Flame retardant and antibacterial properties of PLA/PHMG‐P/APP composites

Abstract Poly(lactic acid) (PLA) has evolved into a commodity polymer with numerous applications. However, its high flammability limits its viability as a perfect alternative to petrochemical engineering plastics. In this study, PLA was modified using polyhexamethyleneguanidine phosphate (PHMG‐P) and ammonium polyphosphate (APP). The flame retardant performance of PLA/PHMG‐P/APP was investigated based on the limiting oxygen index (LOI), vertical burning test (UL‐94), thermogravimetric analysis (TGA), cone calorimetry (CC), scanning electron microscopy (SEM), Fourier‐transform infrared spectroscopy (FTIR), and Raman Spectrometry. Qualitative and quantitative methods were used to determine the antibacterial properties of PLA composites. The LOI of PLA‐10% (P:A = 1:4) was 31.7% and was rated V‐0 in the UL‐94 V‐0 test. The antibacterial properties of the composites reflected the antibacterial effects of PLA‐10% (P: A = 1:4) against Escherichia coli and Staphylococcus aureus , with the antibacterial rates reaching 93.41% and 93.26%, respectively. PHMG‐P and APP had a synergistic flame‐retardant effect and improved the flame retardancy of PLA while exhibiting excellent antibacterial properties.