Preparation Technology And Properties Of PA6/PANI Nanofiber Membranes

With the development of science and technology,people pay more attention to the research of functional composite nanofibers membrane.Electrostatic spinning technology is one of the most effective means of the preparation of nanometer fiber membrane,but to get a series of electric conductivity and electromagnetic shielding performance of functional nanofiber membrane,must improve the biological activity of nanometer fiber surface with surface modification technology.Polyamide-6(PA6)nanofibers membrane was prepared by electrostatic spinning with wire electrode.A series of morphology was evaluated,including fiber diameter,void fraction,mechanical properties,air permeability,moisture-penetration performances.Polyamide-6/polyaniline composite nanofiber membrane excellent electric conductivity and electromagnetic shielding performance was prepared through in situ chemical polymerization of aniline monomers on the surface of the PA6 nanofibers membrane.The main work of this paper as follows:Firstly,a suitable amount of polyurethane was dissolved in acid/acetic acid.This solution was electrospun in electrostatic spinning device.The optimum parameters was obtained by the combination of single factor experiment and orthogonal experiment method,which the mass fraction is 12%,a voltage of 70 kV was applied directly to the wire electrode,the distance between two wire electrode was maintained at 18 cm and the movement speed of reservoir was kept constant at 100 mm/min.Secondly,the performance of void fraction,mechanical properties,air permeability,moisture-penetration performances was evaluated.The experimental results show that the fiber diameter and film thickness has a direct effect on gas rate,and gas content can be used as evaluation index of breathable fiber membrane permeability.PA6 nanofiber membrane rupture strength can reach 20 MPa,the elongation at break can reach 70%,gas rate between 70-90%,and the moisture transmission can achieve 6971 g/(m2.24 h).The result indicate nanofiber membrane have excellent mechanical property and air permeability.Thirdly,Polyaniline(PANI)was coated on the resulting nanofiber surface via in-situ polymerization to form flexible PA6/PANI composite nanofibers with conductivity.The results of scanning electron microscopy(SEM)show that surface of PA6 nanofiber was evenly coated on a layer of polyaniline.The results of the TG show that polyaniline can improve the thermal stability of composite fiber membrane.The results of conductive performance show that the fine process of in-situ polymerization of polyaniline is that the concentration of the aniline monomer is 0.6 mol/L,dipping time is 40 min,concentration of ammonium persulfate is 0.6 mol/L and the processing time is 20 s.The conductivity of the composite can reach 0.37S/cm,after heat treatment,and water to wash,the conductivity decreased only one or two orders of magnitude,shows that the combination of polyaniline and PA6 nanofibers are stable.The shielding effectiveness reach 10 dB and the rate of shield over 87% in the 0.3MHz to 2500 MHz frequency range.