Improvement of Natural Fiber Composite Materials by Carbon Fibers

International audienceThe purpose of this work is the improvement of flax fiber-reinforced composites obtained by vacuum molding in order to encourage their insertion into industrial products. The relatively high degree of porosity in these kinds of composites, due to the lack of compatibility between epoxy matrix and flax fibers and the hydrophilicity of flax fiber, remains a major constraint to their use in the industrial world. Hence, we have used a combination of carbon fibers with those of flax in order to optimize the properties of the assembly. Several stacking sequences have been tested in order to analyze the influence of the addition of carbon fibers on the water recovery behavior and the mechanical tensile behavior according to their position inside the laminate. It has been shown that adding surface carbon plies presents a barrier effect for the water sorption by limiting the creation and the percolation of internal porosities. The same effect is observed on tensile behavior where stacking sequences with external carbon fiber plies are more resistant than stacking sequences with internal carbon plies