A flame-retardant and transparent wood/polyimide composite with excellent mechanical strength

Transparent wood (TW), as a promising structural material, has attracted considerable attention owing to the high transmittance, excellent toughness, outstanding modulus and mechanical strength. Despite the encouraging achievements on TW materials have been made, their widespread applications are still restricted by the intrinsic flammability. Herein, in this work, a flame-retardant TW/polyimide (FRTW/PI) composite has been prepared by successfully impregnating polyimide into delignified porous wood template. As expected, the FRTW/PI composite maintains good self-extinguishing properties after leaving the fire source within 2 s. Additionally, the FRTW/PI composite exhibits an enhanced mechanical strength of 169 MPa, which is 42 times higher than that of natural wood (NW) and much higher than other previously reported values. This work put forwards an effective approach for the fabrication of FRTW/PI composite and holds a great promise as colored glass for future buildings.