Targeted modification of black phosphorus by MIL-53(Al) inspired by “Cannikin's Law” to achieve high thermal stability of flame retardant polycarbonate at ultra-low additions

To tailor the enhancement strategies for polymers according to structure, inspired by the concept of “Cannikin's Law”, this work proposes and exemplifies a novel strategy for reinforcing the carbonate linkages to simultaneously improve the thermal and fire safety of polycarbonate (PC). Herein, we introduce MIL-53(Al) to functionalize black phosphorus (BP@MIL-53) via a simple method of hydrothermal. As expected, the incorporation of BP@MIL-53 (1.0 wt%) in PC, resulted in an increase in T1% of 32 °C and 41 °C under nitrogen and air respectively, along with the reduction of 49.4% and 19.3% for peak heat release rate and total heat release. Moreover, PC/BP@MIL-53-1.0 passed the V-0 rating of UL-94 with a high limiting oxygen index (LOI) value of 30.5%, which achieved the dual purpose of simultaneously enhancing the thermal stability and flame retardancy of PC. In addition, the addition of flame retardants had no effect on the tensile strength of the PC. These results demonstrate the high flame retardant efficiency of BP@MIL-53 at ultra-low addition levels. Moreover, these results also illustrate the forward-looking nature of the strategy of tailoring flame retardants to the properties of the substrate. This work combines the advantages of black phosphorus (BP) and Mental organic frameworks (MOFs) materials. The carbonate linkages reinforcement approach provides a viable, new, and scalable idea for polyester compounds' thermal and fire safety properties.