Breaking the Intrinsic Performance Trade‐Off Dilemma of Plasticized PVC : Halogen‐Free Multi‐Functional Modification via Magnesium Hydroxide/Carbon Black Hybrid Fillers

Plasticized poly(vinyl chloride) (PVC) is a core foundational material for flexible cable sheaths, electronic packaging and building interior components, yet it faces a long‐standing bottleneck: single‐filler modification cannot achieve simultaneous optimization of flame retardancy, antistatic performance, thermal conductivity and mechanical properties, resulting in severe performance trade‐offs in practical service. Herein, we fabricated multifunctional plasticized PVC composites using magnesium hydroxide (MH) and carbon black (CB) as hybrid functional fillers, and systematically elucidated their multi‐property synergistic regulation mechanism. Results show that 5 wt% CB enables the composite to reach the conductive percolation threshold with long‐term stable antistatic performance even in humid environments; all composites achieve UL‐94 V‐0 rating without dripping, with a maximum limiting oxygen index (LOI) of 33.8%. The dual fillers construct a continuous three‐dimensional thermal conductive pathway, boosting the thermal conductivity to 0.50 W·m −1 ·K −1 (1.8 times that of the unfilled control), while maintaining excellent mechanical properties and industrial processability. This work clarifies the multi‐property synergistic mechanism of MH/CB hybrid fillers, providing a feasible, low‐cost strategy for the design and industrial production of high‐performance multifunctional PVC composites.