Poly(butylene succinate) (PBS)/wood flour (WF) composites with different WF content were prepared by twin-screw extrusion at 160 °C. With increasing WF content, the tensile strength of the PBS/WF composite without polymeric diphenylmethane diisocyante (pMDI) decreased, while that of the composite with pMDI increased. The addition of kraft lignin (KL) deteriorated the tensile properties of the composites both with and without pMDI. The melt flow index (MFI) decreased with increasing WF content, but increased with increasing KL content. The addition of pMDI caused an increase in the melt viscosity of the PBS/WF and PBS/WF/KL composites, resulting in a decrease in the MFI. The composites had lower thermal stability than neat PBS. The exotherms of the PBS/WF (50/50) composite appeared at a higher temperature than that of the neat PBS, but the PBS/WF/KL (50/50/20) composites had similar exotherms as the neat PBS. The addition of KL caused a decrease in the crystallization rate of PBS.
Keywords: kraft lignin; pMDI; twin-screw extrusion; wood-plastic composite.