A silicon polyphosphoramide was synthesised and tested as a PIN flame retardant for bio-based polylactide plastic. The commercially available chemicals dimethyl methylphosphonate (DMMP) and 1, 3-Bis(3-aminopropyl) tetramethyl-disloxane (BATDMS) were one-step reacted without solvent, to produce an experimental polymeric silicon – phosphorus – nitrogen containing PIN flame retardant (silicon polyphosphoramide, DM-Si). At % loading of DM-Si, LOI (limiting oxygen index) of PLA was increased from 19.8 to 27.9 and peak heat release rate reduced by 15%, achieving UL 94 V-0 (3 mm). Tensile strength and transparency were not significantly modified, and toughness was improved.
“A Si-containing polyphosphoramide via green chemistry for fire-retardant polylactide with well-preserved mechanical and transparent properties”, J. Feng et al., Chemical Engineering Journal 431 (2022) 134259 https://doi.org/10.1016/j.cej.2021.134259