• Fibers and Polymers
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• v.5 no.1
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• pp.25-30
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• 2004

The present paper reports the impact of thermal treatment on the characteristics of core-sheath type hybrid technical yarns. The core-sheath type hybrid yams 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 yams with polyester multifilament in core increases with treatment temperature. The hybrid yarns with glass multifilament in core are least affected by thermal treatment.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.2
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• pp.224-234
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• 2013

This study investigates the fabrication of core-sheath nanocomposite fibers by locating germanium (Ge) and silicon dioxide ($SiO_2$) nanoparticles selectively in the sheath layer by co-axial electrospinning. Co-axially spun fibers were prepared by electrospinning a pure PVA solution and Ge/$SiO_2$/PVA solution as the core and sheath layer, respectively. Core-sheath nanocomposite fibers were electrospun under a variety of conditions that include various feed rates for the core and sheath solutions, voltages, and concentric needle diameters, in order to find an optimum spinning condition. Ge/$SiO_2$ nanocomposite fibers were also prepared by uniaxial electrospinning to compare fiber morphology and nanoparticle distribution with core-sheath nanofibers. Using scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray analysis, it was demonstrated that the co-axial approach resulted in the presence of nanoparticles near the surface region of the fibers compared to the overall distribution obtained for uni-axial fibers. The co-axially electrospun Ge/$SiO_2$/PVA nanofiber webs have possible uses in high efficiency functional textiles in which the nanoparticles located in the sheath region provide enhanced functionality.

• Fashion & Textile Research Journal
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• v.17 no.3
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• pp.462-475
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• 2015

This paper investigated the characteristics of the physical properties of woven fabrics according to the yarn structure and fibre property. It was found that wicking property of woven fabrics made of sheath/core hybrid yarn were better than those of siro spun and siro-fil hybrid yarns, which was caused by platform for transport of moisture vapor by filaments on the core part of sheath core hybrid yarns. In drying property, the fabric specimen woven by PP/Tencel sheath core hybrid yarns as a warp and Coolmax/Tencel spun yarn as a weft showed quick drying property, which was caused by the sheath core hybrid yarn structure as drainage of water moisture and coolmax fibre characteristics as quick dry material. Concerning to breathability and thermal conductivity as heat transport phenomena, it was observed that breathability of fabrics woven with hybrid yarns such as sheath core and siro-fil in the warp and hi-multi filaments in the weft showed the lowest water vapor resistance, which was explained as due to for air gap in the fibres of the spun yarns to restrict the wet heat transport from perspiration vapor. Thermal conductivities of the fabrics woven with PET/Tencel siro-fil yarns in the weft and hybrid yarns such as sheath core and siro-fil in the warp revealed the highest values, which was observed as due to higher thermal conductivity of PET than PP and more contact point between fibres in the siro-fil and sheath core hybrid yarns.

• Polymer(Korea)
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• v.37 no.1
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• pp.52-60
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• 2013

Partially hydrolyzed cellulose acetate (CA) fibers were prepared by treating CA fibers in aqueous $Na_2CO_3$ solutions of various concentrations. The deacetylation of CA fibers was confirmed through FTIR spectra and WAXD patterns. The hydrolysis was confined to the surface part of the CA fiber by controlling the treatment conditions. The resultant fibers had a sheath-core structure with a sheath component of regenerated cellulose and a core of non-hydrolyzed cellulose acetate. The SEM images of the surface-hydrolyzed CA fibers, the core of which was dissolved out using acetone as the solvent, showed that the sheath thickness increased with increasing alkaline concentration, indicating an increase in the hydrolyzed fiber, i.e., regenerated cellulose. Polarized FTIR analysis of the polyimide film rubbed with velvet fabrics of surface-hydrolyzed CA fibers showed that polyimide molecules were preferentially oriented to the rubbing direction.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.396-406
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• 2018

In this study, a polydioxanone (PDO) and poly(L-lactic acid) (PLLA) sheath-core biphasic monofilament was designed to develop an esophageal stent with improved mechanical properties and controlled biodegradability. The radial force of PDO/PLLA sheath-core stent was 10.24 N, while that of PDO stent was 5.64 N. Deteriorations of tensile strength, elastic modulus and elongation during degradation test were also delayed on PDO/PLLA group. Hyaluronic acid-dopamine conjugate and $BaSO_4/PDO$ conjugate coating layers provided improved tissue adhesion strength and reasonable X-ray contrast, respectively. Taken all together, the sheath-core filaments with tissue adhesive and radiopaque properties will be useful in designing esophageal stents.

• Textile Coloration and Finishing
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• v.21 no.4
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• pp.1-10
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• 2009

This paper surveys the physical properties of sheath/core nylon/PET high hollow composites filaments and its fabrics according to the various elution conditions such as concentration of elution, eluted time and eluted temperature. For this purpose, sheath/core nylon/PET filament was texturized and four kinds of fabric specimens were woven with different warp and weft densities. These grey fabrics were eluted with two kinds of concentrations of NaOH (30g/l, 40g/l), three kinds of eluted temperatures $50^{\circ}C,\;60^{\circ}C,\;85^{\circ}C$) and two kinds of eluted times (60min, l20min). The elution characteristics of these specimens were investigated and discussed with different elution conditions. In addition, the mechanical properties such as extensibility, bending rigidity, shear modulus and compressional work of these specimens aceording to the elution conditions were analysed and summarized with cross-sectional shapes of eluted filaments measured by SEM.

