LAUSR

Abstract The hollow glass beads (HGB) was melt blended with biodegradable poly (lactic acid) (PLA) and intumescent flame retardant (IFR) by twin-screw extruder (TSE) to improve the flame retardancy. The flame retardant properties and thermal stability of biodegradable PLA/IFR/HGB composites were investigated by limiting oxygen index (LOI), vertical burning (UL-94), cone calorimeter tests (CCT) and thermogravimetric analysis (TGA). The result of the LOI can be as high as 35.5% with only 2% HGB and 10% IFR addition. And the thermal stability of the PLA/IFR blends were enhanced by the partial substitution of IFR with HGB. The lowest peak of heat release rate (pHRR) was achieved by introduction of 1 wt% HGB, with a remarkable decrease in pHRR (72.3%). What's more, the residues of PLA/IFR/HGB composites after CCT were characterized by scanning electron microscope–energy dispersive spectrometer (SEM–EDS) and laser Raman spectroscopy (LRS). All the results revealed that the addition of HGB had synergistic effect on the flame retardancy of PLA/IFR composites.