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.