A Comparative Study on Selected Properties of Post-Dyed Spandex-Blended Interlock Knitted Fabrics Produced from Virgin and Recycled PA6 Yarns
Received: 17 February 2026 | Revised: 19 April 2026 | Accepted: 26 April 2026 | Online: 6 June 2026
Corresponding author: Tho Luu Thi
Abstract
This study presents a controlled comparative evaluation of selected properties of post-dyed interlock-knitted fabrics produced from virgin and recycled PA6/spandex yarns under nominally matched structural and wet-processing conditions. To reduce the influence of major structural variables, the two fabrics were prepared with the same nominal interlock structure, blend ratio, yarn linear density, and dyeing and finishing route. The investigation included a comparison of basic structural parameters, FTIR absorption bands, strip-test elasticity-related behavior, dimensional change after laundering, and water-absorption performance. The results showed that the two fabrics had nearly identical mass per unit area, thickness, course density, and wale density before performance testing. FTIR analysis confirmed that the main characteristic absorption bands of polyamide remained detectable in both samples after dyeing. Under the investigated conditions, the recycled Polyamide 6 (PA6) fabric exhibited lower maximum force and elastic recovery, but higher extension and permanent deformation, as well as higher washing shrinkage and a shorter water-absorption time than the corresponding virgin PA6 fabric. These findings indicate that the two material systems did not exhibit equivalent post-dyeing behavior but instead showed different balances of mechanical resilience, dimensional stability during laundering, and wetting behavior. The main contribution of this study lies in the side-by-side evaluation of chemical signature, elasticity-related behavior, laundering dimensional change, and wetting performance in post-dyed PA6/spandex interlock fabrics produced from virgin and recycled PA6 yarns under nominally matched conditions. Within the scope of this controlled two-sample comparison, the study provides comparative evidence on the technical feasibility of recycled PA6 in spandex-blended interlock fabrics and clarifies the associated property trade-offs.
Keywords:
polyamide 6, recycled polyamide 6, interlock knitted fabric, spandex, elastic recoveryReferences
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Copyright (c) 2026 Tho Luu Thi, Mai Nguyen Thi, Hai Nguyen Van
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