静电纺纤维素纳米晶体/壳聚糖-聚乙烯醇复合纳米纤维的制备与表征

通过探索纤维素纳米晶体（CNC）添加量对壳聚糖-聚乙烯醇（CS-PVA）基体性能的影响,为静电纺CNC/CS-PVA复合纳米纤维的制备提供理论支撑。以CNC、CS和PVA为原料,采用静电纺丝法成功制备不同CNC含量（质量分数）的静电纺CNC/CS-PVA复合纳米纤维,并通过SEM、TGA和FTIR等分析手段对CNC/CS-PVA复合纳米纤维的微观结构和性能进行了表征。结果表明：添加CNC后静电纺CNC/CS-PVA复合纳米纤维直径变大,表面变粗糙,力学性能和热学性能提高;随着CNC含量的增加,静电纺CNC/CS-PVA纤维的杨氏模量（E）和抗拉强度（σ）先增强后减弱,而外延起始温度继续上升。当CNC含量为3wt%时,静电纺CNC/CS-PVA复合纳米纤维力学性能最好,相比于CS-PVA复合纳米纤维,E和σ分别提高了43.9%和24.8%;当CNC含量为20wt%时,静电纺CNC/CS-PVA复合纳米纤维直径分布不均匀,可以观察到单根纤维表面存在少量的球状结构物质,同时外延起始温度达到328.83℃;FTIR分析得出,CNC与CS和PVA之间只存在分子间的相互作用而没有发生化学反应;随着溶液的酸性减弱,碱性增强,不同CNC含量的静电纺CNC/CS-PVA复合纳米纤维稳定性逐渐提高,而CNC含量对其稳定性影响不大。     

Characterization and mechanical properties of electrospun cellulose acetate/graphene oxide composite nanofibers

Graphene oxide incorporated cellulose acetate composite nanofibers were prepared via an electrospinning technique. The weight percentage of graphene oxide varied from 0.05 to 1.5 wt.% in the polymer solution. The morphologies and crystal structures of the resultant composite nanofibers were investigated by scanning electron microscopy and X-ray diffraction. The specific interaction was demonstrated by Fourier-transform infrared spectroscopy. Tensile test was performed to measure the mechanical properties of the prepared cellulose acetate/graphene oxide composite nanofibers. 1.5 wt.% cellulose acetate/graphene oxide composite nanofibers showed the highest tensile strength and Young's modulus.     

Fabrication and characterization of electrospun CdS-OH/polyacrylonitrile hybrid nanofibers

CdS-OH/polyacrylonitrile (PAN) hybrid nanofibers with strong photoluminescence and photocatalytic hydrogen production efficiency were synthesized by one-step co-electrospinning for the first time. The suspension of CdS-OH nanoparticles (size: 5 nm) in N,N-dimethylformamide (DMF) was mixed with PAN/DMF solutions to make spinning solutions, followed by electrospinning to make CdS-OH/PAN hybrid nanofibers. Their morphology and structure were characterized by SEM, TEM, XRD and fluorescence spectrophotometer. TEM and XRD measurements proved that the crystallographic structure of CdS-OH nanoparticles is identical to that of CdS. The CdS-OH nanoparticles were evenly distributed in PAN nanofibers of 320 nm in diameter. Thermogravimetrical analysis demonstrated that hybrid nanofibers were more thermally stable than neat PAN nanofibers. The hybrid nanofibers displayed excellent photoluminescent property. Additionally, they showed good photocatalytic hydrogen production efficiency with a rate of 13.5 μmol/h g fiber containing 60 mg of CdS-OH nanoparticles.     

Crosslinking of the electrospun polyethylene glycol/cellulose acetate composite fibers as shape-stabilized phase change materials

In a previous study, polyethylene glycol/cellulose acetate (PEG/CA) composite ultrafine fibers have been prepared by electrospinning. In order to improve their water-resistant ability and thermal stability for potential thermal storage applications, in this study, the electrospun PEG/CA fibers were crosslinked by using toluene-2, 4-diisocyanate (TDI). The morphology and thermal properties of the crosslinked fibers were investigated via SEM, DSC and TG, respectively. The results showed that the fibrous morphology of the crosslinked fibers was well preserved even after 24 h immersing in deionized water. Meanwhile, the crosslinking also led to an improvement on the thermal stability, but brought a decrease of the enthalpy compared with the original electrospun fibers.     

