The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Gareth R. Williams - One of the best experts on this subject based on the ideXlab platform.
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electrospinning using a teflon coated Spinneret
Applied Surface Science, 2013Co-Authors: Qian Xiang, Deng-guang Yu, Gareth R. WilliamsAbstract:Abstract In this paper, we report for the first time the use of a Teflon-coated Spinneret for electrospinning processes. Polyvinylpyrrolidone (PVP) and zein were explored as filament-forming polymers, and electrospinning undertaken using both Teflon-coated tubing and traditional stainless steel tubing as Spinnerets. Scanning electron microscope observations demonstrated that both the PVP and zein nanofibers produced using the Teflon-coated Spinneret are narrower than those from the stainless steel equivalent. Electrospinning using a Teflon-coated Spinneret resulted in smaller interfacial drawing forces counteracting the electrical forces on the spinning fluids. The Teflon-coated material thus takes advantage of the electrical forces more efficaciously than the steel analog. A molecular mechanism rationalizing the influence of the Spinneret surface on electrospinning is proposed.
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Electrospinning using a Teflon-coated Spinneret
Applied Surface Science, 2013Co-Authors: Qian Xiang, Yong Mei Ma, Miao Jin, Deng-guang Yu, Gareth R. WilliamsAbstract:In this paper, we report for the first time the use of a Teflon-coated Spinneret for electrospinning processes. Polyvinylpyrrolidone (PVP) and zein were explored as filament-forming polymers, and electrospinning undertaken using both Teflon-coated tubing and traditional stainless steel tubing as Spinnerets. Scanning electron microscope observations demonstrated that both the PVP and zein nanofibers produced using the Teflon-coated Spinneret are narrower than those from the stainless steel equivalent. Electrospinning using a Teflon-coated Spinneret resulted in smaller interfacial drawing forces counteracting the electrical forces on the spinning fluids. The Teflon-coated material thus takes advantage of the electrical forces more efficaciously than the steel analog. A molecular mechanism rationalizing the influence of the Spinneret surface on electrospinning is proposed. © 2013 Elsevier B.V. All rights reserved.
Deng-guang Yu - One of the best experts on this subject based on the ideXlab platform.
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Electrospun acetaminophen-loaded cellulose acetate nanofibers fabricated using an epoxy-coated Spinneret
E-polymers, 2015Co-Authors: Xia Wang, Xiaoyan Li, Ying Li, Deng-guang YuAbstract:AbstractThis paper reports the investigation about the usage of an epoxy (EP)-coated Spinneret for the preparation of medicated electrospun nanofibers. Cellulose acetate (CA) and acetaminophen (APAP) were used as the polymeric carrier and model drug, respectively. The electrospinning was undertaken using both EP-coated Spinneret and traditional stainless steel capillary as Spinnerets. According to the images from scanning electron microscopy, it is obvious that the nanofibers produced using the EP-coated Spinneret had a finer diameter and a narrower size distribution (450±90 nm) than nanofibers fabricated using stainless steel equivalent (660±180 nm). In vitro dissolution tests revealed that the sustained-release profiles of nanofibers from the EP-coated Spinneret were superior to those of their stainless steel equivalents, although APAP existed in a similar amorphous state in both nanofibers. Because the EP-coated material can exploit the electrical forces more effectively than its steel analogue, it can enhance the electrospinning technique for producing polymeric functional nanofibers.
