【作者】 高强；

【导师】 朱新生；

【作者基本信息】 苏州大学 ， 材料学， 2009， 硕士

【摘要】 静电纺丝是制取超细纤维的重要方法。聚苯乙烯(PS)是一种应用广泛的离子交换基材,其电纺纤维有着广泛的应用前景。本文首先用乳液聚合制备出系列高分子量聚苯乙烯,然后进行聚苯乙烯静电纺丝与增强热处理,然后采用浓硫酸进行磺化处理,制备磺化超细聚苯乙烯离子交换纤维膜,最后研究其吸附性能。具体研究内容包括:聚苯乙烯的分子量和浓度、辅助电极和添加剂十二烷基苯磺酸钠(SDBS)对电纺分裂行为和电纺膜形态和性能的影响;热增强处理和多壁碳纳米管(MWCNT)对聚苯乙烯电纺纤维膜形态与力学性能的影响;磺化反应对磺化聚苯乙烯(SPS)纤维形态结构与性能的影响;SPS纤维膜对阳离子艳红模拟染料废水的吸附性能。采用乌氏粘度计测量PS粘均分子量,采用高分辨率高速摄像仪研究纺丝射流分裂行为,采用扫描电镜观察纤维形貌,采用红外光谱仪分析磺化效果,使用热重分析仪分析SPS纤维热稳定性,使用电子万能试验机测试纤维膜的拉伸性能,并使用紫外分光光度计评价SPS纤维膜对阳离子艳红水溶液的吸附作用。得出以下主要结论:(1) PS的分子量和浓度影响电纺性和纤维形态与性能。PS分子量越大,纺丝时稳定射流越长,鞭动不稳定区域变小,纤维平均直径变粗,且纤维平均直径与粘均分子量的1.831方成正比。随PS分子量增大,分子链缠结点增多,超细纤维膜拉伸断裂强度增大。PS3丁酮溶液的可纺浓度范围为8-15 w/v %。其中最稳定纺丝浓度为10 w/v%,纤维形态优良,平均直径为1.9μm。(2)辅助电极推迟了射流分裂过程,电纺膜面积变小和面密度增大,所得超细纤维平均直径略增大、形态良好。辅助电场强度越大,会聚现象越明显.辅助电极的管长对射流分裂行为无影响,而管径影响显著。SDBS加入使电纺溶液的表面张力、电导率增加和粘度下降。SDBS使稳定射流长度减小,纤维平均直径减小。所得电纺膜面密度下降,光泽性良好,均匀性提高,电纺膜力学性能提高明显,容易从收集屏上取下。同时使用辅助电极和添加SDBS情况下所得纤维膜与无辅助电极、无SDBS的PS纤维膜相比,收集面积变小,同时电纺膜均匀性,可揭性明显提高。(3)通过热处理和添加少量多壁碳纳米管可以改善PS纤维膜的力学性能。热处理时,在溶剂中处理时间,热处理温度、时间、压力均影响纤维膜形态和性能。添加1wt%MWCNT的PS纤维膜热处理后拉伸强度最大。(4)红外与扫描电镜结果显示,随着磺化时间增加,与磺酸根相关吸光度增大,纤维表面依次出现褶皱沟槽与细微“颗粒”特征,纤维的吸水性增大,初始热失重温度降低,磺化程度加大。磺化反应未造成PS主链降解,拉伸断裂强度变化不明显。SPS超细纤维膜对阳离子红染料去除率高。且纤维膜用量越大,吸附速度越快,吸附过程遵循Lagergren准二级动力学。设计了动态吸附装置,SPS超细纤维膜可以实现对阳离子艳红染料模拟废水的吸附处理,能在较长时间内保持高的去除率,但去除率随过滤水量的增加缓慢降低。本论文的特色与创新之处在于:1、率先探讨了辅助电极和十二烷基苯磺酸钠对聚苯乙烯电纺分裂行为和电纺纤维形态与性能的影响,使用辅助电极和十二烷基苯磺酸钠控制收集面积,改善均匀性和提高了PS纤维膜的可揭性。2、率先研究了热增强处理对PS纤维膜形态和力学性能的影响,这种热处理显著改善了纤维膜拉伸强度。3、研究了磺化聚苯乙烯电纺纤维膜对模拟染料废水阳离子红溶液的静、动态吸附行为,为其应用提供理论基础和参考依据。更多还原

