A polymeric phosphorus – nitrogen PIN FR was synthesised without using solvent achieving UL 94 V-0 in PLA at 2% loading. The polyphosphoramide DM-H was synthesised in a two-step, one-pot controlled condensation reaction, without solvents or catalysts, using HAD (1,6-hexanediamine) and DMMP (dimethyl methyl-phosphonate), resulting in an oligomer MW = 6 800 g/mol containing c. 7 -11 wt% N and 12 – 16 wt% P. Fire performance was tested for PLA (poly lactic acid= at 0 – 3% loading DM-H. At 2% DM-H, LOI of PLA was increased by 50%, peak heat release rate was reduced by 11% and UL 94 V-0 was achieved (3.2 mm). The mechanical performance characteristics of PLA were not significantly modified by 2% loading of DM-H.
“One-Pot, Solvent- and Catalyst-Free Synthesis of Polyphosphoramide as an Eco-Benign and Effective Flame Retardant for Poly(lactic acid)”, J. Feng et al., ACS Sustainable Chem. Eng. 2020, 8, 16612−16623 https://dx.doi.org/10.1021/acssuschemeng.0c05931