同轴静电纺丝制备聚环氧乙烷—聚丙烯酸核—壳纳米纤维

发布时间：2018-04-18 06:42

本文选题：同轴静电纺丝技术 + 核-壳纳米纤维　；参考：《东华大学》2017年硕士论文

【摘要】：氢键是一种比离子键、配位键等化学键弱的多的相互作用,但却在改善聚合物相容性、提高复合物的稳定性、显著改善化合物的物理特性和结晶结构等方面起着非常重要的作用。而氢键既可以在本体中形成,也可以在各种界面上形成。目前,氢键在界面上形成的主要研究是利用氢键做为层层自组装技术的驱动力制备界面氢键复合膜,但是关于在界面上形成氢键的复合纤维的文章却鲜有报道。这主要是因为制备界面氢键复合纤维操作困难,而且纤维尺寸不可控。同轴静电纺丝为制备在界面上形成氢键的核-壳复合纤维提供了一个简单有效的方法。本文以聚环氧乙烷(PEO)作为氢键受体,聚丙烯酸(PAA)作为氢键供体,因为PEO可与PAA可形成构象较为伸展、流体力学体积较大PEO/PAA氢键复合物。首先,我们分别纺制了不同浓度,不同电压下的PEO和PAA纳米纤维膜,探究了聚合物溶液性质,纺丝工艺和环境对纤维形貌的影响,为制备核-壳纳米纤维奠定一定的实验基础。并通过SEM对纤维形貌进行表征,DSC和纤维强力测试仪对纤维膜的热力学性能和机械性能进行表征。而FI-IR光谱则是为了测试纤维膜中氢键的形成和强弱。PAA是一种具有良好机械性能,热力学稳定性能的聚电解质,其亲水官能团-COOH良好的化学活性,使PAA被广泛用于高吸水性树脂,污水中染料和金属离子的吸附等方面。但PAA本身易溶于水,所以需要对PAA进行交联,提高其在水中的稳定性,本实验以EG作为交联剂,H2SO4作为引发剂,并将纺制好的PAA纳米纤维膜放在不同交联温度下进行热处理。探究了交联剂的浓度,PAA纺丝液浓度和电压对PAA纳米纤维膜形态的影响及交联温度,交联时间对PAA纳米纤维交联程度的影响。通过同轴静电纺丝法分别制备了PEO-PAA和PEO-PAA/EG核-壳纳米纤维。通过利用SEM对核-壳纤维的表面进行表征,利用TEM对纤维的核-壳结构进行表征,制备出直径均匀,核-壳结构完善的同轴纳米纤维。在实验过程中,不断改变核给液速度,制备出不同界面面积的核-壳纳米纤维,并通过FT-IR光谱对其进行表征,验证了在核组分PEO和壳组分PAA界面上形成了氢键。此外,还对两种核-壳纳米纤维进行热交联,通过纤维强力测试仪对热交联前后的核-壳纳米纤维膜的力学性能进行表征。
[Abstract]:Hydrogen bond is a much weaker interaction than ionic bond, coordination bond and other chemical bond, but it improves the compatibility of polymer and the stability of complex.It plays an important role in improving the physical properties and crystal structure of the compounds.Hydrogen bonds can be formed both in the body and at various interfaces.At present, the main research on the formation of hydrogen bond on the interface is to use hydrogen bond as the driving force of the self-assembly technology to prepare the interface hydrogen bond composite film, but there are few reports on the formation of hydrogen bond composite fiber on the interface.This is mainly due to the preparation of interfacial hydrogen bond composite fiber difficult to operate, and the size of the fiber is not controllable.Coaxial electrostatic spinning provides a simple and effective method for the preparation of core-shell composite fibers with hydrogen bonding at the interface.In this paper, poly (ethylene oxide) (PEO) was used as hydrogen bond receptor and polyacrylic acid (PAA) as hydrogen bond donor, because PEO and PAA can form conformational extension and hydrodynamic bulk PEO/PAA hydrogen bond complex.Firstly, PEO and PAA nanofibers with different concentrations and different voltages were prepared, and the effects of polymer solution properties, spinning process and environment on the morphology of the fibers were investigated, which laid a certain experimental foundation for the preparation of core-shell nanofibers.The morphology of the fiber was characterized by SEM and the thermodynamic and mechanical properties of the film were characterized by fiber strength tester.The FI-IR spectrum is designed to test the formation of hydrogen bonds in fiber membrane and its strength. PAA is a kind of polyelectrolyte with good mechanical and thermodynamic stability. Its hydrophilic functional group -COOH has good chemical activity, which makes PAA widely used in superabsorbent resin.Adsorption of dyes and metal ions in sewage.However, PAA is easily soluble in water, so it is necessary to cross-link PAA to improve its stability in water. In this experiment, EG was used as crosslinking agent and H _ 2SO _ 4 as initiator, and the spun PAA nanofiber films were treated at different crosslinking temperatures.The effects of crosslinking agent concentration and voltage on the morphology of PAA nanofibers and the effects of crosslinking temperature and crosslinking time on the crosslinking degree of PAA nanofibers were investigated.PEO-PAA and PEO-PAA/EG core-shell nanofibers were prepared by coaxial electrostatic spinning.The core-shell nanofibers with uniform diameter and perfect core-shell structure were prepared by using SEM to characterize the core-shell fiber surface and TEM to characterize the core-shell structure.In the process of experiment, core-shell nanofibers with different interface areas were prepared by changing the rate of nucleation feeding, and characterized by FT-IR spectra. It was verified that hydrogen bonds were formed at the interface of nuclear component PEO and shell component PAA.In addition, two kinds of core-shell nanofibers were thermally crosslinked. The mechanical properties of core-shell nanofibers before and after thermal crosslinking were characterized by fiber strength tester.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ340.64;TB383.1

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