静电纺丝法制备聚己内酯纳米纤维的工艺研究

以可生物降解的两亲性聚合物-聚己内酯(PCL)为原料,三氯甲烷和N,N-二甲基酰胺(DMF)为混合溶剂,采用静电纺丝技术制备了不同尺寸的PCL纳米纤维,研究了不同的PCL溶液浓度和针头尺寸相关工艺参数对纳米纤维微观形貌结构和尺寸分布的影响,同时对有序PCL纳米纤维的制备工艺进行了初步研究。     

静电纺聚乳酸纳米纤维的制备及其孔结构调控

为了调控聚乳酸(PLA)纳米纤维的孔结构,采用静电纺丝技术,以PLA母粒为原料,三氯甲烷(CF)和N,N-二甲基甲酰胺(DMF)按一定比例混合的溶液为溶剂,制备了平均直径在1.37μm的PLA纳米纤维,并对其结构进行表征。结果表明,PLA纳米纤维的平均直径随着纺丝液中CF含量、聚合物浓度、环境湿度的增加而增大;随纺丝电压和灌注速度的增大而呈减小的趋势。同时,环境湿度对纤维表面孔结构有显著影响。随着湿度的增加,纤维表面孔的分布密度增加,且形状由圆形转变为椭圆形。此外,与表面光滑的PLA纳米纤维(2.4 m²/g)相比,所制备的PLA多孔纤维的比表面积提升了10倍(24.0 m²/g)。     

气流-静电纺丝法制备聚对苯二甲酸乙二酯纳米纤维

采用50%苯酚和50%1,1,2,2-四氯乙烷的混合溶液为溶剂,通过气流-静电纺丝法制备了聚对苯二甲酸乙二酯(PET)纳米纤维。利用扫描电镜(SEM),研究了聚合物分子质量、溶液浓度、电压、接收距离(喷丝孔到接收板的距离)对电纺纤维形态结构的影响。结果表明:随着聚合物分子质量和溶液浓度增加,纤维平均直径也随之增加;纤维平均直径随电压的增加而减小;随接收距离的增加,纤维平均直径先减小后增加。最佳工艺条件为:聚合物特性黏度为0.818 dL/g,溶液质量分数为15%,电压为32 kV,接收距离为23 cm,所得PET电纺纳米纤维平均直径为85 nm。     

静电纺丝法制备聚碳酸酯基聚氨酯纳米纤维的研究

以N,N-二甲基甲酰胺(DMF)和四氢呋喃(THF)为混合溶剂配制聚碳酸酯基热塑性聚氨酯(PU)纺丝溶液,通过静电纺丝法制备PU纳米纤维。重点研究了纺丝溶液浓度、混合溶剂中DMF和THF的体积比、纺丝电压和纺丝溶液流速对PU纳米纤维形态、直径及其分散性的影响。结果发现,纺丝液浓度为12%,混合溶剂中DMF与THF体积比为1∶1,纺丝电压为10 kV,纺丝溶液流速为0. 8 m L/h时,通过静电纺丝法制得的PU纳米纤维粗细均匀,表面光滑,纤维之间无粘连现象,形成的纳米纤维膜空隙率高。     

不同溶剂对静电纺聚乳酸纳米纤维形态结构的影响

以聚乳酸（PLA）为原料,分别用三种不同的溶剂制得三种纺丝液并采用静电纺丝法,制备了聚乳酸纳米纤维。探讨了溶剂、电压、溶液质量分数对纤维形貌和直径的影响。结果表明,溶剂是决定PLA超细纤维形成的关键因素,三氯甲烷（CHC l3）与二甲基甲酰胺（DMF）混合溶剂（体积比为9∶1）是PLA静电纺丝较为理想的溶剂。在PLA质量分数为6%、极距15 cm、电压25 kV,流量2.5 mL/h的工艺条件下,可制备直径为1 200 nm左右的PLA纤维。     

