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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Textile Science and Engineering
Journal Basic Information
Journal DOI :
The Korean Fiber Society
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Volume & Issues
Volume 41, Issue 6 - Dec 2004
Volume 41, Issue 5 - Oct 2004
Volume 41, Issue 4 - Aug 2004
Volume 41, Issue 3 - Jun 2004
Volume 41, Issue 2 - Apr 2004
Volume 41, Issue 1 - Feb 2004
Selecting the target year
Dynamic Characteristics of a Steady State Bundle Flow
Huh You ; Kim Jong Seong ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 387~393
Drawing is a mechanical operation that changes the material thickness by using the speed difference between the feeding and delivery devices. When the material is in the form of a bundle or bundles made of staple fibers, this attenuation operation is called 'bundle drawing' or g'draftingg'. Drafting is being used widely in manufacturing staple yarns, which is indispensable for the textile industry. However, the bundle processed by this operation has more or less defects in the evenness of linear density. Such irregularities cause many problems not only for the product quality but also for the efficiency of the successive processes. In this research, a mathematical model for the dynamic behavior of the bundle fluid is set up on the basis of general physical laws using physical variables, i.e. linear density and velocity in the dynamic state of the bundle processing. The conservation of mass and the momentum are applied, while the movement of individual material is taken into account. The constitutive model relating the surface force to the deformation of bundle is given, considering a representative bundle movement. Then, a fundamental equation system is simplified in a steady state, which could delineate the characteristics of the process dynamics. On the basis of the simplified model, simulation is performed, and the results are confirmed by experiments. This study shows that the bundle fluid, in drafting operation, can have a jerk at the exit, when the model parameters representing inter-fiber friction and velocity variance of constituent fibers are adjusted to the experimental results. Even at low draft ratios, the bundle can break, if the parameters are not maintained adequately by controlling the process conditions.
Influence of the Groove Angle of Draft Roll Cylinder on the Irregularity of Ring Spun Yarn
Huh You ; Kwack Do Woong ; Kim Jong Seong ; Kim Seung Hoon ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 394~399
In the textile industry, new staple yam manufacturing systems are aiming at higher production rate and better product quality. Most of all, many recent researches are focused on improving the yam qualities by introducing new accessory devices which lead to finer and more uniform staple yam, in which the working principle is to diminish the loss of staples in forms of edge fibers at the spinning triangle. This paper deals with developing a new method that can produce more uniform yams, while using the conventional ring-spinning method. The leading ends of the staples on the same line of the front roll cylinder are grasped by the draft rolls with a certain phase difference in nipping time, to which we refer as the nipping time delay method. The nipping time delay is realized by introducing grooved front roll cylinders with various groove angles. Then, we identify the effect of the new method on the yam irregularity and also try to find the optimum condition for minimizing the yam irregularity. Experimental results confirm that the groove angle of the front roll cylinder influences the output yam uniformity and yam hairiness. There also exists an angle range between 7 to 10 degrees that minimizes the yam irregularity
Fine Structure Formation and Physical Properties of Poly(butylene terephthalate) Fibers in High Speed Melt Spinning
Lee Sun Hee ; Cho Hyun Hok ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 400~406
The effect of take-up velocity on the fine structure and properties of PBT fibers are investigated using WAXD, density, birefringence, DSC, dynamic viscoelasticity, TMA, tensile test, etc. An increase in take-up velocity caused an increase in both the density and the birefringence. In the results of WAXD equatorial profiles, the increase in the take-up velocities resulted in the formation of (010) and (100) reflections of
and the reflection peak became sharper at the take-up velocity of 6 km/min. The initial modulus of the fiber increased when the g' fraction increased, the tenacity depended more on fractions of
, i.e. the total crystallinity. The thermal properties of high speed spun PBT fibers were measured with DSC, dynamic viscoelasticity, TMA, etc. Endothermic curves became sharper with increasing take-up velocities, and endothermic melting peaks are shifted to high temperatures. Therefore, crystal structure was well developed in the fiber obtained at high take-up velocities. The
peak is shifted and the intensity is decreased with temperature. That is, the packing density of the PBT fiber is high when the take-up velocity and orientation of amorphous region is increased. The shrinkage has a tendency to decrease with increasing take-up velocity.
Physical and Thermal Properties of Polyvinylchloride Fiber Blended with Chlorinated Polyvinylchloride
Kim Hwan Chul ; Kim Jong Chun ; Sung Baek Man ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 407~412
Thermal and mechanical properties of CPVC(chlorinated PVC) are better than those of PVC. CPVC was blended with PVC to increase properties of PVC fiber. Blending ratio of CPVC was changed and thermal, rheological and mechanical properties were investigated in this study. Thermal stability and melt viscosity increased with increase in CPVC content. Fiber was spun by melt spinning method and drawn using heat plate. Tenacity increased and elongation decreased with increase in CPVC content. Heat shrinkage decreased with increase in CPVC content and heat treating temperature. Onset temperature of DSC endotherm peak corresponded to the treated heat temperature.
