Green organic-inorganic coatings for flexible polyurethane foams: Evaluation of the effects on flame retardancy, antibacterial activity, and ideal mechanical properties

Flexible polyurethane foams (FPUFs) have high flammability accompanying with massive heat release and toxic smokes containing -NCO groups and HCN release, resulting in causing serious pollution and threatening human lives. Therefore, it is necessary to reduce the toxic products release while endowing FPUFs with flame retardancy . In this work, phosphorylated chitosan (PSPLCS) was prepared through an eco-friendly, cost-effective and simple process, and paired with ZnO to form the films which acted well with excellent flame retardancy, smoke suppression and antibacterial properties on FPUFs. FPUF-PSPLCS/Zn 3 self-extinguished and reached up to the UL-94 V-0 rating, the PHRR value decreased by 59%, and the char residues at 700 °C significantly enhanced. By investigating the released products during the thermal degradation and the structure of char residues, the flame-retardant mechanism was concluded that the decreased production of flammable and toxic gases resulted in burning asphyxiation, and denser char layers established exceptional heat and O 2 barriers. Furthermore, FPUF-PSPLCS/Zn 3 exhibited 99.99% antibacterial rates on both Escherichia coli and Staphylococcus aureus. Fortunately, the coatings had barely affected the mechanical properties. The flame-retardant and antibacterial FPUFs have been successfully prepared, and this work proposes a new and easy tread for the construction of multi-functional coatings.