Developing highly flame-retardant PA6-based composites via in-situ PPS nanofiber network

This study investigates the enhancement of flame-retardant properties in polyamide 6 (PA6) composites through the incorporation of nanofibrillated polyphenylene sulfide (PPS) and a flame retardant, ammonium sulfamate (AS). By strategically combining a fibrillar PPS component (15 wt%) with a minimal AS concentration (1 wt%), the composite achieves a UL 94-V0 rating and a heightened limiting oxygen index (LOI) of 33.8 %. Rheological analyses reveal the formation of an entangled fibril network, contributing to a solid-like response that effectively suppresses flame propagation and prevents dripping. Micro-combustion calorimetry (MCC) results demonstrate a synergistic effect between the PPS nanofibril network and AS, leading to a significant 17 % reduction in peak heat release rate (PHRR) in PA6-nanofibrillated PPS-AS composites, showcasing improved flame-retardant properties compared to neat PA6. Despite a trade-off in mechanical properties, this research presents a promising strategy for enhancing the flame-retardant performance of PA6 composites, offering valuable insights for addressing fire safety challenges in PA6 applications.