Properties and characteristics of polylactide blends: Synergistic combination of poly(butylene succinate) and flame retardant

A study on the influence of flame‐retardant types, poly(butylene succinate) (PBS) contents, and combination of flame retardant and PBS on the mechanical, thermal, morphological, and flame retardancy properties of polylactide (PLA) and PLA/PBS blends was investigated. Blending of PLA, PBS, and flame retardant was prepared by a twin screw extruder. Tricresyl phosphate (TCP) and montmorillonite (MMT) were used as a flame retardant, whereas PBS acted as a flexible material for enhancing the fire resistance and toughness of PLA, respectively. The results revealed that the introducing of TCP and MMT greatly improved the impact strength of the PLA. The impact toughness of PLA blends with 20 wt% of PBS increased to about 244% that of neat PLA. The addition of flame retardants markedly improved the limiting oxygen index of PLA from 18.0% to 30.1% and 24.3% for the blends containing TCP and MMT. The V‐0 rating in UL‐94 testing was achieved with PLA/TCP blend. Elongation at break, impact toughness, and thermal stability of PLA significantly increased with the increment of PBS concentration. The synergistic effect of flame retardant and PBS afforded the PLA blends with outstanding increase of impact resistance. Furthermore, the flame retardant of TCP in the system not only affected dripping behavior and total flame time of PLA/PBS blends but also improved limiting oxygen index values due to the forming of char layer and inhibiting of burning mechanism.