Studies On HTCC/PVA Electrospun Composite Nanofiber Membrane And Its Properties

There are a large number of microorganisms like various bacteria,fungi and viruses that are invisible to the naked eyes,exiesting in the environment.These bacteria multiply in quantities rapidly under mild conditions,in which increases infection year by year,resulting in continuous emerging of some drug-resistant bacteria.In daily life,skin infections or defects inevitably cause many diseases.Therefore,the study of high-performance antibacterial nano dressings is of great scientific and clinical significance.As a simple and effective method of preparing nanofibers,electrospinning is a good way for preparation of antibacterial textiles.The microfibers were obtained from the polymer by applying an electric field.The diameter of the fibers prepared by this method can reach nanometer level.It has the advantages of high porosity,large specific surface area and small pore size.What's more,the small pore diameter is also favorable for the release of the composite antibacterial agent.The single dressing composited from the fiber membrane reduces the changing times of dressing and leads to the reduction of disruption for new tissue.In a certain sense,it is a promising dressing material for wound medication in the future development of ideal new antibacterial controllable dressings.In this paper,polyvinyl alcohol?PVA?was used as the substrate,and dimethyldiallyl ammonium chloride was grafted onto the molecular structure of chitosan by the initiator in the molecular structure of the original chitosan to systhesize quaternary ammonium chitosan?HTCC?.Subsequently,HTCC and PVA were mixed at a concentration ratio of 0:10,2:8 and 4:6.Then the HTCC/PVA composite nanofibers with controllable diameter were prepared by electrospinning.The influence of the concentration of the spinning solution on the surface structure of the fiber was determined by the control variable method to determine the optimum concentration of 10 wt%.In addition,infrared spectroscopy?FTIR?,transmission electron microscopy?TEM?,scanning electron microscopy?SEM?,surface elemental analysis?EDS?,and specific surface area?BET?of the nanofiber membrane obtained after the synthesized HTCC and the optimized spinning solution concentration are performed.The thermal gravimetric analysis?TG?and other tests were used to characterize the surface morphology,chemical composition,pore size distribution and thermal stability of HTCC/PVA composite nanofiber membranes.Additionally,the filtration performance,the antibacterial property,the moisture permeability performance,and the mechanical properties of the prepared antibacterial composite nanofiber membrane were also tested.The results of the characteristic peaks in the infrared spectrum show that the chitosan is successfully quaternized and the microscopic images of the transmission electron microscope indicate a uniform and smooth morphology for the obtained HTCC/PVA composite nanofiber membrane with the fiber of a diameter in about 300 nm.Which contributes to about 20.15%for the surface nitrogen content.The PVA and HTCC/PVA nanofiber membranes have pore sizes of about 125 nm and 160 nm while the specific surface areas are about 5.46 m²/g and 8.53 m²/grespectively.The maximum removal rates of PM₁₀,PM_2.5 and PM_1.0 for HTCC/PVA composite nanofiber membrane are 92%,86%and 82%.The good filtration effect indicated excellent single-guide wet performance and outstanding mechanical properties with more than 99%inhibition rate against E.coli and S.aureus antibacterial activities.Secondly,in order to compare the organic antibacterial composite nanofiber membrane,nano silver with a diameter of about 60 nm was prepared by reducing AgNO₃ by NaBH₄.Then,nano silver was prepared into a Ag NPs/PVA composite nanofiber membrane by compounding PVA at a concentration ratio of 1%and 3%.Infrared spectroscopy?FTIR?,transmission electron microscopy?TEM?,scanning electron microscopy?SEM?,X-ray diffraction analysis?XRD?,surface elemental analysis?EDS?,specific surface area of synthetic nano-silver and Ag NPs/PVA composite nanofiber membranes?BET?,thermogravimetric analysis?TG?and other tests are to characterize such properties of Ag NPs/PVA composite nanofiber membranes as surface morphology,chemical composition,pore size distribution and thermal stability.The filtration performance and the antibacterial property were tested by the prepared antibacterial composite nanofiber membrane.The results of the test show that the particle size of the synthesized nano-silver is about 60 nm.The PVA nanofiber membrane has a diameter of 100-200 nm.Compared with the original PVA nanofiber membrane,the Ag NPs/PVA nanofiber membrane shows a certain continuity and disorder with its fiber diameter of about 270-400 nm.The surface silver content of the nanofiber membrane is about31.26%.The pore diameters of the PVA,Ag NPs?1%?/PVA and Ag NPs?3%?/PVA nanofiber membranes are mainly in 100-125 nm,while the specific surface area is between 18.35 m²/g and25.00 m²/g.Good filtration effect exhibited the maximum removal rates of 94%,89%and 82%for Ag NPs/PVA composite nanofiber membranes for PM₁₀,PM_2.5 and PM_1.0,respectively.When the nano silver content reaches 3%,the inhibition rates of the two colonies are over 99%,implying excellent antibacterial property.