Compatibilization and reinforcement of highly filled wood flour/polyethylene composites via peroxide‐induced grafting and crosslinking

Abstract The industrialized development of biocomposites effectively promotes the high‐value utilization of waste biomass resources, generating substantial economic benefits. However, in highly filled systems (≥50 wt.%), wood flour agglomeration and poor interfacial compatibility between components significantly degrade the performance of the final biocomposites, thus restricting their applications. In this work, we developed a low‐maleic anhydride grafted and microcrosslinking polyethylene matrices specialized for highly filled (50–70 wt.%) biocomposites for enhancing their mechanical properties. The successful grafting of maleic anhydride (MAH) onto polyethylene molecular chains and the formation of a crosslinked structure were evidenced by a characteristic infrared absorption peak at 1792 cm⁻¹ and a new torque peak. Grafting of polyethylene matrix with MAH enhanced the adhesion between wood and matrix, as well as the dispersion of wood within the matrix. Adding a small amount of peroxide (0.09 wt.%) improved the tensile, flexural, and impact strengths of the composites by up to 120%, 125%, and 209%, respectively, compared to unmodified composites. This study proposes a simple and cost‐effective method for low grafting and microcrosslinking modification of the polyethylene matrix, and the innovative application of this method in the highly filled system of wood flour yields significant results and expands their applications in construction materials. Highlights Matrix grafting enhances wood flour dispersion and interfacial compatibility. Initiator‐induced crosslinking structure promotes matrix plastic deformation. Grafting and crosslinking enhances mechanical properties of composites. Fine wood flour particles enhance the absorption of impact energy in composites.