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Artigo Científico | Propriedades Mecânicas | Inglês | 05/05/2003
Autores: Gustavo W. de Menezes, José Roberto M. d Almeida, Sergio N. Monteiro
Palavras-chave: ageing, epoxy resins, mechanical properties
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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