Performance analysis of socks produced by auxetic yarns for protective applications

The present work reports application of auxetic yarns in development of abrasion resistant socks which can be used for better serviceability without shoes even on rough surfaces. Socks used in the current research were produced by using helical auxetic yarns which consist of different combinations of high performance and conventional materials e.g. Kevlar P-AR (para-aramid), cotton, elastomeric yarn, polyamide (PA6) and polyester with same linear density of 74 Tex. Three different types of fabrics were produced e.g. flat knit, sandwich half terry short and sandwich half terry long. For investigating the auxeticity, all samples were subjected to tensile loading and the resulting change in their thickness was measured. Abrasion resistance and other comfort related properties e.g. air permeability, vertical wicking and absorbency were also evaluated. The influence of different yarn combinations, twist levels and fabric types on abrasion resistance and breathability of socks were investigated by using fractional (half) factorial design. Statistical analysis was performed for the obtained results by using analysis of variance. Conventional socks samples were also produced in all fabric types for comparison with the auxetic materials. From the results it was concluded that the overall abrasion resistance of auxetic yarn-based sock is higher than conventional cotton sock. Results also revealed that abrasion resistance was increased by 46% in flat knit socks sample, 50% in sandwich half terry short sample and 58% in sandwich half terry long sample as compared to conventional cotton sock. In addition to this all the socks samples exhibited good comfort/breathability properties.