Immobilization of ferric tannate on wood fibers to functionalize wood fibers/diphenylmethane di-isocyanate composites

[Display omitted] •Tannic acid treated wood fibers can adsorb ferrous ion.•Composites from treated fibers have improved hygroscopicity and flame-retardancy.•An eco-friendly method for preparing multifunctional fiber composites was proposed. Conventional natural fiber-based composites present substantial limitations regarding their dimensional stability, and flame retardancy, among other attributes. Our research focuses on examining and enhancing the properties of multifunctional fiber composites. In the initial phase, tannic acid (TA) was immobilized on wood fibers which absorbed the ferrous irons in the aqueous phase. Finally, the carriers were recycled to prepare composites via compounding with diphenylmethane di-isocyanate. The produced composites exhibited a 28 % improvement in dimensional stability compared with the control sample, while achieving significant enhancements in stiffness, hygroscopicity and flame-retardant properties due to the presence of TA-Fe complexes. Furthermore, the heat release rate and smoke production rate were decreased by 33 % and 77 %, respectively. The highly functional and versatile composites in this research are expected to possess a wide array of household applications.