Kilogram-Scale In Situ Growth of Cerium–Zinc Layered Double Hydroxides on Ammonium Polyphosphate for High-Performance Halogen-Free Flame-Retardant ABS Composites

The halogen-free flame-retardant acrylonitrile-butadiene-styrene (ABS) composites were fabricated by combining cerium–zinc layered double hydroxides in situ growth on the surface of ammonium polyphosphate (Ce/Zn-LDH-APP) in a kilogram-scale strategy with phosphoramide derivative (DPPIP). The resulting ABS composite achieved UL-94 V-0 rating with the limiting oxygen index (LOI) of 28.1%. Notably, compared with neat ABS, the peak heat release rate (pHRR) and peak smoke production rate (pSPR) were reduced by 76.0 and 69.6%, respectively. Analysis of the flame-retardant mechanisms revealed that the strong catalytic cross-linking effect of Ce/Zn-LDH and the enrichment of phosphorus, cerium, and zinc in the residues promoted the formation of the robust protective charring layers in the condensed phase. Simultaneously, the excellent synergistic gaseous flame-retardant effect occurred through radical quenching and the release of nonflammable gases from the decomposition of DPPIP and ammonium polyphosphate (APP). Furthermore, the surface modification of APP with the nanoeffect of Ce/Zn-LDH enhanced interfacial compatibility with the ABS matrix through a “mechanical interlocking” effect, thereby mitigating the deterioration of mechanical properties. This work presented a feasible and promising large-scale preparation strategy for high-performance and halogen-free flame-retardant ABS composites.