A two-step method for fabricating bamboo culm coated with MgAl-LDHs and its fire resistance properties

Abstract

To enhance the fire-resistance of bamboo, the bamboo was first exposed to sodium hydroxide solution, and then immersed in a suspension of magnesium aluminum layered double hydroxides (MgAl-LDHs) to fabricate modified bamboo (NLB) with a coating of MgAl-LDHs on the surface. X-ray photoelectron spectroscopy showed that the surface of bamboo was coated by the MgAl-LDHs after modification. Fourier transform infrared spectroscopy analysis demonstrated that more hydroxyl groups were available on the bamboo surface after pretreatment with sodium hydroxide solution. The morphology of the MgAl-LDHs coating was firmer and denser with evidence from scanning electron microscopy and energy dispersive X-ray spectrometry. Leaching resistance was thereby enhanced. In addition, the cone calorimeter results showed that the peak heat release rate of the NLB was 29.1% lower than that of untreated bamboo, the total heat release decreased by 24.4%, the smoke release rate and total smoke release decreased by 40.5% and 47.8%, respectively, and the peak of carbon monoxide production decreased by 26.7%. The maximum average heat dissipation rate decreased by 24.0%, and the shape of residual charcoal of the NLB was more complete than that of untreated bamboo after fire. Therefore, NLB has excellent fire resistant and smoke suppression properties.