Effect of maleic anhydride grafted polyethylene on the properties of chopped carbon fiber/wood plastic composites

Chopped carbon fibers reinforced wood plastic composites were fabricated using a two-step extrusion process. As a coupling agent, maleic anhydride polyethylene was added for improving the interfacial adhesion between the chopped carbon fibers and plastic matrix. The results showed that the mechanical properties of the maleic anhydride polyethylene-added composites were significantly improved compared to that without maleic anhydride-grafted polyethylene. Tensile strength, flexure strength and impact strength were increased by 97%-133%, 113%-119% and 181%-251%, respectively, which were very close to the strengths of structural timber. The adding of maleic anhydride polyethylene also influenced the electrical property of chopped carbon fibers reinforced wood plastic composites. The volume electrical resistivity of the composites with maleic anhydride polyethylene was higher. The scanning electron microscopy was used to examine the morphology of brittle fracture cross-section paralleled to the extrusion direction. It was observed that the interfacial adhesion was improved with the incorporation of maleic anhydride polyethylene. Chopped carbon fibers were coated by high-density polyethylene and the bonding connections were formed on the fiber surfaces. The distribution direction of chopped carbon fibers was parallel to the extrusion direction and dispersed more uniformly in the maleic anhydride polyethylene-added composites.