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1.
A series of blend nanofiber mats comprising poly(vinyl alcohol) (PVA) and polyurethane (PU) were prepared by dual-jet electrospinning in various parameters. Orthogonal experimental design was used to investigate how those parameters affected on fiber diameters and fiber diameter distribution. Altogether three parameters having three levels each were chosen for this study. The chosen parameters were tip-to-collector distance (TCD), voltage and tip-to-tip distance (TTD). Fiber diameters, thermal properties, mechanical properties and hydrophilicity of the blend nanofiber mats were examined by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), tensile test, contact angle and water absorption test, respectively. The results showed that the optimum conditions for PVA/PU blend nanofiber mats fabricated by dual-jet electrospinning were TCD of 20 cm, voltage of 18 kV and TTD of 4 cm. Besides, the thermal stability of PVA/PU blend nanofiber mats had been improved compared with pure nanofibers. Furthermore, the elongation and tensile strength of the blend nanofiber mats were significantly increased compared with pure PVA and pure PU, respectively. And the blend nanofiber mats exhibited well hydrophilicity.  相似文献   

2.
Well-aligned PMIA nanofiber mats were fabricated by electrospinning and then hot-stretching along the fiber axis was used to improve the mechanical properties of nanofibers in this paper. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Differential scanning calorimetry (DSC) were used to characterize the morphology and properties of nanofibers. The results showed that the nanofibers became thinner and better alignment than the as-spun nanofibers after hotstretching, and the average diameter of the nanofibers decreased with the increasing of the tensile force. In the same time, hotstretching improved the crystallinity and T g of the as-spun PMIA nanofibers. The tensile strength and modulus of the hotstretched nanofiber mats peaked at ca.50 % and ca.196 % respectively at the tensile force of 12 N compared with the as-spun nanofiber mats.  相似文献   

3.
Easy fabrication, porosity, good mechanical properties, and composition controllable of the electrospun nanofiber mat make this material a promising candidate for wound dressing applications. In the present study, nylon6/gelatin electrospun nanofiber mats are introduced as novel wound dressing materials. The introduced mats were synthesized by electrospinning of nylon6 and gelatin mixtures, three mats containing different gelatin content were prepared; 10, 20 and 30 wt%. Interestingly, addition of the gelatin did not affect the mechanical properties of the nylon 6, moreover the mat containing 10 wt% gelatin revealed higher mechanical properties due to formation of spider-net like structure from very thin nanofibers (～10 nm diameter) bonding the main nanofibers. Biologically study indicates that gelatin incorporation strongly enhances the bioactivity performance as increasing the gelatin content linearly increases the MC3T3-E1 cell attachment. Overall, the obtained results recommend exploiting the introduced mats as wound dressing material.  相似文献   

4.
In this work, PA-6 core and PMMA shell composite nanofiber mats together with pure PMMA and PA-6 nanofibrous membranes were obtained through electrospinning. Two kinds of transparent composites were fabricated by hot pressing multilayers of the composite nanofiber mats and of the interlaced pure PA-6 with PMMA nanofibrous membranes, respectively, under the same processing condition and with the same amount of PA-6 nanofiber content. Tensile properties and visible light transmittances of the two transparent composites were characterized. It has been found that both the tensile behavior and the visible light transmittance of the composites obtained from the composite nanofiber mats were better than the counterparts from the interlaced pure PA-6 and PMMA nanofibrous membranes. With a minor loss of less than 10 % in the transparency, a maximal increase of around 20 % in the tensile modulus and tensile strength has been recognized for a transparent composite from the composite nanofibers. Although less efficient, the tensile strengths of the composites from the interlaced nanofibrous membranes were all higher than that of a transparent panel processed from the pure PMMA nanofibers.  相似文献   

