Ant colony algorithm guided synthesis of flame retardants for enhanced polylactic acid flame retardancy

Polylactic acid (PLA) is an emerging environmentally friendly material, but its flammability limits its application in various fields. This study employed ant colony optimization and random forest algorithms to optimize the limiting oxygen index (LOI) of PLA/nitrogen-phosphorus flame retardant systems and identify key influencing factors. The results demonstrate that the C–P(N) 2 =O bond serves as the critical structural feature for achieving high flame retardancy in PLA at low additive loadings. Based on this finding, the research team synthesized a novel nitrogen-phosphorus flame retardant. Thermogravimetric analysis (TGA) revealed that the synthesized PDAZ flame retardant promoted char formation, increasing the residual carbon content at 800 °C from 0 % to 4.95 %. Cone calorimetry tests (CCT) showed an 11.1 % reduction in peak heat release rate (pHRR) and a 48 % improvement in fire performance index (FPI). Remarkably, the addition of only 3 wt% of this flame retardant increased the LOI of PLA to 30.5 %. This study provides an innovative strategy for accelerating the development of flame-retardant PLA materials.