Comparative study on flame retardancy of multiple solid super acids-containing epoxy resin composites

Five different solid superacids (SO42-/TiO2-MXOY), including SO42-/TiO2-CuO, SO42-/TiO2- ZrO2, SO42-/TiO2Fe2O3, SO42-/TiO2-MnO, and SO42-/TiO2-MoO3, were successfully synthesized and characterized. Then, the fire retarded performance, smoke suppression and thermal stability of the epoxy resin (EP)/melamine coated ammonium polyphosphate (MAPP)/SO42-/TiO2-MXOY composites were investigated in details. The results showed that these SO42-/TiO2-MXOY can effectively enhance the limiting oxygen index (LOI) values of the EP/MAPP composites. Compared with that of the EP/MAPP composites, the total heat release (THR) values of the EP/ MAPP/SO42-/TiO2-Fe2O3, EP/MAPP/SO42-/TiO2-ZrO2, EP/MAPP/SO42-/TiO2-MnO and EP/MAPP/SO42-/ TiO2-MoO3 composites were remarkably reduced by 6%, 27 %, 32 % and 25 %, respectively, and the peak of heat release rate (PHRR) values of the EP/MAPP/SO42-/TiO2-Fe2O3, EP/MAPP/SO42-/TiO2-ZrO2, EP/MAPP/ SO42-/TiO2-CuO, EP/MAPP/SO42-/TiO2-MnO and EP/MAPP/SO42-/TiO2-MoO3 composites were reduced by 0.3 %, 56.8 %, 23.6 %, 26.9 % and 36.9 %, respectively. Moreover, for the solid superacids-containing EP composites, the initial decomposition temperatures (Ti) and the temperatures at the maximum mass loss rate (TMax) were advanced, and the char yields at 800 degrees C were much increased, which was indicated the considerable effect on the thermal degradation and char formation. Hence, the MAPP and SO42-/TiO2-MXOY had good synergistic flame retardancy and smoke suppression, and the best for SO42-/TiO2-MnO.