5.
Poly(vinyl alcohol) (PVA)/zirconium oxide (ZrO2) composite nanofibers with a skin-core structure were prepared and the effect of ZrO2 particle content on uniform web formation was investigated. The optimized polymer concentration, tip to collector distance, and applied voltage for electrospinning were 11 wt%, 12 cm, and 20 kV, respectively. Skin-core PVA/ZrO2 composite nanofibers containing up to 12 wt% ZrO2 were successfully prepared, but it was difficult to obtain PVA/ZrO2 composite nanofiber webs via conventional electrospinning. Increasing the amount of ZrO2 caused the morphology of the PVA/ZrO2 composite nanofibers to become a non-uniform nanoweb with irregular nanofiber diameters. While it was difficult to obtain a uniform nanofiber web containing a content of ZrO2 over 6 wt% for conventional electrospinning, a more uniform nanofiber web could be obtained at up to 9 wt% ZrO2 using a skin-core dual nozzle. More uniform webs could also be obtained when ZrO2 was in the skin rather than the core.  相似文献   

6.
Poly(vinyl alcohol) (PVA)/Ag-zeolite nanofiber webs were prepared with different concentrations of Ag-zeolite nanoparticles by the electrospinning technique. Scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), transmission electron microscopy (TEM), Fourier transform-infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Instron, and antibacterial activities analysis were utilized to characterize the morphology and properties of the PVA/Ag-zeolite nanofiber webs. The study results showed that the polymer concentration, applied voltages and tip-to-collector distances were the main factors influencing the morphology of the electrospun nanofiber webs. The introduction of Ag-zeolite nanoparticles improved the mechanical properties and thermal stability of the PVA nanofiber webs. TEM data demonstrated that the Ag-zeolite nanoparticles were well distributed within the nanofiber. FTIR revealed a possible interaction between the PVA matrix and the Ag-zeolite nanoparticles. These fibers showed an antibacterial efficacy of 99.8 % and over against Staphylococcus aureus and Klebsiella pneumoniae at Ag-zeolite concentrations of 1 % and over, because of the presence of the silver nanoparticles in the zeolite.  相似文献   

7.
The tussah silk fibroin (TSF) nanofibers with 611 nm diameters were prepared by electrospinning with the solvent hexafluoroisopropanol (HFIP). And then, the TSF nanofibers were crosslinked by 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide/N-Hydroxysuccinimide (EDC/NHS) crosslinking agent. The morphology and microstructure of the crosslinked TSF nanofibers were characterized by scanning electron microscopy (SEM), Fourier transforms infrared analysis (FTIR), X-ray diffraction, Instron electronic strength tester, and cell culture. After treatment with EDC/NHS crosslinking agent, the TSF nanofibers swelled and its average diameter increased from 611 to 841 nm. FTIR and X-ray diffraction results demonstrated that random coil, ??-helix, and ??-sheet co-existed in the TSF nanofiber mats, but the content of ??-sheet increased from 25.26 to 45.34 %, and the random coil content decreased from 32.47 to 24.94 %. Compared with the electrospun pure TSF nanofiber mats, the crosslinked TSF nanofiber mats exhibited a lower breaking tenacity and initial modulus, which were 5.51 MPa and 9.86 MPa, respectively. At the same time, the extension at break of the crosslinked TSF nanofiber achieved 109.38 %. In cell culture evaluation, the crosslinked TSF nanofibers were found to support cell adhesion and spreading fibroblast L373 and bone marrow mesenchymal stem cells (BMSCs), which had potential utility in a range of tissue engineering.  相似文献   

8.
The core-sheath nanofibers consisting of polyurethane (PU) core and PU composites sheath with multi-walled carbon nanotubes (MWNTs) were prepared by electrospinning. At low MWNT concentration, MWNTs appeared highly aligned along the fiber axis with some curving in nanotubes, whereas in case of high concentration, some aggregation of MWNTs appeared due to difficulty in full dispersion of nanotubes. In comparison of the single component nanofiber webs, the core-sheath nanofiber webs showed much better mechanical properties of modulus and breaking stress, including an exceptional elongation-at-break. It indicates that the CNT-incorporated core-sheath structure is very effective for enhancing the mechanical properties of nanofiber webs. In addition, the core-sheath nanofibers demonstrated the fast shape recovery, compared with one component fibers of pure shape memory PU and PU/MWNTs, which provides the possibility of fabricating more sensitive intelligent materials.  相似文献   

