Flame-Retardant and Smoke-Suppression Properties of Bamboo Scrimber Coated with Hexagonal Boron Nitride

Abstract

In order to improve the flame-retardant properties of bamboo scrimber, chitosan (CS) and polyvinyl alcohol (PVA) were used as the film-forming substances, and hexagonal boron nitride (h-BN) was used as the flame-retardant substance to prepare h-BN flame-retardant coatings, which were coated on the surface of the bamboo scrimber. The effects of the h-BN flame-retardant coatings with different quality concentrations on the flame-retardant properties of the bamboo scrimber, as well as on the morphology of the residual carbon, were investigated using the analytical methods of FTIR, environmental scanning electron microscopy, thermogravimetric analysis, combustion test, and coating adhesion test. The results showed that the h-BN flame-retardant coating could improve the thermal stability of the bamboo scrimber and that the higher the mass concentration, the better the thermal stability of the h-BN. Compared to the control, the time to ignition (TTI) of the 5% h-BN flame-retardant-treated specimens increased by 56%; the peak heat release rate (Pk-HRR), total heat release (THR), and total smoke production (TSP) decreased by 9.92%, 7.54%, and 32.35%, respectively; however, due to the presence of PVA, the peak smoke production rate (Pk-SPR) increased by 17.78%. The 5% h-BN coating had very good adhesion, with an adhesion grade of zero. In conclusion, the h-BN coating could be well-adhered to the surface of the bamboo scrimber, and the 5% h-BN flame-retardant coating had a better flame retardancy compared to other treatments, meaning that it could provide a new strategy for improving the flame-retardant properties of bamboo scrimber for construction use.