Abstract
Green composites have high specific strength and rigidity that are comparable to those of glass fiber
reinforced plastics (GFRP) and other artificial fiber reinforced plastics. A recently developed unidirectional
sheet of flax fibers is available as a laminate similarly to carbon fibers. Laminates generally have low strength
in the thickness direction. Although Zanchor is often applied to overcome this shortcoming, Zanchor effects on
the mechanical properties of green composites remain unclear. For this study, artificial entanglement was
created by needle-punching of a unidirectional flax fiber sheet. Epoxy resin matrix composites were produced
using hot-pressing to elucidate tensile property changes. Results show that needle-punching decreased the
tensile strength and Young’s modulus in the fiber direction, although these properties increased in the
direction vertical to the fiber. Furthermore, by quantifying the out-of-plane fiber orientation, we assessed
effects of two fiber-orientation changes deriving from needle-punching.
