Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE A bio-based epoxy vitrimer asphalt containing dynamic imine bonds is developed to address the irreversibility of conventional thermosetting epoxy asphalt. The optimized formulation shows balanced mechanical performance, adequate paving workability, and evident thermal crack closure, providing a sustainable strategy for self-healing and longer-lasting pavement materials.

ABSTRACT
Thermosetting epoxy asphalt possesses outstanding mechanical strength, fatigue resistance, and durability, making it a preferred material for demanding pavement applications. However, its permanent cross-linked structure limits crack self-healing and recyclability, raising sustainability concerns. In this study, a novel bio-based epoxy vitrimer asphalt was developed by curing epoxy soybean oil (ESO) and commercial epoxy resin (E51) with a synthesized imine-containing amine curing agent (TPA/D400). The incorporation of ESO not only enhances the renewable content but also contributes to a dynamic covalent network based on reversible imine bonds. Among the prepared samples with vitrimer contents ranging from 30 to 70 wt%, the composite with 50 wt% vitrimer (EEA50) demonstrated optimal comprehensive performance, exhibiting a tensile strength of 1.28 MPa and an elongation at break of 106.46%, which meets the specification requirements for heavy-duty pavement. Fluorescence microscopy revealed a homogeneous phase morphology in EEA50, indicating good compatibility. Remarkably, scratch tests at 180°C showed that EEA50 could achieve significant crack closure within 120 min, attributed to the exchange reactions of dynamic imine bonds within the vitrimer network. This work presents a sustainable epoxy asphalt alternative, combining bio-based resources with vitrimer chemistry to address the limitations of conventional thermosetting epoxy asphalt in pavement engineering.