共查询到20条相似文献，搜索用时 31 毫秒
1.
Mahbube Sadat Musavi Jad Seyed Abdolkarim Hosseini Ravandi Hossein Tavanai Razieh Hashemi Sanatgar 《Fibers and Polymers》2011,12(6):801-807
The aim of this paper is to investigate vertical wicking in polyacrylonitrile (PAN) electrospinning nanofiber yarn using image
analysis. Colored liquid rising phenomenon into the yarn and the distance of liquid rise were determined as a function of
time. The kinetics of capillary rise follows the Lucas-Washburn equation. The results show that capillary rise rate coefficient
is being reduced with increasing yarn twist, due to the reduction of continuity and size of capillaries. Increasing heat treatment
stretch from 0 % (draw ratio=1) to 50 % (draw ratio=1.5) increases the capillary rise rate coefficient, due to the more homogeneity
of capillary spaces in the yarn structure and increasing heat treatment stretch from 50 to 100 % (draw ratio=2) reduces capillary
rise rate coefficient, because of the low capillary length. The present study indicates that an appropriate choice in production
parameters of nanofiber yarn is all important in obtaining the desired properties of capillary rise. 相似文献
2.
The moisture transport expressed with wicking is one of the most important aspects in clothing science and strongly effects on the quality of clothes. Wicking is a spontaneous transport of liquid driven into a porous system by capillary forces. Furthermore, the packing density has a direct relation with the yarn structure. At the present work, the effects of yarn count and twist factor on the wicking height and packing density of lyocell ring-spun yarns was investigated. Achieving the objectives of this research, an image processing method was developed to determine the packing density of samples. Experimental results were also used to develop a regression model to predict the wicking height based on the packing density, yarn count, twist factor and rising time. The results demonstrated that the correlation coefficient between the predicted and measured wicking height was 0.98 indicating the capability of the presented model to predict the wicking height of lyocell ring-spun yarns. 相似文献
3.
In this paper, the capillary rise method was applied to evaluate the wicking property of polyester filament yarns. Effects
of twist, monofil cross sectional shape and texturing on the wicking height were discussed in details. The results indicated
that with the increase of twist level, the wicking height ascends until reaching the maximum height, and then descends. It
is also observed that under the same twist level, the wicking height of the five-leaf low-stretch yarn is the largest among
all those three kinds of yarns, and then is that of the conventional low-stretch yarn. The wicking height of the parallel-drawn
yarn is the smallest. 相似文献
4.
In this study, various concentrations of polyethylene terephthalate (PET) polymeric solution were investigated to produce hollow nanofiber yarn. First, the electrospining apparatus was designed in a way that to put PVA multifilament in the core and to twist PET nanofibers onto multifilament yarn as a sheath simultaneously, followed by dissolving PVA yarn in hot water, PET hollow nanofiber yarn was produced. In this survey, it has been observed that the average thickness of sheath increased by increasing concentrations of PET polymeric solution. Results showed that maximum efficiency of extracting the PVA multifilament from the hollow yarn under certain conditions (concentration of 18 % (w/v) of PET, applied voltage of 10 kV, and flow rate of 0.0526 ml/h) was more than 85 %. The mechanical and physical properties of PET hollow yarns were investigated and indicated that the hollow nanofiber yarns at concentration of 30 % and 18 % polymeric solution had the lowest strength and the highest regain moisture, respectively. 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.
The present paper reports the interaction effect of yarn twist, yarn count and number of plies on wicking behaviour of plied
cotton yarn. A three-variable factorial design technique proposed by Box & Behnken was used to investigate the combined interaction
effect of the above variables. Both the vertical as well as horizontal wicking experiments were carried out with liquids of
varying surface tensions, like distilled water, saline water and petrol. Each wick samples were subjected to nine different
types of wicking related tests. The yarn count and number of plies in the cotton wick was found to play major role in wicking
related properties, whereas the effect of twist in plied cotton wick was not that prominent when the twist per unit length
of single and plied yarns were the same and in opposite direction. The rate of vertical wicking for saline water was found
to be significantly lower than that of distilled water. The rate of horizontal wicking for distilled water was less than that
of vertical wicking of distilled water. Use two or three parallel strands instead of one resulted in marked increase of vertical
wicking. 相似文献
7.
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
8.
The formation of a symmetric electrospinning triangle zone (E-triangle) via a technique based on using two oppositely charged
nozzles is described for fabricating continuous twisted nanofiber yarn of polyamide (Nylon 66). This study shows how changing
the dimensions and geometry of the E-triangle influences the distribution of nanofiber tension and diameter in this zone,
and consequently how it affects the nanofiber yarn strength. The twist effect on the E-triangle geometry was investigated
by changing the rotational speed of the twister plate of values of 96, 160, 224 and 288 rpm. The results showed that by increasing
the twist rate, the apex angle of the E-triangle increased, whereas the height and width of the Etriangle decreased. An energy
method was adopted to study the distribution of tension on nanofibers in the E-triangle. Considering a constant spinning tension,
it was observed that the gradient of the nanofiber tension curve was steeper and the extreme values of tension on nanofibers
were increased by increasing the twist rate. Furthermore, the mean diameter reduction of nanofibers confirmed these results.
It is concluded that mechanical properties of nanofiber yarn have been considerably improved by increasing the twist rate
and changing the shape of the E-triangle. 相似文献
9.
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
10.
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
11.
12.
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
13.
