Influence of β-FeOOH nanorods and ammonium polyphosphate on reducing the fire hazard of epoxy resins composites

β-FeOOH nanorods were synthesized and introduced into ammonium polyphosphate (APP) and epoxy resins (EP) composites, with subsequent investigation into improving the fire safety of epoxy resins (EP) composites. The limited oxygen index, UL-94 test and cone calorimeter test were adopted to investigate the flame retardant properties of the composites, and thermogravimetric analysis was used to study the thermal performance of the composites. The cone calorimetry results revealed that synergistic effects between β-FeOOH nanorods and APP can lead to not only the reduction of peak heat release rate compared with those of EP (85.6% reduction), but also the improvement on the smoke suppression performance such as CO, CO2 and SPR. Raman spectroscopy, FTIR and X-ray photoelectron spectroscopy of the char layers were adopted to investigate the flame retardant mechanism of the flame retardants composites. Generally, the reduced fire hazard of epoxy resins composites is due to synergistic effects between β-FeOOH nanorods and APP, which will provide stable char layers to trap the degrading polymer radicals.