【作者】 王慧；

【导师】 覃小红；

【作者基本信息】 东华大学 ， 纺织材料与纺织品设计， 2011， 硕士

【摘要】 本文以二醋酸纤维素(CA)为原料,选取不同种类的单一溶剂或者多种溶剂的混合液,进行静电纺丝试验。经过初步的探索研究,找出了环保有效的溶剂体系,并成功地用静电纺丝方法制备了二醋酸纤维素纳米纤维。而后,进一步对不同溶剂体系下制备的纳米纤维的外观、细度、内部结构和性能进行了系统地分析,为二醋片静电纺纳米纤维应用的开发与研究等提供了试验依据。本文研究得到的两种有效的溶剂体系分别为：一是丙酮溶液,二是丙酮和二甲基乙酰胺(DMAC)以质量比为2:1的混合溶液。针对两种溶剂体系下制备的静电纺CA纳米纤维膜,分别运用扫描电子显微镜(SEM)观察其形貌和细度,分析制备工艺参数,主要是纺丝液的浓度、纺丝电压和接收距离,三者分别对纤维形态和细度的影响。研究得出的结论：1)各纺丝参数对两种溶剂体系下制得的纳米纤维细度的影响规律一致,即纤维的直径均随溶液浓度的增加而增大,随纺丝电压的增大而减小,随接收距离的增大而减小；2)以丙酮为溶剂和以混合溶液为溶剂时,制备纤维细度最小的工艺条件相同,均为纺丝液浓度为8%、纺丝电压25kV、纺丝间距25cm；3)三参数对纤维细度的影响强弱顺序均依次为溶液浓度、纺丝电压、接收距离。为进一步了解两种纳米纤维的内部结构的变化,以及纺丝加工参数对内部的影响,使用红外光谱和X射线衍射方法进行测试并分析。观察发现两种纤维大分子链上的-OH基团与-CH3数量均比原CA明显减少,-C-H与-C=C-键伸缩振动强度均有所减弱；两种静电纺纳米纤维的结晶度、晶粒尺寸相比原CA均有不同程度降低。以丙酮为溶剂时,不同纺丝参数下制得的纤维内部结构差异较小,其中溶液浓度的影响较显著。根据不同溶剂体系下纺得纤维内部结构的变化情况,进一步研究了其热性能方面的差异。总体来看,两纤维的热稳定性均比原二醋片有所减弱,其中结晶度小的纤维,即混合溶剂纺得纤维,其热稳定性相对差些。这一结论主要与纤维内部结构的差异有关。通过进一步观察扫描电镜图,对比分析了两种纤维的形态差异以及各自纺丝过程中的特殊现象,发现使用混合溶剂时,纺得纤维的细度较小,直径均匀度较好。这一现象,充分说明纤维的直径与形态很大程度上,与溶剂的挥发性有关。通过试验总结,得出较为理想的溶剂体系是质量比为2：1的丙酮和DMAC混合液。更多还原

【Abstract】 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.更多还原