Preparation of a halogen-free flame retardant and its effect on the poly(L-lactic acid) as the flame retardant material

A novel flame retardant (POCODA) was synthesized using the POC and ODA. The POCODA/APP as a synergistic flame retardant (FR) was incorporated into the poly(L-lactic acid) (PLA) to investigate effects of this synergistic FR on the thermal stability, combustion behavior and flame retardancy on the PLA. The limited oxygen index (LOI) value of the PLA-based composites gradually increased with an enhancement in the amount of the POCODA/APP. Except the PLA/5%APP, the V-0 level achieved for other composites. Both the POCODA and POCODA/APP exhibited the self-extinguishing effect on the PLA in the UL-94 test. The pHRR, THR, TSP and other combustion performance parameters of the composites reduced, compared to neat PLA, and the PLA/2%POCODA/10%APP composite exhibited the dense and continuous carbon residue after the CONE measurement and showed most excellent flame retardance. With combination of the results of the SEM, TG-IR and PY-GC/MS measurement, the flame retardant mechanism of the PLA/2%POCODA/10%APP composite was also proposed and discussed in detail.