Effect of Spinning Conditions on the Fiberweb Properties of Acrylics during Electrospinning
Shim Hyun Joo ; Lee Seung Hoon ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 413~418
The electro-spinning conditions, such as, concentration of polymer solution, electric potential, die to collector distance(DCD), electric conductivity of collector, and additives on the change of fiberweb structure and fiber diameter, have been investigated. The results showed that the electric potential and die to collector distance affect the fiber diameter and the fiberweb uniformity. The difference of the electric conductivity of collector and the additives did not affect the fiber diameter, however, the uniformity of the fiberweb was significantly affected. The optimum spinning conditions for the electrospinning of polyacrylonitrile were found as follows; the electrical potential should be in the range of 25 to 30 kV, the DCD 15 cm, and the concentration of polymer solution should be between 12 to
The Rheological Properties of the Solutions of PVDF in DMAc for Electrospinning
Ji Byoung Hwa ; Kim Byoung Chul ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 419~423
The solutions of polyvinylidene fluoride (PVDF) in dimethyl acetamide (DMAc) were rheologically investigated. In the dilute concentration regime, the solutions gave values of Huggins constant lower than 0.52, which decreased with increasing temperature. This suggests that DMAc is a good solvent and the solvating power is increased with increasing temperature. The solutions exhibited an inflection point on the log-log plot of
. Further, the slope was slightly decreased with increasing temperature from 10 to
. At high concentrations, the solutions did not show lower Newtonian flow region. Further, raising temperature from 10 to
increased viscosity and yield stress of the solutions. Increasing concentration had the same effect on the rheological properties as increasing temperature. Relaxation time
increased as the concentration and temperature increased.
A Study on Characterization of Nonwoven Mats via Electrospinning under Vacuum
Kim Hyung-jun ; Jung Yoon-ho ; Khil Myung-seob ; Kim Hak-yong ; Bang Ho-Ju ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 424~432
The exploitation of technologies based on electro spinning have been limited due to poor understanding of the process and consequent limitation in process control, productivity and reproducibility. To control the effect of the environmental parameter, which is one of important electro spinning parameters, the vacuum process was introduced because the magnitude of electric field in vacuum is not limited by the low dielectric breakdown strength of air. For this study, PCL dissolved in a mixture of N,N-dimethylformamide (DMF) and methylene chloride (MC) was electrospun as a form of nonwoven mats consisting of nano-sized fibers under vacuum and they have been analyzed using SEM and DSC. The PCL nonwoven mats via electrospinning under vacuum showed the characteristic spinning behavior observed at atmospheric pressure. In addition, results obtained from tensile test showed that PCL nonwoven mats via electrospinning under vacuum have better mechanical properties than those prepared at atmospheric pressure.
Filtration Characteristics of Poly(Acrylonitrile-co-Methylacrylate) Electrospun Web
Jeong Se Kwan ; Lim Dae Young ; Byun Sung Won ; Chung Yong Sik ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 433~439
Non-woven fabrics of electrospun fibers show larger specific surface area and much smaller pore size than conventional ones, which make them excellent candidates for filtration media and membrane applications. Electrospinning combines the charging of polymer and the spinning of the fibers as an one-step process. We made the filter media from poly(acrylonitrile-co-methylacrylate) via electrospinning and evaluated the filtration characteristics. The filtration efficiency and the pressure loss increased with higher level of applied voltage, collector speed, and calendering pressure. This resulted from the decrease of pore diameter. Especially, the increase in basis weight of the web can improve the filtration efficiency without rapid pressure loss.
Characterization of Nano-fiber Webs' Pore Structure Using a Morphological Image Processing
Kim Jooyong ; Lee Jung Hae ; Lim Dae Young ; Byun Sung Won ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 440~445
An image processing algorithm has been developed in order to anlyze the nanofiber web images from a high magnification microscope. It has been known that precise pore detection of thick webs is extremely difficult mainly due to lack of light uniformity, difficulty of fine focusing and translucency of nanofiber web. The serial morphological image processing techniques of edge detection, dilation, opening, skeletonization and dilation have been applied to images for accurate pore detection followed by connect-component labeling for computing mean pore size and standard deviation of pore sizes. The pore detection algorithm developed has been found to show excellent performance in characterizing the porous structure, thus being a promising tool for the on-line quality control of eletrospun fiber manufacturing.
Derivation of Covariance-Length Function for Nonwoven Uniformity(I) -1- D Signal Case-
Kim Jooyong ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 446~450
A method is introduced for deriving the 'covariance length curve (Cov-L)' from the existing variance length curve. Some critical information hidden in existing variance length curve will be revealed through the Cov-L derived. It includes the correlation between any arbitrary measurement lengths, which is not readily available from the variance length curve but that is critical. Correlation functions of arbitrary measurement lengths are derived directly from the variance length curve given without requiring any further information. Use of the correlation functions has more advantages over the traditional V-L curves. First, they represent a yarn diameter (or mass) profile both in scale (resolution) and frequency (periodicity) rather than in scale only which is the case for V-L curves. Second, periodicities hidden in seemingly irregular signals are easily detected and revealed by the correlation functions. It is also beneficiary that the functions are readily available from a V-L curve without further efforts for measurement and analysis.
