Mechanical characterization and optimization of a new unidirectional flax/paper/epoxy composite

Flax fibers are superior to E-glass fibers in terms of specific Young modulus. Many researchers have recently tried to exploit this feature and use flax fibers in polymeric composites to compete with glass fiber composites. In this work, a new type of unidirectional flax/paper reinforcement obtained after resin transfer molding with epoxy is investigated. Reinforcement's parameters (paper ply and flax ply surface densities) and manufacturing parameters (forming pressure and drying temperature) are optimized to obtain the best possible composite strength and modulus. Internal bond strength between flax and paper layers is also investigated. Results show that at equivalent Vf the new flax/paper/epoxy composite is superior, in both specific strength and modulus, to another flax/epoxy composite (without the paper layer). It also surpasses the specific stiffness of a unidirectional E-glass/epoxy composite and the specific strength of a commercially available similar reinforcement.