A phosphorus- and nitrogen-containing DOPO derivative as flame retardant for polylactic acid (PLA)

The preparation of high-efficient flame-retardant PLA remains a major challenge due to the unavoidable loss in mechanical properties. In this study, a DOPO derivative containing phosphorus and nitrogen in the molecular structure with amino as terminal group (DOPO-NH2) was incorporated into PLA to improve the flame resistance. The addition of this DOPO derivative on the thermal stability, flame retardancy and mechanical properties of PLA was investigated. With loading of only 5 mass% DOPO-NH2, the LOI value increased to 26% and UL-94 V-0 was attained. The heat release rate showed obvious decrease by microscale combustion calorimetry. Moreover, the mechanical properties of PLA/5DOPONH(2) composite have not deteriorated significantly due to the low loading and the existence of hydrogen bond between DOPO-NH2 and PLA matrix.

Automated summary

The study successfully improved the flame resistance of PLA by incorporating a phosphorus and nitrogen-containing DOPO derivative (DOPO-NH2), achieving an LOI value of 26% with just 5% mass of DOPO-NH2 added. The hydrogen bonds formed between DOPO-NH2 and the PLA matrix maintained the mechanical properties of the composite.