| Cellulose acetate, as the derivatives of cellulose, is a kind of environmental friendlymaterial with good biocompatibility and biodegradability, furthermore because of its goodprocessing performance, CA is commonly used to replace the natural cellulose as the substratematerial in the electrospinning. CA has a wide array of application in the field of cigarette flters,textiles and biomedicine. With the improvement of living standards, higher requirements abouthealth function of supplies are put forward, more attentions are paid to the antimicrobial products.In this dissertation, CA was modified by nano-scaled inorganic antimicrobial agents throughelectrospinning. The properties of the spinning solution were evaluated by rotary rheometer,automatic surface tensiometer and conductivity meter. The CA composite fibers werecharacterized by the scanning electron microscope (SEM), transmission electron microscope(TEM), ultraviolet spectrophotometer (UV-vis), thermo-gravimetric apparatus (TGA) and X-rayphotoelectron spectrometer (XPS) potential to investigate morphology, microstructure, thermalstability, elemental composition and the valence change. The antibacterial performance of CAcomposite fibers was evaluated by using agar diffusion method. The main results achieved in thispaper were listed as following:1. CA nanofibers had been prepared by electrospinning, and electrospinning parameter wasinvestigated. Solvent, concentration of CA, voltage and flow rate had a certain effect on fibermembrane morphology. The results showed ribbon like morphology was noted for the CAnanofbers produced from acetone and mixture of acetone/H2O while electrospinning inacetone/DMAc (7/3w/w) and acetone/DMAc/H2O (7/2/1w/w/w) system resulted in thecylindrical shape. Furthermore, in the mixed solvent system of acetone/DMAc/H2O (7/2/1w/w/w), high quality CA nanofibers were obtained under the optimized electrospining conditionsas following:10-14wt%of CA,15-17KV of voltage,0.3-0.5mL/h of flow rates.2. A series of antimicrobial ultrafne fbers with silver nanoparticles (AgNPs) weresuccessfully prepared by direct electrospinning of cellulose acetate(CA) solution with silvernitrate, following by UV irradiation. This article focused on the effect of different solvents and concentration of AgNO3on the fiber morphology, dispersity and grain size of AgNPs. The resultsshowed that the mixed solvent of Acetone/DMAc/Water（7/2/1w/w/w）was appropriate forelectrospinning along with a uniform distribution of AgNPs on the fibers. Moreover, the diameterof nanofiber decreased with the increasing of the concentration of AgNO3. XPS and TGA resultsdemonstrated that Silver ions in CAnanofbers were photoreduced intoAgNPs by UV irradiation,which were stabilized by interactions with carbonyl oxygen atoms in the CA. However, thethermal stability of CA composite nanofibers had decreased. The zone of inhibition experimentsdemonstrated that AgNPs/CA composite nanofibers with a judicious content of AgNPs showedvery strong antimicrobial activity against Escherichia coli and Staphylococcus aureus.3. Two kinds of AgNPs/TiO2/CA composite nanofibers were successfully achieved byelectrospinning, in which the TiO2and titanium isopropoxide (TTIP) acted as support of TiO2nanoparticles, respectively. The SEM showed that content of AgNO3and TiO2had a certain effecton fiber morphology. AgNPs/CA/TiO2composite nanofibers had optical response in both theultraviolet region and visible region. Furthmore, the interaction between carbonyl oxygen atoms ofCA and AgNPs weakened following the introduction of TiO2, which improved the thermalstability of the composite nanofibers. The zone of inhibition experiments showed that two kinds ofAgNPs/TiO2/CA composite nanofibers exhibited good bacteriostatic effect against Escherichiacoli and Staphylococcus aureus. In addition, compared with the AgNPs/CA nanofibers, because ofthe introduction of TiO2, the antibacterial properties of AgNPs/TiO2/CA composite nanofibers hadsignificantly improved at equal amount of AgNO3. |
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