Engenharia de Materiais (UACSA)
URI permanente desta comunidadehttps://arandu.ufrpe.br/handle/123456789/2913
Siglas das Coleções:
APP - Artigo Publicado em Periódico
TAE - Trabalho Apresentado em Evento
TCC - Trabalho de Conclusão de Curso
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3 resultados
Resultados da Pesquisa
Item Gesso de revestimento destinado à construção civil reforçado com nanopartículas de óxido de grafeno: análise da resistência mecânica(2024-03-01) Firmino, Daniel Ardiles; Ghislandi, Marcos Gomes; http://lattes.cnpq.br/3409757365313853; http://lattes.cnpq.br/3378137503705619Plaster is a widely used material in civil construction, employed for both structures and general coatings. Graphene Oxide, known for reinforcing structures and being utilized as a reinforcement in civil engineering, is expected to provide additional strength to the structure when incorporated into plaster. This study focused on reinforcing plaster coating with graphene oxide at a concentration of 0.01% by mass, aiming to optimize mass and examine its mechanical properties. A comparison was made between samples with and without oxide addition. The graphene oxide was obtained through the modified Hummers method. Two characterization techniques, X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), were employed for morphological and structural analysis. Sample preparation adhered to parameters outlined in the NBR 12128 (ABNT, 2019) and NBR 12129 (ABNT, 2017) standards. The results revealed that plaster with added graphene oxide exhibited a reduction of over half in compressive strength compared to plaster without the additional load. SEM images highlighted the accumulation of graphene oxide in specific regions of the plaster, potentially contributing to this decrease in strength.Item Nanocompósitos de PVA reticulado /óxido de grafeno para fabricação de membranas dessalinizadoras(2023-09-15) Melo, Niraldo Mateus Medeiros; Ghislandi, Marcos Gomes; http://lattes.cnpq.br/3409757365313853; http://lattes.cnpq.br/2987470779254166The scarcity of drinking water is a growing concern; the limited availability of freshwater and increased demand due to population growth, urbanization and industrial activities have exacerbated this problem. This study investigates the use of graphite to synthesize low-cost graphene oxide (GO) and modify commercial membranes by polymeric crosslinking with Polyvinyl Alcohol (PVA)/Citric Acid (CA), aiming to improve its properties for retaining salts from brackish water. The samples were characterized by optical analysis and mechanical stability tests, X-ray diffractometry (XRD), and differential scanning calorimetry (DSC), to investigate changes in the physicochemical, thermal, and microstructural properties of the modified membranes. Characterization via DSC confirms the polymeric crosslinking in membranes modified with PVA in relation to pure polyamide (PA) membranes, and characterization by XRD indicates traces of crystallization due to the PVA-AC interaction. The filtration results obtained showed that polyamide membranes crosslinked with 0.75 mg of OG (PA0.75/RET) obtained better efficiency in the salt retention test (54.77±2.68%) and permeate flux (1.42±0.28 L/m². h. bar) using magnesium sulfate solution. This study confirms the importance of polymeric cross-linking in OG-modified membranes for mechanical stability and salt retention efficiency.Item Síntese de nanomateriais de grafeno para utilização em nanocompósitos poliméricos(2019-07-11) Nogueira, Nathália Maria Barbosa; Ghislandi, Marcos Gomes; http://lattes.cnpq.br/3409757365313853; http://lattes.cnpq.br/3264027755950807Because of its unprecedented physical and chemical properties, graphene has attracted the attention of researchers searching to produce composite materials with unique properties. In this way, it has been studied the incorporation of graphene oxide loads into polymers and analyzed their influence on the mechanical, electrical and thermal behavior of the resulting composites. In this work, we present the preparation and the influence of the incorporation of graphene oxide (GO) on polyvinyl alcohol (PVOH). The mechanical reinforcement, by the incorporation of 0.5 wt%, 0.1 wt% and 1 wt% of graphene oxide into the polymer matrix, was estimated. The strategy involved the production of graphite oxide from graphite, using the modified Hummers method. The method was carried out by the addition of sulfuric acid (H2SO4), potassium permanganate (KMnO4) and hydrogen peroxide (H2O2), followed by the exfoliation of graphite oxide into sheets of graphene oxide by the use of ultrasound, and finally the preparation of the GO / PVOH nanocomposites by a simple solution mixing method. The synthesized materials were characterized by X-ray diffraction, Raman spectroscopy, and gravimetry. The analysis of the GO / PVOH films were carried out via tensile and UV-vis tests. Gravimetry showed that the solution of graphite oxide synthesized had a homogeneous concentration. X-ray diffraction (XRD) showed that the oxidative process of graphite precursor into graphite oxide was efficient. The stress-strain analysis confirmed the increase in mechanical strength of the polymeric film with the incorporation of graphene oxide load, while for the strain it was not possible to obtain conclusive data. The optical analysis showed a whitening of the film during the tensile test, indicating an alignment of the polymer chains and crystallization of the films. The UV-vis spectra showed that the pure PVOH film exhibited a high transparency, however, for the films with 0.1wt%, 0.5wt% and 1.0wt% GO this transparency decreased considerably.