9.
In the present study, we introduce poly(caprolactone) (PCL) nanofibers that contain hydroxyapatite (HAp) nanoparticles (NPs) as a result of an electrospinning process. A simple method that does not depend on additional foreign chemicals has been employed to synthesize HAp NPs through calcination of bovine bones. Typically, a colloidal gel consisting of PCL/HAp has been electrospun to form nanofibers. Physiochemical aspects of prepared nanofibers were characterized for FE-SEM, TEM, XRD and FTIR which confirmed nanofibers were well-oriented and had good dispersion of HAp NPs. Parameters affecting the utilization of the prepared nanofibers in various nano-biotechnological fields have been studied; for instance, the bioactivity of the produced nanofiber mats was investigated while incubated with stimulated body fluid (SBF). The results from incubation of nanofibers in SBF indicate that incorporation of HAp strongly activates precipitation of the apatite-like materials because the HAp NPs act as seeds that accelerate crystallization of the biological HAp from the utilized SBF.  相似文献   

10.
As a kind of high-performance fibers, PTFE fiber has been widely used in many fields because of its unique characteristics. In this study, the poly(tetrafloroethylene) (PTFE) nanofibers manufactured by electrospinning method was reported. The gel-spinning solution of poly(tetrafluoroethylene)/poly(vinyl alcohol)/boric acid (PTFE/PVA/BA), which was prepared by the gel process of the mixture of PTFE, PVA, BA and redistilled water, was electrospun to form PTFE/PVA/BA composite nanofibers. After calcinating, the PTFE nanofibers with diameters of 200 nm to 1000 nm were obtained. The fibers before and after calcinating were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), FT-IR spectrum analysis and X-ray photoelectron spectroscopy (XPS), respectively, and the mechanical and hydrophobic properties of the fibers were also investigated. The results showed that the PTFE nanofiber membranes could be electrospun effectively used the gel-spinning solution of PTFE/PVA/BA, and may realize the applications in the fields of high-temperature filtration, catalyst supports, battery separator and so on.  相似文献   

11.
Functionalization of cellulosic nanofibers was established to develop antibacterial bandages. The functionalization was conducted through preparation of carboxymethyl cellulose (CMC) containing different metal nanoparticles (MNPs) such as copper nanoparticles (CuNPs), iron nanoparticles (FeNPs) and zinc nanoparticles (ZnNPs). Fourier Transform Infrared spectroscopy was used to characterize CMC containing MNPs and scanning electron microscopy coupled with high energy dispersive X-ray (SEM-EDX) to study the surface morphology of CMC with and without MNPs. Furthermore, back scattering electron detector was used to show the position of metal nanoparticles on the microcrystalline CMC. In addition, UV-visible spectroscopy was used to confirm MNPs formation. Nanofiber mats of CMC containing MNPs were synthesized using electrospinning technique. Surface morphology of electrospun CMC containing MNPs was characterized using SEM. The obtained data revealed that elctrospun CMC nanofibers containing MNPs were smooth and uniformly distributed without bead formation. The average fiber diameters were in the range of 150 to 200 nm and the presence of MNPs in the nanofiber did not affect the size of the electrospun nanofiber diameter. Transmission electron microscopy (TEM) images displayed that MNPs were existed inside and over the surface of the electrospun nanofibers without any agglomeration. The average particle diameters of MNPs were 29-39 nm for ZnNPs, 23-27 nm for CuNPs and 22-26 nm for FeNPs. Moreover, Water uptake of electrospun nanofiber mats and the release of MNPs from nanofibers were evaluated. Nevertheless, electrospun CMC nanofibers containing MNPs had an excellent antibacterial activity against Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus.  相似文献   

12.
Electrically conductive nanofibers were fabricated from elastic polyurethane (PU) and PU/multiwalled carbon nanotubes (MWCNTs) nanocomposite by electrospinning method. The nanocomposites were electrospun at various MWCNTs loading. Electron microscopy was used to investigate nanofibers morphology and dispersion of MWCNTs in the electrospun nanofibers. The results showed that the presence of the MWCNTs promoted the creation of fibrous structures in comparison with the PU without MWCNTs. On the other hand, increasing the MWCNTs content resulted in a slight increase in the average fiber diameter. TEM micrographs and mechanical properties of the electrospun mats indicated that the homogeneous dispersion of MWCNTs throughout PU matrix is responsible for the considerable enhancement of mechanical properties of the nanofiber mats. Electrical behavior of the conductive mats was also studied, in view of possible sensor applications. Cyclic experiments were conducted to establish whether the electrical properties were reversible, which is an important requirement for sensor materials.  相似文献   

