Synergistic Dual Dynamic Covalent Networks Enable High-Performance and Self-Healing Polyurethane and Its Anticorrosion Applications

Intrinsic self-healing polymers have gained significant attention due to their potential to extend material lifespan and enhance sustainability. However, balancing mechanical strength and self-healing performance remains a challenge for self-healing polymers. This study presents a dual dynamic covalent bond strategy by incorporating two chain extenders, 2,5-bis(4-hydroxyphenyl) disulfide (BHPS) and furandimethanol (FDME), into the polyurethane structure. A cross-linked network was formed via the Diels–Alder reaction between FDME and bismaleimide (BMI), which worked synergistically with dynamic disulfide bonds to effectively address the challenge. When the molar ratio of BHPS to FDME was 1:1, the material exhibited a tensile strength of 31 MPa, toughness of 97 MJ·m–3, outstanding self-healing capability at 100 °C, and multiple recyclability. Electrochemical tests demonstrated its potential as a self-healing anticorrosion coating. This molecular design strategy effectively addresses the challenge of balancing mechanical performance and self-healing efficiency in polymers, providing a new approach for sustainable functional materials.