【作者】 杨尚斌；

【导师】 钱竞芳； 丁彬；

【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】 静电纺丝即聚合物喷射静电拉伸纺丝法,与传统方法截然不同。首先将聚合物溶液或熔体带上几千至上万伏高压静电,带电的聚合物液滴在电场力的作用下在毛细管的Taylor锥顶点被加速。当电场力足够大时,聚合物液滴克服表面张力形成喷射细流。细流在喷射过程中溶剂蒸发或固化,最终落在接收装置上,形成类似非织造布状的纤维毡。静电纺制备的纤维具有较高的比表面积、较高的孔隙率,这使得静电纺纳米纤维在信息、能源、环境、生物医学、国家安全等领域都具有广泛的应用潜力。美国人Formhals早在1934年就提出了静电纺丝的概念,然而直到最近十年,随着纳米纤维的兴起,人们才给予静电纺丝极大的关注,做了较系统的理论和实验研究。目前,静电纺纤维的直径一般在100-500nm,只有纤维的直径降低到50nm以下时,材料所产生的纳米效应才最为显著。但是目前的静电纺技术还不能大量制备50nm以下的纤维,这很大程度限制了纳米纤维的应用。如何降低纤维直径和提高产量是静电纺发展遇到的最大挑战。各国研究者经过数十年的努力,通过深入研究静电纺工艺参数和原理试图大量制备50nm以下的纤维,但是收效甚微。本课题首先研究了静电纺的发展历史及现状,以及在静电纺过程中对纳米纤维产生影响的各种重要参数。本课题以聚丙烯酸(PAA)为主要原料,借助于FE-SEM为主要分析手段,首先分析了溶液体系对静电纺纳米蛛网形态和直径的影响。实验发现,以95%乙醇和去离子水共同作为溶剂进行纺丝时,随着乙醇的比重升高,纳米蛛网的数量增加。在此基础上,该课题还讨论了电纺参数,如电压、湿度、添加物、粘度和电导等对纳米蛛网的数量和形态的影响。最终获得了大量连接在普通静电纺纤维之间、平均直径小于50nm的、具有类似于蜘蛛网结构的纳米蛛网。本课题研究了纳米蛛网的形成过程,并借助高速摄像机对静电纺过程进行观察,获得了大量静电纺纳米蛛网的形成过程图。结合现有静电纺理论,得出静电纺过程中射流分裂成液滴是形成纳米蛛网的关键。更多还原

【Abstract】 Electrospinning is exert voltage on polymer solution to got nanofiber which is different from traditional methods. At the beginning, the polymer solution or melt bring thousands of high voltage. The charged droplet in the capillary was accelerated under the force of electrostatic force. When the electric force is large enough, the droplet can overcome surface tension to formation of a thin stream. Due to solvent evaporation in the electric field, nanofibers what like non-woven mats were got in the receiver. Electrospun nanofibrous membranes with relatively high surface area and microporous structure can be applied in various potential applications such as information technology, energy, environment, biomedical, national security, etc.Early in 1934, Formhals proposed the concept of electrostatic spinning. Until the past decade with the rise of nanofibers, it was given great attention to electrospinning. Many researchers did theoretical and experimental studies systemicly on electrospinning. Currently, the diameter of electrospun fibers is generally between 100 nm and 500 nm. Only the diameter below 50nm, the performance of nanofibers can be significantly better than normal nanofiber. However, the fibers which diameter below 50 nm can not got easily by the current technology, which largely limits the application of nanofibers. How to reduce the fiber diameter and increase production is the biggest challenge in electrospinning. Through studying the process parameters and principles of electrospinning trying to prepare a large number of fibers which diameter below 50nm, but with little success.Firstly, the history and status of electrospinning were introduced in this paper, and which factors influence on the formation nano-membrane. In this topic, polyacrylic acid (PAA) is the main materials with some other auxiliary materials. And the system of electrostatic spinning solution was analyzed in forming nano-net and in reducing the diameter of nanofiber with the aid of FE-SEM. The 95% ethanol and deionized water were together as solvent for electrospinning. In this experiment, we found that with increasing the proportion of the ethanol in solvent, the number of nano-net was also increased. On this basis, some other electrospinning parameters were also discussed, such as voltage, humidity, additives, viscosity and electric conductivity. Through the experiment, we finally got numerous nano-nets that comprise interlinked ultrathin nanowires with diamerer below 50nm.In order to study the forming of nano-nets, we got the authentic process of electrospinning in forming nano-nets by high speed camera. With the existing electrospinning theory, it concluded that the electrostatic jet split into droplets is the key factors to form nano-nets in electrospinning.更多还原