Fabrication of Microfiber Bundles via Melt Electrospinning Technique

Abstract

Polypropylene (PP) yarn has the advantages of low density, excellent mechanical properties and good abrasion resistance. Its fiber preparation process is low cost and environmentally friendly. The process of preparing PP yarns involves forming stable fibers, aggregating the fibers into bundles, and twisting the bundles to form yarns. However, in the melt electrostatic spinning process, the poor uniformity of the melt reaching the nozzle position leads to an unstable fiber generation process during spinning, which increases the difficulty of directly and continuously collecting the fibers and forming fiber tows. In this paper, a melt-differential electrostatic spinning method using unilateral airflow assistance is proposed for the preparation of PP fiber tows. In this method, the melt at the nozzle is stretched and cooled to form fibers under the action of an electric field. Assisted by a unilateral airflow, these fibers can be further stretched and cooled before contacting the electrode plate, and are finally collected on a rotating roll to form fiber bundles. In this paper, the effects of voltage, airflow rate, and collection roller speed on the morphology and mechanical properties of fibers and their assemblies are investigated. The experimental results show that the addition of auxiliary airflow significantly improves the collection efficiency of fibers when the speed of unilateral auxiliary airflow is controlled within 2.5 m/s compared with the experimental results without auxiliary airflow, and the number of fibers in each fiber bundle increases under the condition of auxiliary airflow. In addition, the auxiliary airflow helps to refine the fiber diameter to 10–20 μm and significantly improves the overall fiber mechanical efficiency. This technology opens up new avenues for the application of PP fibers in a wider range of applications and shows good prospects for development.