Polypropylene/hemp woody core fiber composites: Morphology, mechanical, thermal properties, and water absorption behaviors

Natural fiber composites composed of polypropylene, maleic anhydride-graft-polypropylene, and hemp woody core fiber were produced by two-roll mill mixing. The hemp woody core fiber was treated by alkaline. The morphology of the polypropylene/hemp woody core fiber composites was studied by scanning electron microscopy technique. The mechanical and thermo-mechanical properties of the polypropylene/hemp woody core fiber composites were determined in tensile, flexural tests, and thermogravimetric analysis, respectively, and discussed. It was found that incorporation of hemp woody core fiber in polypropylene increased the tensile and flexural modulus. Note that the stiffness of short hemp woody core fiber/polypropylene composites was markedly improved. However, the flexural and impact strength of polypropylene/hemp woody core fiber composites was reduced compared to the neat polypropylene. Incorporation of hemp fiber increased the water uptake compared to the neat polypropylene. It was established that the Fick's law was fairly applicable to the water absorption results. The stiffness and thermogravimetric analysis behavior of the polypropylene/hemp woody core fiber composites were markedly affected by the surface treatments.