Circular Textiles: Closed Loop Fiber to Fiber Wet Spun Process for Recycling Cotton from Denim

Abstract

Textile waste is a major waste source found in landfills around the world today, due to increases in population, fast fashion cycles, and inefficient recycling technologies. Here we demonstrate a textile recycling process whereby waste denim is dissolved into a binary solvent and a regenerated cellulose fiber is wet spun. We show that using this process the spun fiber can be regenerated whereby the original color of the waste garment is maintained or regenerated in the absence of color. The retention of color can be significant since the regenerated fibers do not need to be redyed, saving considerable water and energy that is typically required in the traditional textile dyeing processes. This process utilized dimethyl sulfoxide (DMSO) as a cosolvent with ionic liquid 1-butyl-3-methylimidazolium acetate ([Bmim]­OAc) for the dissolution of the denim waste. The addition of the cosolvent allowed fast dissolution of the cellulosic materials while reducing the viscosity of the spinning dope. The regenerated discolored cellulose fibers produced had similar mechanical properties and morphology to that of viscose fibers, a common regenerated cellulose fiber used extensively in the textile industry. Furthermore, the utilization of binary IL solvent with high DMSO concentration (1:4) reduces the overall process cost. Synopsis: Recycling waste denim creating a regenerated cellulose fiber which can retain the color of the starting textile item or the color can be removed leaving a neutral fiber.

Recycling of vat and reactive dyed textile waste to new colored man-made cellulose fibers

“…This can be achieved via different systems such as the viscose process, 19 the NMMO-based Lyocell process, 20 alkali/urea, 21 or a mixture of 1-butyl-3-methylimidazolium acetate and DMSO. 22 Similarly, [DBNH] [OAc] can be used to recycle colored textile waste. 23 However, there are more than 10 000 different dyes used in textile manufacturing and identifying the exact chemical compound(s) in textile waste is nearly impossible.…”

Cellulose dissolution and regeneration using a non-aqueous, non-stoichiometric protic ionic liquid system

“…(Walker 2004;King et al 2011;Hauru et al 2012;Greaves and Drummond 2015;Meenatchi et al 2017;Becherini et al 2019). Ionic liquids in mixtures with dipolar aprotic solvents such as dimethyl sulfoxide, c-valerolactone and 1-methylimidazole have also been shown to solubilize cellulose quite readily (Xu et al 2013;Zhao et al 2013;Gale et al 2016;Holding et al 2017), which has greatly enabled the spinning of cellulose fibers using ionic liquids (Hauru et al 2014;Sixta et al 2015;Ma et al 2019). Spinning of fibres requires extrusion of highly viscous cellulose solution into a coagulant bath (Hauru et al 2014(Hauru et al , 2016Sixta et al 2015).…”

Cellulose Fibers for High-Performance Textiles Functionalized with Incorporated Gold and Silver Nanoparticles

“…This requires colorants and finishing agents to tolerate the chemical environment of the recycling process so that the original color and other selective properties can be transferred from the waste material to the new textile product. In principle, it has been shown that in certain cases, dyes can resist the conditions of the Viscose and the Lyocell process (Haule, Carr & Rigout 2016;Eltz 1995), alkali/urea systems (Liu et al 2019), or mixtures of ionic liquids and DMSO (Ma et al 2019). Nonetheless, systematic studies on the recyclability of dyes within these fiberspinning processes are still missing.…”