Flame retardancy of water‐based intumescent coatings with etherified melamine–formaldehyde and polyvinyl acetate copolymer hybrid resin

Abstract This study investigated etherified melamine–formaldehyde (MF) and polyvinyl acetate copolymer hybrid resins with different intumescent formulations to improve the flame retardancy of plywood. The CO and CO 2 emissions of intumescent coatings were also investigated. The miscibility of two resins is indicated by a single cure peak. Intumescence with a hybrid resin demonstrated better flame retardancy relative to that with a pure etherified MF resin. The results of scanning electron microscopy and a cone calorimeter test indicated that a lower binder resin (BR) content enhances fire retardancy and forms an ideal char. Furthermore, an evaluation of total heat release in addition to CO and CO 2 emissions (for 300 s) revealed that the intumescent coating had the same flame retardancy when the BR content was increased by 40%. The survival duration of the chemical structures of the phosphocarbonaceous chars was verified using Fourier‐transform infrared spectroscopy and solid‐state phosphorus‐31 nuclear magnetic resonance analyses.