Effect of synergistic flame retardancy on the flame retardant and smoke suppression properties of bamboo fiber composites

Bamboo fiber composites (BFCs) possess significant potential for application in the automotive industry. However, the flammability of bamboo fibers and the substantial amount of smoke generated during combustion hinder their application to some extent. Considering the low flame retardancy of a single flame retardant, BFCs were prepared by incorporating ammonium polyphosphate (APP) and nanomagnesium hydroxide (NMH) in this work. The synergistic effect and flame retardant mechanisms were investigated through mechanical properties testing, thermogravimetric analysis, limiting oxygen index testing, cone calorimetry testing, and X-ray photoelectron spectroscopy. When the optimal ratio of APP to NMH was 6:4, the pyrolysis reaction of BFCs was the most difficult to occur, and the oxygen index value reached the noncombustible level. Compared with those of the untreated materials, the peak heat release rate and total smoke production of BFC/6A4N decreased by 45.65% and 59.68%, respectively. APP and NMH exhibited significant synergistic effects during combustion, which enhanced both the flame retardant and smoke suppression properties in the condensed and gas phases, making it a promising synergistic system for BFCs. This work provides possibilities and safety assurances for the preparation of flame retardant and smoke suppression bamboo fiber/phenolic resin composites, promoting the development of materials towards multifunctional and high-performance applications while ensuring cost-effectiveness.