Effect of spinning conditions on the mechanical properties of PA6/MWNTs nanofiber filaments

Carbon nanotube (CNT ) reinforced composite materials is a hot research issue now , but CNT/polymer composite nano-scale fibers still cannot be obtained readily, not mention to successfully prepare continuous CNTs/polymer composite nano-scale fiber filaments manufactured by electrospinning. In this paper, continuous filaments constructed of nano-scale PA6/MWNTs fibers in single-axis orientation were obtained by an improved wet-electrospinning technique. The effects of the concentrations of MWNTs, spinning speed and post-drawing on the mechanical properties of PA6/MWNTs nanofiber filaments were studied. The results show that when the concentrations of MWNTs is below 0.8 wt%, the increase of MWNTs content enhances the Young’s modules and breaking stress but reduces the breaking strain, while the breaking stress decreases when the MWNTs concentration exceeds 0.8 wt%. The Young’s modules and breaking stress increased as the spinning speed raised at the range of 1.8–9.0 m/min, but declined when the speed exceeded 9.0 m/min. The mechanical properties of the as-spun filaments can be improved by either dry or wet post-drawing, and the breaking stress of the wet post-drawn filaments was improved 2.64 times while that of the dry post-drawn filaments 2.28 times.