Biomimetic Organic-Inorganic Hybrid Magnesium Oxychloride Cement as Green Adhesive for Biomimetic Organic-Inorganic Hybrid Magnesium Oxychloride Cement as Green Adhesive for Wood Industry

Abstract

Benefiting from the negative carbon footprint of wood, wood composites have been considered as eco-friendly alternative building materials. However, adhesives for bonding wood components are mainly formaldehyde-based resins, which are highly combustible and continuously release volatile hazardous substances during service. Therefore, the development of magnesium oxychloride cement (MOC) as wood adhesive is highly compliant with environmental regulations and green material requirements. Unfortunately, the extensive application of MOC adhesive is hindered by poor water resistance and weak interfacial interaction with wood. Herein, an oyster-inspired organic-inorganic hybrid strategy was proposed to develop MOC with high adhesion strength and excellent water resistance. Specifically, the renewable chitosan (CS) and tartaric acid (TA) were selected as organic reinforcing constituents to construct a dense double chelating network in MOC, which induced the structural regulation at the bonding interface, thus enhancing the cohesion strength and interfacial properties. Thanks to the biomimetic organic-inorganic hybrid structure, the dry and wet shear strength of the MOC-CS-TA reached 3.08 MPa and 1.77 MPa, making increases of 27.27% and 53.91% compared to the control sample, respectively. Meanwhile, the MOC-CS-TA adhesive presented excellent flame-retardant properties compared with urea-formaldehyde resin adhesives and soy protein adhesives. The design path presented here provides workable guidance for the preparation of eco-friendly cementitious materials and green wood composites in further applications.

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