Polyaniline‐Functionalized Needle Coke as a Phosphorus/Nitrogen‐Rich Hybrid Filler for Flame‐Retardant and Antistatic Rigid Polyurethane Foam

Rigid polyurethane foam (RPUF) combines low density and thermal‐insulation capability but is limited by flammability, smoke release, and electrostatic charge accumulation. A phosphorus/nitrogen‐rich conductive hybrid, N,N′,N″‐tris(3‐aminophenyl)phosphoric triamide‐PANI@NC (MBNP), was prepared by forming an N,N′,N″‐tris(3‐aminophenyl)phosphoric triamide/polyaniline (MB/PANI)‐derived functional shell on needle coke (NC) and incorporated into RPUF. The design uses NC as the conductive carbon framework, while the MB/PANI‐derived shell improves filler‐matrix compatibility and contributes to phosphorus/nitrogen‐assisted charring. Compared with pristine NC, MBNP is more favorable for preserving foam skeleton integrity and constructing conductive pathways. At 9 wt% loading, MBNP/RPUF achieves a UL‐94 V‐0 rating and a surface resistance of 4.4 × 10 7 Ω. Relative to pure RPUF, the peak heat release rate, total heat release, peak smoke production rate, and total smoke production decrease by 33.5%, 13.9%, 31.9%, and 28.7%, respectively. The compression strength increases from 0.23 to 0.48 MPa, although the bending strength remains below that of pure RPUF. TG‐IR and char analyses indicate reduced volatile release and formation of a compact P/N‐containing carbonaceous layer. This work demonstrates a practical surface‐functionalized NC‐based hybrid‐filler strategy for multifunctional RPUF composites.