Flame retardant modification of poplar wood based on sustainable impregnation solution with high biomass content

Fast-growing poplar with the dominant characteristic of short rotation plantation offers a potential solution to the growing market demand for wood. However, its practical applications are limited due to shortcomings such as high flammability and poor dimensional stability. To address these issues, this study introduced a facile impregnation process involving the in-situ polymerization of bio-based furfuryl alcohol (FA) and ammonium phytate (AMP) to enhance the flame retardancy and dimensional stability of poplar. The biomass content was higher than 95% for this impregnation solution. The thermal stability experiments revealed that the residual char mass of AMP/FA-wood at 800°C increased by 305% compared to unmodified poplar. Moreover, the AMP/FA-wood demonstrated superior flame retardancy, achieving UL-94 V-0 rating and a high limiting oxygen index of 36.3%. Additionally, it exhibited decreased heat release and total smoke production of 48.9% and 79.8%, respectively, in comparison to unmodified poplar wood. The impressive flame retardancy of AMP/FA-wood was ascribed to the incorporation of AMP through the nitrogen-phosphorus synergistic intumescent mechanism. Notably, the in-situ polymerization of FA during the modification process, the AMP/FA-wood displayed exceptional dimensional stability which was confirmed by the moisture content, anti-swelling efficiency, and water absorption tests. Hence, AMP/FA-wood with its excellent flame retardancy, thermal stability, and dimensional stability, holds promise as a reliable wood supply for various applications such as furniture, home decor, construction, and building.