Improvement of the Weavability of Natural-Fiber Reinforcement for Composite Materials Manufacture

Natural fibers are an alternative to man-made fibers for the manufacturing of preforms intended for composite applications. Some of the textile manufacturing processes, such as spinning technology, are not suitable for the production of optimized preforms for composite materials. Those preforms are made of yarns, whose features (twisting in particular) lead to difficulties during impregnation step and to fiber disorientation when compared to the yarn axis. The purpose of this study is to produce woven preforms from flax and hemp rovings, instead of yarns. Rovings, which have a low twist level, are not suitable for weaving technology. An improvement of their mechanical properties with chemical treatment is suggested, and its influence on the feasibility of the weaving process and on the textile and mechanical properties of different scales (fiber, roving, preform and composite scales) is studied. The chemical treatment used leads to an improvement of the roving tenacity and the weavabilty without damaging fibers and composite properties.