纺丝工艺对聚丙烯中空纤维宏观结构的影响

主要讨论了纺速、泵供量、氮气通量、空气纺程和纺丝温度等纺丝工艺条件的设置对纤维宏观结构的影响，为设计具有合理宏观结构的中空纤维膜提供参考。     

中空纤维膜的现状与研究进展

综述了中空纤维膜的现状和研究进展,包括中空纤维膜的发展历史、中空纤维膜的制备方法、中空纤维膜的工业应用等几个方面,提出了中空纤维膜应用存在的问题,对这个方面所存在的问题和今后发展方向进行了展望,并提出建议。     

巡视中空纤维膜的研发和产业进展

介绍了国内外用于人工肾的中空纤维透析膜、用于废水处理的微滤、超滤中空纤维及膜生物反应器（MBR）、用于海水淡化的中空纤维反渗透膜、用于气体分离及有机物代精馏的中空纤维膜、用于双亲和性吸附蛋白质的固定双配合剂多微孔中空纤维膜、用于回收海水资源的微滤和纳滤膜、用于脱氧核糖核酸链（DNA）切片的内含亲水性聚合物的中空纤维膜以及新型电池隔膜.     

中空纤维膜的制备技术及应用

概述了中空纤维膜的制备技术,具体介绍了现有中空纤维膜的熔融纺丝、湿法纺丝技术,同时介绍了中空纤维膜的用途,及展望了中空纤维膜的广阔发展前景。     

热塑性聚氨酯中空纤维/SiO2气凝胶隔热材料的制备及性能研究

以热塑性聚氨酯中空纤维为增韧材料,正硅酸乙酯为硅源,采用溶胶-凝胶技术制备了热塑性聚氨酯中空纤维/SiO2气凝胶隔热材料.考察了纤维类型、中空纤维铺设方式、中空纤维规格对SiO2气凝胶隔热性能的影响.结果表明:中空纤维增韧SiO2气凝胶的隔热性能略低于纯SiO2气凝胶,但其韧性有了显著提高.中空纤维垂直铺设,采用合适的内径及壁厚的中空纤维能获得较好隔热性能的SiO2气凝胶隔热材料.     

东丽有微孔的中空纤维

东丽公司应用共混聚合物纤维技术、复合纺丝技术开发出了从纤维表面向中空部有贯通微孔的尼龙溶出中空纤维“WINCALL”。本文介绍它的制造方法、截面形状、特性等情况。1溶出中空纤维“WINCALL”纤维截面有中空部分,从纤维表面到中空部贯通有微细孔。服用穿着时,由微细孔吸取汗     

中空纤维膜的开发与应用进展

中空纤维膜作为一种特种纤维,近年来发展迅猛,已应用到各个领域。作者综述了中空纤维膜的开发与应用现状,包括中空纤维膜的发展历史、制备方法、改性方法及应用等几个方面,最后展望了中空纤维膜制备技术和应用领域的发展趋势。     

中空纤维受力过程有限元分析及其实验

针对中空纤维在加工及其使用过程中纤维中空容易失效而降低保暖效果这一问题,通过建立纤维中空结构的有限元力学模型,对比研究不同中空结构的纤维受压后截面的应力、应变的变化,从而间接反映不同中空结构的抗压能力,从理论上说明不同中空纤维的中空结构抗失效能力,并通过实验进行验证。     

用于给水系统的可持续曝气的外压式中空纤维膜系统

正本实用新型的一种用于给水系统的可持续曝气的外压式中空纤维膜系统,其特征在于:包括水池、至少一个外压式中空纤维膜组件、曝气装置、产水管道以及清洗管道;每个外压式中空纤维膜组件均安置在水池中,其中,外压式中空纤维膜组件上的外压式中空纤维膜的膜丝束方向水平横置浸没于水池的水体中;曝气装置的出气口     

不同中空涤纶弯曲弹性比较

通过建立力学模型,比较一系列圆形中空涤纶弯曲弹性,导出不同圆形中空涤纶弯曲弹性、线密 度、中空度的关系及其弯曲弹性的差异。结果表明:在中空纤维体积一定下,其弯曲弹性随中空度的增加而 增强;线密度一定时,中空纤维的弯曲弹性则随中空度增加而降低;在纤维中空度一定时,其弯曲弹性随线密 度增加而降低,且不同纤维的弯曲弹性有差异。     

纺丝条件对PVDF/PVC中空纤维膜性能的影响

采用干-湿法纺丝工艺制备PVDF/PVC共混中空纤维膜,通过对水通量、孔径、截留率等的测试,研究了挤出速率、芯液流量、干纺程对PVDF/PVC中空纤维膜性能及结构的影响,并进行了详细的理论分析。试验结果表明挤出速率与膜通量存在最大值,芯液流量与膜通量及截留率呈线性关系,干纺程的影响效果跟挤出速率类似。可以通过改变纺丝条件来制备性能不同的中空纤维膜。     

