Melo, José Daniel DinizMoura Filho, Carlos Gomes de2022-03-082021-11-19MOURA FILHO, Carlos Gomes de. Mecanismo de autorreparo assistido por pressão para epóxi contendo partículas de poli (etileno-co-ácido-metacrílico) (EMAA). 2021. 83f. Dissertação (Mestrado em Ciência e Engenharia de Materiais) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2021.https://repositorio.ufrn.br/handle/123456789/46453Materials with self-healing capability offer great potential to improve life and long-term reliability in many applications. Poly (ethylene-co-methacrylic acid) (EMAA) has been studied as repair agent for thermosetting polymers and the formation of bubbles has been described as a pressure delivery mechanism to push the molten thermoplastic into the crack plane, thus promoting healing. This study investigates the effects of temperature, time, and particle size of EMMA particles as parameters related to the self-healing mechanism. EMMA particle sizes larger than 355 µm and between 125 µm and 355 µm and temperatures of 130 °C, 155 °C, and 180 °C were considered. Thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC) were performed to investigate thermal properties and material degradation. Melt Flow Rate (MFR) tests were also performed on EMAA. Hot stage microscopy was used to investigate the dynamics of bubble formation resulting from condensation reactions between EMAA and epoxy. The results were compared with those observed using EMAA on a glass substrate. Thermal analysis showed no degradation of EMAA and epoxy at the temperatures considered for the healing process. The results indicate that the number of bubbles increased with time, irrespective of temperature and particle size for EMAA on epoxy or glass substrate. Then, the number of bubbles decreased with time for EMAA on the glass substrate, regardless of temperature and particle size. The collapse of bubbles was not observed in epoxy substrate for the processing times evaluated. Ultimately, the results suggest that self-healing cycles using smaller particles at a temperature of 180 °C and processing times enough to consume reactional functional groups available are parameters that may favor the pressure delivery mechanism with a subsequent collapse of bubbles.Acesso EmbargadoAutorreparo intrínsecoCiclos alternativosResinas epóxiAgente de cura imiscívelTermoplásticomasterThesis