Designing hierarchical ternary structure based on NiAl LDH anchored phosphorus-doped g-C3N4 dotted with Fe3O4 nanoparticles towards improving the fire safety of thermoplastic polyurethane

Abstract

High fire hazard of generating a great deal of heat and toxic volatiles has been deemed as notorious issue of thermoplastic polyurethane (TPU), severely impeding its practical usage. Hence, a hierarchical ternary structure (FNPCN) based on NiAl LDH anchored phosphorus-doped g-C3N4 dotted with Fe3O4 nanoparticles is rationally designed as flame retarded additive for TPU. Specifically, by adding 1.0 wt% FNPCN, the obvious reductions of 30.9% and 21.8% in peak heat release rate and total heat release are obtained, suggesting the suppressed heat release. Meanwhile, a marked decrease of 31.9% in peak smoke production rate is discovered, implying the reduced fire toxicity. Moreover, the direct evidence for hindered releases of toxic CO and HCN gases is provided by TG-IR spectra. These results jointly corroborate the efficacy of FNPCN in impairing the fire hazard of TPU, originating from its physical barrier and chemical catalyst characters. This work may shed a light on the designing of hierarchical ternary structure, optimizing their prospects in polymer-matrix composite and other areas.