Mussel-inspired magnesium oxychloride cement-based wood adhesive produced via the synergy of inorganic fiber enhancement and multiple reinforcement network

Abstract

Magnesium oxychloride cement (MOC) is a promising substitute for formaldehyde-based adhesives for wood bonding due to its low carbon footprint, formaldehyde-free and flame-retarding natures. However, the poor water resistance and weak interfacial compatibility with wood limits their practical applications. Herein, inspired by mussels, we reported an eco-friendly and versatile strategy to develop MOC-based wood adhesive with desirable water resistance, high adhesive strength and strong bonding interface. Amino-functionalized sepiolite (KSep) was selected as the nano fillers and inorganic fibers to enhance the structural compactness and resist cracks propagation of MOC. Gallic acid (GA) was employed as the crosslinking agent to induce multiple reinforcement network based on phenol-amine crosslinking and ion chelation in MOC system. The synergy of inorganic fiber enhancement and multiple reinforcement network not only strengthens the cohesive properties, but also enhances the physical anchorage and chemical reactions at the bonding interface, thus endowing MOC with outstanding adhesion ability to wood. The MOC/KSep/GA composite exhibits dry and wet shear strength of 2.63 MPa and 1.75 MPa, being respectively 14.85 % and 42.28 % higher than those values of the pristine MOC. This strategy provides a new route for the development of high-performance cementitious materials and adhesives.