Bio-based phosphorus flame retardant achieves UL 94 V-0 in polyvinyl alcohol with good mechanical and UV performance. The bio-based PIN FR was produced by reacting phytic acid (phosphorus-rich and widely available in plant seeds) and ethylenediamine at room temperature (both dissolved in ethanol, 3:1 ratio). With 15% loading of the PIN FR, PVA achieved UL 94 V-0 (0.5 mm) with no burning dripping, versus Non Rated for neat PVA. LOI was increased by c. 50% and peak heat release rate decreased by nearly 70%. Tensile strength and elongation at break of PVA-15%FR were not significantly different from neat PVA (both are actually improved at 5% FR), probably because of hydrogen bonding between PVA and the PIN FR. 15% PIN FR also decreases UV transmission by 20-45% (in 0.1 mm film). Despite the PIN FR being bio-based, tests suggest some cytotoxicity of the PVA-FR composites, compared to neat PVA or to control.
“Design of a bio‑based flame retardant for polyvinyl alcohol with superior flame retardant, mechanical and UV‑blocking properties”, C. Wang et al., J. Polymer Research (2023) 30:228, https://doi.org/10.1007/s10965-023-03611-y