Superior Water-Resistant Poly(2-hydroxyethyl methacrylate phosphate) Flame Retardant and a Transparent, Flame-Retardant, and Biodegradable Poly(lactide) Blend Film

An environmentally friendly and superefficient flame retardant poly(2-hydroxyethyl methacrylate phosphate) (PHEMAP) was synthesized through precipitated polymerization of 2-hydroxyethyl methacrylate phosphate (HEMAP). The cross-linked PHEMAP microscale particles exhibited superior water resistance and high thermal stability, which could effectively prevent the release of phosphorus-containing compounds into the environment. Poly(lactide) (PLA) with only 0.5 wt % PHEMAP achieved UL-94 V-0 rating, and its limited oxygen index (LOI) value was 28%. Remarkably, the PLA/PHEMAP films maintained good transparency, owing to their similar refractive indices and uniform dispersion of PHEMAP microparticles in the PLA matrix. This study explored a kind of sustainable, transparent, and superefficient flame-retardant PLA blend film to expand its potential application in mobile phones, automotive interiors, and three-dimensional (3D) printing fields.