Improve the mechanical property and flame retardant efficiency of the composites of poly(lactic acid) and resorcinol di(phenyl phosphate) (RDP) with ZnO‐coated kenaf

Summary The kenaf coated with zinc oxide (ZnO) was prepared and characterized by X‐ray diffraction, scanning electron microscopy, and X‐ray photoelectron spectroscopy. The ZnO‐coated kenaf and the flame retardant resorcinol di(phenyl phosphate) were blended with poly(lactic acid) (PLA) by solution compounding and melt blending to prepare the flame‐retarded PLA composites. The thermal stability, the mechanical property, and the flame retardancy of the PLA composites were improved evidently. The tensile strength of the prepared PLA composites could reach up to 62.3 MPa in comparison with 55.4 MPa of the pure PLA. The dense and compact char residues were observed after the combustion of the PLA composites containing ZnO‐coated kenaf, whereas there were serious dripping phenomena and no char formation during the combustion of the pure PLA. The use of ZnO‐coated kenaf could increase flame retardant efficiency obviously. The mechanism of flame retardancy was discussed.