As a kind of bulk industrial solid waste, the massive accumulation of iron tailings has caused serious waste of resources and environmental pollution. In this study, a silane coupling agent (KH550) was used to modify the surface of iron tailings to produce MIT, and it was compounded with ammonium polyphosphate (APP) on thermoplastic polyurethane (TPU) to prepare a series of TPU/APP/MIT composites. Thermogravimetric (TG), cone calorimetric (CCT), thermogravimetric infrared, scanning electron microscopy, and Raman techniques were also used to analyze the combustion performance, smoke toxicity, and microscopic morphology. The TG test results showed that the compounding of APP and MIT significantly improved the residual carbon value of TPU composites at 700 C. CCT test results showed that the TPU/APP/MIT composites exhibited excellent flame retardancy and smoke suppression. Compared with pure TPU, PHRR, THR, and TSR of TPU/APP15/MIT10 composite decreased by 85.56%, 87.83%, and 86.17%, respectively, the peak release rates of CO and CO 2 decreased by 69.26% and 90.34%, respectively. The above studies showed that APP and MIT have excellent flame retardant and smoke suppression effect on TPU materials, providing more opportunities for the study of TPU composites and metallurgical solid waste utilization.

Rigid polyurethane foam (RPUF) has many excellent properties, but its flammability has been a challenge for the application of RPUF compounds. In this research, piperazine pyrophosphate (PAPP) and expandable graphite (EG) were added to the RPUF matrix to improve the fire performance of RPUF. Thermogravimetric analysis (TGA) revealed that PAPP and EG contributed to the early decomposition of the FR‐RPUF matrix, and the char residue of RPUF‐3 reached 37.1 wt% when the PAPP: EG ratio was 1:1. The flame‐retardant test indicated that the FR‐RPUF composites reached the V‐0 level, and the limiting oxygen index (LOI) value of RPUF‐4 was 28.8%. In addition, cone calorimeter tests showed that the addition of flame retardants reduced the peak heat release rate (PHRR) and total heat release (THR), further improving the fire performance of the compounds. The analysis of the char residue confirmed the formation of a denser char residue and significant improvement in the graphitization degree due to the PAPP/EG synergistic effect, indicating that the char residue could effectively isolate oxygen and heat and act as a flame retardant in the condensed phase.