纳米纤维多孔膜的制备及其在空气过滤中的应用

发布时间：2018-04-04 22:00

本文选题：静电纺丝　切入点：空气过滤　出处：《东华大学》2015年硕士论文

【摘要】：随着我国工业化的发展,空气污染日益严重。空气污染对人类及其生存环境造成严重的危害。尺寸小于2.5μm的悬浮颗粒是对人体呼吸道及肺外器官造成危害的主要诱因,并且是空气污染的最主要来源之一。因此为了给我国人民带来良好的生存环境,制备出能有效的降低空气中极小污染颗粒的过滤材料是至关重要的。传统微米级纤维无纺布具有较多的性能缺陷:空气过滤效率较低,能耗高,不能够过滤掉大部分的小颗粒。为了克服这一问题,本课题采用静电纺丝法一步制备出具有多级结构的高空气过滤性能的纳米纤维膜材料,并对其结构和性能进行表征。采用静电纺丝技术制备出了聚苯乙烯(PS)超细纤维、PS/多壁碳纳米管(MWCNTs)复合纳米纤维,并对其纤维形态结构、直径大小及空气过滤性能进行了表征。通过PS纺丝溶液浓度变化调控制备纯PS纤维多孔膜,并通过在PS纺丝液中添加不同含量MWCNTs调控纤维形态结构。SEM结果表明PS/MWCNTs复合纤维表面形成“褶皱”型和“山峰”型纳米级突起,增加了复合纤维表面的粗糙度,且纤维直径明显降低。空气过滤性能测试结果发现这种多级结构使复合膜的过滤效率相比光滑的纯PS纳米纤维膜大幅增加,过滤性能得到明显改善。在85L/min气流速度下,PS/MWCNTs复合膜过滤效率高达99.95%,空气阻力为374.6Pa。选择尺寸较粗的微米级PS纤维(~2μm)和相对较细的纳米级PS/MWCNTs复合纤维(~800 nm)进行混纺,调复合膜堆积密度可使得混纺膜空气阻力降为235.4Pa,而仍能保持高的过滤效率(99.68%)。采用静电纺丝技术制备出了聚偏氟乙烯(PVDF)纳米纤维/纳米蛛网多级结构的复合纤维膜,并对其纤维和蛛网形态结构及空气过滤性能进行了表征。通过探索添加剂的种类、电纺中环境湿度和接收基底种类与纳米蛛网结构形态之间的关系,寻找最优的改性工艺。SEM的结果表明PVDF纺丝溶液中添加1wt%的十二烷基苯磺酸钠(SDBS),施加30KV的电压和25%的环境相对湿度,并以铁纱网作为接收基底的条件下能够制备出高覆盖率(97%),形态结构最好(纤丝直径为20nm,孔直径为246nm)的纳米蛛网。空气过滤性能测试结果发现PVDF/SDBS纳米纤维/纳米蛛网复合膜在低流速条件下具有优越的过滤性能(过滤效率为99.5%,空气阻力为66.9Pa),清洁方法简单和更加轻薄的特性。将这种过滤材料运用在家用纱窗上,通过降低纤维膜厚度制备出了,高过滤效率(95%)具有一定透光性(透光率40%)的纳米纤维膜。表明了这种纳米纤维膜可以运用在家用纱窗中来过滤空气中极小的污染颗粒,并且其优越的过滤性能在其他空气过滤的应用中也有广泛的应用前景。
[Abstract]:With the development of industrialization in China, air pollution is becoming more and more serious.Air pollution causes serious harm to human beings and their living environment.Suspended particles with size less than 2.5 渭 m are the main inducement to harm human respiratory tract and extrapulmonary organs, and are one of the most important sources of air pollution.Therefore, in order to bring a good living environment to our people, it is very important to prepare filtration materials that can effectively reduce the air pollution particles.Traditional micron fiber nonwoven fabric has many performance defects: low air filtration efficiency, high energy consumption, can not filter out most of the small particles.In order to overcome this problem, nanofiber membrane with multistage structure and high air filtration performance was prepared by electrostatic spinning method, and its structure and properties were characterized.PS / MWCNTscomposite nanofibers were prepared by electrospinning technique, and their morphology, diameter and air filtration performance were characterized.The pure PS fiber porous membrane was prepared by adjusting the concentration of PS spinning solution.By adding different content of MWCNTs to PS spinning solution, the results showed that the surface of PS/MWCNTs composite fiber formed "fold" type and "peak" type nano-protuberance, which increased the surface roughness of composite fiber.The diameter of fiber decreased obviously.The results of air filtration performance test showed that the filtration efficiency of the composite membrane was significantly higher than that of the smooth pure PS nanofiber membrane, and the filtration performance was obviously improved.The filtration efficiency of 85L/min / MWCNTs composite membrane was 99.95 and the air resistance was 374.6 Pa.Polyvinylidene fluoride polyvinylidene fluoride (PVDF) nanofibers / nanocobweb multistage composite fiber membranes were prepared by electrospinning technique. The morphology and air filtration properties of PVDF nanofibers and cobwebs were characterized.By exploring the relationship between the types of additives, the environmental humidity in electrospinning and the types of receiving substrates and the structure and morphology of nano-cobweb,The results of searching for the best modification technology. SEM showed that adding 1 wt% sodium dodecylbenzene sulfonate to PVDF spinning solution, adding 30KV voltage and 25% environmental relative humidity,Under the condition that the iron yarn net is used as the receiving substrate, the nanocrystalline cobweb with high coverage rate of 97% and the best shape and structure (the diameter of filament is 20 nm and the diameter of pore is 246 nm) can be prepared.The results of air filtration test showed that PVDF/SDBS nanofiber / nano-cobweb composite membrane had excellent filtration performance at low flow rate (filtration efficiency 99.5, air resistance 66.9 Pa, cleaning method simpler and lighter).The filter material was applied to the home screen and the nanofilament membrane was prepared by reducing the thickness of the fiber membrane with high filtration efficiency and a certain transmittance (transmittance of 40%).It is shown that this kind of nano-fiber membrane can be used in household screen to filter the tiny particles in the air, and its excellent filtration performance also has a wide application prospect in other air filtration applications.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X51;TQ051.893

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