A thirty-one page review paper, based on nearly eighty publications, summarises developments and perspectives for bio-based PIN flame retardants for synthetic polymeric materials. Renewable PIN FRs discussed are based on: tannic acid, phytic acid (a plant molecule containing 60% phosphorus by weight), isosorbide, diphenolic acid, DNA, lignin and β-cyclodextrin. Main applications illustrated are in epoxy, EVA, PPE and PLA (polylactic acid). An important challenge identified is incompatibility between low-molecular weight, hydrophilic bio-based molecules and hydrophobic polymers and research is addressing this by rendering bio-based PIN FRs “reactive” (covalent bonding to the polymer) but this can impact material properties. Another challenge is bottlenecks in supply of relevant bio-based molecules.
“Recent Advances in Bio-Based Flame Retardant Additives for Synthetic Polymeric Materials”, C. Hobbs, Polymers 2019, 11, 224 https://doi.org/doi:10.3390/polym11020224