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• A bio-based P/N-based melamine-aggregate (MPA) is prepared for use in PA6. • Combination use of MPA and ADP significantly decreases the heat release of PA6. • Synergistic effects between MPA and ADP at certain ratio are demonstrated. Engineering polyamide 6 (PA6) is preferred for its superior mechanical properties, yet the intrinsic flammability restricts its industrial applications. As one of the biomass phosphorus-containing chemicals, phytic acid (PA) is favorable for its high phosphorus content and aggregation ability, making it expected to enhance the fire retardancy of PA6. Herein, a melamine-phytate aggregate (MPA) is prepared by electrostatic interaction in aqueous solution, and applied as a synergist for aluminum diethylphosphinate (ADP) in PA6. The strong synergistic effect exists between ADP and MPA towards PA6, especially when their mass ratio is 3:1 and the total loading is 18 wt%. Compared to the neat PA6, this formula allows for remarkable decreases in peak heat release rate (PHRR), total heat release (THR), and maximum average heat release rate (MARHE) by ∼ 48 %, ∼ 27 %, and ∼ 30 %, respectively, as well as a high synergistic efficiency of ∼ 43 % in PHRR. This PA6 composite also presents a V-0 rating in the vertical burning (UL-94) test and a high limiting oxygen index (LOI) of 29.7 %. This work offers an eco-friendly strategy for developing bio-based P/N fire-retardant aggregates for fabricating PA6 materials with high fire safety. [Display omitted] [ABSTRACT FROM AUTHOR]

• Atom-economic synthetic strategy of a P/N fire retardant (APN) is developed. • 3 wt% APN significantly improves the fire safety of PLA. • The toughness of PLA increases by 85% but maintaining its tensile strength. Renewable and biodegradable polylactide (PLA) has excellent mechanical strength but is highly flammable which restricts its practical applications. Many phosphorus/nitrogen (P/N)-based flame retardants are effective in PLA, but their high addition loading usually decreases the mechanical strength of the PLA bulk. For polyphosphoramides, despite high fire-retardant efficiency, their chemical synthesis often generates chemical wastes as byproducts. Herein, we report an atom-economic and highly efficient oligomeric P/N fire retardant (APN) prepared using a mild Michael addition polymerization with no byproducts. Using only 3 wt% APN, the resulting PLA exhibits desired fire retardancy including a UL-94 V-0 rating and a limiting oxygen index of 37.6%. Furthermore, the toughness of the fire-retardant PLA increases by 85% compared to pure PLA, with both tensile strength and thermal stability preserved. This work offers an atom-economic strategy for synthesizing highly efficient P/N fire retardants for use in the creation of fire-resistant PLA with robust mechanical properties. Atom-economic synthesis was developed to synthesizing a P/N-containing fire retardant for creating fire-retardant PLA. [Display omitted] [ABSTRACT FROM AUTHOR]

• MXene/PP composites are prepared by hot-pressing PP non-woven fabric coated with functionalized MXene. • The final composite exhibits an EMI shielding performance of ∼90 dB (8–12 GHz, thickness ∼400 μm). • The resultant MXene/PP composites are mechanically robust with a superior anti-fatigue capability. • The resultant MXene/PP composites exhibit a self-extinguishing capability. Flame-retardant composites with high electromagnetic interference (EMI) shielding performance are desirable for electronic device packaging. Despite great potential of MXene for high EMI, it still remains a great challenge to develop high-performance flame-retardant polymer/MXene composites with excellent EMI shielding effectiveness because of the poor oxidative stability of MXene. Herein, phosphorylated MXene/polypropylene (PP) composites are prepared by coating phosphorylated MXene on PP fabric followed by spraying polyethylenimine (PEI) and hot-pressing. The phosphorylated MXene proves to be more durable against oxidation than pure MXene due to the protection effect of polyphosphates. Upon hot-pressing, melted PP fibers are fused together at their contact points and thus as-prepared composites are bi-continuous with two interpenetrating phases. The composites show significantly improved thermal stability and flame retardancy relative to pure PP, with a low total heat release (THR) of 3.7 kJ/g and a heat release rate (HRR) of 50.0 W/g, which are reduced by 78% and 87%, respectively. In addition, the composites exhibit a high electrical conductivity of ∼36,700 S/m and an EMI shielding performance of ∼90 dB over the whole frequency range of 8–12 GHz with a thickness of ∼400 μm. The as-developed PP/MXene composites hold great promise for reliable protection of next-generation electronic devices working in complex environments. [ABSTRACT FROM AUTHOR]