磁场辅助静电纺PAN纳米纤维有序度的研究

采用磁场辅助静电纺丝法制备了有序聚丙烯腈(PAN)纳米纤维,分析了PAN/二甲基甲酰胺(DMF)溶液浓度、纺丝电压、注射速度、磁铁间距和溶剂DMF及DMF与二甲基亚砜(DMSO)混合溶剂等因素对PAN纤维有序度的影响。结果表明:随着PAN/DMF溶液中PAN浓度增大,PAN纤维有序度逐渐增大;注射速度对纤维有序度影响不明显;随着纺丝电压和磁铁间距增大,PAN纤维有序度先增大后减小;DMSO的加入,使溶液可纺性降低,不利于纤维有序排列;对于PAN/DMF溶液体系,适宜的磁场辅助静电纺丝的工艺参数为PAN质量分数12%,纺丝距离12 cm,电压14 k V,注射速度0.5 m L/h,磁铁间距2.5 cm,纺丝得到的PAN纳米纤维的有序度为92%。     

基础理论

<正>TQ 340.120143009聚乳酸-聚己内酯共混物的电纺纤维:形态和取向Lu Liangliang…;IndustrialEngineering Chemistry Re-search,2012,51(9),p.3682(英)文章中运用静电纺丝成功制备聚乳酸(PLA)-聚己内酯(PCL)生物可降解共混物有序纤维束和无规取向的纤维网。对于网状纤维来说,两种聚合物的共混比和复配溶剂的配比是影响纤维形态的重要因素。研究结果表明,含PCL质量分数较低的纤维比含PCL质量分数较高的纤维形态更均一、纤维的平均直径更高。此外,加入少量二甲基甲酰胺(DMF)作     

静电纺丝热塑性聚氨酯纳米纤维的制备

将N,N-二甲基甲酰胺（DMF）和四氢呋喃（THF）按体积比0：4、1：3、2：2、3：1、4：0混合作为溶剂,确定配比后,在不同浓度、电压下对热塑性聚氨酯（TPU）溶液进行静电纺丝。结果表明,DMF与THF的体积比对聚氨酯静电纺丝纤维的形貌、直径及其均匀性有明显影响,当混合溶液体积比为2：2,浓度为0．18g／mL,电压为26kV时,TPU纺丝液纺丝效果最佳,得到最理想的纤维;纤维直径随DMF含量的增多而减小,但当DMF含量过多时,纤维上容易出现液滴,纤维形貌变差;TPU纺丝液浓度增大,纤维直径增大;电压增大,纤维直径减小。     

静电纺丝工艺参数对丝素/壳聚糖纳米纤维的形貌及直径的影响

以98%的甲酸为溶剂,不同质量分数的再生丝素溶液和3.5%的壳聚糖溶液以质量比70:30共混静电纺丝。用扫描电子显微镜(SEM)观察了丝素质量分数、电压和极距(喷丝口到收集装置的距离)对丝素/壳聚糖纳米纤维的形貌及直径的影响。正交试验结果表明:在丝素/壳聚糖溶液静电纺丝的工艺参数中,对纤维平均直径的影响因素由大到小依次为丝素质量分数、电压、极距。单因素试验表明:丝素/壳聚糖纳米纤维的平均直径及其分布范围随丝素质量分数的增加而增大;在15￣30kV范围内纤维的平均直径随电压增大而减小;当极距大于12cm时,对纤维直径影响不大。最佳工艺条件为:丝素质量分数13%,电压30kV,极距为12cm,制得的纳米纤维平均直径104nm。     

溶剂对静电纺PA6纤维可纺性的影响

分别用甲酸、六氟异丙醇(HFIP)或甲酸与醋酸(HAc)、N,N-二甲基甲酰胺(DMF)、HFIP的混合溶剂溶解聚己内酰胺(PA6),通过静电纺丝法制备了纳米级的PA6纤维。结果表明:甲酸作为溶剂时,PA6可纺丝溶液质量分数为8%～22%,所纺出的PA6纤维直径为50～300 nm;HFIP作为溶剂时PA6可纺丝溶液质量分数为8%～18%,纤维直径为50～500 nm;甲酸与HFIP,HAc,DMF的混合溶剂对纺丝状态及纤维直径分布的影响均表现为随第2种溶剂的加入,纤维直径的分布变广,平均直径增加;HAc的加入能提高PA6溶液的可纺性。     

Effect of the addition of a fugitive salt on electrospinnability of poly(?-caprolactone)