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higher quality quercetin sustained release ethyl cellulose nanofibers fabricated using a Spinneret with a teflon nozzle
Colloids and Surfaces B: Biointerfaces, 2014Co-Authors: Chen Li, Zhuanhua Wang, Deng-guang YuAbstract:Abstract This study investigates the usage of a Spinneret with a Teflon nozzle for fabrication of higher quality drug sustained-release electrospun nanofibers. Ethyl cellulose (EC) and quercetin were used as a filament-forming polymer matrix and an active pharmaceutical ingredient, respectively. The electrospinning was conducted using both a traditional stainless steel Spinneret and a Spinneret with a Teflon nozzle. Experimental results demonstrated that a Teflon-fluid interface at the Spinneret's nozzle provided a better performance for implementing electrospinning than a traditional metal-fluid interface in the following aspects: (1) keeping more electrical energy on the working fluids for an efficacious process; (2) exerting less negative effect on the fluid to draw it back to the tube; and (3) making less possibility of clogging. The resulted nanofibers from the Spinneret with a Teflon nozzle exhibited higher quality than those from the traditional Spinneret in those: (1) smaller diameter and narrower distribution, 520 ± 70 nm for the former and 750 ± 280 nm for the later, as indicated by the field emission scanning electron microscopic images; and (2) better sustained-release profiles of quercetin from the former than the latter, as demonstrated by the in vitro dissolution tests. The new protocols about usage of Teflon as a Spinneret's nozzle and the related knowledge disclosed here should promote the preparation and application of electrospun functional nanofibers.
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electrospinning using a teflon coated Spinneret
Applied Surface Science, 2013Co-Authors: Qian Xiang, Deng-guang Yu, Gareth R. WilliamsAbstract:Abstract In this paper, we report for the first time the use of a Teflon-coated Spinneret for electrospinning processes. Polyvinylpyrrolidone (PVP) and zein were explored as filament-forming polymers, and electrospinning undertaken using both Teflon-coated tubing and traditional stainless steel tubing as Spinnerets. Scanning electron microscope observations demonstrated that both the PVP and zein nanofibers produced using the Teflon-coated Spinneret are narrower than those from the stainless steel equivalent. Electrospinning using a Teflon-coated Spinneret resulted in smaller interfacial drawing forces counteracting the electrical forces on the spinning fluids. The Teflon-coated material thus takes advantage of the electrical forces more efficaciously than the steel analog. A molecular mechanism rationalizing the influence of the Spinneret surface on electrospinning is proposed.
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Ketoprofen/ethyl Cellulose Nanofibers Fabricated Using an Epoxy-coated Spinneret
2013Co-Authors: Xiaoyan Li, Deng-guang Yu, Cai-tao Fu, Rui Wang, Xia WangAbstract:The present study investigates the preparation of sustained release drug-loaded nanofibers using a novel epoxy-coated Spinneret. With ethyl cellulose (EC) and ketoprofen (KET) as the filament-forming matrix and the active pharmaceutical ingredient, Drug-loaded composite nanofibers are generated smoothly and continuously with few user interventions. Field-emission scanning electron microscopic observations demonstrated that the composite nanofibers prepared using the epoxy-coated Spinneret have better quality than those from a traditional stainless steel Spinneret in terms of diameter and its distribution. Both of the composite nanofibers are in essential a molecular solid dispersion of EC and KET based on the hydrogen bonding between them, as verified by XRD and ATR-FTIR results. In vitro dissolution tests show that the nanofibers resulted from the new Spinneret provide a finer sustained KET release profile than their counter-parts. Epoxy-coated Spinneret is a useful tool to facilitate the electrospinning process through the prevention of clogging for generating high quality nanofibers.
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Electrospinning using a Teflon-coated Spinneret
Applied Surface Science, 2013Co-Authors: Qian Xiang, Yong Mei Ma, Miao Jin, Deng-guang Yu, Gareth R. WilliamsAbstract:In this paper, we report for the first time the use of a Teflon-coated Spinneret for electrospinning processes. Polyvinylpyrrolidone (PVP) and zein were explored as filament-forming polymers, and electrospinning undertaken using both Teflon-coated tubing and traditional stainless steel tubing as Spinnerets. Scanning electron microscope observations demonstrated that both the PVP and zein nanofibers produced using the Teflon-coated Spinneret are narrower than those from the stainless steel equivalent. Electrospinning using a Teflon-coated Spinneret resulted in smaller interfacial drawing forces counteracting the electrical forces on the spinning fluids. The Teflon-coated material thus takes advantage of the electrical forces more efficaciously than the steel analog. A molecular mechanism rationalizing the influence of the Spinneret surface on electrospinning is proposed. © 2013 Elsevier B.V. All rights reserved.
