PIN flame retardants show varying impacts on fire performance and smoke emissions from rigid polyurethane foam. Seven combinations of P-based, inorganic and nitrogen flame retardants and nano-fillers were tested and compared to pure rigid PU foam: triethylphosphate (TEP), dimethylpropanphosphonate (DMPP), cyclic phosphorus compound, aluminum hydroxide (ATH), ammonium polyphosphate (APP), zinc borate, multi-walled carbon nanotubes (MWNTs) and nanosized titanium dioxide. One combination showed negative effects both on fire performance (peak heat release rate pHRR, MARHE) and on smoke emission. The other six PIN combinations reduced pHRR and MARHE. A combination of 11% total loading of the three phosphorus PIN FRs, 15% zinc borate and 3% carbon nanotubes achieved nearly -20% pHRR and improvement of all four measured smoke parameters (- 10% total smoke release, – 13% maximum smoke density). Volatile organics in fire gases were analysed, concluding that nano-fillers reduced the amount and number of occurring products, but nano-particles were not analysed in fire gases.
“Analysis of flammability and smoke emission of rigid polyurethane foams modified with nanoparticles and halogen-free fire retardants”, K. Salasinska et al., J Therm Anal Calorim (2017) 130:131–141 https://doi.org/10.1007/s10973-017-6294-4