Manufacturing of post-consumer waste cotton pulp and its regenerated cellulose fiber

Disposing waste textiles through landfills and incineration leads to significant resource wastage and environmental pollution. The recycling and utilization of textile waste have gained increasing attention. This study aims to transform cotton textile waste into cellulose pulp, which is further processed into a regenerated cellulose membrane via the viscose process (NaOH/CS₂). The research explores the optimal preparation techniques and evaluates the influence of NaOH on the properties of waste cotton pulp. Furthermore, it investigates the physical and chemical characteristics of the waste cotton pulp and the regenerated cellulose membrane. The results indicated that the waste cotton pulp contained 97.6 % α-cellulose after the alkaline cooking process. The optimal conditions for the alkaline cooking of waste cotton pulp were determined to be: a cooking temperature of 140 °C, an alkali concentration of 4 wt%, a cooking time of 120 min, a hydrogen peroxide dosage of 1 wt%, a solid-liquid ratio of 1:7, and a pressure of 0.5 MPa. Waste cotton and wood pulp were mixed and rapidly converted into cellulose sulfonate through alkali and carbon disulfide treatment. The mechanical strength of the regenerated cellulose membrane decreased as the proportion of waste cotton pulp increased. When the waste cotton pulp content reaches 60 %, the strength of the regenerated cellulose membrane decreases by 35 % from 67.44 MPa to 38.57 MPa. Furthermore, The regenerated cellulose fibers produced through wet spinning with a mixed spinning solution demonstrated commendable performance. This study presents a novel and high-value-added approach for the chemical recycling of waste cotton fabric, marking a significant advancement in textile recycling from waste cotton materials.