Chong Chang Yang - One of the best experts on this subject based on the ideXlab platform.
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The Study of Surface Smooth Finish of Spinneret Hole Bottom Manufactured by Drills of Different Materials
Advances in Mechanical and Electronic Engineering, 2020Co-Authors: Chong Chang YangAbstract:The resistance of the melts in spinning can be reduced by improving the surface finish of Spinnerets, avoiding eddy current and decreasing the frequency of lousiness and breaking of fibers, to improve efficiency in the production of the finished product and quality. High-speed steel and carbide drill have a significant impact on the surface smooth of Spinnerets considering their carbon content and other alloy elements and their own texture multiphase. According to the three chosen materials, this paper analyzes and compares the differences in the surface finish of Spinneret hole bottom though mechanical engineering experiments and draws the conclusion that the best way to get smooth surface finish is processed by carbide drill, and the higher the spindle rotation speed of the tool, the better the surface finish.
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Study and Design on the Automatic Drying Machine of Spinneret
Advanced Materials Research, 2014Co-Authors: Dong Wang, Yang Zhou, Chong Chang YangAbstract:This paper introduced Spinneret cleaning technology. Aiming at the probles of noisy, low-efficiency, high-intensity, artificial drying in actual Spinneret drying process of the factory, the process of Spinneret automatic drying is studied and an automatic Spinneret drying machine is designed. An experiment is conducted on the prototype of the machine, which shows that the work efficiency has increased dramatically and the noise has decreased obviously.
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The Development of the Automatic Cleaning Machine for Spinneret Orifice
Advanced Materials Research, 2014Co-Authors: Xiao Dong Fu, Pei Feng, Chong Chang YangAbstract:The automatic cleaning requirements of Spinneret orifices were analyzed. The three-dimensional positioning system for Spinneret orifices cleaning, combining the XY horizontal motion platform and Z axis electric translational platform, was determined. The cleaning device of Spinneret orifices was designed. The control system of automatic cleaning for Spinneret orifices was developed based on Labview and the experimental analysis of the prototype was done in this paper.
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Research on Automatic Single-Station Shoveling Spinneret Machine
Applied Mechanics and Materials, 2014Co-Authors: Xiao Dong Fu, Chong Chang YangAbstract:The automatic cleaning technology of melt spinning process status was introduced in this paper. The problem was analyzed that the cleaning efficiency of manual cleaning is unstable using the previous shoveling Spinneret. A new automatic cleaning device was developed called automatic shoveling Spinneret machine and the operating principle of the automatic shoveling Spinneret machine is described. The machine can replace manual cleaning through a company's test.
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The Study on the Automatic Drying Machine of Spinneret Based on PLC Control Technology
Applied Mechanics and Materials, 2013Co-Authors: Hui Fu, Qian Cheng Zhao, Chong Chang YangAbstract:Spinneret cleaning technology is introduced in this paper. For the status of the actual production of low-efficiency, high-intensity artificial drying of the Spinneret, an automatic drying process of Spinneret is studied and an automatic drying machine of Spinneret is studied based on PLC control technology. An experiment is conducted for the prototype of the automatic drying machine of Spinneret. The experiment shows that the work efficiency of the drying machine is more than 3 times of the artificial drying and working a low noise environment is achieved.
Qian Xiang - One of the best experts on this subject based on the ideXlab platform.