天然纤维素/聚丙烯腈抗菌纳米纤维的制备与表征

为了拓展天然纤维素材料的应用,在综合国内外对天然纤维素材料、纳米材料和抗菌材料相关研究的基础上,首先,利用LiCl/二甲基乙酰胺(DMAC)溶剂体系配置了不同共混比例的天然纤维素/聚丙烯腈纺丝液,采用静电纺丝技术制备了纤维素/聚丙烯腈纳米纤维。然后,用铜氨溶液对纳米纤维进行了抗菌处理,制备了具有一定抗菌功能的纤维集合体。最后,采用SEM观察不同共混比例下纳米纤维的微观形貌;采用TG和DSC表征其热性能;采用FTIR和表面接触角测量仪表征共混后纳米纤维的化学组成和亲水性的变化;采用振荡法测定纳米纤维的抗菌性能。结果表明:通过静电纺丝技术可制得直径在200~400nm范围内的纤维素/聚丙烯腈纳米纤维。随着纤维素含量的提高,纳米纤维的表面越来越粗糙,粘连愈加严重,且直径离散度也变大。当纤维素与聚丙烯腈的共混质量比大于75∶25时,纤维的直径标准偏差由纯聚丙烯腈纤维的100nm以下变为150nm以上。纤维素/聚丙烯腈纳米纤维具有良好的热性能,与纯纤维素纳米纤维相比热稳定性有一定提高,当纤维素与聚丙烯腈的共混质量比为25∶75时热稳定性最好。纤维素/聚丙烯腈纳米纤维的亲水性优于普通医用纱布的。经过铜氨溶液抗菌处理的纳米纤维具有良好的抗菌性能,对金黄色葡萄球菌和大肠杆菌的抑菌率分别为82%和75%。     

Continually fabricating staple yarns with aligned electrospun polyacrylonitrile nanofibers

Modified electrospinning apparatus has been developed for continually fabricating nanofiber staple yarns. For this purpose, a pair of rotating metal tubes was introduced to collect the aligned electrospun nanofibers and then twist them into yarns. Between the metal tubes, a rotating plastic tube was inserted to wind the yarns. By adjusting the rotation speed of all tubes, the twist of the nanofiber staple yarns can be controlled. The mechanical behaviors of polyacrylonitrile nanofiber staple yarns have been carried out as well. The results show that the nanofiber staple yarns hold excellent mechanical behaviors, which are capable of using as functional textile fabrics.     

Mechanical properties of electrospun PVA/MWNTs composite nanofibers

Composites of polyvinyl alcohol (PVA) and multi-walled carbon nanotubes (MWNTs) were prepared by electrospinning. A PVA/MWNTs solution was electrostatically spun to form filler wrapped nanofibers, with a diameter of ∼ 100-200 nm. As the concentration of filler in the composite was varied, the coloration of the fiber sheets changed. The SEM and TEM analyses of the fiber sheets revealed that the deformation of the fiber increases with increasing nanotube concentration. The mechanical properties were studied using a universal testing machine (UTM). The analysis is presented in detail. It is argued that the degree of dispersivity orientation and anisotropy of the nanotubes and the amount of interfacial stress in the filler/polymer are the predominant factors determining the variation in the tensile properties of the composites with the filler concentration.     

Glassy carbon nanofibers from electrospun cellulose nanofiber

Journal of Materials Science - Glassy carbon nanofibers (g-CNFs) with diameter of ca. 45 nm were prepared from electrospun cellulose nanofibers (CelluNFs) by two sequential steps:...     

A review: carbon nanofibers from electrospun polyacrylonitrile and their applications

Carbon nanofibers with diameters that fall into submicron and nanometer range have attracted growing attention in recent years due to their superior chemical, electrical, and mechanical properties in combination with their unique 1D nanostructures. Unlike catalytic synthesis, electrospinning polyacrylonitrile (PAN) followed by stabilization and carbonization has become a straightforward and convenient route to make continuous carbon nanofibers. This paper is a comprehensive and state-of-the-art review of the latest advances made in development and application of electrospun PAN-based carbon nanofibers. Our goal is to demonstrate an objective and overall picture of current research work on both functional carbon nanofibers and high-strength carbon nanofibers from the viewpoint of a materials scientist. Strategies to make a variety of carbon nanofibrous materials for energy conversion and storage, catalysis, sensor, adsorption/separation, and biomedical applications as well as attempts to achieve high-strength carbon nanofibers are addressed.     

LaOCl nanofibers derived from electrospun PVA/Lanthanum chloride composite fibers

Electrospun nanofibers of poly (vinyl alcohol) (PVA)/Lanthanum (Ш) chloride (LaCl₃) composite were employed to prepare the LaOCl nanofibers by calcination. TG-DSC was used to investigate the thermal property of precursor, while FT-IR, XRD, FESEM and TPD were employed to characterize the derived LaOCl nanofibers. Results indicate that the addition of LaCl₃ leads to the formation of fork segments in the structure of electrospun PVA/LaCl₃ composite nanofibers, therefore, changing the decomposition behavior of the fibers. Pure LaOCl fibers with a diameter range of 90-220 nm can be obtained by calcination of electrospun PVA/LaCl₃ composite nanofibers at 700 °C for 7 h. The resultant LaOCl nanofibers show a good sensing behavior for CO₂ gas.     

