Construction of High-Performance Road Sealant Based on Super-Tough Polyurethane with Dual Dynamic Synergistic Networks.

Currently, developing super-tough polyurethanes and their high-performance road sealants that combine high strength, high toughness, and multifunctionality remains a significant challenge. In this work, super-tough polyurethane elastomers (PUAZn-X) were successfully synthesized using polytetrahydrofuran (PTMG) and diphenylmethane diisocyanate (MDI) as raw materials. A hierarchical hydrogen-bonding network was constructed through chain extension with 2,2-bis-(hydroxymethyl)-propionic acid (DMPA), combined with dynamic zinc-ion coordination crosslinking. The hierarchical hydrogen bonds maintain dynamic equilibrium under external stress, endowing PUAZn-X with high elasticity and fatigue resistance. The coordination bonds between carboxyl groups and Zn2+ enhance intermolecular interactions, resulting in high tensile strength (37.4 MPa) and elongation at break (1557.6%). The metal coordination bonds, associated with both cohesion and adhesion strength, facilitate timely energy dissipation in response to applied external stress, thereby improving adhesion performance. The self-prepared road sealant prepared using PUAZn-X features a low application temperature and exhibits enhanced mechanical properties, adhesion, high-temperature resistance, and water resistance after curing, with a pull-off strength reaching 2.1 MPa. It can mitigate interfacial adhesion failure under external stress. This study thus provides an alternative approach for the design and preparation of advanced road sealants.