An efficient flame-retardant and smoke-suppressant agent by coated hollow glass microspheres with ammonium molybdophosphate for thermoplastic polyurethane

In this article, an efficient flame-retardant and smoke-suppressant agent HGM@AMP was prepared by coated hollow glass microspheres (HGM) with ammonium molybdophosphate (AMP) and applied in thermoplastic polyurethane (TPU). The fire safety characteristics including heat and smoke production of TPU composites were investigated using cone calorimeter test (CCT), smoke density test (SDT), thermogravimetric analysis/infrared spectrometry (TG-IR), etc. The CCT results revealed that HGM@AMP could significantly decrease the heat release rate (HRR), total smoke release, smoke factor and so on. For example, when the loading of HGM@AMP was 0.5 mass%, the peak HRR value of the sample was decreased to 512.4 kW m−2, reduced by 55.1% compared with the sample containing the same loading of HGM (1141.8 kW m−2). The SDT results indicated that HGM@AMP could obviously improve the luminous flux of TPU composites in the test with or without flame, decreasing the production of smoke. And the TG-IR results showed that HGM@AMP can improve the thermal stability of TPU composites at high temperature. In all, HGM@AMP would make a great influence in improving the fire safety of TPU.