• Textile Coloration and Finishing
• /
• v.21 no.6
• /
• pp.12-21
• /
• 2009

The dyeing property of direct-spinning type and seaisland type 0.2D micro polyester nonwoven fabrics was characterized by three disperse dyes (Dorosperse Red KFFB, Blue KGBR, Yellow KRL) at $120^{\circ}C$ and $130^{\circ}C$. Before and after reduction cleaning, dyeing fastness was evaluated and the thermomigaration after heat setting at $180^{\circ}C$ for 60 min were also evaluated. Direct-spinning type fabric showed better dyeing property, wash fastness, and light fastness, but worse rub fastness than seaisland type fabric. The dyeing property and fastness of direct-spinning type fabric increased at higher dyeing temperature, whereas seaisland type fabric exhibited lower dyeing fastness and the increase of thermomigration at higher dyeing temperature. Non-fixed dye in fiber surface was removed by reduction cleaning process, then dyeing fastness was improved and thermomigration decreased. The higher dye uptake of direct-spinning type non-woven fabric caused the increase of dye molecule migration from fiber internal to fiber surface, so this fabric showed larger thermomigration than seaisland type non-woven fabric.

• Textile Coloration and Finishing
• /
• v.32 no.4
• /
• pp.239-244
• /
• 2020

Polyethylene (PE) micro-fiber have been prepared at different hot air temperature (60, 80 and 100 ℃) and different pressure (20, 40, 60 and 80 kPa) by melt centrifugal spinning technique. The parameters of melting centrifugal spinning including polymer contents, rotational velocity, temperature of hot air and pressure were optimized for the fabrication process. The study showed that 8000 rpm rotational velocity, 80 ℃ heated hot air and 40 kPa air pressure are the best condition to obtain uniform and strong PE fiber. The prepared PE fibers were analyzed by field emission scanning electron microscope and universal testing machine and found that fibers with reduced diameter and improved tensile strength are obtained at hot air condition.

• Polymer(Korea)
• /
• v.32 no.4
• /
• pp.334-339
• /
• 2008

Recently electro spinning is a widely used simple technique to prepared micro- to nanometer-sized fiber of various polymers. In general, a normal multiple-nozzle electro spinning system has been difficult to achieve high production-rate fabricating micro/nanofibers due to the interference of electric field between individual nozzles in the process. To reduce the interference effect of electric field between nozzles, we developed a multi-nozzle electrospinning system supplemented with auxiliary electrodes. Poly($\varepsilon$-carprolactone)(PCL), which has good mechanical property and biocompatibility, was electrospun by the multi-nozzle electro spinning system. Electrospinnability, product rate, and size uniformity of spun fibers for the system with and without auxiliary electrodes were characterized. As a result, the multi-nozzle electrospinning system supplemented with auxiliary electrodes provides excellently stable processability and showed high mass productivity of PCL-nanofibers relative to a normal multi-nozzle electro spinning system.

• Textile Coloration and Finishing
• /
• v.28 no.3
• /
• pp.125-133
• /
• 2016

In this study, efforts were made to enhance the mechanical properties of the poly(vinyl alcohol) (PVA) fibers of medium molecular weight(number-average degree of polymerization=1735) varying the ratio in $DMSO/H_2O$ mixed solvent and spinning/drawing conditions. The gel fibers prepared from pure DMSO were opaquely frozen in the coagulating bath of $-20^{\circ}C$. However, transparent gel fibers were formed without freezing for the mixture to contain water less than 80wt%. As the amount of water in the mixture increased the residual solvent in the coagulated gel fibers decreased ranging from 85 to 42wt%. The complex viscosity increased with increasing PVA concentration in 80/20 $DMSO/H_2O$ exhibiting remarkable shear thinning at 18wt%. In the Cole-Cole plot, the 18wt% PVA solutions gave a deviated curve from 12 and 15wt% ones. Thus the optimum PVA concentration for the spinning processing of medium MW PVA solutions in 80/20 $DMSO/H_2O$ was determined to 18wt% with rheological concept. Low degree of drawing during hot drawing process in the dry state was available for high bath draft in the coagulation bath. The most improved mechanical properties were observed by applying the highest possible draw ratio attained by reducing bath draft over multi-step drawing process. In the given bath draft, linear relationship was observed between both tensile strength and modulus and draw ratio showing the inflection points at the draw ratio of 19.5 and 18.0 for tensile strength and modulus, respectively.

