Recycling of waste melamine formaldehyde foam as flame-retardant filler for polyurethane foam

In the present research, the waste leftovers of a thermoset polymer foam with intrinsic flame resistance, melamine formaldehyde foam (MF), were pulverized to fine powder and added into polyurethane foam (PUF) as a flame-retardant filler. A series of characterizations were employed to investigate the obtained MF powder and the properties of the new flame retardant PUF. It was revealed that the pulverization process could produce fine MF powder. Moreover, it showed that the incorporation of MF powder could greatly decrease the heat release rate (HRR) and flammability of PUF without obvious impairment of mechanical property. Combined with a small amount of guanidine phosphate (GP), it could achieve quick self-extinguishment of the modified PUF. The process for recycling waste MF is easy and cheap, indicating an eco-friendly way for waste MF recycling, as well as a successful preparation of a low-cost and halogen-free flame retardant PUF.