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electrospinning using a teflon coated Spinneret
Applied Surface Science, 2013Co-Authors: Qian Xiang, Deng-guang Yu, Gareth R. WilliamsAbstract:Abstract In this paper, we report for the first time the use of a Teflon-coated Spinneret for electrospinning processes. Polyvinylpyrrolidone (PVP) and zein were explored as filament-forming polymers, and electrospinning undertaken using both Teflon-coated tubing and traditional stainless steel tubing as Spinnerets. Scanning electron microscope observations demonstrated that both the PVP and zein nanofibers produced using the Teflon-coated Spinneret are narrower than those from the stainless steel equivalent. Electrospinning using a Teflon-coated Spinneret resulted in smaller interfacial drawing forces counteracting the electrical forces on the spinning fluids. The Teflon-coated material thus takes advantage of the electrical forces more efficaciously than the steel analog. A molecular mechanism rationalizing the influence of the Spinneret surface on electrospinning is proposed.
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Electrospinning using a Teflon-coated Spinneret
Applied Surface Science, 2013Co-Authors: Qian Xiang, Yong Mei Ma, Miao Jin, Deng-guang Yu, Gareth R. WilliamsAbstract:In this paper, we report for the first time the use of a Teflon-coated Spinneret for electrospinning processes. Polyvinylpyrrolidone (PVP) and zein were explored as filament-forming polymers, and electrospinning undertaken using both Teflon-coated tubing and traditional stainless steel tubing as Spinnerets. Scanning electron microscope observations demonstrated that both the PVP and zein nanofibers produced using the Teflon-coated Spinneret are narrower than those from the stainless steel equivalent. Electrospinning using a Teflon-coated Spinneret resulted in smaller interfacial drawing forces counteracting the electrical forces on the spinning fluids. The Teflon-coated material thus takes advantage of the electrical forces more efficaciously than the steel analog. A molecular mechanism rationalizing the influence of the Spinneret surface on electrospinning is proposed. © 2013 Elsevier B.V. All rights reserved.
Taishung Chung - One of the best experts on this subject based on the ideXlab platform.
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elimination of die swell and instability in hollow fiber spinning process of hyperbranched polyethersulfone hpes via novel Spinneret designs and precise spinning conditions
Chemical Engineering Journal, 2010Co-Authors: Natalia Widjojo, Taishung Chung, Davis Yohanes Arifin, Martin Weber, Volker WarzelhanAbstract:Abstract This study has successfully demonstrated that a proper combination of novel Spinneret designs and spinning parameters can effectively counteract the die swell as well as flow instability phenomena, i.e. extrudate distortion, in the hyperbranched polyethersulfone (HPES) hollow fiber spinning. Attempts are also made to unravel the die swell and flow behavior differences between HPES and linear polyethersulfone (LPES) membranes spun using various Spinneret designs and spinning conditions. In terms of flow stability, it is revealed that short conical Spinnerets with a flow angle of 60° as well as short round flow channel Spinneret with a flow angle of 30°, can reduce or eliminate extrudate distortions. Apart from Spinneret designs, this study also accentuates the importance of a proper choice of spinning conditions for each specific Spinneret to achieve flow stability and reduce die swell, namely: (1) bore fluid composition; (2) dope flow rate; (3) spinning temperature; and (4) take-up speed. Experimental results concluded that a proper combination of Spinneret design and these four spinning parameters is the key to stabilize the spinning process. It is found that a high take-up speed spinning and a high non-solvent concentration in the bore fluid can fully eliminate die swell and enhance flow stability in the HPES hollow fiber spinning using short and conical or round Spinnerets.
