静电纺丝纳米纤维毡的过滤性能研究

发布时间：2018-07-07 13:23

本文选题：静电纺丝 + 纳米纤维　；参考：《华南理工大学》2015年硕士论文

【摘要】：当前环境问题成为持续热点,空气过滤行业日益受到国人的关注。纳米材料的高比表面积、高孔隙率以及理化性质等非常适合空气过滤,这一领域的研究和应用也有了长足进展。静电纺丝技术作为纳米纤维毡成型的重要方法,可以有效的控制纳米材料的微观和宏观结构,成为当前研究纳米纤维空气过滤材料的重点。本文研究工作主要可以分为三步:从静电纺丝工艺角度开始深入研究,通过调整参数获得预期的纤维形貌结构,研究纤维微观形貌和过滤条件对材料过滤性能的影响;然后考察基布材料及结构对纳米纤维材料的过滤性能的影响,并对比实际口罩产品研究纳米过滤材料的特点;为了实现高效低阻的目的,深入研究纳米材料的三维结构对过滤性能的影响,并尝试混杂和梯度结构等办法改良纳米材料的微观结构,以期找到恰当的方法提高过滤品质。静电纺丝参数(电压、接受距离、分子量及分布、溶剂和溶液浓度等)对成型的纳米纤维毡微观结构有很大的影响,而且对于不同的静电纺丝体系,相关参数的影响作用不同。以粘度较低的聚合物A溶液为例,其在高电压情况下,会出现部分粗纤维,从而形成纤维直径分布较宽的纳米纤维毡;降低接收距离会形成分布更加混乱的纤维毡。聚合物分子量及分子量分布和静电纺丝成型的纳米纤维直径及直径分布有正相关性。研究发现纳米纤维堆积的三维结构是协调过滤效率和气阻的关键。过滤测试条件的不同可能反映出同一材料不同的过滤性能。对于聚合物B纳米纤维,Na Cl颗粒的过滤测试中,纺丝电压较低的样品过滤效率和气阻都较高,油性测试反映的结果相反。经过大量数据的分析可以看出,气阻和流量有直接关系,气阻随流速增大而增大,而且滤材的蓬松程度是决定气阻的关键。流量对过滤效率的影响,一方面跟颗粒大小有关;另一方面跟滤材性质有关。折叠和堆叠都可以很好的保留了原有滤材的微观结构,从而保证了材料的过滤性能。纳米纤维层口罩的过滤效率比PFE大25%,且随着测试时间快速增加趋向于过滤极限,气阻也呈现直线上升。通过用较粗的纤维材料和聚合物A纳米纤维层恰当搭配可以达到高过滤效率低气阻的目的。混杂可以获得纤维分布更宽的纤维毡,恰当比例的混杂提高材料整体的过滤性能和材料强度。混入玻纤有助于提高过滤性能,而且玻纤的加入量太多会降低了改善效果。总体来说混杂和梯度都可以有效的提升材料整体的过滤性能,存在一个最佳范围。
[Abstract]:At present, the environmental problem has become a persistent hot spot, and the air filtration industry has been paid more and more attention by Chinese people. The high specific surface area, high porosity and physical and chemical properties of nanomaterials are very suitable for air filtration, and great progress has been made in the research and application of this field. As an important method of nano-fiber felt forming, electrostatic spinning technology can effectively control the microstructure and macroscopic structure of nano-fiber, and become the focus of research on nano-fiber air filter materials. The research work in this paper can be divided into three steps: from the perspective of electrostatic spinning technology, the desired fiber morphology structure was obtained by adjusting the parameters, and the effects of fiber morphology and filtration conditions on the filtration properties of the materials were studied. Then, the effects of substrate material and structure on the filtration performance of nano-fiber materials were investigated, and the characteristics of nano-filtration materials were studied by comparing the actual mask products; in order to achieve the purpose of high efficiency and low resistance, The influence of three dimensional structure of nanomaterials on the filtration performance was studied in depth, and some methods such as hybrid and gradient structure were tried to improve the microstructure of nanomaterials in order to find a proper way to improve the filtration quality. The parameters of electrospinning (voltage, acceptance distance, molecular weight and distribution, solvent and solution concentration) have great influence on the microstructure of nanofiber felt, and have different effects on different electrostatic spinning systems. Taking polymer A solution with low viscosity as an example, some coarse fibers will appear at high voltage, which will form nano-fiber felt with wide fiber diameter distribution, and fiber felts with more chaotic distribution will be formed by decreasing the receiving distance. The molecular weight and molecular weight distribution of polymer are positively correlated with the diameter and diameter distribution of nanofibers formed by electrostatic spinning. It is found that the three-dimensional structure of nanofibers is the key to coordinate filtration efficiency and air resistance. Different filtration test conditions may reflect different filtration properties of the same material. The filtration efficiency and gas resistance of the samples with low spinning voltage were higher than those of the samples with low spinning voltage, but the results of oil test were opposite. Through the analysis of a large number of data, it can be seen that there is a direct relationship between the gas resistance and the flow rate, and the air resistance increases with the increase of the flow rate, and the fluffy degree of the filter material is the key to the determination of the gas resistance. The effect of flow rate on filtration efficiency depends on particle size on the one hand and filter properties on the other. Both folding and stacking can preserve the microstructure of the original filter material, thus ensuring the filtration performance of the material. The filter efficiency of nano-fiber layer mask is 25% higher than that of PFE, and the gas resistance increases linearly with the rapid increase of testing time. High filtration efficiency and low air resistance can be achieved by proper collocation of coarse fiber material and polymer A nanofiber layer. Fiber felts with wider fiber distribution can be obtained by mixing. The proper proportion of hybrid materials can improve the overall filtration performance and material strength. Mixing glass fiber helps to improve the filtration performance, and too much glass fiber will reduce the improvement effect. Generally speaking, mixing and gradient can effectively improve the overall filtration performance of the material, there is an optimal range.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ340.1;TB383.1

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