Influence of the sampling area of the stem on the mechanical properties of hemp fibers

Natural fibers appear to be a promising alternative to glass fibers for the reinforcement of polymer matrix composites. However, the wide dispersion of their mechanical properties slows down their development. The aim of this study was to evaluate the influence of the sampling area of the stem on the mechanical properties of hemp fibers. Tensile tests were carried out on fibers extracted from the bottom, the middle, and the top of one stem. The results show there is only slight variations between the different areas: fibers from the middle exhibit higher tensile strength and ultimate elongation than top and bottom fibers, but there are no differences in terms of stiffness. A strong dependence of the fiber mechanical properties on their diameter is observed. This dependence induces more dispersion of the properties than the sampling area, thus it seems relevant to consider the whole stem to extract fibers, without defining distinct areas. (C) 2010 Elsevier B.V. All rights reserved.