Phytic acid-based hybrid complexes for improving the interfacial property and mildew-resistance of heat-treated bamboo

Thermally glue-laminated bamboo timber has become the most promising woody resource in the world. However, the poor glued bonding property and poor anti-mild property limit its practical applications. Current scholars focus on crack-free, flattened bamboo boards and its application. Herein, inspired by the natural phosphoric acid complexes, Phytic Acid-based hybrid complexes were fabricated on the bamboo surfaces for improving its interfacial property and mildew resistance. SEM-EDS mapping results showed that the phytic acid-based hybrid complexes were successfully coated on the bamboo surface. The average penetration depth values (AP) and effective penetration depth values (EP) of heat-treated bamboo increased from 10.55 µm and 79.32 to 15.69 µm and 98.12 µm. A large amount of phytic acid penetrates into the bamboo cell-matrix and a large number of hydrophilic groups attach to the bamboo inner tissue during the impregnation process. Thus, the grafted long-chain groups in phytic acid cross-link with the crown energy groups in phenolic resin, thus increasing the AP of phenolic resin and improving the interfacial property. Additionally, the modified bamboo samples exhibited better anti-mildew properties than those of the control.