Preparation and properties of lignin-based vitrimer system containing dynamic covalent bonds for reusable and recyclable epoxy asphalt

Conventional epoxy asphalt is a thermosetting material that is difficult to reprocess and cannot be easily recycled after disposal. In this study, a lignin-based epoxy asphalt (ELEA) with thermoplastic and thermosetting properties was prepared by introducing a lignin-based vitrimer system, which has a dynamic, covalently bonded, cross-linked ester network, into the asphalt. The mechanical properties (tensile strength, 1.605 MPa; elongation at break, 382.38 %) also meet the requirements of epoxy asphalt for steel bridge deck pavement. The viscosity, thermal properties and high-temperature reversibility of ELEA show that ELEA has good operability, thermal stability and potential for recycling, in line with the trend towards the development of a circular economy. The use of biomass-based derivatives for the epoxy resin and curing agent in ELEA also reduces dependence on non-renewable petroleum resources and provides a useful reference for the high-value and efficient development and utilization of industrial lignin.