Removal of spandex from nylon/spandex blended fabrics by selective polymer degradation

As the use of fabrics containing spandex for apparel applications is expanding, developing eco-friendly technologies to recycle the industrial as well as post-consumer waste for spandex blended fabrics becomes increasingly important. As is known in the industry and demonstrated in this study, spandex may be removed from blended fabrics by dissolving it in solvents such as N,N-dimethylformamide, but the use of such solvents is undesirable for economical and environmental reasons. The main focus of this study was to develop an alternative process for removing the spandex component in a nylon/spandex blended fabric (NSBF) by selective degradation so that the nylon component can be recovered for recycling. In this process, the fabric first underwent a heat treatment step, followed by a washing process. For the heat treatment, the effect of temperature, water-to-fabric ratio, and pressure were studied. Treatment at 220℃ for 2 hours under atmospheric pressure was found to be very effective, allowing the degraded spandex residues to be readily washed off in ethanol, while the nylon component retained its original morphology. With the removal of spandex in NSBF, a decrease in -CON- absorption peaks in the Fourier transform infrared–attenuated total reflectance spectra of the fabrics was observed.