Graphene Oxide Nanocoating Prevents Flame Spread on Polyurethane Sponge

Many current flame retardant technologies for polymeric materials contain environmentally harmful compounds, negatively impact processing and mechanical properties. In an effort to tackle these issues, graphene oxide (GO) nanocoating was deposited on the surface of polyurethane sponge (PUS) to reduce its flammability via layer-by-layer (LbL) assembly method. The results indicated that GO was evenly distributed on the surface of PUS to form GO coating PUS (PUS@ GO) composites. This coating system completely eliminated melt dripping of sponge upon exposure to the direct flame from a butane torch. According to the result of cone calorimeter test, PUS@ GO composites exhibited excellent flame retardancy. In particular, PUS@ GO composites submerging into 5 mg center dot mL(-1) GO suspension, had significant reduction in the PHRR value (53.3%), THR value (35.9%), SPR value (61.8%), TSR value (81.9%), and peak CO production value (65.8%). Such significant improvement in flame retardancy suggested that GO nanosheets were good candidate as a flame-retardant LbL coating to reduce the flammability of PUS.