Effect of surface treatment of short carbon fibers on the properties of wood flour/high density polyethylene composite

Wood flour/high density polyethylene (WF/HDPE) composite provides environmental benefit. To improve WF/HDPE properties, the short carbon fibers (SCF) were introduced to WF/HDPE and short carbon fiber reinforced wood flour/high density polyethylene composite (SCF-WF/HDPE) was prepared. The surfaces of SCF were treated by three methods, including gas-phase, liquid-phase and gas-liquid dual-phase oxidization, to enhance the interface bonding between short carbon fibers and plastic matrix. Then the short carbon fiber-wood flour/high density polyethylene (SCF-WF/HDPE) composites were prepared by extrusion process. The mechanical, dynamic mechanical and rheological properties were measured to evaluate the effectiveness of the treatment methods. SEM shows that the surface roughness of carbon fibers increases after the surface treatment, which enhances the interfacial bonding with HDPE matrix; The DMA reveals the storage modulus increases. The results demonstrate that the surface treatment significantly improves the mechanical properties, thermal dynamic property and creep performance of WF/HDPE composite. The best surface treatment method is gas-phase treatment. Comparing with the WF/HDPE composite without carbon fibers, the composite containing gas-phase treat carbon fibers increases in tensile strength by 34.5%, flexural strength by 23%, and impact strength by 54.7%.