Synthesis of flame-retardant, bactericidal, and color-adjusting wood fibers with metal phenolic networks

Wood fibers are used as raw materials for construction and furniture owing to their specific mechanical performance, cost, and availability. However, the unsatisfactory flame retardancy and antibacterial properties of wood fibers have limited their application. In this study, the flame-retardant and antibacterial wood fibers were synthesized via metal phenolic networks (MPNs). Successive immersion of tannic acid (TA) and ferrous salt was conducted to modify wood fiber with the fabrication of a TA-Fe-wood complex, which was then superficially coated with a layer of silver nanoparticles (AgNPs) to fabricate TA/Fe/AgNPs@wood fibers via a redox reaction. Compared with untreated wood fibers, the TA/Fe/AgNPs@wood fibers demonstrate a 71.5 % reduction in peak heat release rate and a 56.5 % reduction in peak smoke production rate as well as increased char formation, indicating a significant improvement in fire resistance. The modified fibers also exhibit excellent antibacterial activity against two common pathogenic bacteria, E. coli and S. aureus. The exterior color of the modified wood fibers was modified by double pulse TA impregnation, solving the problem that MPNs darken the substrate. These fibers can be widely used in the fields of adsorption, construction, paving and greening.