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1.
Seyedeh Nooshin Banitaba Golchehr Amini Ali Akbar Gharehaghaji Ali Asghar Asgharian Jeddi 《Fibers and Polymers》2017,18(12):2342-2348
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
2.
Jianxin He Yuman Zhou Kun Qi Lidan Wang Pingping Li Shizhong Cui 《Fibers and Polymers》2013,14(11):1857-1863
In order to fabricate continuously twisted nanofiber yarns, double conjugate electrospinning had been developed using two pairs of oppositely charged electrospinning nozzles. The principle and process of this novel yarn spinning method were analyzed, and the effect of applied voltage, nozzle distance between positive and negative, solution flow rate and funnel rotating speed on the diameters, twist level and mechanical properties of resultant PAN nanofiber yarns were investigated in this paper. The results indicated that electrospun nanofibers aggregated stably and bundled continuously at the applied voltage of 18 kV, the nozzle distance of 17.5 cm between positive and negative, the overall flow rate of 3.2 ml/h and the flow ratio of 5/3 for positive and negative nozzles. The resultant nanofiber yarns had favorable orientation and uniform twist distribution, and the twist level of nanofiber yarns increased with the increase of the ratio of funnel rotating speed and winding speed. The diameters and mechanical properties of nanofiber yarns depended on their twist level. The diameters of prepared PAN nanofiber yarns ranged from 50 µm to 200 µm, and the strength and elongation of PAN nanofiber yarns at break were 55.70 MPa and 41.31%, respectively, at the twist angle of 41.8 °. This method can be also used to produce multifunctional composite yarns with two or more components. 相似文献
3.
Yuman Zhou Hongbo Wang Jianxin He Kun Qi Bin Ding Shizhong Cui 《Fibers and Polymers》2018,19(10):2169-2177
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
4.
This study examined the effects of the total porosity, pore size, and cover factor on the moisture and thermal permeability of woven fabrics made from DTY (draw textured yarns) and ATY (air jet textured yarns) composite yarns with hollow PET (polyethylene terephthalate) yarns. The wicking of the hollow composite yarn fabrics was found to be superior to that of the high twisted yarn fabrics, which may be due to the high porosity in the hollow composites yarns, but this was not related to the cover factor. The drying characteristics of the hollow composite yarn fabric with high porosity were inferior compared to the high twisted yarn fabrics due to the large amounts of liquid water in the large pores, which resulted in a longer drying time of the fabric. The thermal conductivity of the hollow composite yarn fabrics decreased with increasing measured pore diameter due to the bulky yarn structure. The effects of the hollowness of the yarn on the thermal conductivity were more dominant than those of the yarn structural parameters. The air permeability increased with increasing measured pore diameter but the effects of the cover factor on the air permeability were not observed in the hollow composite yarn fabrics. The effects of porosity on the moisture and thermal permeability of the woven fabrics made from the hollow composite filaments were found to be critical, i.e., wicking and air permeability increase with increasing porosity. In addition, the drying rate increased with increasing porosity and the thermal conductivity decreased with increasing pore diameter, but were independent of the cover factor. 相似文献
5.
Jianxin He Yuman Zhou Lidan Wang Rangtong Liu Kun Qi Shizhong Cui 《Fibers and Polymers》2014,15(10):2061-2065
Continuously twisted polyacrylonitrile/viscose nanofiber core-spun yarns were fabricated through novel self-designed multi-nozzle air jet electrospinning set-up. The effect of voltage, solution flow rate, air flow rate and funnel rotating speed on coating rate of core-spun yarn, nanofiber diameter, twist level and mechanical property were discussed. The results showed that polyacrylonitrile/viscose nanofiber core-spun yarns with perfect nanofiber orientation and uniform twist distribution could be obtained at voltage of 32 KV, solution flow rate of 32 ml/min and air flow rate of 1000 ml/min, and the spinning speed could reach to 235.5 cm/min. The diameters of outer coated nanofiber distributed from 100 nm to 300 nm, and nanofiber coating rate could reach to 70.4 %. In addition, the strength and elongation at break increased from 30.82 MPa to 69.65 MPa and from 28.34 % to 43.29 % at the twist angle of 46.6 °, respectively. 相似文献
6.