【Abstract】 Electrospinning is a very important method to fabricate ultra-fine fibers. Polystyrene is a widely used raw material for ion exchange. Its electrospun fibers may find great potential applications at many aspects of industry and enviromental protection.The objective of this study is to prepare and to estimate the application of sulfonated ultrafine polystyrene (SPS) fibrous membranes (SPSFM) via several steps: firstly preparing PS with designated molecular weight, and then fabricating electrospun PS fibers, and then converting them into sulfonated PS fibrous membranes and finally evaluating the cationic dye adsorption performance of the SPSFM. The additions of sodium dodecyl benzene sulfonate (SDBS), multi-walled carbon nanotubes (MWCNT) into electrospinning dopes and implementation of tubular auxiliary electrode were applied to improve the electrospinning behaviour and electrospun fiber morphology and properties. The solvent steam stewing of electrospun nonwoven mats was used to increase the mechanical strengths of the nonwoven mats. The morphology, structure, properties and cationic dye adsorption of the SPSFM were examined by infrared spectroscopy, scanning electron microscopy, thermogravimetry, universal testing machine and ultraviolet-visible spectrophotometry. The results showed that,(1) The molecular weight and concentration had effects on the electrospinnablity, morphology and properties of PS electrospun fibers. The length of the stable electrospinning jet and the diameter of the resultant fibers were increased with the increase of molecular weight of PS, with the average fiber diameter proportional to the power of 1.831 of viscosity-average molecular weight, the tensile strength at break of ultrafine fibrous membranes increased also with the increase of molecular weight. The suitable solution concentration for electrospinning is 8-15w/v%.(2) The auxiliary tubular electrode postponed the splitting of the electrospinning jets, and thus the area of the electrospun fibrous membrane became much smaller and its density greatly increased, meanwhile, the average diameter of electrospun ultrafine fibers with good morphology slightly increased. The diameter of the auxiliary electrode remarkably affected the jet splitting behaviour. The stronger the electric field was, the more obvious convergence was achieved. The surface tension and electric conductivity of the PS solutions were increased whereas the viscosity was decreased in the presence of SDBS, and thus the splitting process during electrospinning was accelerated with the average diameter of the fibers being gradually reduced. Although the area densities of the electrospun membranes were decreased after addition of the surfactant, the uniformity and the mechanical property of the glossy membranes were remarkably improved, meanwhile, the membranes can be much more easily taken off from the aluminum foil collector.(3) The tensile properties of PS ultrafine fibrous membranes have been greatly improved after heat treatment. The time of immersion in methyl ethyl ketone steam, heating time, temperature and pressure of the process all affect the morphology and mechanical properties. The addition of 1wt% MWCNT to PS obviously improved the tensile strength of PS ultrafine fibrous membrane. The PS fibrous membranes with 1wt% MWCNT after heat treatment showed the biggest tensile strength.(4) With the increase of sulfonation time, the ultrafine fiber surfaces appeared successively many tangential grooves and a lot of outshoots, and the water uptake of the membranes was gained much, and the mechanical properties implied no negative effect due to sulfonation. Cationic dye adsorption of SPSFM demonstrated high adsorption rate and efficient removal. The adsorption with the membranes observed the Lagergren pseudo-second order kinetic process. High efficient removal can be maintained for a long time in the dynamic absorption.The feature and innovations are the following:(1) The effects of the auxiliary tubular electrode and SDBS on the jet splitting behaviour and properties of polystyrene fibrous membranes were studied.The area of polystyrene fibrous membranes was controlled. The uniformity and the detachability of electrospun fibrous membrane from the collector were imporved with SDBS.(2) The heat treatment of electrospun fiber membrane was carried out. The tensile strength of the membrane was improved remarkably.(3) The dynamic adsorption of synthetic cationic dye waste water was conducted with sulfonated polystyrene fibrous membrane, and this would serve as a reference for further investigation in the wastewater treatment.更多还原