Effect of different weft-knitted structures on the mechanical performance of bio-based flexible composites

This work investigates composites from renewable resources that exhibit high flexibility. The effect of three different weft-knitted structures on the tensile properties, flexural properties, tear resistance and puncture impact properties is analyzed in combination with two different flexible matrix materials. Furthermore, the potential of the knitted structures in flexible composites is compared to a woven fabric and comprehensively discussed. The tear resistance and the total absorbed energy in puncture impact tests were unaffected by the matrix material. Among the knitted structures, the highest tensile strength, tear resistance and impact properties were achieved with the interlock structure, whereas the double jersey with tuck stitch structure resulted in the lowest flexural modulus. However, a much higher tensile strength was achieved with the woven fabric, at the expense of a higher flexural modulus. Overall, knitted structures proved promising to be used in bio-based flexible composites for applications requiring high flexibility without the need for high tensile strength.