Preparation Of Modified Nano-zinc Oxide And Its Antibacterial Application On PET Nanofiber Membranes

Polyethylene terephthalate(PET)fiber is widely used in modern textile industry because of its good dimensional stability,good washability and low cost.However,due to the high surface area of the fiber,the textile made of PET fiber is easy to absorb bacteria during wearing,and the bacteria will grow and reproduce rapidly under the nutritional conditions such as human sweat,which is harmful to human health and safety.Therefore,it is of great significance to endow PET fiber with excellent antibacterial properties.As an inorganic photocatalytic antibacterial agent,nano-ZnO has high safety,broad antibacterial spectrum and remarkable antibacterial effect.It is a hot spot for developing antibacterial materials.In order to make nano-ZnO more efficiently antibacterial and play a good application effect,in this paper,silane coupling agent and organic antibacterial agent Schiff base were used to modify it.And then the obtained antibacterial powder was blended with PET solution to prepare PET composite antibacterial nanofiber membrane by electrospinning.The obtained PET fiber membrane not only has excellent antibacterial properties,but also has fast preparation speed,saves time and cost,and has good development prospect.The main research contents and conclusions are as follows:(1)In order to improve the dispersion of nano-ZnO in PET polymer matrix,nano-ZnO,ethyl glycolate and isocyanatopropyltriethoxysilane(IPTS)were used as raw materials to prepare modified ZnO nanoparticles(I-ZnO)with different IPTS amounts by dehydration condensation.The infrared and X-ray diffraction structure characterization of nano-ZnO before and after modification proved that the surface modification of nano-ZnO was successful,and IPTS would not affect the crystal structure of ZnO nanoparticles.The effects of IPTS with different amounts on the dispersion of nano-ZnO were investigated.The results showed that I-ZnO(3)(IPTS amount was 25% of nano-ZnO amount)had the best dispersion effect.The average particle size of ZnO nanoparticle aggregates was the smallest,396.9 nm,and the particle size distribution coefficient was 0.081.The maximum coating amount of IPTS on the surface of I-ZnO(3)was 4.66%.Compared with unmodified nano-ZnO,the inhibition zone widths of I-ZnO(3)against Staphylococcus aureus and Escherichia coli were expanded from 2.5 mm to 3.5 mm.(2)The synthesized chitosan cinnamaldehyde Schiff base SCSB was compounded with I-ZnO(3)to further improve the antibacterial activity of nano-ZnO.The infrared and X-ray diffraction analysis of the prepared IZnO-SCSB with different compounding ratios showed that there was a strong hydrogen bond between I-ZnO(3)and SCSB,and the addition of SCSB changed the original arrangement of I-ZnO(3)molecular chains.The thermal stability,dispersion and antibacterial properties of IZnO-SCSB with different proportions were tested and analyzed.The results showed that the addition of I-ZnO(3)improved the thermal stability of SCSB in IZnO-SCSB.With the increase of SCSB content in IZnO-SCSB,the dispersion and antibacterial properties of the sample powder gradually deteriorated.When I-ZnO(3)and SCSB were compounded at a ratio of 4:1,the powder had good dispersion and optimal synergistic antibacterial effect.The size of IZnO-SCSB nanoparticles was 40～50 nm.The inhibition zone widths of antibacterial agent 4IZnO-1SCSB against Staphylococcus aureus and Escherichia coli were 6.5 mm and 4.5 mm respectively,the growth adaptation periods were 6 h and 4 h respectively,the minimum inhibitory concentrations were 0.175 mg/m L and0.7 mg/m L respectively,and the minimum bactericidal concentrations were 0.7 mg/m L and0.9 mg/m L respectively.(3)Different amounts of 4IZnO-1SCSB were added to the PET polymer solution and mixed evenly.PET/4IZnO-1SCSB composite antibacterial nanofiber membranes with different proportions were prepared by electrospinning.4IZnO-1SCSB improved the agglomeration of nano-ZnO in PET polymer matrix and realized uniform dispersion.With the increase of 4IZnO-1SCSB content in the composite membrane,the average diameter of the fiber gradually decreased,the melting point of the composite membrane almost remained unchanged,and the crystallization temperature and crystallinity of the composite membrane gradually decreased.The thermal stability,permeability,antibacterial,mechanical and hydrophobic properties of composite membranes with different proportions were investigated.It was found that with the increase of 4IZnO-1SCSB mass fraction,the thermal stability of composite membranes decreased,the permeability,hydrophobicity and antibacterial properties of composite membranes enhanced.When the mass fraction of 4IZnO-1SCSB was1 wt%,the mechanical properties of composite membrane were the best,and the breaking strength and elongation at break were 2.39 MPa and 240.86% respectively.When the addition amount of 4IZnO-1SCSB exceeded 1 wt%,the antibacterial rate of composite membranes against Staphylococcus aureus and Escherichia coli were more than 90%,and the antibacterial performance of composite membranes were good.When the addition amount of4 IZnO-1SCSB was 3 wt%,the antibacterial rate of composite membrane against Staphylococcus aureus and Escherichia coli reached 99.80% and 97.08% respectively.