Super-efficient fire safety poly(lactide) enabled by unique radical trapping

Abstract

Poly(lactic acid) (PLA) as a promising bio-plastic will decompose to small molecule flammable volatiles via chain scission, which thus exhibit poor fire safety and highly restrict its real-world applications. Herein, we report a novel multifunctional furan bio-based fire retardant (F-FR). The comprehensive properties of the F-FR in PLA were investigated systematically. As a result, the multifunctional F-FR exhibited not only good thermal stability, high crystallization behavior and excellent transparency, but also super-efficient fire safety regarding self-extinguishing. It was interesting that only trace 0.8 wt% loading of F-FR in PLA was needed to attain the UL-94 V-0 grade. For the first time, the LOI result of PLA with 2 wt% F-FR was as high as 48.0%. More importantly, the unique furan radical trapping mechanism from theoretical and experimental results in the gas phase was simulated and proved by quantum chemical calculations and the compositions and structures of molecules from the degradation and pyrolysis of F-FR, oxygen and PLA radicals. This work offers a useful and green strategy for developing super-efficient eco-friendly additives, enriches the fire-safety mechanism of PLA, and has promising broad application in engineering materials.