Synergistic effect of MXene on the flame retardancy and thermal degradation of intumescent flame retardant biodegradable poly (lactic acid) composites

The effect of Ti3C2 MXene nanosheets on the intumescent flame retardant (IFR) poly (lactic acid) (PLA) composites was investigated among a series of PLA/IFR/MXene, which were prepared by melt blending 0–2.0 wt% MXene, 10.0 wt%– 12.0 wt% IFR and PLA together. The results of limiting oxygen index (LOI) and vertical burning (UL-94) discover that the combination of 0.5 wt% MXene and 11.5 wt% IFR synergistically improves the fire safety of PLA to reach UL-94 V-0 rating with LOI value of 33.0%. The PLA/IFR/MXene composites perform an obvious reduction in peak of heat release rate (HRR) in cone calorimeter tests (CCTs). Furthermore, the carbon residues after CCTs were characterized by scanning electron microscope (SEM), laser Raman spectroscopy (LRS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is demonstrated that both the titanium composition of the MXene structure and the characteristics of the two-dimensional material enhance the PLA/IFR/MXene composite materials' ability to produce a dense barrier layer to resist burnout during thermal degradation. [Display omitted]