Bioinspired Robust Mechanical and Waterproofing Properties of Moisture‐Curing Polyurethane With Multiple Hydrogen Bonding Networks

ABSTRACT Moisture‐curing polyurethane (MCPU) is widely used in waterproofing applications due to its excellent adaptability and ease of construction. However, traditional MCPU suffers from poor mechanical properties, primarily due to low curing efficiency and limited molecular chain extension. Inspired by the layered structure of spider silk, a mechanical MCPU is developed by incorporating adipic dihydrazide (ADH) as a chain extender to construct multiple hydrogen bonding networks within the MCPU matrix. These networks facilitate molecular chain extension and promote the formation of a controllable microphase separation structure, significantly enhancing the mechanical properties of MCPU. The resulting MCPU exhibits remarkable mechanical properties, achieving a tensile strength of 8.64 MPa and an elongation of 2448.32%, which are 2.14 times and 7.00 times higher than the ASTM D6947/D6947‐16 standards (4.14 MPa and 350%), respectively. Furthermore, the MCPU coatings demonstrate exceptional waterproofing capabilities, withstanding 1 m of static water pressure for 1 month and enduring −0.1 MPa dynamic pressure for 2 h. Therefore, this work presents a novel and effective strategy for enhancing the mechanical and waterproofing properties of low‐molecular‐weight MCPUs, offering significant potential for advanced industrial applications.