首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Application of electrospun nanofibrous scaffolds has received immense attention in tissue engineering. Fabrication of scaffolds with appropriate electrical properties plays a key role in neural tissue engineering. Since fibers orientation in the scaffolds affects the growth and proliferation of the cells, this study aimed to prepare aligned electrospun conductive nanofibers by mixing 1 %, 10 % and 18 % (w/v) doped polyaniline (PANI) with polycaprolactone (PCL)/poly lactic-coglycolic acid (PLGA) (25/75) solution through the electrospinning process. The fibers diameter, hydrophilicity and conductivity were measured. In addition, the shape and proliferation of the nerve cells seeded on fibers were evaluated by MTT cytotoxicity assay and scanning electron microscopy. The results revealed that the conductive nanofibrous scaffolds were appropriate substrates for the attachment and proliferation of nerve cells. The electrical stimulation enhanced neurite outgrowth compared to those PLGA/PCL/PANI scaffolds that were not subjected to electrical stimulation. As polyaniline ratio increases, electric stimulation through nanofibrous PLGA/PCL/PANI scaffolds results in cell proliferation enhancement. However, a raise more than 10 % in polyaniline will result in cell toxicity. It was concluded that conductive scaffolds with appropriate ratio of PANI along with electrical stimulation have potential applications in treatment of spinal cord injuries.  相似文献   

2.
Firstly, the effects of the spinning temperature, spinning voltage, tip-to-collector distance and ambient temperature on the diameter of melt-electrospinning polypropylene (PP) fibers were studied. The results showed that with the increase of the spinning temperature, spinning voltage and tip-to-collector distance, the fiber diameters first decreased and then increased. However, when the ambient temperature increased, the fiber diameters increased gradually. Secondly, based on the previous results, the response surface methodology (RSM) was used to investigate the combined effects of processing parameters on fiber diameters and establish a second-order polynomial equation to predict the fiber diameter. The results showed that the effect order of four factors on fiber diameter was as follows: spinning temperature > tip-to-collector distance > ambient temperature > spinning voltage. Moreover, the fiber diameter predicted by response surface analysis fitted well with the experimental result. Finally, three layer melt-electrospinning PP webs with different fiber diameters were online compounded with conventional non  相似文献   

3.
Electrospinning has been recognized as an efficient technique for the fabrication of neural tissue engineering scaffolds. Many approaches have been developed on material optimization, electrospinning techniques, and physical properties of scaffolds to produce a suitable scaffold for tissue engineering aspects. In this study, structural properties of scaffolds were promoted by controlling the speed of fiber collection without any post-processing. PLGA scaffolds, in two significantly different solution concentrations, were fabricated by the electrospinning process to produce scaffolds with the optimum nerve cell growth in a desired direction. The minimum, intermediate and maximum rate of fiber collection (0.4, 2.4, 4.8 m/s) formed Random, Aligned and Drown-aligned fibers, with various porosities and hydrophilicities. The scaffolds were characterized by fiber diameter, porosity, water contact angle and morphology. Human nerve cells were cultured on fiber substrates for seven days to study the effects of different scaffold structures on cell morphology and proliferation, simultaneously. The results of MTT assay, the morphology of cells and scaffold characterization recommend that the best structure to promote cell direction, morphology and proliferation is accessible in an optimized hydrophilicity and porosity of scaffolds, which was obtained at the collector linear speed of 2.4 m/s.  相似文献   

4.
Atmospheric plasma advantages for mohair fibers in textile applications   总被引：1，自引：0，他引：1  
In this study, mohair fibers were treated by air and argon plasma for modifying some properties of fibers. The fibers were evaluated in terms of their hydrophilicity, grease content, fiber to fiber friction, shrinkage, dyeing, and color fastness properties. The surface morphology was characterized by SEM images. The results showed that the atmospheric plasma has an etching effect and increases the functionality of a wool surface, which is evident from SEM and FTIR-ATR analysis. The hydrophilicity, dyeability, fiber friction coefficient, and shrinkage properties of mohair fibers were improved by atmospheric plasma treatment.  相似文献   

