Synergistic effect of strontium stannate and ammonium polyphosphate on flame-retardant and smoke-suppressant of flexible polyurethane foam

The flexible polyurethane foam (FPUF) has been modified with the flame-retardant system of strontium stannate (SrSnO3) and ammonium polyphosphate (APP). Synergistic effect of SrSnO3 and APP on flame-retardant and smoke-suppressant of the FPUF has been investigated by using X-ray diffractometer (XRD), limiting oxygen index (LOI), UL-94, cone calorimeter (CONE), scanning electron microscope (SEM), smoke density chamber and flue gas analyzer. It can be found that the LOI of the modified FPUF was increased, the horizontal combustion level was increased to FH-1. And the peak heat release rate (PHRR) and total heat release (THR) were obviously reduced. Additionally, the addition of synergistic flame retardants effectively suppressed the generation of a large amount of smoke after the addition of APP. The current results indicated that the synergistic effect of SrSnO3 and APP can efficiently improve the flame-retardant and smoke-suppressant of FPUFs and the flame-retardant and smoke-suppressant effect were the best when SrSnO3 was 5 wt% and APP was added 20 wt%, respectively.