Accessible preparation of a novel nitrogen‑phosphorus synergetic nanocellulose-based flame retardant with excellent char-forming ability for enhancing the anti-melting droplet property of PA66.

Developing eco-friendly and effective flame retardants is crucial for enhancing the fire resistance of polymeric materials. This study developed a novel nitrogen‑phosphorus (NP) synergistic nanocellulose-based flame retardant (CNC-PEI-PA) by grafting polyethyleneimine (PEI) and phytic acid (PA) onto the CNC. CNC-PEI-PA demonstrated remarkable thermal stability, char-forming ability, and antibacterial activity.