Design of High‐Performance <scp>PA6</scp> / <scp>GF</scp> Composites: Simultaneous Enhancement of Flame Retardancy and Mechanical Strength via a Novel <scp>MCA</scp> / <scp>MPP</scp> / <scp>TMK</scp> Hybrid System

ABSTRACT To address the challenge of deteriorating mechanical properties in flame‐retardant glass‐fiber reinforced polyamide 6 (PA6/GF) composites, a novel hybrid flame retardant system, comprising melamine cyanurate/ammonium polyphosphate (MCA/MPP) and titanate‐modified kaolin (TMK), was designed and incorporated into PA6/GF. The morphology and interfacial interactions of the composites were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The fire resistance was evaluated by limiting oxygen index (LOI), vertical burning (UL‐94), and cone calorimetry tests. The results demonstrated a superior synergistic effect between MCA/MPP and TMK. The composite achieved a V‐0 rating in the UL‐94 test and a high LOI value of 26.7%. Cone calorimetry revealed a significant reduction in peak heat release rate (PHRR) and total heat release (THR), indicating an enhanced charring layer mechanism. Remarkably, the mechanical performance was simultaneously enhanced, attributed to the improved dispersion and interfacial adhesion by TMK; the flame retardancy was attained with relatively little sacrifice of mechanical properties. The tensile strength, notched impact strength, flexural strength, and flexural modulus reached 123.5 MPa, 10.5KJ/m 2 , 174.1 MPa, and 6989 MPa, respectively. This work provides a viable strategy for developing high‐performance PA6/GF composites with excellent fire safety and robust mechanical properties for advanced engineering applications.