Flame-retardant and antibacterial flexible polyurethane foams with high resilience based on a P/N/Si-containing system

In this work, the coatings used phosphorylated chitosan (PCS) and GP-108 via the dip-coating method presented exceptional flame retardancy and antibacterial properties for flexible polyurethane foams (FPUF). PCS/GP@FPUF with 35% weight gain of PCS/GP can receive the UL-94 V-0 rating and obtain a 32% reduction of peak heat release rate value compared with that of FPUF, and it remains relatively dense char residues. The effective heat of combustion of PCS/GP@FPUF is 21.6 kJ/g, presenting a 22% decrease compared with that of FPUF. Meanwhile, the PCS/GP coatings mainly have the condensed-phase flame-retardant mechanism associated with the analysis of char residues and the volatile products released through the thermal degradation process. X-ray photoelectron spectroscopy results confirm that the char residues of PCS/GP@FPUF consist of highly-graphitized carbon and it formed P-N-Si synergistic char layers. In addition, the antibacterial rates of PCS/GP@FPUF against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are 99.99%, and the incorporation of GP-108 does not influence the antibacterial properties of PCS. Importantly, the resiliency of FPUFs has been slightly influenced. Briefly, the flame-retardant and antibacterial FPUFs with wonderful resiliency are hopeful to be applied as filler materials for vehicle seats and obtain longer service lives.