Improved Mechanical Properties and Flame Retardancy of Wood/PLA All‐Degradable Biocomposites with Novel Lignin‐Based Flame Retardant and TGIC

Abstract In this study, a type of all‐degradable flame retardant wood/poly(lactic acid) (PLA) biocomposite (FPW) with low cost and excellent mechanical properties is prepared and studied. A novel lignin‐based phosphorus‐containing flame retardant (LMD) is synthesized first. PLA, wood powder, poly(butyleneadipate‐ co ‐terephthalate), triglycidyl isocyanurate (TGIC), and LMD are then melt‐blended to prepare FPW. The limiting oxygen index value of PLAF25L15‐4T (25% of L15MD and 4% of TGIC) reaches 28.6%. Furthermore, the residue at 700 °C is up to 31.3%, which apparently helps to increase the flame retardancy of FPW. Its tensile strength is as high as 48.7 MPa. The interfacial compatibilization is much improved as proved by scanning electron microscopy observation. This should be due to the in situ interfacial reaction between PLA, wood, and TGIC, and the lignin component both in wood and LMD. The obtained PLA biocomposite with improved mechanical and flame retardant properties is promising for its wide applications.