Mechanical behavior of flax/polypropylene commingled nonwoven at dry scale: Influence of process parameters

Currently, nonwoven fabrics made with natural and thermoplastic commingled fibers have been extensively used in the composite industry due to their light weight and low processing and material costs. As two key parameters in the manufacturing of nonwoven fabrics, the needle-punching and material surface densities influence strongly the mechanical properties of nonwoven fabrics and their reinforced composite parts. Compared to most studies focused on the composite stage, the present experimental investigation is performed at the dry fabric stage, and the influence of the needle-punching and material surface densities on the mechanical behavior of nonwoven fabrics will be analyzed through tensile and bending tests. The results show that increasing the material surface of the nonwoven fabric leads to a better mechanical behavior, but that such variations do not modify the phenomenon of anisotropy of nonwoven fabrics. By contrast, increasing the needle-punching density can strengthen generally the homogeneity of nonwoven fabrics.