One-pot solvent-free green strategy to fabricate ultra-efficient polyphosphoester flame retardant for Poly(Lactic acid)

Tremendous attention has been dedicated to crafting eco-friendly flame retardants with excellent comprehensive performance via green means. Herein, a novel ultra-efficient polyphosphoester (PPE) flame retardant was synthesized via a facile one-pot method of solid-phase polycondensation reaction. PPE was then employed as a multifunctional additive for high-performance poly (lactic acid) (PLA). Benefiting from the dual-phase flame-retardant effect, the resultant PLA composite with merely 0.5 wt% PPE exhibited a desired limiting oxygen index (LOI) value of 26.1 %, and a satisfactory V0 rating of UL-94 (1.6 mm) with well-preserved mechanical properties. Due to the nucleating effect of PPE on PLA, the mechanical properties and crystallization ability of the PLA composites were both gradually enhanced as PPE content increased from 0.3 to 1.5 wt%. The designed ultra-efficient approach, enhancing fire safety and mechanical properties simultaneously at a low content, lays a foundation of an affordable, eco-friendly, and versatile flame retardant for potential applications of PLA.