Flame Retardant Enhancement of Bio-Based Polyamide 56/6 Via a Multi-Branched, Nitrogen-Phosphorus Dual Synergistic Organic Flame Retardant

The development of polyamide materials with fire safety is of great importance at this stage. In this study, a novel nitrogen-phosphorus bis-system flame retardant with a multi-branched structure was prepared and applied to the new bio-based polyamide 56/6 (PA56/6). The LOI of FRPA56/6@MC8% reached 26.6% when the MC content was 8 wt%, and the UL-94 test result was V-0. According to the results of cone calorimetry test, the amount of heat release (THR) of FRPA56/6@MC and the peak heat release rate (PHRR) decreased by 22.9% and 41.0%, respectively, which indicated that the flame retardant MC promoted the flame retardancy of PA56/6. Moreover, the study delved into the pyrolysis kinetics and mechanisms of polyamide materials, crucial for understanding the flame-retardant modification of polyamides. In this work, a series of kinetic parameters, such as the pyrolysis activation energy (E) of PA56/6 were obtained through four isoconversion models: Friedman, KAS, FWO, and STK, and the pyrolysis modeling mechanism of PA56/6 was further investigated using two non-isoconversion models: Coats-Redfern and Criado. Overall, this study presents an innovative strategy for enhancing the flame retardant properties of PA56/6, with the potential for application in automotive components and other pertinent fields.