纳米纤维膜在空气净化中的应用研究进展

面向空气净化的应用需要,开发高效净化材料已成为研究热点之一,其中具有相互连贯孔结构的纳米纤维膜在高效空气净化领域展示出巨大的应用前景。对于纳米纤维膜对空气净化效果的评估指标通常包括过滤效率和过滤阻力。本文介绍了串珠、蛛网和复合等结构纳米纤维膜的研究进展,分析了驻极式纳米纤维膜在高效除尘方面的应用现状,探讨了银纳米颗粒和半导体金属氧化物改性纳米纤维膜在抗菌和除有机易挥发性气体等多功能性空气净化中的应用可行性,指出了高效低阻、功能化是纳米纤维膜用于空气净化领域的研究重点。并提出今后应高度关注多污染物对纳米纤维空气净化膜性能的影响,深入研究具有多功能协同作用的纳米纤维空气净化膜,以期获得更广泛的应用。     

静电纺丝纳米纤维膜空气过滤研究进展

静电纺丝纳米纤维膜具有高比表面积、孔径小、孔隙率高、纤维均一性好等优点,在空气过滤及个体防护等领域表现出巨大的应用潜力.总结了近年来国内外关于静电纺丝法制备高效低阻和功能化(抗菌、可降解、疏水和耐高温)新型空气过滤材料的最新研究成果,分析和讨论了现有研究中存在的问题,并对未来的发展方向进行了展望.     

静电纺丝纳米纤维及其在生物气溶胶过滤中的应用

简要介绍了静电纺丝制备纳米纤维的原理以及纤维形态的主要影响因素;从静电纺丝纳米纤维的过滤效果、抗菌性能和力学性能等方面综述了其应用于生物气溶胀过滤材料的研究进展;指出静电纺丝纳米纤维大规模生产已取得突破,且抗菌改性效果持久,适合应用于生物气溶胀过滤领域,今后应进一步提高纳米纤维的力学性能及质量稳定性,具有良好的应用前景。     

高效空气过滤用PTFE膜材料的结构和性能

聚四氟乙烯(PTFE)膜高效空气过滤材料以其过滤效率高、初始阻力小和无硼释放等优点,在电子工业洁净室中得到了广泛的应用,然而目前尚缺乏PTFE膜与传统滤材结构及性能的系统对比研究。本文选取了两种商业应用的PTFE膜高效滤材,采用扫描电子显微镜、孔径分析仪、自动滤材测试仪等多种表征手段对材料的微观结构和过滤性能与超细玻璃纤维(简称玻纤)滤材进行了较为全面的对比研究,结果表明,PTFE膜本质上也是一种纤维类滤材,其纤维平均直径为60～85nm,远低于玻纤滤材的668.8nm;高效PTFE膜的过滤效率与玻纤滤材相当,且其初始阻力不及玻纤滤材的50%,但PTFE膜滤材的容尘性能不及玻纤滤材,更适合应用于有再生或预过滤装置的场所。     

Aerosol filtration performance of nanofibrous mats produced via electrically assisted industrial-scale solution blowing

Highly efficient polyamide 6 (PA6)-based nanofibrous air filter media was developed for particulate matter (PM) removal in the ambient atmosphere. The PA6 nanofibrous mats exhibited 85% PM0.3 capture performance at a cost of 164 Pa pressure drop when the multiple-nozzle solution blowing system was set to 8 m/h fabric winding speed. However, an increase in the winding speed at a constant feeding rate lowered the filtration efficiency to 62% due to the less amount of nanofibrous mats collected on the substrate. The application of electrical field at the same parameters allowed us to produce a filter media having FFP3-level filtration performance, which means 99% PM0.3 capture performance. This was attributed to a fine fiber diameter (116 nm), higher solidity value (0.149), and lower average pore size (2.28 μm). These results show that the electrically assisted solution blowing provides a feasible route for the production of high-quality nanofibrous filter media.     

