Preparation Of Polyacrylonitrile Electrospun Membrane And Its Piezoelectric Properties

Polyacrylonitrile,a material widely used as filtration,adsorption and polymer composite,has excellent weather resistance and chemical resistance.Besides,high dipole moment?3.5D?make it possible for PAN to be polymer piezoelectricity material.Thus,PAN has been selected as the material and the piezoelectricity of it has been studied in this literature.Membranes were all manufactured by electrospun method.First of all,random PAN and PVDF nanofibers were prepared by plate electrospinning device.And the advantages and disadvantages of them were obtained by output voltage test,dielectric constant test and dielectric loss test.Moreover,different PAN membranes were prepared from changing spinning concentration and heat treatment time.The piezoelectricity of PAN and the influence of different conformation for the piezoelectricity have been studied by output voltage test,dielectric constant test,dielectric loss test,infrared spectroscopy?FTIR?and X-ray diffraction?XRD?tests.The receiver changed from plate to roller,and orientated PAN nanofibers have been prepared via roller electrospinning device.Output voltage test,FTIR and XRD tests have been done to analyze the influence of different conformations made by different roller speeds and heat treatment methods on the piezoelectricity of PAN.BaTiO₃ nanoparticles were mixture with PAN powder in DMF solution after modified by silane coupling agent?KH550?and random PAN/BaTiO₃ nanocomposites were prepared by plate electrospinning device.The piezoelectricity of PAN/BaTiO₃ nanocomposites were analyzed by output voltage test,dielectric constant and dielectric loss tests.And the influence of BaTiO₃ nanoparticles on conformation for PAN was studied by FTIR and XRD test.?1?Compared with PVDF,the output voltage of PAN was one-third of PVDF and dielectric constant of PAN was seventh of PVDF,while the dielectric loss of PVDF was more than twenty times the PAN.So the appearance of PAN polymer piezoelectric material could make up for the application defects of PVDF made by its high dielectric loss.PAN membranes of 12wt.%after heat treatment at the temperature of 140? revealed the biggest content of zig-zag conformation,leading to the greatest piezoelectricity.?2?Orientated PAN nanofibers could be obtained by changing the speed of the roller,and when the speed of the roller was 1200r/min,the orientation of PAN nanofibers reached the best.The stretch on PAN nanofibers from the roller could promote the transformation of conformation from 31 helical conformation to zig-zag conformation.And when the speed of the roller was 1200r/min,the biggest content of zig-zag conformation could be found in PAN membrane,resulting in good piezoelectricity.What's more,tension heat setting could further promote the transformation of conformation from 31 helical conformation to zig-zag conformation based on the stretch on PAN nanofibers from the roller.Therefore,the piezoelectricity of PAN membrane at the roller speed was 1200r/min after tension heat setting revealed better.However,contraction heat setting could promote the transformation of conformation from zig-zag conformation to 31 helical conformation,leading to the worst piezoelectricity of PAN membranes.?3?The results showed that there was a uniform distribution of BaTiO₃ nanoparticles modified by silane coupling agent?KH550?in PAN nanofibers.The output voltage and dielectric constant of PAN/BaTiO₃ nanocomposites holding content of BaTiO₃ nanoparticles at 12.5%were both increased by 300%compared with PAN membrane,while the dielectric loss of PAN/BaTiO₃ nanocomposites holding content of BaTiO₃ nanoparticles at 12.5%was decreased by 67%compared with PAN membrane.The results of FTIR and XRD showed that BaTiO₃ nanoparticles promoted the transformation of conformation for PAN from 31 helical conformation to zig-zag conformation,consequently enhanced the piezoelectricity of PAN.