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the effects of Spinneret dimension and hollow fiber dimension on gas separation performance of ultra thin defect free torlon hollow fiber membranes
Journal of Membrane Science, 2008Co-Authors: Na Peng, Taishung ChungAbstract:Abstract A defect-free as-spun hollow fiber membrane with an ultra-thin dense-selective layer is the most desirable configuration in gas separation because it may potentially eliminate post-treatments such as silicone rubber costing, simplify membrane manufacture, and reduce production costs. However, the formation of defect-free as-spun hollow fiber membranes with an ultra-thin dense-selective layer is an extremely challenging task because of the complexity of phase inversion process during the hollow fiber fabrication and the trade-off between the formation of an ultra-thin dense-selective layer and the generation of defects. We have for the first time successfully produced defect-free as-spun Torlon ® hollow fiber membranes with an ultra-thin dense layer of around 540 A from only a one polymer/one solvent binary system at reasonable take-up speeds of 10–50 m/min. The best O 2 /N 2 permselectivity achieved is much higher than the intrinsic value of Torlon ® dense films. This is also a pioneering work systematically studying the effects of Spinneret dimension and hollow fiber dimension on gas separation performance. Several interesting and important phenomena have been discovered and never been reported: (1) as the Spinneret dimension increases, a higher elongation draw ratio is required to produce defect-free hollow fiber membranes; (2) the bigger the Spinneret dimension, the higher the selectivity; (3) the bigger the Spinneret dimension, the thinner the dense-selective layer. Mechanisms to explain the above observation have been elaborated. The keys to produce hollow fiber with enhanced permselectivity are to (1) remove die swell effects, (2) achieve finer monodisperse interstitial chain space at the dense-selective layer by an optimal draw ratio, and (3) control membrane formation by varying Spinneret dimension.
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the effects of flow angle and shear rate within the Spinneret on the separation performance of poly ethersulfone pes ultrafiltration hollow fiber membranes
Journal of Membrane Science, 2004Co-Authors: Kai Yu Wang, Takeshi Matsuura, Taishung ChungAbstract:The effects of dope flow rate and flow angle within a Spinneret during spinning hollow fiber membranes on the morphology, water permeability and separation performance of poly(ethersulfone) ultrafiltration hollow fiber membranes were investigated. For this purpose, two Spinnerets with different flow angles were designed and used. The dope solution, containing polyethersulphone (PES)/N-methyl-2-pyrrolidone (NMP)/diethylene glycol (DG) with a weight ratio of 23/41/36, which was very close to its cloud point (binodal line), was used in order to speed up the coagulation of nascent fibers so that the relaxation effect on molecular orientation was reduced. The wet-spinning process was purposely chosen to fabricate the hollow fibers without extra drawing. Therefore, the effects of gravity and elongation stress on fiber formation could be significantly reduced and the orientation induced by shear stress within the Spinneret could be frozen into the wet-spun fibers. Experimental results suggest that higher dope flow rates (shear rates) in the Spinneret produce UF hollow fiber membranes with smaller pore sizes and denser skin layers due to the enhanced molecular orientation. Hence, the pore size and the water permeability decrease, but the solute separation increases. Hollow fibers spun from a conical Spinneret have smaller mean pore sizes with larger geometric standard deviations, thus exhibiting lower water flux and greater solute separation than hollow fibers spun from a traditional straight Spinneret. In addition, SEM studies indicate macrovoids response differently for the 90° straight and 60° conical Spinnerets when increasing the dope flow rate. Macrovoids can be significantly suppressed and almost disappear in the 90° Spinneret at high dope flow rates. This phenomenon cannot be observed for the 60° conic Spinneret.
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effect of shear stress within the Spinneret on hollow fiber membrane morphology and separation performance
Industrial & Engineering Chemistry Research, 1998Co-Authors: Taishung Chung, Soo Khean Teoh, M P SrinivasanAbstract:The effects of shear stress and shear experience within a Spinneret during hollow fiber spinning on membrane morphology, gas separation performance, and thermal and mechanical properties have been experimentally determined. We purposely spun the hollow fibers using a wet phase inversion process and water as the external coagulant with the belief that the effect of gravity (elongational stress) on fiber formation can be significantly reduced and the orientation induced by shear stress within the Spinneret can be frozen into the wet-spun fibers. In addition, we chose 80/20 NMP/H2O as the bore fluid with a constant bore fluid to dope fluid flow rate ratio in order to minimize the complicated coupling effects of elongational stresses, uneven internal and external solvent exchange rates, and substructure resistance on fiber formation and separation performance. Asymmetric hollow fibers for gas separation were spun from a 37% poly(ether sulfone) (PES)/N-methyl-2-pyrrolidone (NMP) dope solution using a Spinneret...
