On the effect of binders on interlaminar fracture energies and R-curves of carbon/epoxy laminates with non-woven micro-fibre veils

The effect of short micro-fibre-based veils on the mode-I and mode-II interlaminar fracture energies and R-curves of composite laminates is investigated in this study—with an emphasis on the role of veil binders. Non-woven polyphenylene sulfide veils with 10 g/m² areal weight and two different binders (i.e. cross-linked styrene-acrylic and cross-linked polyester), and non-woven carbon veils with 10 g/m² areal weight and four different binders (i.e. cross-linked styrene-acrylic, cross-linked polyester, polyester and polyvinyl alcohol) are used for interleaving composite laminates. Carbon/epoxy laminates are manufactured by vacuum-assisted resin infusion with out-of-autoclave curing. The mode-I and mode-II fracture behaviour of the laminates are investigated. The results show that the binders used in the manufacturing of veils can considerably affect the fracture energy, crack path and R-curve behaviour, and that the effect of binders is more pronounced in the laminates with carbon veils than in the laminates with PPS veils.