Electrospinning of ethyl–cyanoethyl cellulose/tetrahydrofuran solutions

In this study, electrospinning was used to fabricate ethyl–cyanoethyl cellulose [(E‐CE)C] fiber from a solution of (E‐CE)C/tetrahydrofuran. The diameter of the thinnest fiber fabricated during the electrospinning was about 200 nm. It was found that the diameters of the fibers and their distribution depend on the processing parameters and properties of the solution, such as viscosity, temperature, and concentration, for example. The morphology of the fiber was also observed by SEM. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 242–246, 2004     

Electrospinning of waterborne polyurethanes

Polyurethane (PU) fibers were obtained by electrospinning of waterborne PU dispersions. As dispersion cannot be electrospun, a water‐soluble polymer (poly (ethylene oxide) (PEO)) was dissolved in the PU dispersion and fibers were obtained from electrospinning the resulting mixture. Pure PU fibers were obtained after removing PEO with water extraction. Continuous PU fibers were obtained using a PU/PEO weight ratio higher than 2.5. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

静电纺PVA/PEO/多壁碳纳米管超细纤维的制备与性能

采用超声波辅助溶液共混的方式制备聚乙烯醇/多壁碳纳米管(PVA/MWCNT)复合溶液,并将该溶液与聚氧化乙烯(PEO)溶液共混,利用静电纺丝技术制备PVA/PEO/MWCNTs复合超细纤维。运用扫描电子显微镜(SEM)、X-射线衍射仪(XRD)、示差扫描量热仪(DSC)方法对不同MWCNTs含量的PVA/PEO/MWCNTs复合纤维的微观形貌、结构和热性能进行了观察分析。结果表明:随着MWCNTs含量的增加,纤维直径显著变细,MWCNTs的加入降低了纤维的结晶性,纤维的热稳定性有所提高。     

利用静电纺丝技术制备多孔聚苯乙烯纤维

利用静电纺丝技术制备聚苯乙烯（PS）聚乙烯吡咯烷酮（PVP）复合纤维,通过除去复合纤维中的PVP成分,成功地制备了PS多孔纤维,并对其进行了SEM谱图分析测试。结果表明,纺丝电压、PS与PVP配比直接影响着复合纤维的微观形态;PS／PVP复合纤维的浸泡时间、浸泡后的干燥方式、PS与PVP配比都会影响PS多孔纤维的表面形态以及纤维的内部结构。     

Electrospinning of polycaprolactone nanofibers using H2O as benign additive in polycaprolactone/glacial acetic acid solution

Considerable efforts have been devoted to the production of polycaprolactone (PCL) nanofibrous structures by electrospinning. However, some toxic solvents have often been used to achieve bead‐free nanofibers. At present, a benign solvent such as glacial acetic acid (GAC) only leads to beaded or microscale fibers. Therefore a study is done to extend the electrospinnability of the PCL/GAC system by the addition of H₂O. The solution properties of conductivity, viscosity, and surface tension were altered by the addition of H₂O, especially increasing the conductivity and viscosity. These properties essential to electrospinning could remain stable for 6 h when the H₂O content was less than or equal to 9 vol %. Then ultrafine PCL fibers with diameters from 188 to 200 nm, 10 times smaller than when dissolved in pure GAC, were electrospun from solutions of PCL with concentrations in the range of 17 to 20 wt % with H₂O content at 9 vol %. Finally, the crystallinity and crystallite size of the resulting fibers were smaller than that of raw PCL pellets. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45578.     

