Effect of oxidized wood flour as functional filler on the mechanical, thermal and flame-retardant properties of polylactide biocomposites

Based on the biodegradable material-polyethylene glycol (PEG)-as the plasticizer, oxidized wood flour (OWF) as the charring agent for polylactide (PLA), a series flame-retardant PLA biocomposites were prepared via melt-compounding and hot-compression. The effect of OWF on the thermal, mechanical and flame retardant properties of biocomposites was investigated systemically. We have found that after the incorporation of PEG and OWF with 10 wt% into PLA, the biocomposite showed higher tensile elongation than pure PLA. Furthermore, the presence of OWF and ammonium polyphosphate (APP) imparted the biocomposite good flame-retardant performance, shown a remarkable reduction on the peak of heat release rate (PHRR), improved LOI value and passed UL94 V-0 rating. Moreover, Scanning electron microscopy-energy dispersive spectra (SEM/EDS) and thermogravimetric analysis coupled with infrared spectrometer (TG-FTIR) were also performed to understand the flame retardant mechanism. These results proved that OWF could be as new functional filler for polymer composites to further improve their flame retardancy.