Phosphorus and nitrogen PIN flame retardant from plant-based phytic acid and furfurylamine (from furfural). Phytic acid is the molecule in which plants store phosphorus in seeds, and is not digestible by humans, pigs and poultry. Furfurylamine is produced from furfural, derived from non-food plant ligno-celluloses (see pinfa Newsletter n°110) and ammonia (synthetic or can be recovered from e.g. anaerobic digesters). Phytic acid and furfurylamine are reacted in water and the resulting phosphorus – nitrogen PIN flame retardant recovered by evaporation and drying. This PIN FR, at 2% w/w loading in PLA (polylactic acid), increased LOI from 19.5 to 22 and achieved UL 94 V-0 (3 mm, neat PLA: Not Rated) and significantly reduced smoke (TSP), but with impacts on the mechanical properties of the polymer. The FR effect is identified as resulting from generation of melting droplets which disperse heat, reduced release of combustible products and improved compactness of char.
“One-step and green synthesis of a bio-based high-efficiency flame retardant for poly (lactic acid)”, G. Ye et al., Polymer Degradation and Stability 192 (2021) 109696 https://doi.org/10.1016/j.polymdegradstab.2021.109696