三氯甲烷／乙醇混合溶剂对聚乳酸电纺成形影响的研究

用一系列不同组分配比的三氯甲烷／乙醇混合溶剂分别配制质量百分比浓度为4％和6％的聚乳酸（PLA）溶液,然后在相同纺丝参数下进行电纺成形。结果发现,随着乙醇在混合溶剂中体积含量的增加,聚乳酸溶液可纺性逐渐变好,电纺纤维的宏观形态也随之改变。研究了聚乳酸的溶液性质,结果认为,溶液可纺性改善的原因是乙醇的加入增强了高分子链之间的缠结程度,同时提高了溶液的电导率;溶液表面张力和表观黏度的改变对可纺性的影响较小。     

Electrospinning of polymer nanofibers loaded with noncovalently functionalized graphene

Pristine graphene/polyvinyl alcohol (PVA) nanofibers were prepared by electrospinning an aqueous solution of polyvinylpyrrolidone‐stabilized graphene and PVA. This is the first report of electrospun nanofibers reinforced with dispersed pristine graphene. We examine the relationship between graphene loading and critical electrospinning parameters. Microscopy indicates uniform fiber formation and excellent graphene dispersion within the fiber. Rheological data indicates that the excellent level of graphene dispersion enhances the modulus of the polymer by 205%. We also find that the graphene significantly increases the fibers' thermal stability (increase of 15°C) and crystallinity (59% increase) above the baseline. In fact, the graphene may act as nucleating points for increased crystallinity. These graphene/polymer nanofibers have the potential to serve in a variety of applications, including electrodes, conductive wires, and biomedical materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

静电纺丝取向纤维的制备及其微结构

静电纺丝是一种简单、快捷的生产亚微米、纳米纤维的新技术。通过静电纺丝制备的取向纳米纤维在电学、磁学以及光学等方面具备独特的的物理性质,在国内外引起了广泛的关注。综述了近年采用静电纺丝技术制备取向纳米纤维的研究进展,同时概括目前得到的纳米纤维的取向结构。     

离心静电纺丝法制备聚醚酮酮纳米纤维

用离心静电纺丝方法,将国产化的高性能工程塑料聚醚酮酮(PEKK)制备成PEKK纳米纤维。对PEKK离心静电纺丝的可纺性、纺丝规律以及最终纤维的性能进行了研究。结果显示,离心静电纺丝能很好解决溶液浓度高、溶剂挥发困难的问题,PEKK的离心静电纺丝可纺性很好,溶液浓度的控制对于纤维形貌和直径影响明显,纺丝纤维的热性能比原材料有所降低。该研究为PEKK纳米纤维的制备开辟了新方向。     

Electrospinning of plant oil‐based,non‐isocyanate polyurethanes for biomedical applications

Non‐isocyanate polyurethanes (NIPU) have rapidly emerged as a sustainable, less toxic, and environmentally friendly alternative to traditional isocyanate‐based thermoplastic polyurethane (TPU) synthesis. TPU is widely used in the medical industry due to its excellent mechanical properties and elasticity. However, little work has been done to synthesize and electrospin NIPU into fibrous mats for biomedical applications. In this work, melt polymerization of a plant oil‐based cyclic carbonate monomer with polyether soft segments and various diamines yielded isocyanate‐free, segmented poly(amide hydroxyurethane)s (PAHUs). Electrospinning of segmented PAHUs afforded ductile, free‐standing fibrous mats with Young's modulus values between 7 and 8 MPa, suitable for tissue scaffold applications. PAHU fiber mats exhibited 3–4 times greater water uptake than the electrospun TPU control, demonstrating potential utility in drug delivery. Fibroblasts adhered to electrospun PAHU fibrous mats with viability values over 90% after 72‐h, validating its biocompatibility. The results highlight the high performance and potential of electrospun isocyanate‐free polyurethanes mats for biomedical application. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46464.     

Electrospinning of circumferentially aligned polymer nanofibers floating on rotating water collector

This work outlines a novel electrospinning process using a rotating water collector. The circumferentially aligned nanofibers are successfully fabricated using this process. The movement and conductivity of the liquid collector are considered as the two prime factors to investigate the interaction between electrospun nanofibers and liquid surface. Through the theoretical analysis of the movement of liquid collector, it is confirmed that the liquid flow velocity demonstrates a tendency to decline from the center of the vortex to the edge of the container. Experimental results show that as the fluid flow velocity increases, the alignment of the nanofibers increases as well. In addition, it is discovered that the conductivity of the water collector demonstrates no significant effect on the alignment of nanofibers. However, the solution with higher conductivity can produce a nanofiber mat with smaller dimension. The present study confirms the versatility of the liquid collector and can be used to prepare nanofiber mats with complicated structures. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48759.     

