|
In order to improve the dispersibility of the single-walled carbon nanotubes in the polymer matrix , to enhance the interfacial bonding between the single-walled carbon nanotubes and a polymer matrix , and thereby to obtain good mechanical properties of the polyacrylonitrile (PAN) nanofiber , the subject single-walled carbon nanotubes added to the polymer coated polyacrylonitrile matrix , the use of electrostatic spinning techniques in the roll speed of 2500r/min, voltage 14-16kV, the flow rate of 0.3ml / h under the conditions to obtain the surface smoothness diameter, evenly distributed along the roll direction of rotation of the PAN- based nano fibers are arranged in parallel and at a certain tension and temperature of the resulting nanofibers hot stretching to obtain excellent mechanical properties of nanofiber . By scanning electron microscopy ( SEM ) , transmission electron microscopy ( TEM ) , differential scanning calorimetry (DSC, TGA analyzer ( TGA ) , Fourier infrared the test ( FTIR ) , X -ray diffraction scan , pole figure scanning , mechanical properties and other tests were used to characterize the microstructure and properties of the nanofibers , the main findings are as follows : (1 ) When adding 0.75wt% of single-walled carbon nanotubes , the mechanical properties of the PAN nanofibers , and after a hot draft single-walled carbon nanotubes enhance the effect of the mechanical properties of the PAN nanofibers more significant . adding 1wt% single-walled carbon nanotubes , because of the single-walled carbon nanotubes dispersed in the PAN matrix degrades , the fiber surface becomes rough , forming a stress concentration point , affecting the improvement of their mechanical properties (2) in a certain temperature and under tension on the nanofibers heat drawing , and SEM, FTIR, X -ray diffraction before and after the heat drawing the PAN nanofibers testing confirmed after heat drawing Hou Nami fiber along the fiber axis arranged better, more closely arranged fibers . the heat drawing Hou Nami fiber crystallinity improved approximately 240.24% , the degree of orientation is about 245.45% increase in degree of crystallinity and degree of orientation are greatly improved. (3) of the the heat drawn before and after the PAN and the PAN / SWNTs nanofiber mechanical properties test results showed that after the heat drawing , due to the substantial increase of the degree of crystallinity and degree of orientation of the nanofibers , the nanofibers tensile strength and elastic modulus is significantly improved , the SWNTs are added and heat drawing can significantly improve the mechanical properties of the PAN - nanofiber .
|