聚合物熔体法制备纳米纤维技术研究现状

针对聚合物熔体法生产纳米纤维效率低、性能不稳定,无法规模化应用的现状,对熔体法制备纳米纤维技术进行了综述。首先根据熔体法制备纳米纤维原理,对现有熔体法制备纳米纤维方法进行分类和对比分析,并结合研究现状,认为将不同单一纳米纤维制备方法进行有机组合是熔体法制备纳米纤维的发展趋势;然后详细综述了熔体法制备纳米纤维的工艺参数与纤维线密度之间的关系,揭示了熔体法纺纳米纤维细化技术的共性问题;最后介绍了熔体微分静电纺丝技术在纳米纤维制备方面的主要成果,通过机制揭示、工艺优化、材料改性等关键技术,熔体微分静电纺丝技术实现了平均直径小于500 nm 纤维的规模化制备。     

Concept of minimum electrospinning voltage (MEV) in electrospinning of PAN–DMF system: effect of distance

Minimum electrospinning voltage (MEV), in a needle–ground plate configuration, is defined as the needle voltage at which the maximum conversion of the polymer dope into nanofibers is achieved in electrospinning. MEV is unique for a set of electrospinning parameters for a given polymer dope and the square of the MEV is directly proportional to the rate of surface formation of the nanofibers in the electrospinning process. In this study, the effect of needle to collector distance on MEV and nanofiber morphology was investigated. The diameter of the nanofibers was found to be primarily dependent on the dope properties and independent of electrospinning process parameters. However, the slope of the plot between (MEV)² and surface formation rate was found to increase with increasing needle to collector distance signifying that the resistance in electrospinning increases linearly with the distance.     

Evaluation of effective needleless electrospinning parameters controlling polyacrylonitrile nanofibers diameter via modeling artificial neural networks

In this study, we aimed to predict the effects of different needleless electrospinning parameters on the diameter of polyacrylonitrile (PAN) nanofibers via artificial neural network method. The various factors, including polymer solution concentration, applied voltage, and spinneret-to-collector distance, were designed to investigate the diameter of PAN nanofibers produced via needleless electrospinning system. Levenberg–Marquardt, Bayesian regularization, and scaled conjugate gradient back-propagation algorithms were used for the analysis. The results indicated that PAN nanofiber diameters had a direct correlation with the polymer solution concentration and applied voltage and an inverse relation with the nozzle-to-collector distance. The Pearson correlation coefficients were significant at <.01% level for all prediction models. The Bayesian regularization mode I achieved the highest regression value (.9944) for the test data set. The regression value was also calculated and the maximum regression value (.9936) was obtained for the Bayesian regularization model I.     

静电纺参数对二醋酸纳米纤维直径分布的影响

为研究二醋酸纳米纤维工艺参数对其直径分布的影响,采用静电纺丝技术制备纳米纤维,对影响纳米纤维形貌的纺丝液质量分数、纺丝距离、电压及纺丝速度等参数进行探讨,对实验工艺进行优化,确定实验最佳参数。借助扫描电镜对制备的纳米纤维形貌进行观察,并应用Photoshop CS 3.0软件对纤维直径进行测量统计。结果表明,纺丝液质量分数、纺丝速度、纺丝距离对纳米纤维直径的影响较为显著,而纺丝电压对纳米纤维直径的影响相对较小。     

非针式静电纺丝工艺及其纳米纤维形态

对新型非针式静电纺丝纳米纤维的开发与抽丝形态及工作参数的设定加以探讨,以聚乙烯醇为抽丝材料,并以水为溶剂.由实验结果可知,高分子溶液浓度及工作电压均需超过一底限值才能顺利工作,在喂料轮至收集板间的收集间距为12 cm的情况下,其纤维平均直径为165 nm,标准差为49 nm,而间距在14 cm的条件下的平均直径为219...     

