Resumo

PEREIRA, Ayrton Alef Castanheira  e  D’ALMEIDA, José Roberto Moraes. Effect of the hardener to epoxy monomer ratio on the water absorption behavior of the DGEBA/TETA epoxy system. Polímeros [online]. 2016, vol.26, n.1, pp.30-37.  Epub 04-Mar-2016. ISSN 1678-5169.  http://dx.doi.org/10.1590/0104-1428.2106.

The water absorption behavior of the DGEBA/TETA epoxy system was evaluated as a function of the epoxy monomer to amine hardener ratio. Weight gain versus immersion time curves were obtained and the experimental points were fitted using Fickian and Non-Fickian diffusion models. The results obtained showed that for all epoxy monomer to hardener ratios analyzed water diffusion followed non-Fickian behavior. It was possible to correlate the water absorption behavior to the macromolecular structure developed when the epoxy/ hardener ratio was varied. All epoxy/hardener ratios present a two-phase macromolecular structure, composed of regions with high crosslink density and regions with lower crosslinking. Epoxy rich systems have a more open macromolecular structure with a lower fraction of the dense phase than the amine rich systems, which present a more compact two-phase structure.

Palavras-chave : water absorption; epoxy resins; hardener to epoxy monomer ratio.

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