Towards repairable composites: healing of mode I and mode II delaminations in woven glass fibre and vitrimer matrix laminates

The widespread use of thermoset matrix composite has led to an increase in hardly manageable composite waste, driving research into alternative material concepts promoting circularity through repairing strategies. In this study, the intrinsic healing of imine-based vitrimer matrix composite after delamination is investigated. Laminates of woven glass reinforced composite were tested in Double Cantilever Beam and Three-Point End-Notched Flexure tests, followed by an ex-situ delamination healing process and retesting. A remarkable recovery of fracture properties was observed: repairing efficiencies of 91 % and 98 % were obtained for mode I and II interlaminar fracture toughness, respectively. Visual inspections confirmed successful healing of damage across all cases. The fracture surface was evaluated for mode I, showing that the crack in the virgin state is a preferred path for the post-healed delamination. Results demonstrate that imine-based vitrimer composites have significant potential of healing delamination cracks.