Nanosheet-coated synthetic wood with enhanced flame-retardancy by vacuum-assisted sonocoating technique

Compared to natural woods, synthetic woods have superior mechanical stability, thermal insulation, and flame retardancy owing to their hierarchically cellular microstructures and intrinsic advantages of the thermosetting matrix. Increasing the long-time fire resistance is very important to the practical application. In this study, we present a novel coating strategy by a vacuum-assisted sonication technique (sonocoating) with a rectorite nanosheet dispersion to create a uniform nanocoating on the channel walls of synthetic wood. Owing to ultrasonic energy and vacuum pressure, the nanosheet dispersion can penetrate deep down to form a layered nanocoating on the channel surface. The coated synthetic woods can withstand fire (400–600 °C) for more than 10 min with 62% mass retainment, surpassing uncoated synthetic woods and natural woods. Therefore, as a lightweight and strong composite with enhanced flame-retardant performance, the coated synthetic woods have huge potential applications in safe and energy-efficient buildings.