不同相对湿度下亲疏水纳米纤维膜空气过滤性能实验研究

利用静电纺丝法制备了表面静态接触角为23.6°的具有亲水功能的PAN/PVP复合纳米纤维膜、接触角为81.2°的PAN纳米纤维膜、接触角为131.9°的具有疏水功能的PAN/PVDF复合纳米纤维膜。利用自行搭建的空气过滤实验台,在40%、55%、70%三种相对湿度下对三种纳米纤维膜进行空气过滤实验,对纳米纤维膜的过滤效率、阻力损失及品质因子进行分析。结果表明：三种纳米纤维膜的过滤效率随着相对湿度的增大而升高,PAN/PVP膜和PAN膜的阻力损失随着相对湿度的增大而增加,PAN/PVDF的阻力损失随着相对湿度的增大而减小;PAN/PVP膜和PAN膜的品质因子随着相对湿度的增大而减小,PAN/PVDF膜的品质因子随着相对湿度的增大而增大,湿度越大,PAN/PVDF纳米纤维膜的过滤性能越显著。     

滑移效应下纤维绕流场及过滤阻力的数值计算与分析

考虑实际纳米/微米纤维表面的流体滑移效应,采用数值方法求解滑移流动机理下纳米/微米纤维绕流场及过滤阻力,分析讨论了Knudsen数Knf和填充率C对纤维近壁面速度分布及纤维过滤阻力的影响规律.结果表明,对纳米/亚微米纤维过滤情形,纤维表面流体的滑移效应导致纤维绕流场与非滑移条件下情形有显著差异,尤其在高填充率下,纤维表...     

Optimizing the electrospinning conditions of polysulfone membranes for water microfiltration applications

Polysulfone (PSU) is a popular material in microfiltration applications. In this study, the preparation of PSU membranes via electrospinning technology was investigated and optimized. Solutions with three different concentrations (15, 20 and 25 wt%) of PSU in dimethylformamide were electrospun at three different feed rates (1.5, 2.5 and 3.5 mL h^?1) and voltages (12.5, 15 and 18 kV). The morphologies of the samples were studied using SEM. The results showed that the samples prepared from a 15 wt% solution concentration have beads‐on‐string morphologies. As the solution concentration is increased to 20 and 25 wt%, the beads disappear and uniform fibers with average diameters ranging from 0.876 to 2.078 μm depending on the voltage and the feed rate are obtained. The optimum electrospinning conditions for the highest wettability with minimum operating pressure were predicted to be a solution concentration of 25 wt%, a feed rate of 3.5 mL h^?1 and a voltage of 18 kV. The prediction was verified by contact angle test measurements and filtration experiments. © 2019 Society of Chemical Industry     

用于空气净化的双疏膜制备及应用进展

工业烟气中经常含有大量油性气溶胶,而传统过滤材料基本都是亲油性的,导致吸附污染严重。双疏型膜材料在面向高湿、含油性气溶胶的复杂烟气体系时,具有分离效率高、抗污染性强和易清洁等优点。本文系统总结了用于空气净化过程的双疏膜材料制备方法,通过对应用过程油性气溶胶与膜表面之间的微观作用分析,阐释了影响膜污染形成与控制的表界面作用机理。最后,对双疏膜材料在空气净化领域的发展前景做了分析和研讨。     

Wettability behavior of solution blow spun polysulfone by controlling morphology

Solution blow spinning (SBS) is used to prepare polysulfone materials (PSf) with different morphologies changing the processing conditions. Morphological study is done by scanning electron microscopy. Materials mainly constituted by beads and fibers are obtained. An optimization strategy based on desirability function approach together with Box–Behnken design is employed to find the best processing conditions to produce PSf materials with tailored morphology. Feed rate and air pressure are the variables of SBS processing conditions with the highest influence on the relative amount of fibers produced while air pressure and a particular balance between work distance and feed rate have the highest impact on the size of fibers. Contact angle measurements are used to understand SBS PSf wettability as a function of morphology. It is demonstrated the possibility of designing PSf materials with particular wettability behavior induced by tailored morphologies obtained from a particular election of SBS processing conditions.     

