Sodium lignosulfonate improve the flame retardancy of carboxymethyl chitosan @ melamine polyphosphate‐containing silicone acrylic emulsion‐based coatings

Abstract To address the flammability concerns of silicone acrylate emulsion (SAE), it is of utmost importance to develop composite coatings that excel in flame retardancy and smoke suppression. In this research, we have utilized carboxymethyl chitosan (CMCS) bonded‐melamine polyphosphate (MPP)/sodium lignosulfonate (LS) to create SAE composite SiPC coatings through the sol–gel method for flame‐retarding plywood. The results obtained that CMCS pretreatment of MPP (CMPP) facilitates the filling of P‐containing components in the SAE composite SiPC coating to further form a continuous and dense cross‐linked structure. Appropriate dosage of LS (2 wt.%) improve the flame retardancy of the coatings, which is manifested the peak heat release rate drops from 237.4 to 142.4 kW m −2 , total smoke production (TSP) is also significantly reduces by 55%. Notably, the coating undergoes a transformation into a nonflammable vitreous polyphosphate barrier layer while burning, effectively preventing the transfer of heat or mass. According to the calculation results of adsorption kinetics, the formaldehyde adsorption rate of the SiPC coating increased by 76.6%. Furthermore, the pyrolysis kinetics identify that the 3D Z.‐L.‐T model governs the coatings' pyrolysis, and the appropriate LS makes the pyrolysis Eα rise from 300.98 to 326.50 kJ mol −1 at 358 – 439°C, indicating enhanced thermal stability. In conclusion, our research has introduced a novel design strategy for developing the SiPC coating with exceptional properties, studies the flame‐retardant mechanisms of SAE composite SiPC coating, promotes the advancement of sustainable urban building materials, and explores a green, clean, and low‐cost ecological technology approach.