氯化锂对静电纺聚丙烯腈纳米纤维结构的影响

静电纺丝是用聚合物溶液或熔体制取纳米纤维的简易方法。当溶液完全绝缘或施加电压不够高时,静电力无法克服表明张力,纤维纺不出来。溶液中加盐后,就能克服这个问题。添加不同质量分数LiCl的聚丙烯腈纺丝液纺得纳米纤维的直径从大到小排列为:4%LiCl>3%LiCl>2%LiCl>1%LiCl。对纺得的纳米纤维内部结构采用X射线衍射和红外光谱法进行分析,发现加盐有利于静电纺丝且不会影响纳米纤维的内部结构。     

Electrospinning and characterization of poly (vinyl alcohol)–sericin nanofibers as a potential for tissue engineering applications

Poly vinyl alcohol (PVA) is a hydrophilic, biocompatible, and biodegradable polymer which has found application in biodrugs and tissue engineering. Sericin accompanying silk is a waste which is produced in scouring silk and has interesting properties which has attracted the attention of researchers. Silk sericin is also hydrophilic, biodegradable, and biocompatible. Moreover, it is cheap and anti-cancerous. Mixture of PVA and sericin in the form of 2D membrane or 3D hydrogels has been employed to heal skin damages. This research aimed at electrospinning PVA–sericin blend nanofibers in the form of a mat which has applications in tissue engineering, using dimethyl sulfoxide (DMSO) as an organic solvent. This research showed that the solution of PVA–sericin in DMSO was electrospinnable; however, the addition of urea to the solution made the electrospinning easier. The electrospinning solution contained ratio of 0:100, 10:90, 15:85, 20:80, and 25:75 sericin (%w/w)–PVA (%w/w). The electrospun PVA–sericin nanofibers had an average diameter in the range of 179–285 nm. X-ray diffractometer and differential scanning calorimetry investigations showed no reaction occurring between PVA and sericin. Polyvinyl alcohol 100% was also electrospun in DMSO. Up to now, the electrospinning of PVA in non-aqueous media has not been reported in the literature.     

丝素与明胶共混静电纺丝

 丝素和明胶以不同质量比共混于甲酸溶剂,将此纺丝液进行静电纺丝,并用扫描电镜观察其形态结构,分析探讨了工艺参数对其形貌和直径的影响,并与相同工艺条件下的纯丝素纳米纤维进行比较。结果表明:在丝素与明胶质量比为70∶30,纺丝液质量分数为11%,极距为13 cm,电压为22 kV的工艺条件下,静电纺纤维平均直径为83.9 nm,纤维直径分布均匀。用明胶共混不仅有利于克服低质量分数丝素纺丝液静电纺丝中出现的珠状物和断头多等问题,而且有望应用于生物组织工程中。     

静电纺丝方法制备纳米纤维的最新进展

综述了电纺制备纳米纤维的基本原理和最新发展，简要回顾了纳米纤维静电纺丝的发展历史，详细阐述了纳米纤维静电纺丝制备方法的最新进展。对文献报道的越来越多聚合物采用静电纺丝法制备纳米纤维，在静电纺丝中要想得到优良的纳米纤维，过程参数十分重要。此外，对各国研究者最近发展的几种新型的静电纺丝装置也进行了讨论。     

氯化钙/甲酸溶解体系下丝素纳米纤维的制备及其性能

采用CaCl2-Formid Acid ( FA)溶解体系溶解脱胶蚕丝形成丝素溶液,再将溶液干燥、去盐,将丝素膜二次溶液于FA溶液获得丝素浓度分别为4%、6%、8%的纺丝液。采用滚筒收集装置进行静电纺丝,讨论不同浓度的丝素溶液的纺丝性能。通过流变、SEM、红外以及体外降解等测试手段表征丝素纳米纤维的性能。结果表明：低浓度纺丝液（4%）的粘度较低,会出现不连续液滴,高浓度纺丝液（8%）所纺纤维直径较粗。本试验所用6%5%纺丝液形成的纤维成形效果良好,直径主要集中在150~250nm区域内。红外分析表明,经75%乙醇处理后会促进丝素分子构象的转变,即从α-螺旋构象向β-折叠的转变。降解实验表明,纤维在PBS、放线菌蛋白酶溶液中的纤维形态发生明显变化,具有可生物降解性。     

漏斗式喷气静电纺聚乙烯吡咯烷酮纳米纤维膜的制备及其表征

为克服传统静电纺丝生产效率低、纺丝过程难以控制、针头易堵塞等问题,实现高效制备高质量纳米纤维膜,在气泡静电纺的基础上,提出了漏斗式喷气静电纺丝技术。以聚乙烯吡咯烷酮（PVP）溶液为纺丝液,通过漏斗式喷气静电纺技术成功地制备了高质量的PVP 纳米纤维膜,并运用控制变量法分析了溶液质量分数、表面活性剂质量分数和施加电压等对纤维膜形貌和质量的影响。结果表明：当纺丝溶液中PVP 质量分数为32%,纺丝电压为60 kV,表面活性剂质量分数为0.1%时,获得的PVP 纳米纤维膜综合性能最佳,其表面形貌良好,纤维直径较细且直径分布较均匀。     