Described in this paper is a novel study focused on producing bead-free ultrafine fibers, with narrow fiber diameter distribution, from Poly(?-caprolactone) (PCL) via electrospinning. High quality product is achieved with the use of a new solvent system that involves an acid-base reaction to produce weak salt complexes, which serve to increase the conductivity of the polymer solution. Additionally, the salt formed dissociates easily and evaporates along with the solvent during the spinning process because its respective acid-base components are volatile at room temperature. This results into the formation of pure PCL nanofibers of ultrafine dimensions. Glacial acetic acid was used as the solvent for the polymer and the organic base pyridine was used to initiate the formation of salt complexes in the solution. Pyridine was added at six different levels to vary the conductivity and examine the latter's effect on fiber morphology. Along with the pyridine content, the polymer concentration was also varied to determine how the two interacted in influencing the size of the fiber and the quality of the structure obtained. It was found that bead-free fibers of sizes lying well within the nano range (140-340 nm) could be produced using the conducting solvent system. Two interesting effects were noted. For a given polymer concentration, the mean fiber diameter increased with increase in pyridine amount. And, lower the polymer concentration, higher was the amount of pyridine required to produce bead-free nanofibers. The combination of these effects along with the fact that the reproducibility of the results was high provided a means of producing fibers with predictable sizes.     

Effects of Electrospinning Parameters on Gelatin/Poly(ϵ‐Caprolactone) Nanofiber Diameter

An electrospinning procedure was carried out to fabricate gelatin/poly(?‐caprolactone) (Gt/PCL) nanofibers. Response surface methodology based on a three‐level, four‐variable Box‐Behnken design technique was used to model the resultant diameter of the as‐spun nanofibers. A second‐order model was obtained to describe the relationship between the fiber diameter and the electrospinning parameters, namely Gt concentration, PCL concentration, content of acetic acid in the overall solvent, and content of Gt solution in the blend solution. The individual and the interactive effects of these parameters on the fiber diameter were determined. Validation experiments verified the accuracy of the model which provided a simple and effective method for fabricating nanofibers with a controllable and predictable fiber diameter.     

聚ε-己内酯/聚乙二醇共混纳米纤维的静电纺丝研究

采用四氢呋喃和无水乙醇为溶剂,利用静电纺丝法制备了聚己内酯(PCL)/聚乙二醇(PEG)共混纳米纤维。研究了共混配比、溶液浓度、无水乙醇的加入以及电纺电压、接收距离等工艺参数对纤维形态和性能的影响。测试结果表明:聚乙二醇和聚己内酯以一定比例共混后改善了聚己内酯纤维毡的亲水性和细胞相容性;随着纺丝原液浓度增加,电纺产品由高分子微/纳米液滴结构渐变为珠状结构较少的平滑纤维,平均纤维直径逐渐增大;一定范围内,纤维平均直径随电压的上升而增大,但与接收距离关系不大;此外,加入无水乙醇后,共混溶液电导率增加,有利于喷射流的劈裂,减少了珠状结构的数量。     

Solvent system for steady state electrospinning of polyamide 6.6

A mixture of formic acid/acetic acid makes it possible to electrospin polyamide 6.6 in steady state conditions. Steady state conditions are essential in nozzle electrospinning to generate a stable process which fabricates reproducible material, permitting industrial upscaling. This study shows that only a limited mixture range of formic acid/acetic acid allows electrospinning of polyamide 6.6 in steady state. Furthermore, the weight concentration in solution; the tip to collector distance and the flow rate have been changed to control the average diameter of the nanofibres. The average diameter increases by increasing weight concentration in solution, increasing volume fraction of acetic acid in the mixture, increasing tip to collector distance and increasing flow rate. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Impact of electrospinning process parameters on the measured current and fiber diameter

In this article, polycaprolactone (PCL) nanofibres were processed by electrospinning using a 3:1 ratio of tetrahydrofuran to methanol as solvent. The solvent choice was motivated by the possibility of greener alternatives to the halogenated compounds most often used for electrospinning. The morphologies and fiber diameters resulting from the electrospinning of PCL solutions at room temperature under various conditions are presented in this article. The material morphology was characterized using scanning electron microscopy and a measuring software. The process was optimized for smaller fibers with a narrower fiber diameter distribution by studying parameters such as polymer concentration, applied voltage, the tip to collector distance (TCD), and the solution flow rate. A comparison analysis was used to separate the current resulting from whipping and that resulting from spraying at high voltage. The fiber diameters obtained under various processing conditions were effectively modeled using the terminal jet theory, referenced in several works. Process parameters were optimal for a 20% PCL concentration spun at a flow rate of 0.5 mL/h, with a TCD of 15 cm and an applied voltage of 8 kV. Fibers spun under these conditions displayed diameters of 546 ± 173 nm. POLYM. ENG. SCI., 55:2576–2582, 2015. © 2015 Society of Plastics Engineers     

