Complex PIN flame retardant’s were experimentally synthesised and tested for fire performance, smoke production rate and release of flammable aromatic compounds in polystyrene at 0-4%. The PIN FRs were reaction products of organic aluminium hypophosphites (AHPi) with graphitic carbon nitride.
Heat release rate was reduced by 28% and smoke release rate by up to 22%. Gram-Schmidt curves show that the PIN FRs reduced the release of pyrolysis products in burning and reduced total evolved gases. The authors suggest that these effects result from both release of phosphorus compounds from the PIN FR are in fire, which scavenge free radicals reducing flammable gas emissions, and char generation, resulting in a physical barrier.
“Graphitic carbon nitride/phosphorus-rich aluminum phosphinate hybrids as smoke suppressants and flame retardants for polystyrene”, Y. Shi et al., J. Hazardous Materials 332 (2017) 87–96 https://doi.org/10.1016/j.jhazmat.2017.03.006