A fully biomass-derived intrinsically flame-retardant phenolic resin: Robust adhesion, fire-safe coatings, and closed-loop upcycling for multifunctional cellulose fibers

A fully biomass-derived TA-PPF phenolic network was rationally designed • TA-PPF integrates intrinsic flame retardancy, robust adhesion, and recyclability • TA-PPF delivers excellent fire safety with an LOI of 64.5% and a UL-94 V-0 rating • TA-PPF extends fire-safety protection to wood and regenerated cellulose fibers To mitigate ecological pollution and fossil-resource depletion caused by traditional petroleum-based materials, biomass-derived functional materials have emerged as promising sustainable alternatives. Herein, a fully biomass-derived phenolic resin (TA-PPF) was developed from renewable feedstocks, which integrated intrinsic flame retardancy, robust adhesion, and value-added reuse capability. TA-PPF exhibited an exceptionally high limiting oxygen index (LOI) of 64.5% and maintained its structural integrity without macroscopic collapse after continuous exposure to a butane flame for 240 s, outperforming many previously reported bio-based and petrochemical flame-retardant materials. Additionally, TA-PPF exhibited robust adhesion to diverse substrates, achieving an adhesion strength of 3.65 MPa on wood and retaining favorable environmental stability in organic solvents, acidic and alkaline media, and under extreme temperatures. Benefiting from its intrinsic flame retardancy and adhesion capability, TA-PPF was further applied as an eco-friendly fire-safety coating for wood, increasing its LOI from 22.3% to 45.4%. Furthermore, inspired by the natural synergy between polyphenols and carbohydrates in plants, waste TA-PPF was repurposed as a functional additive for regenerated cellulose fibers, producing multifunctional composite fibers with excellent flame retardancy and ultraviolet protection, as evidenced by an LOI of 33.5% and an ultraviolet protection factor (UPF) of 136.63. This work provides a sustainable strategy for developing high-performance bio-based resins, fire-safety coatings, and multifunctional regenerated cellulose fibers. Download: Download high-res image (380KB) Download: Download full-size image