Ageing of the DGEBA/TETA epoxy system with off-stoichiometric compositions

AUTOR(ES)

d'Almeida, José Roberto Moraes, Menezes, Gustavo Wagner de, Monteiro, Sérgio Neves

FONTE

Materials Research

DATA DE PUBLICAÇÃO

2003-06

RESUMO

An investigation was carried out on the room temperature ageing of off-stoichiometric DGEBA/TETA epoxy formulations. The results obtained show that the epoxy rich mixtures have their inherent brittleness increased by the ageing treatment due to recrystalization of the unreacted epoxy monomers, although homopolymerization could also play a minor role. The initial reaction steps dominated by the amine addition reactions control the macromolecular structure and the mechanical performance of the stoichiometric and near stoichiometric formulation with excess of epoxy monomer. Plasticization due to absorbed -OH results on a significant increase of the deformability of these formulations. The amine rich mixtures have the more stable structures, although plasticization due to moisture absorption from the surrounding environment also produces an increase on the deformability of all, but one, of the formulations investigated.

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