Fabrication of polyacrylonitrile nanofibrous yarns by extended nozzleless electrospinning: Effects of process parameters on yarn morphology and mechanical properties

Polyacrylonitrile (PAN) nanoyarns were fabricated using a nozzleless electrospinning system incorporating rotating disc spinnerets and a controlled twisting mechanism. The effects of key processing parameters, including applied voltage and twister rotational speed, on yarn morphology and mechanical performance were systematically investigated. Increasing twisting speed improved fiber consolidation, with optimal performance achieved at 375 rpm, producing yarns with a maximum tenacity of 5.31 ± 1.07 cN/tex and a linear density of 61.4 tex. Both lower and higher rotational speeds resulted in reduced yarn strength due to insufficient fiber packing or structural irregularities. Increasing applied voltage enhanced jet stretching and fiber alignment; however, excessive voltage reduced mechanical performance, with tenacity decreasing from 2.71 ± 0.67 cN/tex at 40 kV to 1.55 ± 0.51 cN/tex and 1.93 ± 0.57 cN/tex at 46 and 52 kV, respectively. SEM analysis confirmed that processing parameters strongly influenced fiber diameter and structural uniformity. Optimized processing conditions enabled the production of mechanically robust and structurally uniform PAN nanoyarns, highlighting their potential for advanced textile, biomedical, and high-efficiency filtration applications.