Manufacturing of flame-retardant flattened bamboo board via partial lignin retention and CaCO₃ mineralization

The flattened bamboo board (FB) has garnered widespread attention recently due to its ability to enhance bamboo utilization and reduce adhesive consumption. However, FB is primarily composed of three macromolecules: cellulose, hemicellulose, and lignin, making it a flammable material. Meanwhile, FB lacks lateral cell tissues, and its relatively low permeability poses challenges for flame-retardant modification. This work introduces an "H₂O₂ pretreatment-vacuum impregnation-curing" strategy to fabricate the fireproofing of a superior CaCO₃-mineralized flattened bamboo board (CaCO₃-FB). The results indicate that H₂O₂ pretreatment not only enhances the liquid permeability of FB but also maintains a lignin retention rate as high as 69.1 %. The partial retention of lignin, which has a bonding effect, preserves the structural integrity of FB. Cone calorimetry tests show that CaCO₃-FB significantly reduces peak heat release rate (PHRR), total heat release (THR), peak smoke production rate (PSPR), and total smoke production (TSP) by 34.6 %, 52.9 %, 22.2 %, and 53.6 %, respectively. Overall, the production of flame-retardant FB is successfully achieved through the partial retention of lignin and mineralization of CaCO₃, which holds great potential to drive significant advancements in the bamboo industry.