0003-3885-9104; http://lattes.cnpq.br/0022988322449627; http://lattes.cnpq.br/8581862005616589; Freitas, Júlio Cézar de Oliveira; Santiago, Rodrigo César; Costa, Bruno Leonardo de SenaThe cementing process is a fundamental stage in the construction of a geothermal well. Its importance ranges from factors such as mechanical stability, such as the support of liners and rock formations, to the hydraulic isolation of the different drilled intervals, restricting the movement of fluids between the formations. Among the materials most commonly used in geothermal wells are blends containing Portland cement and silica flour. This mixture is used to control retrogression, a process which consists of reducing the compressive strength of cement pastes when subjected to high temperatures, common in geothermal wells, which can easily reach 300 °C. Rice husk ash (RHA) is a sustainable source of silica that has been widely applied as a partial replacement for cement as an alternative to crystalline silica. The aim of this work was to develop cement blends with varying proportions of silica flour and RHA for use in geothermal wells. The pastes were subjected to 300 °C and 2000 psi for 7, 14 and 28 days. After this period, compressive strength tests and physical-chemical characterizations were carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Increasing the concentration of RHA in the blends increased the mechanical strength by up to 4X when compared to the reference paste (water and cement only), as well as proving to be mechanically superior when compared to blends containing only silica flour, showing that the interaction between silica flour and CCA produces promising results in the geothermal well scenario. It was also noted that this interaction formed a denser microstructure in addition to maintaining the microstructures characteristic of cementitious materials subjected to high temperatures, which may explain why there was an increase in compressive strength in the blends containing CCA in their composition. Based on the above, blends containing CCA and Silica Flour are a sustainable alternative for application in geothermal well scenarios.Master Thesis Análise da produção de scaffolds porosos por impressão 3D(Universidade Federal do Rio Grande do Norte, 2023-08-18) Bezerra, Isaac de Santana; Ito, Edson Noriyuki; https://orcid.org/0000-0001-7784-9035; http://lattes.cnpq.br/7249500407405478; https://orcid.org/0000-0002-9542-6017; http://lattes.cnpq.br/3484566484081519; Vilar, Caroline Dantas; http://lattes.cnpq.br/7861700022912054; Silva, Erik dos Santos; Gomes, Felipe Pedro da CostaThis work analyzed the feasibility of producing porous scaffolds by 3D printing (3DP) via melt-deposition modeling (FDM) of Poly(lactic acid) (PLA) with azodicarbonamide (AZDN) blowing agent. A selection of the polymer matrix was carried out based on mechanical, rheological and morphological tests, comparing Poly(acrylonitrile-co-butadiene-co-styrene) (ABS), Poly(ethylene terephthalate) bottle grade (PETG) and PLA, both by means of injection molding, as well as by IMP3D, using nozzles with diameters of 0.3; 0.4; 0.5; 0.6; 0.8; 1.0. After weighing the productive efficiency, the processability, and the mechanical results obtained, 3DP and PLA were selected as the most suitable technique and material for the production of porous scaffolds. Subsequently, the PLA was subjected to a closed cycle of five consecutive processes in a twin screw extruder, verifying by the visual and rheological changes, that the material maintained good rheological properties after the thermal cycles. The PLA was mixed with the expanding agent azodicarbonamide (AZDN) in a twin-screw extruder, and plasticized in a singlescrew extruder, obtaining PLA filaments with inert AZDN, for subsequent printing of porous scaffolds, in proportions in percentages per hundred resin of: 100/0; 100/2; 100/4; 100/6; 100/8. The rheological, morphological and uniaxial traction characterizations of the developed materials were carried out, noting the increase in PLA viscosity when subjected to more thermal cycles. The morphologies pointed to a greater emergence of pores for the compositions with higher concentration of AZDN, so that the larger pores were preferentially present in the central regions of the filaments, in addition to showing that the temperature control influences the size of the pores obtained, reaching biodegradable and biocompatible porous structures.