Impact of multilayering on the filtration performance of clean air filter media

Fibrous filter media are commonly used to remove airborne particles that are harmful to human health and the environment. Although filter media are often multilayered for various reasons, no systematic study of the impact of multilayering on filter media performance has been reported. In this paper, direct numerical simulations with the lattice Boltzmann method are used in order to shed light on the impact of multilayering on the performance of clean bimodal fibrous filter media in a Stokes flow regime. Virtual model clean filter media with up to eight layers and various fibre formulations are compared in terms of permeability or pressure drop, capture efficiency, and quality factor. A careful analysis of the results revealed that multilayering had no statistically significant impact on the performance of the clean filter media. At best, the impact of multilayering was similar to that of the inherent variability of such random structures. Fibre formulation was found to be a more efficient way of improving the performance of the filter media. Placing interlayered air gaps between fibrous layers also slightly improved the quality factor by facilitating the flow at the interfaces of the fibrous layers. These findings will guide future studies on the performance of multilayered filters with more complex flow conditions, such as those encountered with inertial or nanofibre-made filter media and with the fouling of filter media.     

Flexible poly(styrene-ethylene-butadiene-styrene) hybrid nanofibers for bioengineering and water filtration applications

Among the thermoplastic elastomers that play important roles in the polymer industry due to their superior properties, styrene-based species and polyurethane block copolymers are of great interest. Poly(styrene-ethylene-butadiene-styrene) (SEBS) as a triblock copolymer seems to have the potential to meet many demands in different applications due to various industrial requirements where durability, biocompatibility, breaking elongation, and interfacial adhesion are important. In this study, the SEBS triblock copolymer was functionalized with natural (Satureja hortensis, SH) and synthetic (nanopowder, TiO₂) agents to obtain composite nanofibers by electrospinning and electrospraying methods for use in biomedical and water filtration applications. The results were compared with thermoplastic polyurethane (TPU) composite nanofibers, which are commonly used in these fields. Here, functionalized SEBS nanofibers exhibited antibacterial effect while at the same time improving cell viability. In addition, because of successful water filtration by using the SEBS composite nanofibers, the material may have a good potential to be used comparably to TPU for the application.     

3D modeling of filtration process via polyurethane nanofiber based nonwoven filters prepared by electrospinning process

Full 3D particle filtration modeling at low pressures considering slip/transition/free molecular flow regime, particle–fiber interactions, air/particle slip, sieve and homogenous flow field has been performed for the polyurethane nanofiber filter prepared by electrospinning process and the obtained theoretical predictions for the filtration efficiency have been compared with the corresponding experimental data. Moreover, the effect of air velocity, viscosity, temperature, pressure and particle–fiber friction coefficient on the produced polyurethane nanofiber filter efficiency has been investigated in more details. In order to take all real structure features of the nanofiber filter into account (such as varying fiber diameter, curvature along its length, inhomogeneity and mat defects), a new approach for 3D nanofiber mat model construction from corresponding SEM images has been proposed and utilized.     

Electrospinning fabrication and characterization of poly(vinyl alcohol)/montmorillonite nanofiber mats

Poly(vinyl alcohol) (PVA)/montmorillonite clay (MMT) nanofiber mats have been fabricated by the electrospinning technique. The PVA/MMT nanofiber mats were characterized by X‐ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and mechanical measurements. The study showed that the introduction of MMT results in improvement in tensile strength, and thermal stability of the PVA matrix. XRD patterns and SEM micrographs suggest the coexistence of exfoliated MMT layers over the studied MMT contents. FTIR revealed that there might be possible interaction occurred between the MMT clay and PVA matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Electret characteristics of melt-blown polylactic acid fabrics for air filtration application

Polylactic acid (PLA) is a biodegradable and biocompatible polymer. Melt-blown PLA electret fabrics have become attractive materials for air filter applications. Its filtration performance mainly depends on the electrostatic effect originating from electrets. How to improve their electret behavior and then to enhance their filtration efficiency has always been challenging. In this article, three melt-blown PLA fabrics with different morphological or crystal structure are made from different process conditions or ingredient. The electrets are formed by means of corona charging technology. Their crystalline and morphological structure was analyzed, and filtration performance was measured. Their charge-trapping feature was studied by thermal stimulating discharge technology. The results proved that the air filtration efficiency of three melt-blown samples improved a lot when electrets were formed. Different crystalline structures of PLA fabrics will result in differences in their electret charge-trapping feature. The PLA fabrics with semi-crystalline characteristics display a regular charge-trapped level distribution and amorphous structure hints the diversity of charge-trapped levels. The deference in filtration resistance is mainly ascribed to the different fiber diameters and their distributions. More narrow distribution of fiber diameter leads to more compact fabrics and to higher filtration resistance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48309.     

