Waste silk selvedge/glass fiber reinforced strip-shaped composite: A critical assessment of twisting and dyeing of silk on mechanical properties

Abstract

With about 11 million tons of waste silk produced each year, waste silk reinforced composites are an important way of high-value utilization. However, the mechanical stability of waste silk reinforced composites remains to be further studied. In this study, we evaluate the flexural and impact properties of waste silk selvedge/glass fiber reinforced strip-shaped composites with different twisting and dyeing structures. The findings reveal that both twisting and dyeing of silk negatively affect the mechanical properties. The twisting structure introduces yarn discontinuity, leading to a 33 % reduction in impact strength. The dyeing process disrupts silk's β-sheet structure, causing a more disordered β-strand structure and a decrease in flexural strength from 448.4 MPa to 412.4 MPa. Further, we determined that untwisting and undyeing waste silk selvedges are suitable for impact-critical application such as automotive bumper. While the twisting and dyeing waste silk selvedges are suitable for non-structural applications requiring aesthetic appeal, such as automotive interiors.This study identifies critical factors influencing mechanical properties of waste silk reinforced composites, benefiting their engineering applications.