A mechanically robust polyurethane elastomer with excellent crack tolerance, recyclability and weathering resistance via microphase dynamic ordering

Abstract

Advanced elastomers that combine mechanical robustness with weathering durability are highly sought-after; however, the inherent trade-off between properties such as strength and toughness makes it difficult to achieve balanced reinforcement in polymers. Furthermore, the lack of recyclability and weather resistance in existing materials leads to significant resource waste. Herein, a polyurethane system is fabricated via a facile eco-friendly method, which combines excellent toughness, crack tolerance and weathering resistance. The molecular design enables outstanding energy dissipation metrics: 275.8 MJ m⁻³ toughness, 171.0 kJ m⁻² fracture energy and 327.8 kJ m⁻² tearing energy. This high performance arises from (1) regularly aligned rigid microdomains that host dense, hierarchical hydrogen-bonding networks and (2) an intrinsic self-reinforcing capability that manifests as mechano-responsive regulation of the soft phase. Crucially, with a dynamic H-bond network, the target PU realizes <15% strength loss after 7 day multi-environmental aging (including alkali, acid, hot air and ultraviolet) and enables high-efficiency recyclability as well as heat- or solvent-activated self-healing.