Structure formation and characterization of PVDF hollow fiber membranes by melt‐spinning and stretching method

Melt‐spinning and stretching (MS‐S) method was proposed for preparing poly(vinylidene fluoride) (PVDF) hollow fiber membranes with excellent mechanical properties. The morphology and properties of PVDF fibers and membranes were investigated by small angle X‐ray scattering (SAXS), differential scanning calorimeter (DSC), field emission scanning electron microscope, mercury porosimeter, and tensile experiment. SAXS results indicated that the stacked lamellar structure aligned normal to the fiber axis was separated and deformed when the fibers were strained, and the long period of the strained fibers increased accordingly. Factors affecting the membrane properties were mainly spin‐draw ratio, annealing temperature, time, and stretching rate. Experimental results showed that the average pore size, porosity, and N₂ permeation of the membranes all increased with the increasing spin‐draw ratios and annealing temperatures. Annealing the nascent PVDF hollow fibers at 145°C for 12 h was suitable for attaining membranes with good performance. In addition, the amount and size of the micropores of the membrane increased obviously with stretching rate. Tensile experiment indicated PVDF hollow fiber membranes made by MS‐S process had excellent mechanical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

The influence of processing parameters on the properties of melt‐spun polypropylene hollow fibers

Isotactic polypropylene hollow fibers were produced by melt spinning. Spinning speeds up to 1880 m/min were used, and sample hollowness (percentage void in cross section) ranged from 0 to 69%. The fiber samples were characterized using dynamic mechanical analysis, birefringence, tensile testing, and differential scanning calorimetry. The hollow fibers were found to have higher crystallinity, orientation, and strength than the analogous solid fibers. In general, the polymer orientation in a hollow fiber was larger than the orientation in a solid fiber, even when the spinning speed for the latter was much larger. For a fixed outer diameter, increasing the hollowness improved fiber properties. However, as hollowness was further increased, fiber properties declined slightly. At a given percentage hollowness, increased spinning speed increased modulus and tenacity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1759–1772, 2002     

Investigation on the effect of spinning conditions on the properties of hollow fiber membrane for hemodialysis application

Polyethersulfone (PES) hollow fiber membranes were fabricated via the dry‐wet phase inversion spinning technique, aiming to produce an asymmetric, micro porous ultrafiltration hollow‐fiber specifically for hemodialysis membrane. The objective of this study is to investigate the effect of spinning conditions on the morphological and permeation properties of the fabricated membrane. Among the parameters that were studied in this work are air gap distance, dope extrusion rate, bore fluid flow rate, and the take‐up speed. The contact angle was measured to determine the hydrophilicity of the fibers. Membrane with sufficient hydrophilicity properties is desired for hemodialysis application to avoid fouling and increase its biocompatibility. The influences of the hollow fiber's morphology (i.e., diameter and wall thickness) on the performance of the membranes were evaluated by pure water flux and BSA rejection. The experimental results showed that the dope extrusion rate to bore fluid flow rate ratio should be maintained at 1:1 ratio to produce a perfectly rounded asymmetric hollow fiber membrane. Moreover, the flux of the hollow fiber spun at higher air gap distance had better flux than the one spun at lower air gap distance. Furthermore, spinning asymmetric hollow fiber membranes at high air gap distance helps to produce a thin and porous skin layer, leading to a better flux but a relatively low percentage of rejection for BSA separation. Findings from this study would serve as primary data which will be a useful guide for fabricating a high performance hemodialysis hollow fiber membrane. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43633.     

Lightweight,robust, porous heterocyclic para-aramid aerogel hollow fibers for multifunctional applications

In nature, many fibers with warmth-retention properties, such as the hair of polar bears and rabbits, both have a hollow cross-section structure. The static air in fiber cavities can effectively inhibit heat conduction and serve as an effective thermal insulator. In this work, the high-performance heterocyclic para-aramid polymer was selected as the spinning solution, and aerogel hollow fiber was prepared by coaxial wet spinning and freeze-drying techniques. The effects of spinning solution concentration and lyophilized solvent on the micromorphology, mechanical properties, and specific surface area of heterocyclic para-aramid aerogel hollow fiber (HPAAHF) were systematically studied. The produced HPAAHF possessed excellent mechanical properties (tensible strength ~3.85 MPa), high specific surface area (~ 260.90 m² g⁻¹), and lightweight advantages. The thermal conductivity of HPAAHF was only 0.0278 W m⁻¹ K⁻¹, indicating its excellent thermal insulation properties. The aerogel fabric exhibited outstanding flame retardancy properties, with a total heat release of only 0.7 MJ m⁻² in the cone calorimetric experiment, making it a self-extinguishing fabric. In addition, phase change material was injected into the hollow structure to obtain aerogel-phase change material composite fibers, which exhibited great energy storage prospects. As a result, the high-performance heterocyclic para-aramid polymer-based aerogel hollow fiber was successfully prepared and had multifunctional applications in thermal insulation, flame retardancy, and heat energy storage fields.     

