Strong and Ultra‐Tough Bio‐Based Waterborne Polyurethane Networks with Repairability, Recyclability, and Tunable Multi‐Shape Memory

Abstract Waterborne polyurethanes (WPUs) attract significant attention for their versatility across various fields, yet optimizing both high strength and toughness remains a challenge. This study successfully develops an ultra‐tough bio‐based WPUs by regulating non‐covalent interactions (hydrogen bonds and electrostatic interactions) and precise cross‐linking. The WPUs are synthesized using 2,2‐dimethylolpropionic acid (DMPA), castor oil (CO), poly(tetramethylene ether glycol) (PTMG), isophorone diisocyanate (IPDI), and ethylenediamine (EDA) as raw materials, constructing a network structure rich in hydrogen bonds and electrostatic interactions. The resulting material exhibits outstanding mechanical properties, including high tensile strength (15.91 MPa), Young's modulus (98.36 MPa), and toughness (107.65 MJ m −3 ), while also demonstrating good repairability, processability, and excellent shape memory capabilities. These well‐designed non‐covalent interactions provide an effective strategy for designing bio‐based WPUs with superior comprehensive performance.