5.
Oxygen plasma pre-treatment was applied to cotton fabric with the aim of improving the water repellency performance of an inorganic-organic hybrid sol-gel perfluoroalkyl-functionalized polysilsesquioxane coating. Cotton fabric was pre-treated with low-pressure oxygen plasma for different treatment times and operating powers. Afterward, 1H,1H,2H,2H-perfluorooctyltriethoxysilane (SiF) was applied to the cotton fabric samples using the pad-dry-cure method. The surfaces of the untreated and modified cotton fibers were characterised using Fourier transform infrared spectroscopy, Xray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The water repellency of the SiF-coated fabric samples was evaluated using static and sliding contact angle measurements with water. The results show that the plasma treatment with the shortest treatment time (10 s) and the lowest operating current (0.3 A) increased the atomic oxygen/carbon ratio of the cotton fiber surface from 0.6 to 0.8 and induced the formation of a nano-sized grainy surface. Increasing the plasma treatment time and/or operating current did not intensify the surface changes of the cotton fibers. Such saturation effects were explained by the large influence of reactive oxygen atoms during the plasma treatment. The measured static water contact angles on the surface of the untreated and plasma pre-treated and SiF-coated cotton fabrics showed that the oxygen plasma pre-treatment enabled the increase of the water contact angle from 135° to ≈150°, regardless of the applied plasma treatment time and discharge power. This improvement in the hydrophobicity of the SiF coating was followed by a decrease in the sliding angle of water droplets by more than 10° compared to the plasma untreated and SiF-coated sample characterized by a water sliding angle of 45°. Additionally, measurements of the water sliding angle revealed that the increase of the static contact angle from 149° to 150° corresponded to a drop of the water sliding angle from 33 to 24°, which suggests that the plasma pre-treatment of 20 s at an operating current of 0.3 A produced the best water-repellent performance of the SiF-coated cotton fabric.  相似文献   

6.
Previous investigation results revealed that after the Low Temperature Plasma (LTP) treatment, the hydrophilicity of wool fiber was improved significantly. Such improvement enhances the wool dyeing and finishing processes which might be due to the changes of the wool surface to a more reactive one. In this paper, wool fibers were treated with LTP with different gases, namely, oxygen, nitrogen and gas mixture (25 % hydrogen/75 % nitrogen). Investigations showed that chemical composition of wool fiber surface varied differently with the different plasma gas used. The surface chemical composition of the different LTP-treated wool fibers was evaluated with different characterization methods, namely FTIR-ATR, XPS and saturated adsorption value. The experimental results were thoroughly discussed.  相似文献   

7.
Melt-electrospinning is an efficient and environmental-friendly technique for producing nano/micro fibers. In this work, the self-layering behavior of poly(ethylene terephthalate)(PET) fiber deposition during melt-electrospinning was investigated based on the electric field simulation analysis by ANSYS and high voltage insulation theory of capacitor for melt-electrospinning configuration. The simulation results demonstrated that during melt-electrospinning process, the electric field strength on the center and lateral surface of the collector changed alternately when some electrically charged jet deposited, making jet depositing location moved around between center and lateral surface, resulted in the formation of the binding fibers separating the inner and outer layers in the deposited PET fiber web. The PET fiber web electrospun in 90 minutes could be laminated freely into thirteen layers. The geometric dimensions of these layers were measured and their morphologies were observed by scanning electron microscopy (SEM). These laminated layers were concentric with almost linearly increasing radius from the inner to the outer. Inner layers featured themselves with appearance of thick center and thin edge, while for outer layers, they presented the appearance of thin center and thick edge. The fibers in the web were quite uniformly and had diameters of about 2 μm.  相似文献   

8.
In recent decades, tremendous research has focused on the production of nanoscale fibers using synthetic polymers, with the goal of fabricating nanofibrous scaffolds for wound healing. However, the hydrophobicity of such polymers typically hinders attachment and proliferation of the cells. In this study, we combined poly-d,l-lactide-co-glycolide (PLGA) and small intestine submucosa (SIS) to fabricate blended nanofibers for wound healing by electrospinning. PLGA and SIS were dissolved in 1,1,1,3,3,3-hexafluoro isopropanol to produce different weight ratios of PLGA/SIS-blended nanofibrous membranes (NFM). Physicochemical characterization of the electrospun NFM was performed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, water contact angle analysis, degradation test and tensile testing. The PLGA/SIS-blended NFM showed improved hydrophilicity and tensile strength. Better infiltration, attachment and proliferation of rat granulation fibroblasts of PLGA/SIS-blended NFMs compared to PLGA NFMs were identified by morphological differences determined by SEM and a water-soluble tetrazolium salt assay kit. Based on our results, the PLGA/SIS blended NFMs were found to be suitable for use as a potential material for wound dressing.  相似文献   