This work describes a novel method for preparing electro-conductive rotor yarns by in situ oxidative chemical polymerization of pyrrole. The effects of different process parameters on electrical resistivity of the yarn were studied by using Box-Behnken response surface design. The concentration of monomer, polymerization time and polymerization temperature were found to influence the electrical resistivity of the yarn. It was observed that electrical resistivity of the yarn increased linearly with increase of measuring length of it. Whereas the effects of yarn twist and tensile strain found to had negative correlation with electrical resistivity of electro-conductive rotor yarns. Microscopic image analysis showed that there was uniform distribution of PPy polymer on the surface of cotton fibres and FTIR analysis depicted possible chemical interaction between polypyrrole and cellulose. 相似文献
14.
Mine Akgun 《Fibers and Polymers》2014,15(2):405-413
The effects of some yarn properties (i.e. type, count, twist level, ply number, unevenness and crimp) and fabric constructional properties (i.e. cover, thickness and balance) on surface roughness values of cotton woven fabrics were investigated. A general overview of the results showed that surface roughness values of fabrics were affected from yarn and fabric properties and the effects were related to fabric balance, fabric cover (not cover factor), fabric thickness and crimp values of yarns in fabric structures. Surface roughness values of fabrics decreased as yarn fineness and yarn twist levels increased but as yarn ply number decreased. Also, surface roughness values gradually decreased from open-end yarn constituting fabrics to combed yarn constituting fabrics. Results showed that different properties of yarns caused changes in yarn crimps in fabric structure and also governed the changes in fabric balance, as well as changes in roughness of fabric surfaces. The changing properties of yarns and impact of these properties on fabric construction affected the formation of cotton fabric surfaces from smooth to coarse. 相似文献
15.
Electric field plays a key role in electrospinning process for nanofiber and nanofiber yarn producing. The electric field distribution of the yarn manufacturing system is simulated by using finite element method analysis. The effects of electric field distribution and intensity were studied to analyze the influence of the electric field on the electrospun nanofiber yarn surface morphology, mechanical, thermal and water absorption properties. The results show that the morphology and diameters of nanofiber and yarn were obviously affected by the electric field with changing the needle distance and applied voltage, which further influence the mechanical performance of the yarn. The needle distance does not much affect the thermal property of the PSA electrospun yarn, whereas the yarn obtains better thermal resistance properties at voltage of 25 kV. The nanoyarn electrospun and assembled under higher applied voltage is proved to have a better wicking property in our research. 相似文献
16.
The quality of ring spun yarns is largely determined by its level of hairiness. The existence of hairiness inevitably affects
the quality of ring spun yarns. This paper presents an innovative method on lowering the level of hairiness of ring spun yarns.
This can be achieved by shooting compressed air to the yarn, through a swirl nozzle comprising a yarn duct and an airjet nozzle
attached to a traditional ring spin frame. When compressed air is applied from the air-jet nozzle to the yarn duct, the swirling
air flow tucks surface fibers of the ring spun yarns into its body. Four controllable variable parameters for the process,
supplied pressure, nozzle position, twist factor and spindle speed, and their effects on the lowering of yarn hairiness will
be clarified. Their impact on the quality of the yarn is statistically analyzed, and the optimum outcome of the combination
of parameters for the process, will thus be determined. 相似文献
17.
Yarn tension is a key factor that affects the efficiency of a ring spinning system. In this paper, a specially constructed
rig, which can rotate a yarn at a high speed without inserting any real twist into the yarn, was used to simulate a ring spinning
process. Yarn tension was measured at the guide-eye during the simulated spinning of different yarns at various balloon heights
and with varying yarn length in the balloon. The effect of balloon shape, yarn hairiness and thickness, and yarn rotating
speed, on the measured yarn tension, was examined. The results indicate that the collapse of balloon shape from single loop
to double loop, or from double loop to triple etc, lead to sudden reduction in yarn tension. Under otherwise identical conditions,
a longer length of yarn in the balloon gives a lower yarn tension at the guide-eye. In addition, thicker yarns and/or more
hairy yarns generate a higher tension in the yarn, due to the increased air drag acting on the thicker or more hairy yarns. 相似文献
18.
Spandex has been successfully applied on modified worsted spinning system to produce spandex core spun yarn. However it’s
difficult to produce wool/spandex core-spun yarn on woolen spinning system with the same modified device because the drafting
device of the two systems is quite different. A new method is introduced to apply spandex on woolen spinning system in this
paper. Core-spun yarn produced in this way has good appearance and quality by comparing with normal yarn. A series of experiments
were carried out to study the influence of spandex drafting ratio and yarn twist factor on tensile properties and elasticity
of core-spun yarns. The results indicate that core-spun yarn with spandex drawing ratio of 2.5 and twist factor of 13.63 has
highest value of tenacity and breaking elongation. 相似文献
19.
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
20.
In this study artificial neural network (ANN) models have been designed to predict the ring cotton yarn properties from the
fiber properties measured on HVI (high volume instrument) system and the performance of ANN models have been compared with
our previous statistical models based on regression analysis. Yarn count, twist and roving properties were selected as input
variables as they give significant influence on yarn properties. In experimental part, a total of 180 cotton ring spun yarns
were produced using 15 different blends. The four yarn counts and three twist multipliers were chosen within the range of
Ne 20–35 and α
e 3.8–4.6 respectively. After measuring yarn tenacity and breaking elongation, evaluations of data were performed by using
ANN. Afterwards, sensitivity analysis results and coefficient of multiple determination (R2) values of ANN and regression models were compared. Our results show that ANN is more powerful tool than the regression models. 相似文献