Core spun yarns are applied for various purposes that especially require the multi-functional performance. This research reports
on the core spinning effect on the yarn strength. We prepared various core yarns by combining different kinds of high tenacity
filaments in core with cotton staples in sheath with various twist levels in the ring spin system. And the tensile strength
was tested to investigate the contribution of the core-sheath structure to the core yarn strength. The influence of the twist
level was also checked up on the relationship between the core-sheath structure and the yarn strength. Results turned out
that the core-sheath weight ratio had influence on the tensile properties of the ring core-spun yarns in different ways according
to the core filaments used for the yarn. Increasing the twists yielded a monotone decreasing strength for the aramid and the
basalt core yarns, while the PET core yarns showed almost unchanged strength, which could be ascribed to the extensional property
of the filaments. 相似文献
7.
The present paper reports the impact of thermal treatment on the characteristics of core-sheath type hybrid technical yarns.
The core-sheath type hybrid yarns are prepared using DREF-III technology. Polyester and glass multifilaments are used as core
components whereas the cotton and polyester staple fibers are the sheath components wrapped around the core filament with
different proportions to form a hybrid structure. The thermal treatment is carried out both in dry and in wet state under
relaxed condition and the thermal shrinkage, sheath-slipping resistance and tensile and bending properties of hybrid yarns
have been studied. Thermal treatment markedly increases the thermal shrinkage and sheath-slipping resistance of hybrid yarns
with polyester multifilament in core, but insignificant effect for yarns with glass multifilament in core. Breaking elongation
of hybrid yarns with polyester multifilament in core increases with treatment temperature. The hybrid yarns with glass multifilament
in core are least affected by thermal treatment. 相似文献
8.
The effect of spinning parameters on core-spun yarns properties manufactured using three-strand modified method (TSMM) was analyzed. Of the various spinning parameters, strand spacing, yarn linear density and yarn twist have a crucial effect on core-spun yarn properties. To achieve the objectives of this research, general physical properties of core-spun yarns together with existing standards were thoroughly studied. First of all, the strand spacing and yarn linear density were optimized. Afterwards, the effects of variation of yarn twist and sheath roving linear density on core-spun yarns properties were investigated. Finally, the physical and mechanical properties of TSMM yarns were compared with those of siro and conventional ring core-spun yarns counterparts. It was found that, the best strand spacing and yarn linear density to produce core-spun yarns are 8 mm and 45 tex, respectively. Results showed that, tenacity of TSMM yarns increases up to a certain twist level beyond which it reduces. The result confirmed that 45 tex yarns produced by three rovings of the same count are superior with regards to tenacity and hairiness. The optimized yarns produced by three-strand modified method enjoy superior physical and mechanical properties in comparison to the ring and siro core-spun yarns. 相似文献
9.
F. Hajiani A. A. Ghareaghaji Ali. A. A. Jeddi S. H. Amirshahi F. Mazaheri 《Fibers and Polymers》2014,15(9):1966-1976
In view of the interest in wicking properties of these flexible structures, analysis of the wicking phenomena in nylon 6.6 nanofiber yarns is carried out by considering the twist rate effects. A novel method is used based on adding a pH-sensitive dye to yarn interstructure and the analysis of color alteration of nanofiber yarn structure, resulting from a shift in pH, during the capillary rise of distilled water. The results show that the addition of pH- sensitive dye has no influence on the average nanofiber diameter and the wicking behavior of yarns. This study shows that in short durations, the kinetic of the capillary rise follows the Lucas-Washburn equation. The Lambertw, a mathematical function, has been incorporated, which helps measure an equivalent structural factor of nanofiber yarns and vertical wicking height at any given time considering the gravitational effects. The statistical results show that the average of equilibrium wicking height and capillary rise rate coefficient tend to decrease with increasing the nanofiber yarn twist, due to the reduction of continuity and size of capillaries. 相似文献
10.
In the present study the influence of the deformation mode, of the specimen elongation deformation, of the fabrics?? weave type, of fabrics?? direction and of the position of seam allowances in respect to the stitching line on the seam slippage in the raw plain, twill and combined-twill weave fabrics was investigated. Fabrics were woven with the warp yarn of 20×2 tex 70 % cotton and 30 % PES blended 2-ply spun yarn and the weft yarn of 18 tex 100 % PES folded multifilament yarn using jacquard weaving machine ??Lindaucer DORNER GmbH??. Seam slippage of the investigated woven fabrics was determined using the new simple and compact technical device suitable to test fabrics for seam slippage property within five different deformation modes: an uniaxial tension of seams with opened seam allowances on the surface of metal table; an uniaxial tension of seams with bent to one side allowances in respect to stitching line on the surface of the metal table; an unrestricted uniaxial tension of seams; a bagging of seams with bent to one side allowances in respect to the stitching line using the plastic hollow cylinder; a bagging of seams with opened seam allowances using the plastic hollow cylinder. The results of the research had proved that seam slippage of the investigated woven fabrics was dependent on the deformation mode, on the elongation of sewn specimens, on the location of allowances in respect to the stitching line, on the fabric weave type as well as on the woven fabric direction. 相似文献
11.
