High-performance and sustainable epoxy resins cured with amine-functionalized lignin for advanced adhesives and wind turbine composites

Epoxy resin, as a crucial high-performance thermosetting polymer, heavily relies on petroleum-based raw materials for its conventional curing agents, making the development of green alternatives essential for sustainable industrial advancement. In this study, amine-functionalized lignin was successfully synthesized and employed as a bio-based curing agent to fabricate a lignin-based epoxy resin (LBER). The application potential of LBER was systematically evaluated as a structural adhesive and in epoxy resin/glass fabric (EP/GF) composites for wind turbine blades. The resulting LBER exhibited high crosslinking density, enhanced thermal stability, and notable solvent resistance. The adhesive formulation (1:0.4) achieved a maximum wood lap-shear strength of 13.84 MPa, while the corresponding EP/GF composite attained a tensile strength of 391.73 MPa. Both materials outperformed the conventional diethylenetriamine-cured epoxy system under extreme temperatures (−196 °C to 200 °C) and in various solvent environments. Life cycle assessment (LCA) and techno-economic analysis (TEA) further confirmed substantial reductions in carbon emissions and competitive cost-effectiveness. These findings demonstrate a practical and promising pathway for transitioning toward green epoxy resin systems, demonstrating strong technical, environmental, and economic feasibility for high-performance adhesives and large-scale composite manufacturing.