Bioinspired design by gecko structure and mussel chemistry for bio-based adhesive system through incorporating natural fibers

The development of eco-friendly, non-formaldehyde, and high-performance bio-based adhesives is a great strategy for relieving environmental pressure and health concern, especially for the wood adhesive industry. In this work, a green soybean meal (SM)-based adhesive with excellent performance was developed by embedding modified kenaf fibers (KF). The synergistic bionic design with gecko structure and mussel chemistry endowed KF with improved rough surface and increased reactive sites, resulting in robust mechanical interlocking and multiple chemical crosslinking ability for SM-based adhesive. The resultant adhesive exhibited excellent bonding properties, compared to the SM adhesive, the wet shear strength was improved from 0.41 MPa to 1.52 MPa, and the moisture absorption was decreased from 10.1% to 8.6%. These results met the standard of type II plywood (≥0.7 MPa) according to the national standard of China (GB/T 9846.3-2004). This eco-friendly SM-based adhesive opens a new way to replace harmful formaldehyde-based adhesives and contributes to the development and use of agricultural and forestry byproducts for practical application.