Flame‐Retardant Performance of PA6 Modified by Amide‐Based Cyclophosphazene Derivative Combined With Aluminum Diethylphosphinate

Polyamide 6 (PA6) is a widely utilized engineering plastic with excellent mechanical performance, electrical insulation, and chemical resistance. However, its low limiting oxygen index (LOI) of 23.2% and severe melt dripping during combustion severely limit its applications. To develop an efficient and eco‐friendly flame‐retardant modification strategy for PA6, a novel cyclophosphazene derivative (ACP) was synthesized via a nucleophilic substitution reaction between HCCP and N ‐acetyl‐p‐aminophenol (APAP). Flame‐retardant PA6 composites were fabricated by melt blending the synthesized ACP with aluminum diethylphosphinate (ADP). The optimized composite achieved a LOI of 28.5%, accompanied by restrained melt dripping, shortened afterflame time, and a UL‐94 V‐1 rating. Char residue characterization indicated that the introduction of ACP effectively homogenized the distribution of phosphorus‐containing components within the char layer, greatly improving the quality and structural integrity of the protective carbonaceous layer.