静电纺丝素纳米纤维非织造膜形态结构研究

静电纺丝可获得丝素纳米级纤维,并以非织造布状排列,广泛用于细胞支架、伤口包覆及药物控释等。用甲酸溶解丝素室温干燥膜,研究了静电纺丝素纳米纤维非织造膜的形态结构,分析其影响因素。结果表明:非织造膜孔隙率为32.3%,孔径80~600 nm;纤维直径与纺丝液质量分数表现出高度显著线性关系,纤维直径随纺丝液质量分数的升高而增大;纤维直径开始随电压的增大而变小,之后变大;电场强度相同,高电压/长距离电场形成的纤维直径小。     

非离子表面活性剂对壳聚糖静电纺丝的影响

以三氟乙酸为溶剂,采用静电纺丝法制备了纯壳聚糖纳米纤维。采用扫描电镜观察纤维的形态,分析纺丝液质量分数及非离子表面活性剂TX-15对纤维形态的影响。研究发现：壳聚糖溶液体系的适纺质量分数范围为3%~6%;通过显著性检验得出纺丝液质量分数对纤维直径有显著性影响;通过添加非离子型表面活性剂TX-15可改善纺丝液的可纺性,质量分数为5%的纺丝液添加质量分数为2.5%的TX-15得到的壳聚糖纳米纤维形态比较好。     

Evaluating and empirical modeling of the electrocatalytic activity and morphology of electrospun polyacrylonitrile/polyaniline/tungsten trioxide nanofibers

Abstract

Electrically conductive polyacrylonitrile/polyaniline/tungsten oxide (PAN/PANI/WO₃) nanofibers were produced through an electrospinning method. The PAN polymer was used to enhance the spinnability of the polyaniline solution. The surface morphology and electrocatalytic properties of the mats were examined by scanning electron microscopy and electrochemical impedance spectroscopy method. Response surface methodology was applied to predict the relation between both the average diameters of the nanofibers and the charge-transfer resistance (R_ct) of nanofibrous mats with the concentration of polyaniline and tungsten oxide. Design-Expert7 software was selected for the response data analysis of the contour plots. Direct relation was observed between the average diameters of the nanofibers with WO₃ concentration in electrospinning solution. However, with increasing polyaniline content, the average diameters of nanofibers decreased. The results showed that both the PANI and WO₃ concentrations (%wt.) had significant effects on the nanofibers diameters. In the case of electrocatalytic activity, the increasing of both composite components in the spinning solutions had positive effect on the lowering of the charge-transfer resistance and the changes were statistically significant.     

静电纺丝纳米纤维的方法与应用现状

主要介绍了利用不同的静电纺丝收集装置设计得到多种排列形式的纳米纤维聚集体及聚合物纳米纤维的应用.说明了静电纺丝技术可以得到各种各样的聚集体,是目前制备纳米纤维比较有效的方法,提高了由纳米纤维制备的产品质量,可以应用于特定的改性方面.     

复合静电纺超细聚丙烯腈纳米纤维的制备

为获得比常规静电纺丝纤维直径更细的聚丙烯腈（PAN）纳米纤维,采用复合静电纺丝方法制备了聚丙烯腈/醋酸丁酸纤维素（PAN/CAB）复合纳米纤维,再溶解掉复合纳米纤维中的CAB组分,得到超细PAN纳米纤维并对其进行氨基化改性后用于吸附直接红23（DR23）染料。研究了PAN和CAB的混合比例、纺丝溶液质量分数和纺丝液挤出速度3个因素对所得ＰＡＮ 纳米纤维直径的影响,并比较了常规静电纺和复合静电纺制备出的PAN纳米纤维改性后的染料吸附量。实验结果表明：该方法制得的PAN纳米纤维的平均直径在50~80 nm范围内,其中当PAN和CAB的质量比为15:85、纺丝溶液质量分数为15%、纺丝液挤出速度为1.5 mL/h、纺丝电压为10 kV、接收距离为20 cm时,得到的PAN纳米纤维的平均直径为50 nm;改性后纳米纤维对DR 23的平衡吸附量达833mg/g。     