Electrospinning polyethylene terephthalate/SiO2 nanofiber composite needle felt for enhanced filtration performance

In this study, polyethylene terephthalate (PET) nanofiber membrane fabricated by electrospinning was newly applied to needle-felt filters. The PET nanofiber membrane was electrospun in an optimal condition. Nanoparticles (SiO₂) were used to reduce the fiber diameter. Polyphenylene sulfide needle felt (PPS NF), hot melt adhesive film, and PET nanofiber membrane were compounded into sandwich-structured composite needle felt (PET/SiO₂ NNF) by heat treatment. The dynamic filtration performance of PET/SiO₂ NNF was compared with that of PPS NF and polytetrafluoroethylene-coated needle felt (PTFE CNF). The results showed that PET/SiO₂ NNF had a lower rate of increase of pressure drop and a higher dust removal rate. The completion cycle of PET/SiO₂ NNF was longer than PPS NF and PTFE CNF, which extended its service life in real applications. The successful synthesis of PET/SiO₂ NNF suggested a new method to synthesize an innovative high-performance needle-felt filter. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48282.     

Electrospinning of chitosan/poly(vinyl alcohol)/acrylic acid aqueous solutions

Chitosan bicomponent fibers were prepared via the electrospinning of chitosan/poly(vinyl alcohol)/acrylic acid aqueous solutions with different concentrations. With a 4% acrylic acid aqueous solution, when the chitosan/poly(vinyl alcohol) mass ratios were lower than 80/20, electrospinning nanofibers could be obtained. With a 90% acrylic acid aqueous solution, when the chitosan/poly(vinyl alcohol) mass ratios were less than 95/5, good nanofibers could be electrospun. The average diameter of the nanofibers gradually decreased, and its distribution became narrower as the poly(vinyl alcohol) concentration increased. Chitosan/poly(vinyl alcohol)/acrylic acid aqueous solutions could be electrospun at various concentrations by the adjustment of the chitosan and poly(vinyl alcohol) concentrations. The effects of the viscosity and conductivity of the blend solution on the morphologies of the fiber mats were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5692–5697, 2006     

Electrospinning of PVA-Calcium Phosphate Sol Precursors for the Production of Fibrous Hydroxyapatite

A precursor solution containing poly(vinyl alcohol) and a calcium phosphate sol is used to produce fibers of hydroxyapatite. The mixture is electrospun at a voltage of 20 kV and the resultant structure is calcined at 600°C for 6 h. Experiments were conducted for polymer molecular weight ( M _W) between 9500 and 155 000 g/mol and sol volume fractions ( V _S) between 0% and 83%. The results indicate that the electrospun fiber diameter can be correlated to the solution viscosity. The polymer molecular weight and sol volume fraction have a significant effect on the ceramic structure. Highly interconnected solid or porous hydroxyapatite fibers with diameters between 200 and 500 nm and crystal sizes between 30 and 50 nm can be produced by controlling M _W and V _S.     

Preparation of Ultrafine Ethylene/Propylene/Diene Terpolymer Rubber Fibers by Coaxial Electrospinning

Elastomeric EPDM fibers with diameters of 200–400 nm are prepared by coaxial electrospinning of PVP/EPDM fibers, subsequent vulcanization of the polymers and finally removal of the outer PVP layer using ethanol. The initially applied PVP layer restricts the elastic recovery of the EPDM fibers. The crosslinking density of the EPDM fibers reaches 8.44 × 10^?5 mol · cm^?3. The original morphology of EPDM is preserved after removing the PVP layer. The ultrafine EPDM fibers are expected to be useful in many fields, such as brittle plastics toughening, as well as applications in extremely high or low temperatures.

