Permeability of Hybrid Reinforcements and Mechanical Properties of their Composites Molded by Resin Transfer Molding

The aim of this study was to carry out RTM experiments to determine in-plane permeability of glass mats, non-woven polypropylene flow media ( PP) and hybrids (glass + PP), with different stacking sequences, and to compare these with various sisal mats and hybrids (glass + sisal). RTM composites were also molded. Permeability decreased for higher fiber content and, for the same fiber volume content, the permeability of the sisal mats was much higher than that of glass mats and also higher than that of the PP non-woven core, often used as an infiltration medium. Besides, a tendency of increasing permeability with sisal fiber length ( up to 30 mm) was noticed. The use of the sisal mat as a flow medium increased the permeability of the hybrid reinforcement and slightly improved the mechanical properties of the composite. Hence, the sisal mat may be indicated in engineering applications as a substitute for commercial flow media, widely used in the process called RTM light.