氯化锂对静电纺PVA溶液稳定段射流的影响

静电纺丝过程中,当溶液完全绝缘或施加电压不够高时,静电力不能克服溶液的表面张力,纺丝无法进行。为克服这个问题,在溶液中加入盐。用聚乙烯醇纺丝液,当添加的LiCL质量分数不同时,纺得的纳米纤维直径从大到小排列顺序为：1% LiCl>0.8% LiCl>0.5% LiCl>0.2% LiCl。研究了LiCl质量分数对于轴向坐标的射流半径的影响机制,推导出直线段（稳定段）部分射流半径与轴向坐标符合如下关系, 的关系,并通过测量添加不同质量分数LiCl的聚乙烯醇纺丝液的射流半径进行实验验证,结果表明实验值与理论值完全吻合。     

静电纺丝法制备木质素基纳米纤维

以N,N-二甲基甲酰胺为溶剂,对不同比例的乙酸木质素（AAL）与聚乙烯吡咯烷酮（PVP）混合溶液,AAL与聚丙烯酸酯（polyacrylate）混合溶液,AAL与聚乙烯醇（PVA）混合溶液三种溶液体系进行静电纺丝。用扫描电子显微镜观察了纳米纤维的表面形貌。结果表明：AAL与PVA混合溶液通过电纺不能得到纳米纤维。通过电纺可以得到直径均匀、表面光滑的AAL与PVP混合纳米纤维,AAL与聚丙烯酸酯混合纳米纤维,并且AAL含量的增加对混合纳米纤维的直径和表面形貌没有明显的影响。进而对单一AAL的静电纺丝进行了研究,分别研究了THF,DMF,乙酸等不同的溶剂体系,发现只有以乙酸为溶剂才能电纺成纤。     

静电纺蛋白质和多糖纳米纤维及其在食品行业的应用进展

静电纺丝技术是一种简单且有效地制备纳米纤维的方法,所得纳米纤维具有纤维直径可控、孔隙率高及比表面积大等优良特性,在生物医学、过滤材料、传感器、酶固定化及食品包装等领域具有良好的应用前景。应用于食品行业的电纺纳米纤维必须生物相容性好、毒性低且可生物降解,故目前常采用蛋白质和多糖等天然聚合物进行静电纺丝。本文主要综述了含蛋白质(大豆分离蛋白、玉米醇溶蛋白、乳清蛋白等)或多糖(壳聚糖、透明质酸、淀粉、普鲁兰多糖等)电纺纳米纤维的制备过程、电纺过程中各主要因素对纤维形貌的影响,所得纳米纤维的特性及其在食品行业,包括抗菌保鲜、抗氧化和控制释放等方面的潜在应用,并展望了静电纺蛋白质和多糖纳米纤维未来的研究方向。     

Fabrication of poly(vinylidenefluoride‐co‐hexafluoropropylene) nanofiber yarns by conjugate electrospinning

Conventional electrospinning is an efficient method to fabricate polymer nanofibers which are usually collected as non‐woven mats. Recently, in order to fabricate a nanofiber yarn, conjugate electrospinning has been developed using coupled spinnerets applied with two high electrical voltages of opposite polarities In this paper, poly(vinylidenefluoride‐co‐hexafluoropropylene) (PVDF‐HFP) nanofiber yarns are prepared by conjugate electrospinning. The effects of the concentration and delivery rate of polymer solution and the distance between coupled spinnerets on the structure of PVDF‐HFP nanofiber yarns are investigated. The structure of the nanofiber yarns is observed by scanning electron microscopy (SEM). The mechanical properties of the nanofiber yarns are measured by electronic fiber strength tester. The results show that the PVDF‐HFP nanofiber yarn consists of a large number of nanofibers aligned well along the longitudinal axis of the yarn, and the nanofibers have diameters ranging from several hundred nanometers to a few microns. The diameter of nanofibers in yarns increases with the increase in the polymer concentration, which significantly affects the structure of nanofiber yarns. The PVDF‐HFP nanofiber yarn electrospun from the polymer solution with a concentration of 45% has the highest tensile strength of 0.25 cN/dtex and an elongation of 180.13%.