Chemically Tailored Natural Fibers via Bionic Nanoenzyme Catalysis for Robust and Tough Bio-adhesive

Sustainable bio-adhesives are considered the most promising alternatives to petroleum-based adhesives. However, the poor strength and low toughness of bio-adhesive have seriously hindered their commercial application. Herein, a strong and tough bio-adhesive with excellent applicability is successfully designed and constructed via the introduction of modified natural fibers (MF). The MF was prepared from an oxidation catalytic system mediated by laccase nanoenzymes and cationic surface modification chemistry. This customization process significantly enhances the micro-interfacial bonding strength between natural fibers and the adhesive matrix. Specifically, the aldehyde and cationic groups in MF can form bridge with the soybean meal protein adhesive (ESM) through covalent bonds and electrostatic interactions, thereby triggering the energy dissipation mechanism through stress conduction. Benefits from these enhancements, the plywood prepared with ESM/MF shows a significant increase in wet strength and adhesion work by 86% (1.21 ± 0.07 MPa) and 2.73 times (558.23 ± 36.49 N·m− 1). In addition, MF can enhance the interfacial bonding strength of the adhesive with various substrates through the formation of hydrogen bonds and coordination bonds. This biomimetic nano-enzyme catalytic strategy addresses the green large-scale preparation problem of natural fiber modification and provided a new insights for the developing high-performance bio-materials.