Synergistic Effect of Magnesium Hydroxystannate with Intumescent Flame Retardants on Thermal and Fire Safety Properties of Polypropylene

Magnesium hydroxystannate [MgSn(OH)6, MgHS] was successfully prepared by a facile coprecipitation method. Then, MgHS was used to intumescent flame-retardant polypropylene systems. Thermogravimetry analysis results indicated that the introduction of MgHS can improve the thermal stability of the intumescent flame-retardant polypropylene system. Limiting oxygen index and UL-94 vertical burning test data show that the addition of MgHS can significantly improve the flame retardancy of intumescent flame-retardant polypropylene system. From the cone calorimetry results, it can be observed that the peak heat release rate is decreased in comparison with intumescent flame-retardant polypropylene. Moreover, the addition of MgHS significantly reduced the gaseous products, especially carbon monoxide.