13.
This study aims to develop a new approach for fabricating hollow nanofibrous yarns by engineering a triple-layer structure (polyvinyl alcohol (PVA) multifilament core surrounded by a layer of PVA nanofibers and a polylactic acid (PLA) nanofiber outer layer). After fabrication of this 3-layer structure, the core portion was extracted, leaving the outer layer intact after dissolving the PVA nanofibers in water. To determine the optimum thickness of the outer layer, hollow nanofiber yarns with five different thicknesses were produced. A hollow nanofiber yarn was also produced using a common method to enable comparison of the methods. In the common method, a core sheath yarn consisting of a PVA multifilament core and a PLA nanofiber outer layer was fabricated, and a hollow yarn was produced by placing the core yarn in hot water. The results revealed facilitation of core extraction from the yarn body of the new 3-layer structure, which occurred due to rapid dissolution of the middle layer. The wicking behavior in the hollow yarn fabricated using the novel method followed the Locus Washburn equation and that of the hollow yarn produced from the core sheath yarn deviated from it. The results demonstrated that tensile properties of hollow nanofiber yarns were improved by increasing the thickness. Furthermore, hemolysis and cytotoxicity assays indicated that the fabricated hollow nanofibrous structure is non-toxic and blood compatible, indicating its potential for use in biomedical applications such as vascular scaffolds.  相似文献   

14.
We reported the preparation and characterization of the poly(vinyl alcohol) (PVA)/BaSO4 hybrid nanofibers prepared by normal and ultrasonic electrospinning, respectively. Compared to normal electrospinning, BaSO4 particles in the resultant PVA/BaSO4 hybrid nanofibers prepared by ultrasonic electrospinning were well-dispersed without severe agglomerations, as confirmed by scanning electron microscopy (SEM) analysis. X-ray diffraction (XRD) analysis indicated that typical crystalline peaks of PVA and BaSO4 particles were dramatically decreased by ultrasonication during electrospinning. Moreover, the size of BaSO4 aggregates became smaller.  相似文献   

15.
In this study, quantum dots (QDs) having the photophysical properties of brightness, photostability and narrow emission were synthesized. The electrospinning has been introduced to be a simple technique for generating ultrathin fibers. Herein, we have synthesized QDs and electrospun polyvinylacetate (PVAc) nanofibers having these strongly luminescing QDs particles. The size and morphology of QDs were recorded with transmission electron microscopy (TEM). The structural nanofiber webs have been discussed by scanning electron microscopy (SEM). And fluorescence properties of strongly luminescing QDs nanofibers were also discussed.  相似文献   

16.
Aminated polyacrylonitrile (PAN-NH) nanofiber mats prepared by electrospinning and then aminated by multiamines with different chemical structures have been used for the immobilization of palladium. The PAN-NH fiber morphologies were characterized by scanning electron microscopy (SEM) and the dispersion of palladium particles on the PAN-NH fiber were examined by transmission electron microscopy (TEM). The catalytic activity and recyclability of the prepared heterogeneous palladium catalysts have been evaluated by the Heck reaction of iodobenzene with n-butyl acrylate. It was found that the catalytic activities of PAN-NH-Pd catalysts could be correlated with the chelating energies of the PAN-NH fiber mats with Pd active species.  相似文献   

17.
CdTe quantum dot/PVA (poly vinyl alcohol) composite nanofiber was successfully fabricated by eletrospinning process. CdTe quantum dots were uniformly dispersed and stabilized into solid nanofiber structure. Spectrofluorometer analysis revealed whenever Q.D??s enter to the PVA solution, due to the aggregation of Q.D??s red shift happens; however, when blend Q.D-PVA solution changes to nanofiber form via electrospining, this shift phenomenon offsets and original fluorescence properties of Q.D??s does not degraded due to excellent individual dispersion of Q.D in the nanofibers structure. It is also turned out that the proportion of Q.D??s incorporated in the composite solution of electrospining has strong influence on the nanofiber morphology. Addition of Q.D??s to PVA solution causes remarkable changes in the conductivity and solution viscosity, therefore different nanofiber morphologies can be obtained as evidenced by scanning electron microscopy. Furthermore, differential scanning calorimetric (DSC) revealed addition of small amount of Q.D??s to the electrospining solution causes strenuous improvement in crystalinity and heat of nanofiber fusion. Fluorescence and transmission electron microscopy (TEM) measurements confirmed the evenly dispersion of the Q.D??s into nanofibers structures.  相似文献   

