Visualização microscópica da dinâmica de reação do poli (etileno-co-ácido-metacrílico) (EMAA) sinterizado sobre resina epóxi
The addition of thermoplastics to the thermosetting matrix of composites as an intrinsic self-healing agent aims to reduce maintenance costs and extend the durability of the material overcoming limitations such as mechanical failures and defects arising mainly from the appearance of microcracks d...
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| Formato: | bachelorThesis |
| Idioma: | pt_BR |
| Publicado em: |
Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/handle/123456789/40348 |
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| Resumo: | The addition of thermoplastics to the thermosetting matrix of composites as an
intrinsic self-healing agent aims to reduce maintenance costs and extend the
durability of the material overcoming limitations such as mechanical failures and
defects arising mainly from the appearance of microcracks during service. One of the
limiting challenges for using this mechanism is the lack of knowledge about the
efficiency of external stimuli and the detailing of intermolecular interactions that occur
internally. In this work, a visualization technique with optical microscopy of hot stage
was utilized to analyze the interactions that occur between the thermoplastic poly
(ethylene-co-methacrylic acid) (EMAA) and the epoxy resin, focusing on the
investigation of the appearance of bubbles. Analyzes of heating of EMMA powder on
the epoxy and glass substrate were performed, for temperatures of 130, 150, and
180 °C and EMAA particle sizes of 125 and 355 µm. The data obtained from
microscopic images resulted in higher amounts of bubbles for the experiments using
the smallest EMAA particle size. The larger grain size of this thermoplastic, 355 µm,
contributed to the formation of larger size bubbles. The sintering temperature
changes the size of the bubbles although and influence in the growth and decay
rates of bubbles number. The comparison between the two utilized substrates proves
the formation of water bubbles providing from condensation reactions when the
EMAA was sintered on the epoxy resin since it was evident the large increase in total
bubbles number at the end of the process when compared to the decay of this
number in the sintering done on the glass substrate. The results obtained from this
study evidence the reaction dynamics and the bubble formation mechanism, which
can be utilized as a tool for planning optimized conditions for repair cycles. |
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