Fire behaviour and morphology of epoxy matrices designed for composite materials processed by infusion

International audienceThe present work is about the investigation of the fire behavior of epoxy networks designed for structural composite materials used in aeronautics. Two high-Tg, infusion-suitable epoxy systems were studied. A model system was based on tetraglycidyl(diaminodiphenyl)methane (TGDDM) as an epoxy prepolymer, and 4,4' methylene bis(2,6-diethylaniline) (MDEA) as a curing agent. A second system was based on a commercial aeronautic formulation specially designed for the infusion process. The triSilanolPhenyl POSS (POSSOH) was chosen as an additive due to the presence of phenyl groups and silanol functions that could possibly react with the network compounds. In this perspective, an aluminium salt (aluminium tri(acetylacetonate)) was introduced in presence of POSSOH in order to enhance the reaction of the additive with the epoxy monomer. The study of the morphology revealed intricate structures, with an overall good dispersion of the POSSOH in the epoxy networks. in terms of fire behaviour, same tendencies were observed for both epoxy networks, i.e. the combined presence of POSSOH and the aluminium-based additive brought significant improvements with a substantial and effective intumescent-like behaviour