Effect of humidity on diameter of polyamide 6 nanofiber in electrospinning process

Abstract

Various thermoplastic polymers have been spun to nanofibers by the electrospinning method, in which a polymer solution is ejected as a fine jet of liquid from the tip of the needle and is deposited on the collector by applying a high voltage to the polymer solution in the syringe. Due to special characteristics of nanofibers such as nanometer sized diameter, high surface area to volume ratio, and higher alignment of molecular chain, they have been used for a wide range of applications such as medical scaffolds and air filters. The morphology and diameter of electrospun fibers are dependent on a number of processing parameters that include the properties of the solution, the operational conditions and the surrounding conditions. The influence of the humidity on the fiber diameter of nanofibers in the electrospinning process has not been clarified yet. Polyamide 6 is an industrially important polymer thanks to its excellent physical properties, e.g. high fatigue strength, low coefficient of friction, and high resistance to chemicals. In this study, the influence of the humidity on the fiber diameter of PA6 in the electrospinning process was investigated by SEM observation and its mechanical properties were evaluated by tensile test. As the amount of humidity increased, the fiber diameters decreased. The tensile strengths of PA6 nanofibers nonwoven fabrics which were electrospun at 25 % and 65 % of humidity were 49±5 MPa and 71±12 MPa, respectively.