Melt Electrospinning Polyethylene Fibers in Inert Atmosphere

Abstract

Electrospinning is commonly used for fabrication of polymer fibers. Melt electrospinning, instead of the commonly used solution electrospinning, offers many advantages in generating polymer fibers without using solvents. However, polymer melts have high viscosity which poses major limitations in producing low diameter fibers. Here, melt electrospinning is investigated at elevated temperatures in inert atmosphere to reduce fiber diameters while suppressing thermal degradation. Two types of spinneret configurations, syringe and wire, with two distinct outcomes are studied. In syringe-based electrospinning, increasing the nozzle temperature from 300 to 360 °C in nitrogen reduced fiber diameter significantly from 33 ± 5 to 10 ± 4 µm. Electrospinning in nitrogen leads to formation of fibers even at a high nozzle temperature of 360 °C, while this temperature leads to thermal degradation when spinning in air. In contrast, increasing the temperature of wire electrospinning setup do not lead to a noticeable reduction in diameter. This is attributed to the viscosity-dependent flow rate in this method. Increasing the temperature leads to increased flow rates, promoting the formation of thicker fibers, while the increased stretchability promotes the formation of thinner fibers. The results clearly demonstrate advantages of developing polymer microfibers in inert atmosphere to avoid thermal degradation with a temperature-independent flow control.