Chitosan Oligosaccharide Cross‐Linked Piperazine Pyrophosphate/Melamine Polyphosphate Modified Silicone‐Acrylic Emulsion‐Based Flame‐Retardant Coating

ABSTRACT Chitosan oligosaccharides (COS) could crosslink phosphorus and nitrogen‐containing flame retardants to construct bio‐based flame retardants with excellent compatibility due to their unique structure. Herein, chitosan oligosaccharide COS is employed to cross‐link piperazine pyrophosphate (PAPP) and melamine polyphosphate (MPP), the as‐prepared COS@PAPP@MPP served as additive to prepare the silicone‐acrylic emulsion (SAE) coating with sol‐gel method. The results show that 2 wt% COS dosage improves the compatibility of PAPP and MPP in the SAE matrix, maintaining the coating's transparency and hydrophobicity, with a water contact angle of 96.72°. The cone calorimetry demonstrates that the COS@PAPP@MPP improves the flame retardancy and smoke suppression of SAE, evidenced by the decreased p‐HRR from 236.7 to 120.3 kW m −2 and 64.08% diminished total smoke production, with the flame retardancy index climbs from 1.00 to 5.04. Because the COS favors the formation of the denser and resilient vitreous residues during combustion, making the pyrolysis activation energy E α increase from 251.43 to 317.65 kJ mol −1 during 368°C–450°C, according to the determined 3D‐Z.‐L.‐T. model through trial thermodynamic. It explores a new and facile design for synthesizing halogen‐free biomass‐doped flame retardants, expanding the COS's crosslinking mechanism for precise construction of organic functional structures.