Effect of Catalyst Concentration on the Properties of Bio-based Epoxy Vitrimer with Dynamically Adaptive Networks^†

Epoxy resins are widely employed in wind turbine blades, drone rotors, and automotive interiors due to their excellent mechanical properties and long service life. However, their insoluble and infusible cross-linked networks pose a significant recycling challenge, particularly with the impending retirement of the first generation of wind turbine blades. In this work, we reported a fully bio-based epoxy Vitrimer (FEP) incorporating a dual-dynamic covalent network design and systematically investigated the influence of the 1,5,7-triazabicyclo4.4.0dec-5-ene (TBD) catalyst on its curing kinetics, thermal/mechanical properties, dynamic exchange behavior, and degradation performance in a mild alkaline solution. Compared to conventional epoxy resins, FEP exhibited superior tensile strength and elongation at break at an optimal TBD concentration (2 wt%), achieving an excellent strength-toughness balance. The presence of TBD accelerated the exchange rates of both disulfide and ester bonds, endowing FEP with notable stress relaxation at elevated temperatures. Moreover, FEP demonstrated complete dissolution in 1 mol/L NaOH within 6 h at 25 °C. These results underscored the exceptional strength, toughness, and recyclability of FEP, positioning it as a promising, environmentally friendly matrix resin for next-generation applications in the new energy sector.