9.
Electrospun fiber scaffolds crafted from polyesters are studied extensively for potential tissue engineering applications. For translation of electrospun fibers into the clinic, the FDA requires analysis and quantification of any organic solvent that may be retained in the fibers since many organic solvents can negatively affect cells and tissues. If a significant amount of solvent is retained, then developing procedures for efficient solvent removal may enhance the clinical potential of these materials. In this study we use fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and nuclear magnetic resonance spectroscopy (NMR) to analyze solvent retention. A correlative analysis shows that both FTIR and TGA accurately predicted retention of two different solvents (HFP and chloroform) in our electrospun PLLA scaffolds, thus validating these procedures. We also assess the efficacy of various fiber treatment methods to facilitate organic solvent removal and conclude that submersion in 70 % ethanol and heat treatment at 100 °C were the most efficient methods of removing solvent from electrospun PLLA fibers.  相似文献   

10.
The complex nature of spinal cord injuries has provided much inspiration for the design of novel biomaterials and scaffolds which are capable of stimulating neural tissue repair strategies. Recently, conductive polymers have gained much attention for improving the nerve regeneration. In our previous study, a three-dimensional (3D) structure with reliable performance was achieved for electrospun scaffolds. The main purpose in the current study is formation of electrical excitable 3D scaffolds by appending polyaniline (PANI) to biocompatible polymers. In this paper, an attempt was made to develop conductive nanofibrous scaffolds, which can simultaneously present both electrical and topographical cues to cells. By using a proper 3D structure, two kinds of conductive scaffolds are compared with a non-conductive scaffold. The 3D nanofibrous core-sheath scaffolds, which are conductive, were prepared with nanorough sheath and aligned core. Two different sheath polymers, including poly(lactic-co-glycolic acid) PLGA and PLGA/PANI, with identical PCL/PANI cores were fabricated. Nanofibers of PCL and PLGA blends with PANI have fiber diameters of 234±60.8 nm and 770±166.6 nm, and conductivity of 3.17×10-5 S/cm and 4.29×10-5 S/cm, respectively. The cell proliferation evaluation of nerve cells on these two conductive scaffolds and previous non-conductive scaffolds (PLGA) indicate that the first conductive scaffold (PCL/ PANI-PLGA) could be more effective for nerve tissue regeneration. Locomotor scores of grafted animals by developed scaffolds showed significant performance of non-conductive 3D scaffolds. Moreover, the animal studies indicated the ability of two new types of conductive scaffolds as spinal cord regeneration candidates.  相似文献   

11.
We investigated the surface modification of jute fiber by oxygen plasma treatments. Jute fibers were treated in different plasma reactors (radio frequency “RF” and low frequency “LF” plasma reactors) using O2 for different plasma powers to increase the interface adhesion between jute fiber and polyester matrix. The influence of various plasma reactors on mechanical properties of jute fiber-reinforced polyester composites was reported. Tensile, flexure, short beam shear tests were used to determine the mechanical properties of the composites. The interlaminar shear strength increased from 11.5 MPa for the untreated jute fiber/polyester composite to 19.8 and 26.3 MPa for LF and RF oxygen plasma treated jute fiber/polyester composites, respectively. O2 plasma treatment also improved the tensile and flexural strengths of jute fiber/ polyester composites for both plasma systems. It is clear that O2 plasma treatment of jute fibers by using RF plasma system instead of using LF plasma system brings about greater improvement on the mechanical properties of jute/polyester composites.  相似文献   

12.
The effect of atmospheric pressure plasma treatment on wettability and dyeability of polysulfonamide (PSA) yarns and aging behavior were investigated. The helium and helium/oxygen plasma-treated PSA yarns were stored for different time varying from 10 to 60 days at the condition of 25 °C and 65 % relative humidity. The water absorption time and K/S value were used to determine the wettability and dyeability of polysulfonamide yarns before and after plasma treatment. The changes in surface morphology and chemical composition were analyzed by Scanning Electron Microscope (SEM) and X-ray Photoelectron Spectroscopy (XPS). The plasma treatments resulted in the decrease in water absorption time and the increase in K/S value, especially for the helium/oxygen plasma-treated PSA yarns dyed with cationic dyestuff. SEM observation confirmed that the PSA fiber surface was roughed and XPS analysis showed that the polar groups on PSA fiber surface increased after the plasma treatments. As plasma treatment time increased and oxygen gas was added, a greater degree of etching was achieved and more polar groups such as hydroxyl and carboxyl groups produced on PSA fiber surface, contributing to a better wettability and thus a better dyeability of the yarns. Almost no apparent aging effect was observed within 10 days. And then with the increasing storage time, the water absorption time and K/S value firstly quickly and then slowly increased and decreased. However, after 30 days, almost no aging effect was observed. The atmospheric pressure plasma treatment had no obviously influence on tensile strength of PSA yarns.  相似文献   