F. Dabirian S. A. Hosseini Ravandi R. Hashemi Sanatgar J. P. Hinestroza 《Fibers and Polymers》2011,12(5):610-615
The development of a modified method to produce heat treated twisted nanofibrous yarns using two oppositely metallic spinnerets
system is presented. This method allows the production of more uniform, stronger twisted poly acrylonitrile (PAN) yarns. The
novelty of this system permits for in-situ heat treating of the nanofiber yarns. The average diameter of twisted nanofiber
yarns is 340.65 μm with 5.8 CV%. The values of the initial modulus and stress of heat treated yarns increase from 1.90 GPa
and 61.30 MPa in untreated one to 4.51 GPa and 116.56 MPa, respectively. In order to quantify the alignment of the nanofibers
Fourier power spectrum (FPS) and image analysis were used. So the treated yarn shows more degree of nanofiber alignments than
the untreated one. 相似文献
12.
A computational approach is proposed for the mechanical analysis of the multifilament twisted yarn based on the Finite Element
Method (FEM). The physical and the geometrical properties of the filaments and the ideal yarn geometrical structure are considered
for the mechanical modelling. The tensile and bending deformations of yarns are simulated for the prediction of the respective
properties and the computation of the deformed shape. Considerable complexity appears in the mechanical analysis of fibre
assemblies, including the structural multiformity, the material nonlinearity and the large deformation effects occurring.
The FEM applying the beam theory enhanced with advanced solution algorithms approved appropriate for the analysis. Besides
the comparison to an existing analytical model, a set of experimental data derived from 2- to 1200-filament twisted yarns
is used for the evaluation of the accuracy of the proposed approach. The effect of the major structural parameters as the
filament radius and the yarn twist in the elastic properties and the bending rigidity is also examined. 相似文献
13.
Young Seok Koo 《Fibers and Polymers》2001,2(3):148-152
Cotton yarns were coated with a polymer solution to hold surface fibers to the yarn body, which caused fiber-fly generation
during knitting process. The physical property of the coated yarn, especially a bending rigidity was investigated in order
to evaluate the performance of the coated yarn during knitting. SEM images showing the surface condition of the coated yarn
demonstrated that the thickness of a coating material increased as the concentration of the coating solution increased. The
results of the bending rigidity measured using KES-FB2 system showed that the bending rigidity of the coated yarn increased
as the concentration of the coating solution increased. The results also revealed the possibility that yarn coated with a
low amount of coating material should be employed for further research of reducing fiber-fly generation during knitting process. 相似文献
14.
Farzaneh Rouhollahi Seyed Abdolkarim Hosseini Farzaneh Alihosseini Alireza Allafchian Fatemeh Haghighat 《Fibers and Polymers》2018,19(10):2056-2065
Polyglycolic acid-poly lactic glycolic acid (PGA-PLGA) electrospun nanofibers containing silver nanoparticles have been produced and twisted into the nanofibrous yarn. The morphology of nanofibers and produced yarns, as well as the mechanical properties of the yarns, were investigated. Furthermore, in vitro antibacterial properties and in vitro degradation behavior of yarns containing various silver nanoparticles were studied. SEM images confirmed that the addition of the silver nanoparticles into the polymer solution increases the fiber diameters. The result of the mechanical test of the yarns alone and used in two different forms of the knots was measured and results showed that the strength of the yarns without the knot was significantly more than that of others. The biodegradability test showed that the mechanical properties and the weight of the yarns were quickly reduced after subjecting to in vitro condition. The result of the antibacterial test indicated that the nanofiber yarns containing %3 silver nanoparticles were the most appropriate sample with a considerably antibacterial activity against both gram-positive bacterium Staphylococcus aureus and gram-negative bacterium Escherichia Coli with inhibition zones of 8.1 and 9.5 mm, respectively; which demonstrated that silver nanoparticles retained their effectiveness after the electrospinning process. Therefore the nanofibrous yarns containing silver nanoparticles could be successfully produced by the electrospinning process with the proper antibacterial property as a candidate for the surgical sutures. 相似文献
15.
