Processing-structure–property relationships in recycled textile waste: Implications for dynamic mechanical performance

A textile waste abundantly generated in the region of Nova Friburgo, Rio de Janeiro, Brazil, was collected, cleaned, and characterized by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and bulk moisture and density measurements. The results indicated a likely elastane/nylon-6 blend with a substantial elastane fraction. The material was subsequently size-reduced, processed in a single-screw extruder, and compression-molded into plates under four distinct processing conditions. Cooling conditions during molding were identified as a key parameter governing the organization of the complex morphology of the textile residue and, consequently, its dynamic-mechanical performance. DMA analyses of specimens extracted from the plates (designated M1, M2, M3, and M4) revealed pronounced differences in viscoelastic response (stress–strain behavior), creep resistance, and in the storage modulus (E′) and loss tangent (tan δ) under time–temperature superposition. In general, either rapid quenching or slow cooling at ambient temperature produced materials with lower crystallinity and increased susceptibility to creep. Conversely, cooling while maintaining the mold at 70°C or 50°C yielded stiffer materials, with enhanced creep resistance and higher crystalline fractions. These findings highlight that the processing route critically determines the attainable structure and, therefore, the potential applications of the recycled material. The experimental observations obtained from the dynamic mechanical analysis were further supported by the thermogravimetric evaluation of the textile residues (M1 to M4 samples).