13.
Chemical treatment of natural fibers is a well-defined means of mechanical property improvement in natural fiberreinforced composites. An understanding of mechanical and thermal properties in these media is essential for evaluating heat transfer, thermal degradation, and overall performance of these composites over their product lifetime. However, very little information is available illustrating the effect of such treatment on the thermal properties of kenaf composites. Also, no study to date has reported the thermal conductivity of individual kenaf fibers. This study reports the effects of fiber treatment (in 6 % NaOH) on thermal transport in unidirectionally oriented kenaf-epoxy composites and individual kenaf fibers. The effective thermal conductivities and thermal diffusivities of chemically treated fiber composites show a general increase over untreated fiber composites (0.210 to 0.232 W/m/K at 28 °C, 0.206 to 0.234 W/m/K at 200 °C). This improvement may be attributed to improved interfacial contact between the fibers and epoxy matrix shown in microstructural images after chemical treatment. The thermal conductivity of individual fibers was evaluated at room temperature using two techniques. Results from both techniques showed slight increases after chemical treatment (0.58±0.53 to 1.0±0.13 W/m/K and 1.2±0.54 to 1.6±0.28 W/m/K) but lacked statistical significance. Any improvement in surface crystallinity after chemical treatment does not appear to affect overall fiber thermal conductivity. A better understanding of thermal transport in kenaf fibers and composites enables better estimation of the performance of these composites in different applications. Moreover, the thermal conductivities of individual fibers are useful in understanding the fiber’s contribution to conduction in different fiber reinforcement configurations.  相似文献   

14.
We report the preparation of polybenzoxazole (PBO) fiber from polyhydroxyamide (PHA) precursor fiber which is free from strong acid such as polyphosphoric acid. We prepared the PHA fibers with different spin-draw ratios (SDRs) using a wet-spinning method and the PBO fibers with an SDR of 3.5 (SDR-3.5 PBO fibers) were prepared by various heat-treatment temperatures, and investigated their morphology, crystalline structure, and mechanical properties. The simultaneous thermogravimetric analysis-mass spectrometry (STA-MS) and field-emission scanning electron microscopy (FE-SEM) results confirmed that the diameter of the SDR-3.5 PBO fiber was much smaller than that of the SDR-3.5 PHA fiber, due to the release of water during the thermal cyclization reaction which forms the PBO structure. The wide-angle Xray diffraction (WAXD) pattern of the SDR-3.5 PBO fiber heat-treated at 350 °C (SDR-3.5 PBO 350 fiber) showed two peaks, at 2θ=14.83 ° and 24.38 °, and the diffraction angles dropped with increasing heat-treatment temperature. In addition, the initial modulus and tensile strength of the SDR-3.5 PBO fiber heat-treated at 550 °C (SDR-3.5 PBO 550 fiber) were found to be 19.1 GPa and 449.2 MPa, which were much higher than those of the SDR-3.5 PHA fiber, 9.3 GPa and 227.0 MPa, respectively.  相似文献   

15.
The surface treatment of high modulus poly(p-phenylene-2,6-benzobisoxazole) (HMPBO) fibers was performed by using a solution of polyphosphoric acid (PPA)/absolute alcohol (EtOH) (1:1, vol:vol) under ultrasonic vibration. The chemical compositions, crystallinity, and surface morphologies of HMPBO fibers were characterized by contact angles, XRD, XPS, TGA, and SEM. Results showed that the hydrophilicity of treated HMPBO fibers was improved, and the contact angles between treated HMPBO fibers and water were decreased. The treated HMPBO fibers exhibited the slight reduction in the single fiber pull-out strength and crystallinity.  相似文献   

16.
Produced via electrospinning, polyurethane (PU) scaffolds have always attracted the interest of medical applications due of their unique properties such as good adhesion, biocompatibility and excellent mechanical strength. However, the poor hydrophilicity and hemocompatibility of PU presented a problem during PU’s application in the manufacturing of biomedical materials. We hypothesized that the incorporation of polyethylene glycol (PEG) and phosphatidylcholine (PC) into electrospinning solution of PU could improve the cell affinity and hemocompatibility. This research focused on fabricating hybrid PU-PEG and PU-PC random/aligned scaffolds through electrospinning technique and comparing their properties as a potential biocompatible scaffold for vascular tissue engineering. PC was doped into a PU solution in order to prepare an electrospun scaffold through the electrospinning technology while crosslinked electrospun PUPEG hybrid scaffolds were fabricated by photoinduced polymerization. The contact angle dramatically decreased from 122.3±0.8° to 39.1±0.8° with doping of PC in electrospinning solution while it decreased from 122.3±0.8° to 41.6±0.8° with doping of PEG. Furthermore, the mechanical properties of PU scaffolds were altered significantly by the addition of PC. The hemolysis and cytocompatibility assays demonstrated that these composite scaffolds could potentially be used as a smalldiameter vascular graft.  相似文献   

