Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Synergistic flame-retardant strategy for EPS foams, comprising synergies of EG/NHP/PSSA in improving anti-ignition, self-extinguishing, and char-forming capabilities and in suppressing peak burning intensity thereof. 7EG/11NHP/2PSSA/EPS achieves an LOI of 31.0%, passes UL94 V-0 rating without melt dripping.

ABSTRACT
Flame retardation has been a vital modification for most polymer materials, especially for the extremely combustible and widely used polystyrene foams in various fields. A synergistic flame-retardant strategy based on expandable graphite (EG), ammonium hypophosphite (NHP), and sodium polystyrene sulfonate (PSSA) was proposed to manufacture high-performance fire-safety expandable polystyrene (EPS) foams with satisfied comprehensive physical and mechanical properties. The influence and working mechanism of EG/NHP/PSSA in inhibiting EPS foam combustibility were studied. The dose-effect relationship results disclosed the multiple synergistic mechanisms of EG/NHP/PSSA in improving the anti-ignition, self-extinguishing, char-forming capability, and suppressing peak burning intensity of EPS foam. 7EG/11NHP/2PSSA/EPS achieved a LOI value of 31.0%, passed UL94 V-0 rating without melt dripping, and self-extinguished within 1 s after two flame applications. The multi-synergy flame retardant mechanism of EG/NHP/PSSA was also disclosed by combustion process monitoring, char residue investigation, and thermal decomposition tracing, including the suppression on the β-scission of EPS foam. This study on the synergistic flame-retardant combination strategy provides new insights for manufacturing high-performance fire-safe polymeric foam materials.