Effect of twisting on the structure and mechanical properties of polypropylene melt-blown micro-nanofiber yarns

Distinguished by their high specific surface area, large surface energy, and numerous active sites, micro-nanofiber yarns offer immense potential for applications in filters, sensors, tissue engineering scaffolds, and drug delivery systems. Nonetheless, the production of these yarns is hindered by prevailing spinning technologies, with, for example, low production rates, yarn uniformity and continuity issues, inadequate mechanical properties, and high costs. To address these challenges, we propose a novel method for fabricating micro-nanofiber yarns, integrating melt-blown technology with a modified ring spinning frame. This approach facilitates the low-cost and high-speed production of uniform and continuous polypropylene melt-blown micro-nanofiber yarns, achieving a maximum production rate of 1219 m/h. Furthermore, a comprehensive investigation was conducted to assess the yarn structure and properties. The results show that twisted-ribbon and wrapped-ribbon forms make up the structure, while mechanical testing reveals an optimal tensile strength and elongation, of 1.4 cN/tex and 49.7%, respectively, at a critical twist factor of 289.83. In addition, the yarns exhibit abrasion resistance increases by up to 222 cycles, which is five times higher than that of the original sliver. Thus, the melt-blown micro-nanofiber yarns have uniform and stable structures, rendering them suitable for conventional weaving processes. This work presents a feasible solution to obstacles in micro-nanofiber yarn production, paving the way for large-scale manufacturing of micro-nanofiber yarns and expanding the scope of their application.