Sucrose-Derived Imine Synergistic Multihydrogen Bonds Enable Tough, Strong, and Rapid Curing Phenolic Resins

The engineered wood industry faces an urgent demand for innovative high-performance phenolic resins with low curing temperatures, high curing rates, and toughness. Here, a sucrose-derived imine synergistic multihydrogen bond cross-linking strategy is proposed to overcome these challenges. Specifically, an imine-based phenolic resin system (OS/ALPF) is designed by combining oxidized sucrose with aminated linear phenolic resins. The optimized 5OS/ALPF-1.6 resin (pH = 1) achieves boiling water lap shear strength and plywood boiling water bonding strength of 1.62 and 1.48 MPa, indicating improvements of 1.34 and 1.32 times over PF, respectively. The debonding work is 818 mJ, representing a 2.93-fold increase compared to PF. These enhancements stem from the synergistic effects of weak imine bonds and multihydrogen bonds within the network. The gel time is reduced from 642 s for PF to 82 s, and the initial and peak curing temperatures decrease from 128.6 and 157.2 °C to 95.5 and 109.6 °C, respectively. Even when cured at 100 °C, the boiling water bonding strength achieves 1.12 MPa, substantially surpassing the 0.12 MPa observed for PF. This strategy provides a high-strength, tough, and low-energy-consumption adhesive solution for the green and high-quality development of the engineered wood industry, particularly suitable for plywood fabrication and bamboo bonding.