     

A Novel Approach to Prepare Uniaxially Aligned Nanofibers and Longitudinally Aligned Seamless Tubes Through Electrospinning

A novel method to produce uniaxially aligned nanofibers is described, in which a pair of parallel auxiliary electrodes at a positive potential is placed between the needle and the collector electrodes. Charged nanofibers ejecting from the polymer solution are pre‐aligned by the electrostatic repulsion originating from the auxiliary electrodes and deposited on the collector electrodes, forming a narrow mat with the fiber segments strongly curved. By adjusting the conductivity and shape profile of the collector, the curved segments can be straightened longitudinally. A seamless tube composed of longitudinally aligned nanofibers can be obtained. Such seamless tubes may be useful as biomaterials in tissue engineering.

     

Electrospinning of gelatin fibers using solutions with low acetic acid concentration: Effect of solvent composition on both diameter of electrospun fibers and cytotoxicity

Gelatin fibers were prepared by electrospinning of gelatin/acetic acid/water ternary mixtures with the aim of studying the feasibility of fabricating gelatin nanofiber mats at room temperature using an alternative benign solvent by significantly reducing the acetic acid concentration. The results showed that gelatin nanofibers can be optimally electrospun with low acetic acid concentration (25%, v/v) combined with gelatin concentrations higher than 300 mg/mL. Both gelatin solutions and electrospun gelatin mats (prepared with different acetic acid aqueous solutions) were analyzed by Fourier transform infrared spectroscopy and differential scanning calorimetry techniques to determine the chemical and structural changes of the polymer. The electrospun gelatin mats fabricated from solutions with low acetic acid content showed some advantages as the maintenance of the decomposition temperature of the pure gelatin (～ 230°C) and the reduction of the acid content on electrospun mats, which allowed to reach a cell viability upper than 90% (analyzed by cell viability test using human dermal fibroblast and embryonic kidney cells). This study has also analyzed the influence of gelatin and acetic acid concentration both on the solution viscosity and the electrospun fiber diameter, obtaining a clear relationship between these parameters. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42115.     

In Situ Viscosity‐Controlled Electrospinning with a Low Threshold Voltage

In the present study, a novel electrospinning method is proposed,where jet formation is aided by shearing the solution in situ. With a generalpolymer solution, viscosity decreases by shearing, that is, the solution isshear‐thinning. Poly(ethylene‐oxide) is used as a model polymer andthe effects of rotation speed, solution concentration, and gap size (the widthof the annular orifice) on the process and the morphology of the obtainedfibers are investigated. It is found that the threshold voltage for generatingmultiple jets decreased from 35 to 12 kV when rotation speed is higher than60 rpm (or shear rate more than 310 s^?1). Additionally, the results show thatfiber diameter increases as the concentration of the solution increases. Thechi‐square two‐sample test is used to compare the distribution of fibersproduced by the capillary method and the novel electrospinning process. Inthe authors' method, the viscosity of the solution can be changed by applyingmechanical forces on it during the electrospinning process, which results inthe initiation of the electrospinning jet at a low threshold voltage. It is alsofound that gap size has a similar effect on fiber diameter as needle diameter in classical electrospinning.     

A Core@sheath Nanofibrous Separator for Lithium Ion Batteries Obtained by Coaxial Electrospinning

A composite core@sheath nanofibrous separator for lithium ion batteries is fabricated via coaxial electrospinning, using thermosetting PI as the core material and PVDF‐HFP as the sheath material. It is demonstrated that the PI@PVDF‐HFP nonwovens display remarkably improved tensile strength up to 53 MPa and high thermal stability up to 300 °C. The electrochemical characterization shows that cells using core@sheath nonwovens as separators display better rate capability and better cycling capacity retention. Considerable mechanical strength, higher thermal stability and preferable rate capability might make this kind of core@sheath nonwovens promising separators for higher‐power application.