High strength tung oil-based adhesive with outstanding wet adhesion for cellulose fiber paper

Abstract

The development of bio-based adhesives is hindered due to poor wet adhesion with wet substrate, limited durability, and lack of recyclability. Herein, we report an amphiphilic silane-oil adhesive synthesized via a one-step coupling reaction between (3-aminopropyl)triethoxysilane (APTES) and tung oil anhydride (TOA). The amphiphilic molecular architecture of the APTES–TOA adhesive facilitates strong adhesion to cellulose fibers, attributed to the polar interactions of the hydrophilic domains and the water-repellent contribution of the hydrophobic moieties. Thus, the APTES–TOA adhesive endows cellulose fiber paper (CFP) with a tensile strength of up to 117.33 MPa. Mechanistically, interfacial adhesion is governed by ion-diffusion-induced formation of a mobile interphase in wet fiber networks, followed by in situ silicification that generates hierarchical mechanical interlocking with cellulose fibers. This dual-stage mechanism significantly enhances the tensile index, tear resistance (2.93 mN m2 g−1), and folding endurance (12-fold) of CFP. Moreover, the adhesive exhibits excellent reusability, retaining stable bonding performance over at least eight cycles. This work offers a generalizable strategy for designing high-performance, sustainable adhesives for cellulose-based materials and beyond.