Characterisation of Fibre Mechanical Recycled Cotton Denim Fibres and the Effects of Their Properties on Yarns and Knits

The purpose of this study was to obtain a holistic view of mechanically recycled cotton from denim fabrics and the repurposing and recycling methods for similar fibres. A pre-consumer denim and three types of post-consumer denims were shredded into new fibres, which were characterised with single-fibre tensile testing, SEM imaging and DSC analysis. The opened cotton fibres were then blended with primary cotton with varying ratios and spun into yarns of 40 tex with a ring spinning machine. A ratio of 75/25 of recycled fibres to virgin fibres was obtained, with promising tensile strength results. Further, the yarns were knitted into single jersey fabrics, and abrasion testing was performed to evaluate their wearing out. Best abrasion resistance was obtained for knits consisting of 100% virgin cotton fibres and the knits consisting of a blend of pre-consumer and virgin fibres. The results suggest the yarns made with mechanically opened fibres are suitable for single jersey knits. SEM and DSC confirm the input of mechanical recycling defines the output. Moreover, the SEM pictures indicate there is little to no damage to single fibres caused by mechanical shredding, causing no further barriers for secondary use as raw materials.