Comparison of different flame‐retardant agents for polylactic acid/fiber composites by a film‐stacking method: Flame‐retardant performance and mechanical properties

Abstract In this investigation, characterization and comparison of the flame retardant performance were conducted for polylactic acid (PLA)/fiber composites featuring the incorporation of different flame retardants (APP, PAPP, and DMH). Based on the results obtained from the Limiting Oxygen Index (LOI) test and cone calorimeter test, it is evident that the intumescent flame retardants (IFR) such as APP and PAPP exhibit better efficacy on improving flame retardancy than DMH. The LOI value of the APP/PLA/F and PAPP/PLA/F composite reaches 35.5% and 27.4%, higher than that of DMH/PLA/F (23.0%). The pk‐HRR of APP/PLA/F and PAPP/PLA/F decreases 27% and 39% compared with PLA/F while the char residue at 500°C was higher than that of DMH/PLA/F (0.3 wt%) with the value of 51.4 and 44.1 wt%. It should be mentioned that the impact strength and tensile strength of PLA/fiber composite incorporating APP surpasses that of PAPP/PLA/F, which is caused by good dispersibility of fabrics among the PLA matrix, coupled with the strengthened interfacial adhesion between the fibers and the polylactic acid matrix. In summary, APP/PLA/F shows the most overall performance. Highlights Properties of PLA/fiber composites with various fire retardants were compared. APP/PLA/F obtained the best overall property while DMH/PLA/F had the worst. APP endows composites with excellent flame retardancy and mechanical property. The LOI value of APP/PLA/F was 35.3%, highest among four composites. Adding APP to PLA/F led to an increase in tensile strength and impact strength.