• Macromolecular Research
• /
• v.17 no.7
• /
• pp.533-537
• /
• 2009

This paper introduces a modified electro spinning system for biomedical wound-healing applications. The conventional electrospinning process requires a grounded electrode on which highly charged electro spun ultrafine fibers are deposited. Biomedical wound-healing membranes, however, require a very low charge and a low level of remnant solvent on the electrospun membrane, which the conventional process cannot provide. An electrohydrodynamic process complemented with field-controllable electrodes (an auxiliary electrode and guiding electrodes) and an air blowing system was used to produce a membrane, with a considerably reduced charge and low remnant solvent concentration compared to one fabricated using the conventional method. The membrane had a small average pore size (102 nm) and high porosity (85.1%) for prevention of bacterial contamination. In vivo tests on rats showed that these directly electro spun fibrous membranes produced using the modified electro spinning process supported the good healing of skin bums.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.12 no.2
• /
• pp.51-56
• /
• 2006

Use of products containing phytoecdysteroid (PE) as active principle has become popular in prominent sericultural areas of India for hastening larval maturation events and synchronizing cocoon spinning activities as an obvious advantage is assured. At times, the present recommendation of administering PE at the onset of spinning results in peak labour requirement at odd hrs. To enable making recommendation for the use of PE on $multi{\times}bivoltine$ silkworm hybrids based on the climatic conditions prevailing in different areas especially with regard to temperature, the experiment was taken up to determine proper treatment times so that the induced spinning will be more orderly and the labour can be leveraged more efficiently. Different brackets of low ($18-22^{\circ}C$), medium ($24-28^{\circ}C$) and high ($29-32^{\circ}C$) temperature were simulated during the latter half of V larval instar and cocoon spinning. PE was administered to $multi{\times}bivoltine$ silkworm ($BL67{\times}CSR101$) hybrid batches as per the recommended dose at three different times viz., 10 am, 4 pm and 10 pm. Three replicates of 100 larvae were maintained for each treatment. Absolute controls were also maintained in each temperature range to compare the results. Cumulative maturation percentage was recorded at 6 hrs interval to ascertain peak mounting span. The influence of the treatment on the cocoon traits also was studied. Based on the peak mounting span, it was evident that in low temperature 10 pm treatment would be better. In medium and high temperature, treatment at 4 pm proved to be a better option. The influence of the treatment times at different temperature range on labour management is discussed.

• Proceedings of the Korean Fiber Society Conference
• /
• 2003.10a
• /
• pp.73-74
• /
• 2003

Silkworms construct cocoons that are strong and resilient structure by their masterful behavior. Knowing the essentials of their skill, we could apply them to building many types of objects. In this research we focused on the some properties of silkworm′s spinneret and body position in their cocoon construction process. Silkworm′s spinning process was measured by two Video camera system and then analyzed to find out some appropriate statistical models representing the behavior. Furthermore, we interested in the locus pattern of spinneret based on "8" and "S" character. We modeled this pattern to the Lemniscate′s curve function, and tried to make a design of plane surface.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.1642-1647
• /
• 2003

The market of the horizontal axis washing machine (drum washing machine) has been growing drastically in Korea by about 80% annually since 2000. As market grows fast, the customerTs demands concerning quality becomes more strict and various. Imbalance sensing is a key technology to reduce the NVH problem in a washing machine, because the laundry is time-variant and uncontrollable source of imbalance, which can cause more than 200kgf exciting force. In this paper, imbalance-sensing methods are briefly reviewed, new acceleration sensing circuits are examined, and finally the control algorithm of spinning process is proposed and validated.

• Journal of the Korean Society for Heat Treatment
• /
• v.18 no.6
• /
• pp.362-368
• /
• 2005

Formation and thermal stability of a quasicrystalline phases in Al-Fe-Mo alloys were investigated by means of melt-spinning process and subsequent heat treatment test. Thermal decomposition and phase transformation process of the as-spun alloys were studied using X-ray diffraction and electron microscopy. The melt-spun Al-Fe-Mo alloys contained an icosahedral quasicrystalline phase with a quasilattice constant of 0.457 nm. Icosahedral phase formed at a composition of $Al_{82.5}Fe_{14}Mo_{3.5}$ as a metastable phase during rapid solidification was transformed into the stable crystalline phases, cubic 1/0 approximant and monoclinic ${\lambda}$-phase, upon heating. A metastable icosahedral and cubic(a = 0.93 nm) phases in as-spun $Al_{65}Fe_{20}Mo_{15}$ alloy were decomposed into two cubic(a = 0.62, 0.31 nm) phases by heat treatment.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1995.10a
• /
• pp.5-9
• /
• 1995

In the dry-jet-wet-spinning process of a hollow fiber membrane, the polymer solution is pumped into a coaxial tube, jet spinneret. The threadline emerging from the spinneret is stabilized by an internal coagulating medium(liquid or gas) as it emerges from the jet orifice. The nascent hollow thread is further stabilized in a quench bath as shown in Fig. 1. In this scheme, three mechanism of formatiota(temperature gradient, solvent evaporation, and solvent-nonsotvent exchange) can be combined. The changes which promote stabilization often play a dominant role in determining the ultimate fiber wall structure as well. Hence, in pratice, hollow fiber stabilization and development of membrane structure are commonly inseparable. However, fiber dimension(the inside diameter and wall thickness of the hollow fiber) is mainly a rheological problem and is determined by dope pumping rate, spinneret diatance from the coagulation bath, inner coagulant flow rate, and fiber draw-rate. Besides rheological phenomena play a prominent part in the final properties of the hollow fiber.