Novel carbon fiber/epoxy composite toughened by electrospun polysulfone nanofibers

Novel carbon fiber/epoxy composite toughened by electrospun polysulfone (PSF) nanofibers was prepared to enhance fracture toughness of the composite, and compared the morphology and toughness to those of composite toughened by PSF films prepared by solvent method. Polysulfone nanofibers with the average diameter of 230 nm were directly electrospun onto carbon fiber/epoxy prepregs to toughen the composite. SEM observations of the polysulfone nanofibers toughened composite revealed that polysulfone spheres with uneven sizes presented uniform dispersion through interleaves of the composite, which was different from those of composite toughened by PSF films. Mode I fracture toughness (G_IC) of the nanofibers toughened composite was 0.869 kJ/m² for 5.0 wt.% polysulfone nanofibers content, which was 140% and 280% higher than those of PSF films toughened and untoughened composite due to the uniform distribution of polysulfone spheres.     

Effect of carbonization temperature on properties of aligned electrospun polyacrylonitrile carbon nanofibers

Aligned electrospun nanofibrous bundle was used as the raw material for pretreatment, preoxidation and carbonization processes to prepare carbon nanofibers in a procedure temperature-controlled sintering furnace. Effect of carbonization temperature on the morphology and structural performance of nanofibers was investigated in present study. Results showed that R_I (the relative intensity radio between Disordered peak and Graphite peak) of nanofibers carbonized at 1000 °C is 0.90, carbon content is up to 85.67%, conductivity is 105.44 S·cm^− 1, Young's modulus is 68.8 ± 0.42 GPa, and fiber strength is 306.0 ± 9.0 MPa, all of which endow the fibers with a superior comprehensive property.     

Electrical and non-linear optical studies on electrospun ZnO/BaO composite nanofibers

Nanocapacitors and nonvolatile ferroelectric random access memories require nanoscale thin film coatings with ferroelectric properties.One dimensional ferroelectric nanofibers are used in ferroelectric...     

Oxolane-2,5-dione modified electrospun cellulose nanofibers for heavy metals adsorption

Functionalized cellulose nanofibers have been obtained through electrospinning and modification with oxolane-2,5-dione. The application of the nanofibers for adsorption of cadmium and lead ions from model wastewater samples is presented for the first time. Physical and chemical properties of the nanofibers were characterized. Surface chemistry during preparation and functionalization was monitored using Fourier transform-infrared spectroscopy, scanning electron microscopy, carbon-13 solid state nuclear magnetic resonance spectroscopy and Brunauer Emmett and Teller. Enhanced surface area of 13.68 m² g⁻¹ was recorded for the nanofibers as compared to the cellulose fibers with a surface area of 3.22 m² g⁻¹. Freundlich isotherm was found to describe the interactions better than Langmuir: K_f = 1.0 and 2.91 mmol g⁻¹ (r² = 0.997 and 0.988) for lead and cadmium, respectively. Regenerability of the fiber mats was investigated and the results obtained indicate sustainability in adsorption efficacy of the material.     

纳米Ag-聚乙烯醇缩丁醛静电纺丝复合纳米纤维的制备及性能

采用静电纺丝技术制备纳米Ag-聚乙烯醇缩丁醛（PVB）复合纳米纤维,获得一类过滤性能和抗菌性能优异的空气过滤材料。采用TEM分析纳米Ag的形貌,采用SEM、FTIR和XRD等表征手段研究纳米Ag-PVB复合纳米纤维的微观形貌、化学结构以及结晶行为,并对其空气过滤性能、透气性能和抗菌性能进行了研究。结果表明：以乙醇为溶剂,当PVB含量为10wt%、纳米Ag含量为0.25wt%时,得到的纤维尺寸均一,平均直径为542.14 nm。性能测试结果表明,纺丝最佳时间为10 min,纳米Ag-PVB复合纳米纤维对PM2.5过滤效率为99.99%,过滤阻力为16 Pa,透气率为155.0 mm/s,并且对大肠杆菌表现出优异的抗菌性能,其抑菌率为95.52%。     

