PIN FR polycarbonate without PFAS

Science review summarises PIN FR solutions for transparent polycarbonate (PC) without PFAS anti-drip agents. Neat polycarbonate is flammable with UL-94 rating of V2 and emission of dense toxic smoke. A range of PFAS substances are used as FR synergists and anti-drip agents in PC, including polytetrafluoroethylene (PTFE), perfluorooctanoic acid (PFOA) and salts, potassium perfluorobutane sulfonate (PFBS/K+, Rimar salt) and perfluorooctane sulfonate (PFOS). Different PIN FR solutions are presented which can achieve UL 94 V-0 in PC without PFAS additives: P-N systems (including phosphate esters, phosphaphenanthrenes, phosphazenes, and phosphines combined with amides, amines, imidazoles, and pyrazines), siloxanes, sulfonates, nano-based. The paper emphasises sulfonates, because they degrade to release SO₂ at the degradation temperature of polycarbonate, resulting in reactions which enhance char formation. They can also act in the gas phase when combined with metal ions. However, they cannot alone achieve UL 94 V-0 in low thicknesses because of flaming dripping.

“Recent Advances and Perspectives in UL 94-0 Rated Flame‐Retardant Polycarbonate: Addressing Challenges Under Per‐ and Polyfluoroalkyl Substances Bans”, T. Sai et al., Safety Science and Technology, 2026; 1:e70001, https://doi.org/10.1002/sst3.70001