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

Five different solid superacids (SO 4 2− /TiO 2 -M X O Y ), including SO 4 2- /TiO 2 -CuO, SO 4 2- /TiO 2 -ZrO 2 , SO 4 2- /TiO 2 -Fe 2 O 3 , SO 4 2- /TiO 2 -MnO, and SO 4 2- /TiO 2 -MoO 3 , 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)/SO 4 2− /TiO 2 -M X O Y composites were investigated in details. The results showed that these SO 4 2− /TiO 2 -M X O Y 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/SO 4 2− /TiO 2 -Fe 2 O 3 , EP/MAPP/SO 4 2− /TiO 2 -ZrO 2 , EP/MAPP/SO 4 2− /TiO 2 -MnO and EP/MAPP/SO 4 2− /TiO 2 -MoO 3 composites were remarkably reduced by 6%, 27 %, 32 % and 25 %, respectively, and the peak of heat release rate (PHRR) values of the EP/MAPP/SO 4 2− /TiO 2 -Fe 2 O 3 , EP/MAPP/SO 4 2− /TiO 2 -ZrO 2 , EP/MAPP/SO 4 2− /TiO 2 -CuO, EP/MAPP/SO 4 2− /TiO 2 -MnO and EP/MAPP/SO 4 2− /TiO 2 -MoO 3 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 ( T i ) and the temperatures at the maximum mass loss rate ( T Max ) were advanced, and the char yields at 800 °C were much increased, which was indicated the considerable effect on the thermal degradation and char formation. Hence, the MAPP and SO 4 2− /TiO 2 -M X O Y had good synergistic flame retardancy and smoke suppression, and the best for SO 4 2− /TiO 2 -MnO.