Enhancing the toughness and strength of flame-retardant PLA blends through triglycidyl isocyanurate driven reactive blending

Flame-retardant modification of polymer materials often compromises their robustness and toughness due to poor interfacial compatibility between flame retardants and the polymer matrix. In this work, we report reinforced, toughened, and flame-retardant polylactic acid (PLA) blends fabricated via reactive blending with methyl vinyl silicone rubber (MVQ), ammonium polyphosphate (APP), 1-oxo-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane-4-acrylate (PEPAA), and triglycidyl isocyanurate (TGIC). MVQ serves as a toughening agent, while APP and PEPAA constitute an intumescent flame retardant (IFR) system. TGIC reacts with APP, introducing epoxy groups that enhance compatibility with the PLA matrix. During injection molding, the MVQ rubber phase becomes well oriented within the PLA matrix, contributing to improvements in both tensile and impact strength. With 3 wt% TGIC, the PLA blend exhibits a tensile strength of 61.8 MPa and an impact strength of 34.1 kJ/m 2 . Meanwhile, the limiting oxygen index (LOI) increases to 32.5%, and all samples achieve a UL-94 V-0 rating. Furthermore, the blends demonstrate reduced heat release, smoke production, and enhanced water resistance. This study presents a strategy for obtaining reinforced and toughened flame-retardant PLA blends by tailoring interfacial compatibility.