Preparation And Research On Environmentally Friendly Cellulose Acetate By Electrosponning

Cellulose Acetate (CA), with different solvents, was used to do the trial experiments of producing nanofibers by electrospinning. After the preliminary researches, two relatively environmentally friendly solvent systems were found, and the CA electrospun nanofibers were successfully made. Then, the morphology, the diameters and the inner structures of electrospun fibers with different solvent systems as well as its thermal properties were analyzed theoretically. These basic studies can be the experimental references for further explorations about the concrete applications of CA nanofibers and the fiber mats.There were two proper and useful solvent systems found in this experiment, one was the single acetone solution; the other was the mixed solution of acetone and DMAC with the weight ratio 2:1. For the two solvent systems, the morphology and the diameter of the nanofibers electrospun with different processing parameters were observed through scanning electron microscopy (SEM), and then the relationships between the diameters and these parameters were analyzed systematically.The results of the research are as following. Fisrt, with the two solvent systems, the influencing phenomenon of all the processing parameters on the diameters of electrospun fibers were the same. The diameters would increase with increasing the concentration, would decrease while the voltage and the distance between the needle and the collecter raised, respectively. Second, the best combination of the three factors for either solvent system to produce the smallest fibers was that the concentration was 8%, the voltage was 25kV, and the distance was 25cm. Then, the influencing intensity of the concentration was the strongest, followed by the voltage and the last one was distance.In order to know well the changes happened in the inner structures of the electrospun fibers, and to analyze the influence of the three important factors on the inner structure, the Infrared Spectrum and the X-ray Diffraction were used. By analyzing the results of the Infrared Spectrum, the changes on the binding groups and the bonds were found in the two electrospun fibers, especially the quantity of the -OH and the -CH3 binding groups, the vibration intensity of the-C-H and the -C=C- bonds. Through the results of the X-ray Diffraction, comparing with the original acetate, the degrees of crystallinity and the crystallite sizes of the two eletrospun fibers decreased differently. With acetone as the only solvent, there were only a few differences among the CA fibers electrospun under different parameters in the inner structure, and the impact of the concentration was relatively distinct.According to the changes in the inner structures of the spun fibers and the CA, the differences in the property among them were researched. Generally speaking, the thermal properties of the fibers became worse than CA, the thermal property of the fibers electrospun from the mixed solvent system with lower crystallinity decreased more. These results had something to do with the changes in the inner structures.By observing and comparing the scanning pictures, the differences in morphology and the diameters between the two fibers, the special phenomena were found and then systematically analyzed. The conclusion was the diameters of fibers electrospun from the mixed solvent system were most the same and more even. To a great extent, this phenomenon was in relation to the volatility of the solvents.After all the experiments, the more useful and efficient solvent system was the mixed Acetone and DMAC with the weight ratio2:1.