Preparation of polysulfone hollow fiber affinity membrane modified with mercapto and its recovery properties. I. Synthesis and preparation of hollow fiber matrix membrane

Several kinds of chloromethyl polysulfones (CMPSF) with different chlorinity and reactive groups were synthesized by Friedel‐Crafts reaction, which could be utilized as reactively matrix membrane materials. The CMPSF hollow matrix membranes were prepared with phase inversion by utilization of the CMPSF/additive/DMAC casting solution and CMPSF as membrane materials. The rheological behavior of CMPSF/additives/DMAC spinning casting solution was studied. The experimental results showed that the spinning casting solution was a pseudoplastic fluid, the apparent viscosity of the spinning casting solution decreased with the increase of shearing rate, and the viscous flow activity energy of the spinning casting solution was inclined to unchange at high shearing rate. The effects of composition of spinning casting solution and process parameters of dry–wet spinning on the structure of CMPSF hollow fiber matrix membrane were investigated. The pore size, porosity, and water flux of membrane decreased with the increase of additive content, bore liquid, and dry spinning distance. With the increase of extrusion volume outflow, the external diameter, wall thickness, and porosity of the hollow fiber matrix membrane increased, but the pore size and water flux of the membrane decreased. It was also found that the effects of internal coagulant composition and external coagulant composition on the structure of CMPSF hollow fiber matrix membrane were different. The experimental results showed that thermal drawing could increase the mechanical properties of CMPSF hollow fiber matrix membrane and decrease the pore size, porosity, and water flux of the CMPSF hollow fiber matrix membrane, and the thermal treatment could increase the homogeneity and stability of the structure of the CMPSF hollow fiber matrix membrane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 758–771, 2006     

Preparation and characterization of microporous polyethylene hollow fiber membranes

Microporous polyethylene (PE) hollow fiber membrane with a porosity of 43% and N₂ permeation of 4.96 cm³ (STP)/cm² s cmHg was prepared by melt‐spinning and cold‐stretching method. It was found that PE with a density higher than 0.96 g/cm³ should be used for the preparation of microporous PE hollow fiber membranes. By increasing the spin–draw ratio, both the porosity and the N₂ permeation of the hollow fiber membranes increased. Annealing the nascent hollow fiber at 115°C for 2 h was suitable for attaining membranes with good performance. By straining the hollow fiber to higher extensions, the amount and size of the micropores in the hollow fiber wall increased, and the N₂ permeation of the membranes increased accordingly. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 203–210, 2002; DOI 10.1002/app.10305     

聚丙烯腈中空纤维膜的研究

本文对聚丙烯腈中空纤维膜的原料组成，中空纤维的纺丝工艺与膜性能的关系，以及纺制不同结构中空纤维膜的纺丝工艺和方法进行了综述，提出了纺制耐热性好的聚丙烯腈中空纤维３膜可能的方法和意义。     

A smart hollow filament with thermal sensitive internal diameter

In this work, a thermoplastic shape memory polyurethane was prepared via melt polymerization and a corresponding shape memory hollow fiber was fabricated via melt spinning. The fiber mechanical properties, especially shape memory effect, were characterized by static tensile, thermo‐mechanical cyclic tensile testing. The hollow fiber switching temperature was the melting transition temperature of the soft segment phase at about 41°C. The tenacity of the hollow fiber was about 1.14 cN/dtex, and breaking elongation was 682%. The shape fixity ratio was above 87% and the recovery ratio was above 89%. The internal diameter of the hollow fiber could be noticeably changed and the deformed fiber cross‐section could be well fixed. Once heated above the soft segment phase melting transition temperature, the hollow fiber internal hole recovered to its original diameter. The results from differential scanning calorimetry, X‐ray diffraction, and dynamic mechanical analysis were used to illustrate the mechanism governing the mechanical properties and shape memory effect especially. Due to the changes of the hollow fiber and the internal diameter affect of the physical properties of the prepared products, this fiber may be used in smart textiles for thermal management, or as stuffing of pillows and mattresses, which can adjust to body contours. Furthermore, the findings suggest that this kind of hollow fiber with thermal sensitive internal diameter could be used in smart filtration, drug‐controlled release, and liquid transportation in vivo. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and microstructure of hollow mesophase pitch-based carbon fibers

Hollow mesophase pitch fibers with rather thin diameter were successfully prepared by spinning through a C-shaped capillary. Die-swell was found to be the main factor affecting the formation of hollow fiber, and this was controlled by varying the spinning temperature. After carbonization at 1000°C, the hollow fibers possess a relatively small outer diameter of 21 μm and an inner diameter of 6 μm, and show better mechanical properties than solid fibers with similar outer diameter. The higher mechanical properties are attributed to the orientation of mesophase molecules which is related to the shape and dimension of the spinneret. The transverse microstructure of hollow carbon fibers is illustrated by scanning electron microscopy (SEM) observations on fracture sections.