News Coatings Technologies
Non-toxic phosphorus-sulfur flame retardants for fire-safe aircraft seat textiles
A new study investigates phosphorus-sulfur compounds as safe and effective flame-retardant solutions for polyamide-based aircraft seat textiles applied via a back-coating method.
Fire safety in aircraft seat textiles is a critical priority for the aviation industry, demanding high standards for both effectiveness and safety of flame retardants. A recent study explored phosphorus-sulfur compounds as non-toxic and efficient flame-retardant solutions, applied using a polyurethane-based back-coating technology on polyamide textiles.
The tested flame retardants demonstrated distinct mechanisms of action. Tetramethyl (DMPS) and tetraphenyl (DPPS) compounds primarily acted in the condensed phase, leading to significant char formation. In contrast, DPPOS and DOPOS exhibited strong gas-phase activity, which was key to improving fire resistance. Only the fabric treated with DOPOS successfully passed the aviation industry’s FAR 25.853 vertical burn test, which requires compliance with a twelve-second burning duration.
Event Tip: EC Conference Frontiers in Fire Protective Coatings
With stricter regulations, rising sustainability requirements and modern construction methods, the field of fire-protective coatings is evolving rapidly. Join leading experts on 13 – 14 April 2026 in Copenhagen, Denmark, to discuss the latest scientific and technological advances, from bio-based flame-retardant systems and enhanced durability testing to next-generation intumescent technologies and digitalisation of certification and performance assessment processes
Gas-phase mechanisms and toxicological safety
The gas-phase activity of DOPOS and DPPOS was confirmed through DIP-MS analyses, which detected phosphorus radicals (PO and PO₂) with high intensity. Despite reduced char formation and limited phosphorus retention, these compounds demonstrated robust flame-retardant performance. Complementary analyses, including cone calorimetry and TGA, supported the interpretation of gas-phase mechanisms.
Preliminary in vitro tests with human lung epithelial cells (A549) and macrophages (THP-1) revealed no cytotoxic effects for DOPOS and DPPOS. These findings highlight their potential as safe and effective candidates for aircraft seat textiles, improving fire safety while prioritising passenger and crew health.
Source: Özer, M. S. et al., Non-toxic sulfone-bridged phosphorus flame retardants for fire-safe back-coated aircraft seat textiles. Prog. Org. Coat. 109833 (2025).