Optimization of centrifugally spun thermoplastic polyurethane nanofibers for air filtration applications

While our knowledge of fiber formation by using conventional nanofiber spinning techniques has increased to a considerable extent, there are still few studies on centrifugal spinning either in academia or in the industry. Centrifugal spinning is a comparatively new method of producing fibers having nano- or microscale diameters. In this study, three main parameters (nozzle orifice diameter, rotational speed, polymer concentration) of centrifugal spinning were optimized to produce air filter media from thermoplastic polyurethane nanofibers. The effect of concentration of polymer solution was found to be a major contributor in TPU fibers optimization estimating 77.5%. After the optimization studies, the average fiber diameter of nanofiber sample produced at optimum conditions (22G needle as an orifice, 4000 rpm, and 10 wt% concentration of polymer solution) was 205 ± 84 nm. Aerosol filtration performance of the produced webs was analyzed. Filtration efficiency of the optimized sample was found to be 99.4% for 0.3 µm particle size at an expense of 98 Pa pressure drop.

Copyright © 2018 American Association for Aerosol Research     

静电纺丝法纺制聚乳酸纳米纤维无纺毡

采用静电纺丝法制备了生物降解聚乳酸(PLLA)纳米纤维无纺毡。分析了纺丝液浓度、电压、接收距离、挤出速度等因素对纤维形态的影响。结果表明:纺丝液的浓度和挤出速度对纤维直径的影响较为明显,溶液挤出速度增大,所得纤维微孔含量及尺寸也增大;适当的电压和接收距离有利于收集无液滴纤维;随着纤维直径的减小,无纺毡的孔径呈减小趋势。在PLLA质量分数为5．7％、挤出速度0．8 mL／h、接受距离 15．5 cm、电压8 kV的静电纺丝条件下,可制备纤维直径为200-400 nm的PLLA纳米纤维无纺毡。     

聚苯砜对苯二甲酰胺/苝系荧光材料复合静电纺膜的制备与表征

聚苯砜对苯二甲酰胺(PSA)纤维在防护领域具有广泛的应用,笔者在其纺丝溶液中引入苝系荧光功能材料POSS-PDI-POSS,通过静电纺制备了PSA纤维膜。研究了助纺剂聚丙烯腈(PAN)、共溶剂氯仿、荧光功能材料的引入对PSA溶液流变、电导率和纺丝成形性能的影响,发现在PAN添加量为3%(w)、氯仿添加量为6%(w)和0.4%(w)的POSS-PDI-POSS时可制备纤维直径集中分布在250～600 nm的纤维膜,该纤维膜可发射550 nm的黄绿色荧光(490 nm光激发)和发射580 nm的红色荧光(530 nm光激发)。     

Design of three-dimensional gradient nonwoven composites with robust dust holding capacity for air filtration

Air pollution has seriously threatened public health in developing countries. However, it is still a big challenge for fabricating a filter with high filtration efficiency, low air resistance, and long service life. Herein, we report a facile strategy to fabricate a multilayered nonwoven composite with a functionally gradient structure for air filtration by a combined method of needle-punch, melt blown, and corona charging techniques. Our integrated multilayer needle-punched/melt blown composite filter could achieve a high filtration efficiency up to 99.52 ± 0.01%, a low pressure drop of 136.87 ± 0.49 Pa, and a satisfied quality factor of 0.03898 ± 0.0001 Pa⁻¹ for sodium chloride particles with an aerodynamic diameter of 0.26 μm at the airflow rate of 85 L min⁻¹. More importantly, the resultant filter exhibited a large dust holding capacity of 23.5 ± 0.41 g m⁻², which indicates a long service life. It is expected that our multilayer needle-punched/melt blown composite fabric may not only serve as a good candidate for air filtration, but also provide a new sight for designing the air filtration materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47827.