Phosphonitrile hybrid metal-polyphenol network: An effective strategy for developing functional PVA composites with flame retardancy, antibacterial and UV resistance

The white pollution caused by non-degradable plastics poses a serious threat to human society and the environment, thus developing biodegradable material is urgent. In this work, a novel phosphonitrile hybrid metal-polyphenol network was constructed and used for the preparation of flame retardant, UV resistant and antibacterial multifunctional polyvinyl alcohol composite (PVA@HCPD-Ag). The limiting oxygen index (LOI) value of PVA@HCPD-Ag was improved to 33.5%, while the peak heat release rate (PHRR) and total heat release (THR) decreased by 35.62% and 47.76%. Besides, the ultraviolet protection factor (UPF) value of PVA@HCPD-Ag was significantly improved from 4.63 of the original PVA to 482.79, while the tensile strength was increased by 10.23%. Furthermore, the inhibition efficacy of PVA@HCPD-Ag for E. coli and S. aureus was up to 98.12% and 99.99%. This work explored the synergistic flame retardant effect of in-situ reduced Ag⁰ and phosphonitrile crosslinked polyphenol network and proposed an advanced strategy for developing high value-added functionalized PVA materials.