Preparation of electrospun nanofibrous polycaprolactone scaffolds using nontoxic ethylene carbonate and glacial acetic acid solvent system

In recent years, solution electrospinning has attracted the interest of researchers due to the possibility to design nanofibrous scaffolds with large surface area to volume ratios. Polycaprolactone (PCL), because of its biocompatibility and easy processability, has been widely used to develop electrospun structures for tissue engineering. However, the use of organic solvents and the poor PCL solution stability still hinder the development of the solution electrospinning process. The relatively benign glacial acetic acid (GAC) as a solvent of PCL was used to fabricate microfibrous fibers or beaded fibers. Thus, ethylene carbonate (EC) as a nontoxic assistant solvent was added to the PCL/GAC solution to successfully fabricate electrospun nanofibrous PCL scaffolds. The stability of the PCL/GAC/EC solution system was demonstrated as the viscosity, which showed no significant change during 48 h. The ultrafine PCL fiber diameter decreased as EC concentration was increased from 0 to 9 vol% and started to slightly increase when EC concentration increased beyond 9 vol%. MTT assay evidenced that MC3T3-E1 cells on the nanofibrous PCL scaffolds exhibited a better enhancement on cell proliferation. In summary, EC was added in PCL/GAC to establish a stable and low toxic solution electrospinning system, which provides promising strategy in tissue engineering field. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48387.     

Morphology of electrospun nylon‐6 nanofibers as a function of molecular weight and processing parameters

In the present study, the morphology and mechanical properties of nylon‐6 nanofibers were investigated as a function of molecular weight (30,000, 50,000, and 63,000 g/mol) and electrospinning process conditions (solution concentration, voltage, tip‐to‐collector distance, and flow rate). Scanning electron micrographs (SEM) of nylon‐6 nanofibers showed that the diameter of the electrospun fiber increased with increasing molecular weight and solution concentration. An increase in molecular weight increases the density of chain entanglements (in solution) at the same polymer concentration; hence, the minimum concentration to produce nanofibers was lower for the highest molecular weight nylon‐6. The morphology of electrospun fibers also depended on tip‐to‐collector distance and applied voltage concentration of polymer solution as observed from the SEM images. Trends in fiber diameter and diameter distribution are discussed for each processing variable. Mechanical properties of electrospun nonwoven mats showed an increase in tensile strength and modulus as a function of increasing molecular weight. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Predicting poly(vinyl pyrrolidone)'s solubility parameter and systematic investigation of the parameters of electrospinning with response surface methodology

The solubility parameters were used to choose the solvent for poly(vinyl pyrrolidone) (PVP) in electrospinning. In this study, a novel method for predicting the contribution value of the pyrrolidone group (a typical part of the PVP molecular structure) was proposed. The solubility parameters of PVP were calculated by this method, and accordingly, ethanol was chosen as the solvent for PVP. What is more, response surface methodology was used to facilitate a systematic investigation on the influence of the PVP solution concentration, feed rate, distance between the tip and collector, and operating voltage on the fiber diameter and morphology in electrospinning. The predicted fiber diameters by the response regression model, and the experimental values were in close proximity. The solution concentration and feed rate both had significant effects on the PVP fiber diameter, and there was some interaction between the solution concentration and the feed rate in this system. In addition, this study provided a train of thought for the electrospinning of polymer fibers with controllable and predictable fiber diameters. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40304.     

稀乙酸对聚乙烯醇水溶液静电纺丝性能的影响

采用质量分数3%乙酸水溶液作为高醇解度聚乙烯醇(PVA)的溶剂,研究了PVA稀乙酸溶液的性质及其静电纺丝工艺。结果表明:加入质量分数3%乙酸,PVA溶液粘度下降,表面张力及电导率提高;纺丝液浓度对PVA稀乙酸溶液的静电纺丝性能影响最大;当PVA稀乙酸溶液质量分数为8%～13%,固化距离15mm,纺丝电压14～18kV时,可制得形态良好的PVA超细纤维无纺毡。