【作者】 于天；

【导师】 胡健；

【作者基本信息】 华南理工大学 ， 制浆造纸工程， 2012， 博士

【摘要】 现代过滤技术要求滤材具有更优秀的过滤性能和更理想的制造、加工性能。为了实现这一目的，直径小于5μm，特别是直径小于1μm的超细纤维被复合到过滤材料中。原纤化超细纤维的超细纤维结构，使它可用于生产效率较高的湿法成型方式来制造高性能空气过滤材料。这是一个新的高性能空气过滤材料研究领域。本文的研究以空气过滤为背景，对原纤化超细纤维的纤维特性及其湿法复合的空气过滤材料进行了研究，认识了这种新型过滤材料的结构与性能之间的关系，并建立了与性能较优的双层原纤化超细纤维复合滤材结构相匹配的理论模型。研究表明：1、原纤化超细纤维的形成历程是一个纤维由大到小，由不扭曲向扭曲，由单分散形态向多分散形态变化的复杂过程。2、通过筛分法获得的最细小原纤化超细纤维FL₅比原纤化处理得到的原纤400更有利于提高滤材的效率、表面过滤特性和匀度。FL₅的平均直径仅为0.24μm。3、随着原纤化程度的加深，原纤化超细纤维的打浆度不断提高，手抄片匀度不断改善，但抄造难度也不断提高，以致原纤260，原纤320和原纤400不适合单独地进行湿法成型抄片。4、随着原纤化程度的加深，原纤化超细纤维手抄片的透气度和孔径值不断下降，孔径分布的峰值不断向小孔径方向偏移——最小的原纤200手抄片的透气度和平均孔径仅为6.3mm/s和0.22μm。5、原纤化超细纤维的双层复合结构比单层结构更能体现原纤化超细纤维复合带来的过滤性能优势——在相同复合量下，双层结构对0.3-0.5μm颗粒的最高过滤效率为93.2%，而此时单层结构仅有38%。6、原纤化超细纤维以分散的方式搭架在基材纤维的表面孔隙上，而不是相互缠结或与主体纤维缠结，可使其过滤效用得到更好的体现。7、通过进一步优化原纤化超细纤维复合滤材的面层结构，可获得更理想的性能：采用“过渡层”复合或玻璃棉纤维面层复合的方式将最小尺寸的原纤化超细纤维FL₅进行复合，复合量仅为1g/m²左右就可以有效提升滤材的综合过滤性能——复合面层配比为MGF₃比FL₅为6:4、定量为1g/m²时，滤材对0.3-0.5μm颗粒的过滤效率由25.8%提升到了了61.1%，获得了最高的品质因子。8、双层结构原纤化超细纤维复合滤材的建模和验证表明，从滤材结构特点与单纤维过滤理论结合的角度出发，可获得与滤材实际性能符合的计算模型。更多还原

【Abstract】 Modern air filtration technology requires filter media with better filtration properties andexcellent processability. To achieve this requirement, the ultrafine fibers with diameter under5μm—especially those under1μm—are utilized by advanced filter media. With theultrafine-fiber structure, the fibrillated ultrafine-fiber can be applied to produce the highperformance filter media via wet-laid process. It’s a new field for high performance filtermedia.The research of this paper is based on high performance air filtration application. Theforming process of fibrillated ultrafine-fiber and its wet-laid filter media will be studied. Andthe relation between structure and performance of media will be illustrated. The research willalso theoretically model the optimal double-layer media which laminated with fibrillatedultrafine fiber mixed layer. This research shows that:1. The forming of fibrillated ultrafine-fiber is a complicated process during which thefibers transform from large to fine, straight to curl and monodisperse size to polydisperse size.2. The fibrillated ultrafine-fiber FL₅with the highest filtration efficiency, surfacefiltration properties and uniformity can be obtained by classifying. And the average fiberdiameter of FL₅is0.24μm.3. With the rising of fibrillation intensity, the beating degree of fibrillated ultrafine-fiberkeeps increasing and the uniformity of its handsheet becomes better and better, while thewet-laid formability of the fibrillated ultrafine-fiber becomes worsen as a result that it isn’tsuitable for sheet forming alone.4. With the rising of fibrillation intensity, the permeability and pore size of the fibrillatedultrafine-fiber handsheet keeps decreasing and the peak of its pore size distribution shiftstowards smaller value.5. Compared with single-layer structure, double-layer structure greatly improves thefiltration properties of media which is composed of fibrillated ultrafine-fiber. In the samecontent of fibrillated ultrafine-fiber, the highest filtration efficiency for0.3-0.5μm particles ofdouble-layer structure media is93.2%, while single-layer structure is only38%.6. The fibrillated ultrafine-fibers bridge the surface pores of substrate in a dispersedfashion leads to better filtration performance. While fibrillated ultrafine-fibers intertwist ortangle with the substrate fibers lead worse.7. Better filtration performance can be obtained by further optimizing the surface layerstructure of the fibrillated ultrafine fiber laminated media: Intermediate-layer or fibrillated ultrafine-fiber mixed layer are applied to improve the filtration efficiency of media withoutincreasing pressure drop significantly. When the basis weight of mixed layer is only1.00g/m²,mixed ratio is6:4（MGF₃:FL₅）, the filtration efficiency for0.3-0.5μm particles of the mediaincreases from25.8%to61.1%and acquires the highest quality factor.8. The modeling and verification of the optimal double-layer media laminated withfibrillated ultrafine-fiber mixed layer suggest the calculation model is reliable which isestablished by the filter media structure and single fiber filtration theory.更多还原