聚砜纳米纤维增韧CFRP的制备及性能

介绍了一种聚砜纳米纤维增韧碳纤维/环氧树脂复合材料的新方法。无规取向的纳米纤维通过静电纺丝直接将纳米纤维接收于碳纤维/环氧树脂预浸布上,实现增韧复合材料的目的。探讨了混合溶剂(丙酮、DMAC)配比和聚砜纺丝溶液浓度对纳米纤维直径及分布的影响,测试了不同含量的聚砜纳米纤维增韧复合材料的型层间断裂韧性（G_ⅡC）,并同相等含量的聚砜溶剂法膜增韧复合材料性能进行了比较。在聚砜质量分数分别为1%、3%、5%的情况下,纳米纤维增韧复合材料的G_ⅡC分别增加54%、130%、177%,高于溶剂法膜增韧的复合材料。微观结构照片表明,纳米纤维增韧复合材料中,相分离后的聚砜小球贯穿于整个复合材料层间,而且呈现无规取向分布的海岛结构。增韧后复合材料的层间剪切强度（ILSS）都有略微的减小,溶剂法膜增韧后ILSS减小更明显。DMTA试验表明,与溶剂法膜相比较,纳米纤维与环氧树脂基体的相容性更好。      

Synthesis and morphology of electrospun PVA/PLZT composite and single phase PLZT nanofibers

Polyvinyl alcohol/lead lanthanum zirconate titanate (PVA/PLZT) composite nanofibers were prepared by the electrospinning method. The PLZT sol was prepared by using lead acetate trihydrate, titanium isopropoxide and zirconium propoxide molecular precursors based on sol-gel procedure. The influence of applied voltage, flow rate and needle-to-collector distance on the composite fiber morphology and diameters has been studied. The nanofibers were characterized by X-ray diffraction, TGA-DSC, FTIR spectroscopy and scanning electron microscopy (SEM). Single phase with perovskite structures PLZT nanofibers were also obtained by calcining the PVA/PLZT nanofibrous mat at 650 °C for 2 h. A linear correlation was observed between the single perovskite phase evolution and the calcination temperature.     

Transparent and flexible cellulose nanofibers/silver nanowires/acrylic resin composite electrode

In this study, we report a novel, eco-friendly and simple method to fabricate cellulose nanofibers (CNFs)/silver nanowires (AgNWs)/acrylic resin (AR) composite electrode. CNFs with average diameter of 15 nm were disintegrated only by one time-pass grinding. Aqueous dispersion of AgNWs was embedded onto the surface of CNFs film by simple vacuum filtration. The final composite electrode was obtained by impregnating CNFs/AgNWs film to AR with the assist of adhesive tape. This electrode with AgNWs density of 134 mg/m² showed low sheet resistance (4 Ω/sq), and high light transmittance (85%) which was 6% lower than that of neat AR. The coefficient of thermal expansion of the composite electrode was as low as 25.32 ppm K⁻¹. The tensile strength and Young’s modulus of CNFs/AgNWs/AR composite film were 35.71 MPa and 1.63 GPa, which were about 8 and 5.8 times larger than neat AR film, respectively.     

Optimizing the mechanical properties of electrospun polycaprolactone and nanohydroxyapatite composite nanofibers

Interest in fabrication of nanofibers using electrospinning has recently increased due to the ability to produce fibers with controlled structures, orientations, and dimensions. Tensile properties of electrospun fibers have not been widely investigated due to the difficulties in handling nanofibers and measuring low load for deformation. In this study, the effects of process parameters on the mechanical properties of electrospun composite nanofibers of polycaprolactone and nanohydroxyapatite were experimentally investigated. Response surface methodology (RSM) was utilized to design the experiments at the settings of solution concentration, voltage, spinning distance and flow rate. Mechanical properties of the electrospun fibers were correlated with these variables using a third order polynomial function. It was found that polymer concentration, voltage and spinning distance were the most effective parameters. The predicted mechanical properties were in good agreement with the experimental results.     

Surface-confined synthesis of silver nanoparticle composite coating on electrospun polyimide nanofibers

A methodology for fabricating hierarchical nanostructures by surface-confined synthesis of silver nanoparticles on electrospun polyimide nanofibers is reported. Through surface-confined imide cleavage at the dianhydride domain via immersion in an aqueous KOH solution, potassium polyamate coatings of accurately defined thickness are formed (at a rate of 25 nm h(-1) ). By utilizing the ion-exchange capability of the polyamate resin, silver ions are introduced through immersion in an aqueous AgNO3 solution. Subsequent reduction of the metal ion species leads to the formation of nanoparticles at the fiber surface. Two modes of reduction, chemical and thermal, are investigated in the report, each leading to distinct morphologies of the nanoparticle coatings. Via thermal reduction, a composite surface layer consisting of monodisperse silver nanoparticles (average diameter 5.2 nm) embedded in a re-imidized polyimide matrix is achieved. In the case of chemical reduction, the reduction process occurs preferentially at the surface of the fiber, leading to the formation of silver nanoparticles anchored at the surface, though not embedded, in a polyamic acid matrix. By regulating the modification depth, control of the particle density on the fiber surface is established. In both reduction approaches, the polyimide nanofiber core exhibits maintained integrity.