Experimental Study On The Mechanical Properties Of Electrospun Nanofibers

With the advent of nanotechnology,the properties and applications of nanomaterials have become a hot research topic among scholars.Thereinto,The mechanical properties of nanofibers are the hotspots of research.Electrospinning is a method which can be used to prepare nanoscale or submicron ultrafine fibers continuously.Nanofibers prepared by electrospinning have many advantages,such as high porosity,large specific surface area,large aspect ratio and good mechanical properties.They are widely used in filter material,tissue engineering,personal protection and other fields.Polyvinylpyrrolidone(PVP)is a non-ionic polymer.Its excellent solubility and physiological compatibility have attracted much attention.It has good application prospects in food,medicine,cosmetics and other fields.It is necessary to study the mechanical properties of the fibers in order to meet the requirements of them in the specific application.Scholars have studied the mechanical properties of the electrospun nanofibers of various materials,but the mechanical properties of electrospun PVP nanofibers have not been reported yet.Therefore,to study the mechanical properties of the electrospun PVP nanofibers has an important guiding significance for its application.In this paper,PVP nanofibers were prepared by electrospinning.Firstly,scanning electron microscope(SEM)was used to observe the electrospun PVP nanofibers membrane.The effects of processing parameters including the solution concentration,the spinning voltage and the needle-collector distance on the fiber diameter and morphology were investigated.It was found that when the solution concentration is between 6 wt% and 10 wt%,the spinning voltage is between 13.5 kV and 20 kV,the inner diameter of needle is 0.51 mm,the injection speed of solution is 0.7 mL/h,and the needle-collector distance of fiber is between 8 cm and 15 cm,can be prepared continuous and non-beaded PVP fibers at room temperature and the relative humidity is below 50%.The fiber diameter is between several hundred nanometers and a few microns.The average diameter of fibers increased with increase in solution concentration,while decreased with increase in spinning voltage and first decreased and then increased with increase in needle-collector distance.Secondly,nano tensile test system was used to carry out the axial tensile test of the single electrospun PVP nanofibers.The mechanical properties of fiber such as tensile modulus,tensile strength and the strain at break were tested,and the change rule between them and fiber diameter was obtained.The results showed that there is no apparent correlation between tensile modulus and fiber diameter,while tensile strength decreased with increase in fiber diameter,and the strain at break increased with the increase in fiber diameter.Finally,the surface roughness of the single electrospun PVP nanofibers was measured by atomic force microscope(AFM).The rule of fiber surface roughness with fiber diameter was obtained,which was used to explain the relationship between tensile strength and fiber diameter.It is found that the surface of fiber has some characteristics such as concave structure and transverse stripe,so it has a certain surface roughness.With the increase of fiber diameter,the surface roughness of fibers gradually increased,and fibers start to appear uneven diameter distribution,beaded structures and other defects.We believe that the presence of fiber surface morphology and fiber defects have a certain effect on the mechanical properties of fibers,so the tensile strength of fibers decreased with the increase in fiber diameter.