天然多酚/Fe3+/HDI多重协同交联的全水相水下粘合剂OA

Based on a poly(vinyl alcohol)/succinic acid system,a multilevel synergistic crosslinking strategy involving two natural polyphenols—tea polyphenols(TP)and tannic acid(TA)—together with Fe3+and hexamethylene diisocyanate(HDI)was developed to realize a high-performance underwater adhesive under fully aqueous conditions.TP and TA provide a high density of phenolic hydroxyl groups,enabling the formation of hydrogen bonding,π-π interactions,and multidentate coordination at wet interfaces,thereby facilitating rapid water displacement and multipoint anchoring.Fe3+ions construct dynamic metal-ligand coordination networks,enhancing energy dissipation and interfacial adaptability,while HDI reacts with hydroxyl groups to generate stable covalent crosslinked structures through urethane and urea linkages.The resulting adhesive exhibits an underwater shear strength of up to 1.7 MPa on metallic substrates and maintains adhesion strengths exceeding 1.0 MPa after 30 days of long-term stability testing,as well as under high-salinity conditions(2.0 M NaCl)and across a wide pH range(1-13).Moreover,the system demonstrates good compatibility with various substrates.This study provides a new structural design strategy for the development of green,high-performance underwater adhesives.