Enhanced mechanical strength of polyethylene-based lignocellulosic-plastic composites by cellulose fibers

Wood flour (WF) of poplar, acid hydrolysis residue (AHR) of corn cob from xylose production, and cellulose fibers (CF) from bleached eucalyptus pulp were compared as functional fillers of lignocellulosic-plastic composites (LPC) in terms of tensile strength and thermal stability. WF showed a negative effect on tensile strength of LPC. AHR-filled LPC at 10% of filling level exhibited an improvement by 8.9%, whereas higher filling level led to a decrease of tensile strength due to poor interfacial compatibility, as revealed by SEM analysis. Remarkably, tensile strength achieved a maximum of 25.8 MPa for CF-filled LPC at 2.5% of filling level, which was an approximately 76.7% improvement compared to the control. Dependence of LPC thermal stability on chemical compositions of fillers was revealed. WF-filled LPC showed a lower onset decomposition temperature compared to the control due to the presence of xylan, while thermal stability of AHR-filled LPC was enhanced due to the presence of cross-linked phenolic polymer lignin.