Resumo

GONZALEZ GARCIA, Filiberto; SAMPAIO, Eduardo M.; NEVES, Alessandra F.  e  OLIVEIRA, Márcia G. de. Evaluation of the adherence of bonded metallic joints with modified epoxy adhesives. Polímeros [online]. 2008, vol.18, n.1, pp.30-44. ISSN 1678-5169.  https://doi.org/10.1590/S0104-14282008000100009.

In this work the adhesive properties of epoxy resins based on diglycidyl ether of bisphenol A have been evaluated. The epoxy resin was modified with butadiene and acrylic copolymers to obtain toughened adhesives. The aliphatic primary amines triethylenetetramine, N-(2-aminoethyl)piperazine and isophorone diamine were investigated as curing agents. The adhesive properties were investigated using the epoxy resins as independent systems as well as the modified resin. The adhesive properties of modified and unmodified epoxy resins were studied using steel alloy (ASTM A36) as adherent. The adherence has been evaluated using three geometric assays of steel-steel bonded joints. The rheological behavior of the adhesives was investigated under isothermal conditions. The rheological parameters associated with the curing reaction such as reaction rate, pot life and gel time of the pure adhesives were related to the chemical structure of the curing agents. The cloud point and the gel time of the modified adhesives were related to the morphology and the reaction rate, respectively. The morphology was characterized by scanning electronic microscopy. The adherence of the adhesive joints at different mechanical solicitations was related to the generated morphology by the dispersed phase of each modifier and the networks structures of the epoxy adhesives.

Palavras-chave : Toughened adhesive; bonded joints; reaction-induced phase separation; morphology.

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