18.
In this study, two biodegradable polymers, polycaprolactone (PCL) and polyvinyl alcohol (PVA) were used to fabricate nanofiber nonwovens (NFNs). Also, the silver nanoparticles (AgNPs) successfully reduced by using tea polyphenols (TP) and incorporated in the NFNs via electrospinning. The morphologies of the NFNs and AgNPs were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), respectively. The PCL nanofibers and PVA nanofibers interweaved each other, and AgNPs with average diameter 1.53±0.15 nm were embedded in the PVA nanofibers. The properties of electrospun NFNs were characterized by pore property, swelling/weight loss, water contact angle, mechanical property, and antibacterial activity. The nanofibers cross-linked to each other forming the 3Dnetwork porous structure with diameter about 1-1.5 μm. Although the hydrophobic PCL was added in the hybrid NFNs, the NFNs still showed hydrophilic propriety, high swelling degree (i.e. swelling degree is 330 % for 48 h), and low weight loss (i.e. weight loss is 22.4 % for 48 h). Also, the hybrid PCL/PVA/AgNPs NFNs exhibited a suitable mechanical property for wound dressings (i.e. tensile strength is 4.27 MPa, and breaking elongation is 88 %). Moreover, the hybrid NFNs effectively inhibited growth of Escherichia coli and Staphylococcus aureus. In summary, this PCL/PVA/AgNPs NFNs may provide a promising candidate for accelerating wound healing.  相似文献   

19.
In this study, Sericin/Poly Vinyl Alcohol (PVA)/Clay (Cloisite 30B) nanofibrous mats are prepared by electrospinning technique for antimicrobial air filtration mask. The process parameters of electro-spinning machine such as acceleration voltage, nozzle flow rate and nozzle & collector distance are optimised on the basis of morphology of fibre observed through scanning electron microscopy (SEM). The optimum conditions for producing nanofibrous mat without bead are acceleration voltage 27.5 kV, nozzle collector distance 8 cm and flow rate 0.8 ml/hr using 10 % (w/v) solution of Sericin/PVA (1:1 wt/wt). The process parameters of electro-spinning machine for the processing of Sericin/PVA/Clay nanofibrous mats with varied clay concentrations ranging from 0.1-0.75 % are also optimized. The spun fibre diameter varied from 300-400 nm at different specified conditions. These nanofibrous mats are characterized for its structural, mechanical and antimicrobial properties. Respirable Suspended Particulate Matter (RSPM) test was conducted to check the particulate matter (PM 2.5) absorption capacity of nanofibrous mats. Results shows that sericin/PVA/clay nanofibrous mat would be a promising material for making protecting clothing based air filtration mask.  相似文献   

20.
Electrospinning is a simple and cost-effective method to prepare fiber with nanometer scale. More importantly, 3D flexible nanofiber yarns that fabricated by electrospinning have shown excellent application prospects in smart textiles, wearable sensors, energy storage devices, tissue engineering, and so on. However, current methods for preparing electrospinning nanofiber yarns had some limitations, including low yarn yield and poor yarn structure. In this paper, a stepped airflow-assisted electrospinning method was designed to prepare continuously twisted nanofiber yarn through introducing stepped airflow into traditional electrospinning system. The stepped airflow could not only help to improve nanofiber yield, but also good for controlling the formed nanofibers to be deposited in a small area. In addition, the experimental methods of single factor variables were used to study the effects of stepped airflow pressure, applied voltage, spinning distance, solution flow rate, air pumping volume and friction roller speed on nanofiber yarn yield, nanofiber diameter, yarn twist and mechanical property. The results showed that prepared nanofiber yarns exhibited perfect morphologies and the yield of nanofiber yarn could reach to a maximum of 4.207 g/h. The breaking strength and elongation at break of the prepared yarn could reach to 23.52 MPa and 30.61 %, respectively.  相似文献   

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