This paper is aiming to develop high shrinkable differential shrinkage and mixed fibre nylon composite yarns by applying the
high shrinkable polyester manufacturing technology. The wet and dry thermal shrinkages and mechanical properties of developed
nylon composite yarns are measured and discussed with processing factors in the spinning and texturing processes. And the
effects of the processing factors on the physical properties of high shrinkable nylon composite yarns are investigated. For
this purpose, twenty seven nylon 30d/12f SDY were prepared with variation of spinning temperature, 2nd godet roller temperature
and draw ratio on the spinning machine. The optimum spinning condition which showed maximum wet thermal shrinkage and stress
was determined and high shrinkable nylon 30d/12f SDY spun under this optimum condition used as a core and three kinds of regular
nylon filaments used as sheath were processed on the texturing machine with variation of 1st and 2nd heater temperatures.
The optimum texturing process condition was decided through analysis of dry thermal shrinkage of these core and sheath nylon
filaments. Finally, high shrinkable differential shrinkage and mixed fibre nylon composite yarns were made under the optimum
texturing condition on the texturing machine, its wet thermal shrinkage was 13.8 %, which was much more higher than that of
regular nylon composite yarns. The differential shrinkage effect of the developed nylon composite yarns was found in the yarn
surface and cross section profiles by microscope and SEM. 相似文献
16.
Polyvinyl chloride (PVC) fibers were melt-spun to prepare mono and multifilament yarns. To find optimum spinning and drawing
conditions, various parameters such as spinning temperature, spinneret diameter, drawing temperature, and drawing ratio were
examined. From the observation of the spinnability under various conditions, we found that the optimum conditions were as
following: the extrusion temperature and die temperature were 175–180°C and 185–190°C, and the drawing temperature and drawing
ratio were 85–95°C and 3.4, respectively. Under these conditions, the spinneret diameter could be reduced to the minimum value,
0.5 mm. Spun PVC filament yarns were subjected to the different yarn texturing process of stuffing box and pin false-twist
method. The PVC yarn fabric was prepared by the knitting of textured yarns. Finally, the anion-emission and antibiotic properties
of the knitted PVC fabrics were precisely evaluated. 相似文献
17.
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
18.
Matin Mahmoudifard Ahmad Mousavi Shoushtari Afshin Mohsenifar 《Fibers and Polymers》2012,13(8):1031-1036
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
19.
The current research discusses the efforts to achieve a Poly(lactide-co-glycolide)(PLGA) nanofiber yarn using two differently charged nozzles with potential application as surgery suture. First, electrospinning parameters such as solution concentration, applied voltage, feed rate were optimized to produce yarn with smooth nanofibers. In order to improve the properties of produced suture, heat setting setup was developed. Two heat setting techniques, including hot water and dry heat were applied, and the influence of the heat setting process on the mechanical properties of yarn was studied. The results showed that heat setting with boiling water was the best method. At first strength, E-modulus and extension of prepared suture were 36.6 MPa, 0.9 GPa and 68.8 % respectively. After improvement with heat setting, strength and E-modulus increased to 63.7 MPa, 2.7 GPa respectively and extension decreased to 29.7 %. Finally, in order to analyze knot performance, two types of surgical knot (square and surgeon) were used, and mechanical properties were investigated. The presence of knot lessens mechanical properties for each two type. Square knot showed better mechanical properties than surgeon’s knot. With square knot strength, E-modulus and extension were 62.1 MPa, 2.1 GPa, 28.6 %, respectively. In vitro study of nanofiber yarn degradation behavior showed that the mechanical properties were decreased. This could be due to greater surface area of nanofibers exposed to surrounding environment. 相似文献
20.
Hyun Jin Koo Gap Shik Chang Seong Hun Kim Wan Gyu Hahm Seong Yoon Park 《Fibers and Polymers》2013,14(12):2083-2087
Mechanical properties and the long-term degradation properties of the recycled PET yarns are typically lower than the virgin PET yarns due to the contaminants coming from non-PET bottles, labels and caps etc. For environmental reasons, recycling of post-consumer polyester bottles into textile fibers has become commercially attractive. We studied mechanical and chemical recycling processes and examined their effects on yarn properties such as tensile properties, thermal characteristics, hydrolysis and photo-degradation. It was found that the virgin and the chemical recycled yarns with sufficient purification show similar processability, physical and mechanical properties, and long-term degradation behavior. The results provide useful information on recycled PET yarns for processability and serviceability for the high-end use. 相似文献