Eco-friendly thermally activated vitrimer resin composites with self-healing mechanical and electrically conducting functional capabilities

Thermosetting polymers are largely employed due to their mechanical properties, adhesion, and resistance to heat, chemicals, and the environment. However, their highly crosslinked structure hinders recyclability. Covalent adaptable networks, enabled by vitrimer crosslinkers, overcome this limitation by allowing remoulding, repair, and reuse. In this work, a bio-based epoxy resin (58 % renewable carbon) was combined with vitrimer hardener at different ratios (1:1, 2:1, 3:1) and reinforced with 3 wt% multi-walled carbon nanotubes (MWCNTs). Increasing vitrimer content improved stress at rupture, reduced glass transition temperature (Tg < 80 °C), and enhanced cyclic stability under in-plane and bending loads. The 2:1 blend and its MWCNT composite demonstrated remoulding, repair, self-healing, and electrical conductivity. The self-healing composite reached adhesive stress of 4 MPa and > 80 % repair efficiency upon heating. Joule heating further enabled rapid self-repair in conductive vitrimer composites. • Vitrimer:bioresin blends and composites with healing capabilities have been developed. • Vitrimer:bioresin blends show up to 80 % of damaged area recovered after thermal treatment. • Composite films also show self-healing capabilities and full functional conductivity recovery. • Functional electrical conductivity healing can be induced taking advantage of the Joule effect.