Laundering-induced property changes in virgin and recycled polyester and nylon fabrics: implications for durability and cleaning performance

Laundering is essential for textile care, yet washing conditions such as temperature and repeated cycles can significantly affect fabric performance. Despite the growing use of recycled fibers in apparel, the influence of material origin (virgin vs. recycled) on performance under repeated laundering remains poorly understood. This study investigates the effects of laundering temperature on the physical properties and cleaning performance of virgin and recycled polyethylene terephthalate (PET) and nylon 6 (NY) fabrics, as well as the effects of repeated laundering cycles on their durability. Cleaning performance is evaluated using water-soluble, oily, and particulate soils. PET maintains dimensional stability and tensile strength due to its high glass transition temperature and hydrophobic nature, whereas NY is sensitive to laundering conditions due to its lower thermal resistance. Under harsh conditions of 60 °C, NY experiences substantial tensile strength loss (up to 66%) and noticeable shrinkage. The influence of material origin differs by fiber type: recycled NY shows reduced tensile strength compared with virgin NY even at 40 °C, whereas PET exhibits origin-associated differences only at 60 °C. Cleaning performance is primarily governed by fiber type rather than material origin. Principal component analysis clarifies trade-offs between cleaning efficiency and fabric integrity, highlighting the need for fiber-specific laundering conditions.