No abstract

The 'circular economy' concept envisages deriving the maximum value out of resources and reducing waste to a minimum. In textiles, that includes the recovery of fiber materials out of used clothing and reusing them in the construction of new clothes. Processes such as mechanical separation, depolymerization treatment, and selective dissolutions of individual polymers are applied. We investigate the approach of selective nondestructive dissolution and recovery of polyamide fiber from mixed textile waste by using the solvent system CaCl 2 /ethanol/water (CEW) based on complexation and decomplexation of polyamide (PA). The results show that PA is precipitated and decomplexed by simple addition of water and a substantial amount of previously incorporated calcium by complexation, is removed. The recovered polyamide shows properties similar to pristine polyamide. Investigation on a mixed textile waste model of polyamide/wool demonstrates that CEW treatment can successfully separate different fiber materials. The nondestructive approach in dissolving PA using CEW, clearly shows the benefit, that PA fiber can be separated by controlled complexation/decomplexation without degradation, thus avoiding the repolymerization step. Furthermore, the solvent system is made of abundantly available materials that are inexpensive and used widely in industrial-scale operations. Thus, the concept will make significant contribution to a green textile recycling approach.

The sol-gel process is an excellent process for coating various substrates and thus imparting new functionalities to the treated material. Cotton fabrics were finished with various silicon alkoxides: tetraethoxysilane, (3-triethoxysilylpropyl)succinic acid anhydride, and (3-glycidyloxy)propyltrimethoxysilane in a one-, two-, and three-step process, applying the pad-dry-cure method. The physico-mechanical parameters: dry crease recovery angle, tensile strength, flexural rigidity, air permeability, abrasion resistance, whiteness index (WI), and water vapor permeability of the as-prepared cotton samples were evaluated. In addition, the coated samples were analyzed by means of Fourier transform-infrared/attenuated reflection spectroscopy, thermal gravimetric analysis, and 3D laser confocal microscopy. To study the wettability, selected alkoxysilane-treated specimens were coated with octyltriethoxysilane. The impregnation with titanium tetraisopropoxide significantly increased the ultraviolet protection factor. The findings make evident that the wrinkle resistance could be improved.