Síntese de microcápsulas de poli (uréia - formaldeído) (puf) preenchidas com diciclopentadieno (dcpd) para aplicação em sistemas de autorreparo de matriz polimérica
Materials with self-repair mechanisms have the ability to repair themselves when damaged, recovering their properties and guaranteeing the structural integrity of the material, , with potential use in applications such as aeronautical structures. The repair is achieved by introducing a microencapsul...
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| Formato: | bachelorThesis |
| Idioma: | pt_BR |
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Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/handle/123456789/40389 |
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| Resumo: | Materials with self-repair mechanisms have the ability to repair themselves when damaged, recovering their properties and guaranteeing the structural integrity of the material, , with potential use in applications such as aeronautical structures. The repair is achieved by introducing a microencapsulated agent in contact with a catalyst in a polymeric matrix. In this work, it was used a system composed by poly(urea-formaldehyde) (PUF) microcapsules (PUF) as the coating material, and dicyclopentadiene (DCPD) as the core material, which was incorporated in an epoxy matrix containing the dispersed Grubbs catalyst. As the microcapsules are broken, when hit by microcracks, the DCPD is released and reacts with the Grubbs catalyst forming poly (DCPD) in the crack plane, based on polymerization by ring opening metathesis (ROMP), thus restoring the integrity of the material. The purpose of this study is to synthesize microcapsules of poly(urea-formaldehyde) (PUF) filled with DCPD as a healing agent. The synthesized microcapsules were analyzed by Fourier transform infrared spectroscopy (FTIR), the morphology and size of the microcapsules were evaluated using scanning electron microscopy (SEM), and the thermal characterization was performed using thermogravimetric analysis (TGA). Epoxy samples with microcapsules were produced and the self-repair mechanism was evaluated by optical microscopy (OM). The experimental results show that spherical microcapsules with a rough surface were obtained with an average diameter of 46 μm. An 82% yield was achieved with an encapsulation rate of 90% by weight. The microcapsules were stable until 200 ° C. There are signs of self-repair verified by the partial closure of the crack in an epoxy sample. |
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