Résumé
Unsaturated permeability evaluation still remains an issue in composite manufacturing. Test liquids, considered as models for resins, have been largely used. Silicone oil is the most common test liquid for permeability measurements and has been used in benchmarks for unsaturated permeability evaluation [1]. But the choice of this liquid relies only on its viscosity which is comparable to the one of a liquid epoxy used for composite manufacturing. Capillary effects have been totally neglected for those measurements and the validity of this assumption has never been verified. Indeed, silicone oil is a totally wetting liquid. Epoxy resin at its liquid state has a very different behavior as it has been proved by the characterization of surface tension and its components for some uncured epoxy resins [2]. Wicking tests in carbon fabric reinforcements were carried out with different test liquids at several temperatures following a procedure established in previous works [3]. Silicone oil was used in comparison with an epoxy resin. Trends of wicking were found to be significantly different proving that the physico-chemical properties have thus also to be considered to choose a model liquid for permeability measurements. To go further, the definition of an unsaturated permeability has to be questioned.