Preparation of modified hollow glass microspheres using Fe2O3 and its flame retardant properties in thermoplastic polyurethane

In this paper, the hollow glass microspheres coated with Fe2O3 (HGM-Fe2O3) were synthesized and characterized by scanning electron microscopy (SEM-EDS) and X-ray photoemission spectroscopy, respectively. Then, the flame retardant and smoke suppression properties of HGM-Fe2O3 in thermoplastic polyurethane (TPU) composites have been investigated intensively using several methods, including cone calorimeter test (CCT), smoke density test (SDT), scanning electron microscopy, and thermogravimetric analysis/infrared spectrometry. The CCT results showed that HGM-Fe2O3 can greatly enhance the flame retardance of polymer matrix materials compared with TPU. For example, HGM-Fe2O3 can reduce heat release rate, total heat release, and smoke release of TPU composites in the combustion process. The SDT results showed that HGM-Fe2O3 can effectively decrease the amount of smoke production in the test. Furthermore, the TG results indicate that HGM-Fe2O3 can decrease the initial decomposition temperature, and change the structure of char residue layer.