A novel and effective method to fabricate flame retardant and smoke suppressed flexible polyurethane foam

Abstract

In the present work, chitosan and magnesium hydroxide (MH) were successfully deposited on the surface of flexible polyurethane foam (FPUF). Due to the strong interaction, the coated foam with 10.3 wt% weight-gain could be prepared by constructing one chitosan layer and one MH layer. Scanning electron microscopy images showed that this coating continuously covered the substrate. The combustion properties of FPUF were investigated by cone calorimeter and smoke density tests, and the gases released during the thermal degradation process were monitored by thermal gravimetric-Fourier transform infrared spectrometry. It was found that the FPUF with a chitosan/MH coating kept its shape and released less black smoke after being exposed to a butane flame for 10 s, while the pure foam was consumed completely. The cone calorimeter test data indicated that a reduction in the peak heat release rate of the foam with 10.3 wt% weight-gain achieved 52.6% relative to pure foam. Remarkably, the smoke density test results showed that the coating can significantly suppress the smoke production of FPUF. Moreover, the evolved gas products of FPUF during the thermal decomposition were effectively decreased after being covered with the hybrid coating.