Preparation And Characterization Of PVA/CS/Gr Nanofiber Membranes By Rotary Linear Needleless Electrospinning

In order to solve the problem of needle blocking and hard industrialization of traditional needle-type electrospinning,a self-designed rotary linear electrode needle-free electrospinning device is used to realize the scale preparation of PVA?PVA/Gr and PVA/CS/Gr nanofiber films.The relationship model between spinning process parameters and PVA nanofiber films diameter was established to realize the structural regulation of PVA nanofiber films.The effects of Gr and CS contents on the microstructure,thermal stability,electrical conductivity and hydrophilicity of PVA/Gr and PVA/CS/Gr nanofiber films were further studied,which provided reference for the feasibility of future application of neural tissue engineering stents.First,The spinnability of PVA nanofibers was studied.The effects of PVA solution concentration,voltage and spinning distance on the morphology and diameter distribution of PVA fiber were investigated,and the relationship model with diameter was established.The results showed that,when PVA solution concentration,solution viscosity and conductivity decreased,fiber diameter and its distribution became narrow.With the increase in spinning distance,the fiber diameter became smaller,and the fiber morphology became better.When the PVA concentration was 10 wt%,the voltage was 80 kV and the distance was 30 cm,the yield reached 6.8 g/h.When the PVA concentration was 5 wt%,the voltage was 80 kv,distance was 30 cm,the smallest diameter of spinning fibers reached 96 nm.The fiber diameter d is exponentially related to the concentration C,and the constant y is 2.06.The spinning voltage is positively correlated with the diameter,and its linear relationship is y=48.3+3.1*x.Secondly,preparation and properties of PVA/Gr nanofiber films.The effect of Gr content on the hydrophilicity,electrical conductivity and thermal stability of nanofiber membranes was investigated.The test results show that the PVA/GR mixture has greater viscosity and electric conductivity than pure PVA solution and can be electrospun into PVA/Gr nanofiber films that have good morphology and diameter distribution.The diameter of the nanofibers is 100 nm and the yield is 2.24 g/h,suggesting that the process qualifies for use in large-scale production.Increasing the content of graphene yields finer nanofibers,a smaller surface contact angle,and higher hydrophilicity of the nanofiber films.The presence of graphene is proven to improve the thermal stability.Finally,preparation and properties of PVA/CS/Gr nanofiber films.The effects of CS content on the microstructure,thermal stability,electrical conductivity and hydrophilicity of PVA/CS/Gr nanofiber membranes.The results showed that the addition of chitosan affected the morphology of PVA/Gr nanofiber mem'brane,the fiber formability decreased,and the fiber diameter decreased.The addition of chitosan increased the hydrophilicity of PVA/Gr nanofiber membrane;FTIR proved The hydrogen bond is formed between CS and PVA,the thermal stability of the PVA/Gr nanofiber membrane is enhanced,and the maximum decomposition rate of the PVA/CS/Gr(9:1)nanofiber membrane is 297.7 ?.The addition of chitosan reduces the surface resistance and improves the electrical conductivity.The preparation and performance of PVA/CS/Gr nanofiber membranes provide reference for the feasibility of future application of neural tissue engineering stents.