DNA encapsulated in nano-scale lignin was tested as a PIN flame retardant in the bio-based polymer poly lactic acid (PLA). DNA (deoxyribonucleic acid = biological genetic material, laboratory purified to >98%, from fish sperm) was encapsulated in nano-scale lignin (using laboratory pure lignosulphate), then grafted to OH-funcitonalised PLA to improve compatibility with PLA polymer. The resulting DNA-lignin-PLA was tested in PLA and in production of PLA foams at 0 – 20 % loading (that is, up to 1.1 %P – 1.7%N). Peak heat release rate was reduced by around one third and LOI (Limiting Oxygen Index) increased by around one half with 20% loading. Also, nucleation of foaming was improved (even at 1% loading) resulting in smaller foam cells and lighter foams.
“Biobased Flame-Retardant Polylactic Acid Foams through Lignin- Based Nanocarriers Encapsulating Deoxyribonucleic Acid”, H. Ridard, T. Mayer-Gall et al., ACS Sustainable Chemistry Engineering 2024 https://doi.org/10.1021/acssuschemeng.4c05886