17.
The object of this work is to develop a flame-retardant viscose fiber containing phosphazene derivative. Hexaphenoxycyclotriphosphazene (HPTP) was synthesized and applied to viscose fiber through wet spinning method, with alkyl polysaccharide glycoside as dispersant. Properties of the fiber were tested and discussed. All flame-retardant samples survived 3 ignitions, according to 45 degree slope burning method. Limiting oxygen index value of the flame-retardant fiber containing 16% flame retardant was 28.6 %. The number decreased to 27.5 % after 30 washing cycles. After burning, inflated carbonized coat was found on the fiber surface in scanning electron microscopy image. Thermal gravimetric analysis and differential scanning calorimetry results indicated that the primary decomposition of fiber was moved up by about 20°C, while secondary decomposition was delayed by around 46°C. Damage on mechanical properties of fibers was insignificant. The introduction of HPTP was compatible and the flame retardancy of viscose fiber was greatly improved with limited negative impact.  相似文献   

18.
Polyacrylonitrile (PAN) precursor fibers were modified for different periods of time using hydrogen peroxide aqueous solution. A variety of tests were employed to characterize the fibers. The modification could induce cyclization and oxidation in the precursor fibers, as reflected by the changes in length and diameter of the fibers, and the results of Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Compared with the unmodified fiber, the modified fibers released less heat during a heating process similar to stabilization of PAN precursor fiber. Also, the modified fibers showed lower characteristic temperatures on differential scanning calorimetry (DSC) thermograms, and lower onset temperature of weight loss on thermal gravimetry (TG) curves. The modified fibers had more surface defects and hence exhibited lower tenacity and tensile modulus. Compared with the unmodified fibers, however, the modified fibers had smoother surface and fewer defects after stabilization. The strain decreased with increasing temperature under a constant tension for all the fibers. At the temperatures above 200 °C, the shrinkage of the fibers decreased with the increase of modification time, because a certain degree of cyclization and oxidation occurred in modified fibers, making them shrink less in the temperature range equivalent to stabilization.  相似文献   

19.
Plant fiber reinforced thermoplastic composites have gained much attraction in structural applications such as building and automotive products. Agricultural residues such as wheat straw, bagasse, and corn stover can also be exploited as readily available natural fiber resources for similar applications. The objective of this study was to extract fibers from wheat straw and also to determine the usefulness of fungal retting of wheat straw before extracting the fibers. Wheat straw was mechanically defibrillated using a laboratory-scale mechanical refiner before and after fungal retting. Fiber characteristics such as physico-chemical and mechanical properties, surface characteristics, and thermal properties of the resultant fibers were measured in order to explore the possibilities of using the fibers as reinforcing materials. Retted fibers were stronger than un-retted fibers. The length and diameter of the retted fibers were lower than the un-retted fibers. FT-IR spectroscopic analysis of the wheat straw fibers indicated the fractional removal of hemicelluloses and lignin from the retted fiber. X-ray photoelectron spectroscopy (XPS) of the fibers showed the partial removal of extractives from the surface of the retted fibers. Also, the oxygen to carbon ratio (O/C) of the fibers illustrated that there is more lignin type surface structure for both retted and un-retted fibers. However, slightly higher ratio of oxygen to carbon in the retted fiber indicated a more carbohydrate-rich fiber than the un-retted fiber. Thermal degradation characteristics demonstrated the suitability of processing wheat straw fibers with thermoplastics.  相似文献   

20.
Plasma treatment is a kind of environmentally friendly surface modification technology, which has been widely used to modify various materials in many industries. Plasma treatment improves the fiber-matrix adhesion largely by roughening the surface of fibers to increase mechanical interlocking between the fiber and the matrix. For this aim, the effect of atmospheric air plasma treatment on jute fabrics has been discussed in this study. The plasma treatment has been employed at different powers and time intervals. The effects of plasma treatment on fiber properties were revealed by wickability, surface roughness, fiber tensile test and pull-out tests. The effect of plasma treatment on functional groups of jute fibers was observed by attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR). Scanning electron microscopy (SEM) images showed the etching effect of plasma treatment on the surface. It can be concluded that plasma treatment is an effective method to improve the surface and mechanical properties of jute fabrics to be used for composite materials.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号