Changes in the Thermal Properties of PTT/PET Melt Blends with Melting Time
Kim Young Ho ; Pang Kyeong ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 451~457
Melt blends of poly(trimethylene terephthalate) (PTT) and poly(ethylene terephthalate) (PET) of various ratios were prepared by mixing at
for different times using twin screw type internal mixer, and their thermal properties were investigated by DSC, DMA and NMR spectroscopy. With increase in mixing time at
, the two melting peaks of PTT/PET blends, corresponding to the melting of PTT and PET, merged to one peak and moved to lower temperatures, while the crystallization temperature moved to higher temperatures. DMA analysis indicated a single glass transition temperature for the PTT/PET melt blends of various compositions prepared by mixing at
for 5 minutes, indicating that the blends are completely miscible in the amorphous region. The transesterification reaction in the PTT/PET melt blends was confirmed bi NMR spectroscopic analysis. Degree of randomness and sequence length of the blends were calculated by using
data. The former increased while the latter decreased as the melt mixing time increased.
Physical Properties of Nylon 6-PEO Copolymer/MMT Nanocomposites via in situ Polymerization
Kim Taeck Hyun ; Lee Jong Soon ; Kim Kap Jin ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 458~466
To improve the impact strength of nylon 6 at low temperature, poly(ethylene oxide) unit was incorporated into nylon 6 main chain. This method, however, was accompanied with some unavoidable problems such as the drastic decrease in modulus and breaking strength and highly increased elongation at break. To resolve these problems, we obtained the nylon 6-PEO copolymer/montmorillonite nanocomposites chips from thein situ polymerization of
in the presence of 12-aminododecanoic acid intercalated montmorillonite using poly(ethylene oxide) diamine as a soft segment and 6-aminocaproic acid as a polymerization catalyst. Their structural, thermal, and mechanical properties were characterized using wide angle x-ray diffraction(WAXD), SEM, DSC, and tensile testing.
Effect of Miscibility on the Crystal Structure and Crystallization Kinetics of PVDF/Poly(ethylene-co-vinyl acetate) Blends(II)
Lee Jong Soon ; Kim Kap Jin ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 467~475
The crystal structure of the blends of poly(vinylidene fluoride) (PVDF) and poly(vinyl acetate)(PVAc), ethylene/vinyl acetate (20/80) copolymer (PEVAc80), and ethylene/vinyl acetate (30/70) copolymer (PEVAc70) has been studied using a polarizing microscope equipped with a heating stage and an FT -IR spectrometer. The spherulitic morphology in the PVDF/PEVAc blend appeared as three different types, i.e., lamellar splay, concentric, and spiral type. As crystallization temperature and the content of amorphous PVAc and PEVAc80 miscible with PVDF increase, concentric ring and spiral ring type spherulites are formed more easily than in the case of PVDF and a PVDF/PEVAc70 blend system. The extinction band periodicity between the bright zone and the dark zone in the ring-banded spherulites observed under a crossed polarization was found to increase with increasing content of PVAc and PEVAc. Furthermore, the periodic distance between neighboring spiral arms increased from the core to the outer edge, and this may be ascribed to the preferential rejection of PEVAc chains into the inter-spiral regions during crystallization. The FT-IR analysis of samples quenched from the melt to various temperatures shows increase in
content as the amounts of PVAc and PEVAc80 blended increase and as the quenching temperature is reduced. In conclusion, the crystal morphology and structure in the PVDFIPVAc and PVDF/PEVAc blend systems were shown to be highly associated with the degree of miscibility of an added amorphous polymer with PVDF.
Effect of Electrokinetic Phenomena on the Dispersion Stability of
Particles in Anionic/Nonionic Surfactant Mixed Solution
Kang In Sook ; Jung Sun Young ;
Textile Science and Engineering, volume 41, issue 6, 2004, Pages 476~482
This study was designed to investigate the relationship between the electro kinetic phenomena such as
of particle and interaction energy between two particles and the dispersion stability. The
Fez03 particles and interaction energy between two particles in anionic/nonionic surfactant mixed solution was relatively higher than that of anionic and nonionic surfactant single solution, and exhibited a maximum at
surfactant concentration and
ionic strength. Our previous research found that the suspending power of anionic/nonionic surfactant mixed solution was relatively higher than that of anionic and nonionic surfactant single solution, and maximum at
surfactant concentration and
ionic strength. Although some deviation exists, the general trend of the dispersion stability of particles was similar to that of electro kinetic phenomena such as
of particle and interaction energy between two particles regardless of solution conditions. Therefore, it could be considered that the dispersion stability of particles was well related with electro kinetic phenomena such as
l of particle and interaction energy of two particles.