Smoke suppression properties of carbon black on flame retardant thermoplastic polyurethane based on ammonium polyphosphate

Flame retardant thermoplastic polyurethane (TPU) composites with low smoke release have been prepared by melt-blending TPU with commercially available carbon black (CB) and ammonium polyphosphate (APP). The experimental data from SDT indicated that an appropriate amount of CB and APP can decrease the amount of smoke production in the test with or without flame. The CCT results showed that CB and APP greatly decrease smoke production rate, total smoke release, and smoke factor of flame retardant TPU composites compared with that of pure TPU. Indeed, CB is considered as an effective smoke suppression agent and a good synergism with APP in flame retardant TPU composites, which can greatly improve the structure of char residue realized by TG and SEM results. The TG and DTG results showed that CB can decrease the initial decomposition temperature and improve the thermal stability at high temperature for flame retardant TPU composites. More interest, the TG-IR study indicates that the volatilized products are CO2, ammonia compound, acid anhydride, water, alkane compounds, and aromatic compounds according to the temperature of onset formation. This is a very meaningful result in fire safety materials fields.