Environmental ageing of aerospace epoxy adhesive in bonded assembly configuration

Nicolas Causse (1) , Eric Dantras (1) , Claire Tonon (2) , Mathieu Chevalier (2) , Hélène Combes (3) , Pascale Guigue (3) , Colette Lacabanne (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
2 Astrium [Toulouse]
3 CNES - Centre National d'Études Spatiales [Toulouse]

Aerospace epoxy adhesive has been subjected to various environmental ageing processes. A comparative study is performed between ageing under vacuum and atmospheric pressure for various ageing temperatures. The macroscopic behaviour of the assemblies is investigated by single lap shear test. Glass transition temperature of the bulk adhesive is followed by differential scanning calorimetry. Molecular mobility of the adhesive in service configuration is studied by dynamic dielectric spectroscopy. No significant difference is noticed due to an ageing under vacuum. A comparison between test results after each isotherm ageing highlights the temperature influence. For ageing of adhesive in a vitreous state, the crosslink density increases. For ageing of adhesive in a rubbery state, a severe decrease of glass transition is observed. The influence of additives and physical ageing is null. This plasticisation effect might be associated with the homogenisation of the structure of epoxy due to the molecular mobility of loose chains.

Mots clés: Epoxy adhesive; Ageing; Space environment; Dielectric spectroscopy; Glass transition

Domaines: Chimie analytique; Chimie inorganique; Polymères

Nicolas Causse, Eric Dantras, Claire Tonon, Mathieu Chevalier, Hélène Combes, et al.. Environmental ageing of aerospace epoxy adhesive in bonded assembly configuration. Journal of Thermal Analysis and Calorimetry, 2013, vol. 114 (n° 2), pp. 621-628. ⟨10.1007/s10973-013-3009-3⟩. ⟨hal-01136617⟩