• Macromolecular Research
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• v.16 no.1
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• pp.21-30
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• 2008

Based on the sheath-core bicomponent composite fibers with modified polystyrene (PS) and the modified polypropylene (PP), composite fibers obtained were further cross-linked and sulphonated with chlorosulphonic acid to produce strong acidic cation ion exchange fibers. The structures of the fibers obtained were characterized using Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) etc. The optimal technology of the fibers obtained is discussed. The static absorption capacity of the sheath-core bicomponent composite cation exchange fibers for $Zn^{2+}$, $Cu^{2+}$ was determined. The absorption kinetics and major factors affecting the absorption capacities of $Zn^{2+}$, $Cu^{2+}$ were studied, and its chemical stability and regenerating properties were probed. The results suggest that cation exchange fibers with better mechanical properties and higher exchange capability were obtained. Moreover, this type of ion exchange fiber has good absorption properties and working stability to various metal ions. Hence, they have higher practicability.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.35-35
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• 2011

Phase change material(PCM) has thermal energy storage and been attracted attention. Latent heat of the organic PCM can keep maintaining temperature when the change of outside energy conditions influence to PCM. Thus, many researchers have interested to thermal energy storage ability and investigated to applications such as thermal storage of solar energy, bioclimatic building, icebank, medical application, clothing industry and so on. Among the many applications, investigation of the PCM in clothing industry is also important because the people has interest functional factor called health-care in the clothing. In addition, PCM can give them mild environment condition such suitable temperature control or humidity. To fabrics, the PCM has various methods such as microcapsule, padding and modified cross-section formation(Sheath/core). Sheath core PCM fabric has a better benefit of durability than other method. However, PCM sheath/core spinning is difficult. In addition, dyeing property is important to use clothing industry due to visual images. In this study, we investigated dyeing properties of Nylon/PCM sheath/core fabrics. Especially, we observed the relation between dyeing property and PCM including ratio. Various temperature and pH conditions were also studied to optimize dyeing properties as acid dye.

• Fashion & Textile Research Journal
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• v.16 no.1
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• pp.145-152
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• 2014

The usage of textile-based sensors has increased due to their many advantages (compared to IT sensors) when applied to body assessment and comfort. Textile-based sensors have different detecting factors such as pressure, voltage, current and capacitance to investigate the characteristics. In this study, textile-based sensor fabrics with sheath-core type conductive yarns were produced and the relationship between capacitance changes and applied load was investigated. The physical and electric properties of textile-based sensor fabrics were also investigated under various laminating conditions. A textile based pressure sensor that uses a sheath-core conductive yarn to ensure the stability of the pressure sensor in the textile-based sensor (the physical structure of the reaction characteristic of the capacitance) is important for the stability of the initial value of the initial capacitance value outside the characteristic of the textile structural environment. In addition, a textile based sensor is displaced relative to the initial value of the capacitance change according to pressure changes in the capacitance value of the sensor due to the fineness of the high risk of noise generation. Changing the physical structure of the fabric through the sensor characteristic of the pressure sensor via the noise generating element of laminating (temperature, humidity, and static electricity) to cut off the voltage output element to improve the data reliability could be secured.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.45-45
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• 2011

최근 환경과 건강에 대한 관심이 증대되면서, 복합기능을 갖는 다기능성 섬유에 대한 요구가 증대되고 있는 실정이다. 일반적으로 기능성은 마이크로캡슐이나 후가공제를 이용하여 일반 섬유 제품에 적용하고 있다. 마이크로캡슐이나 후가공제가 적용된 일반 섬유제품은 일상생활 속에서의 마찰 및 세탁 등으로 인해 기능 저하가 발생된다. 이러한 문제점을 개선하기 위해 특수 방사 기술을 이용하여 다기능성을 갖는 섬유 제조 기술이 개발되고 있다. 다기능성 섬유소재 및 응용제품은 그 제조 공정성이 우수하고, 염색 가공 등의 후 공정 조건에 의해 기능성 저하를 초래하지 않고, 지속시간이 오래 유지해야하는 조건을 만족해야한다. 이러한 기능성 저하 문제를 해결하고 내구성 향상 및 기능성의 지속 시간을 오래 유지하기 위하여 복합 방사 기술을 이용하여 이형 단면 원사, Sheath-Core 단면 원사 등이 개발되고 있다. 개발된 기능성 원사의 경우 일반 원사와 다른 형태의 염색성을 보일 수 있으며, 염색 온도 및 염색 시간 등 염색 조건이 달라질 수 있다. 본 연구에서는 식물 등에서 추출한 천연 항균 유기물을 마이크로캡슐화하여 이형단면의 심부에 담지된 형태인 Sheath(Nylon: 50%)-Core(PP MB: 50%) 원사의 염색성 평가 시험을 실시하였다. 시험 방법은 Sheath-Core 원사와 일반 Nylon 원사와 염착 거동 시험을 통해 비교해 나타냈고, 염색 전 후의 물성을 비교해보았다. 또한 염색성 평가 시험을 토대로 기능성 원사의 염색 온도와 시간에 따른 색차 비교 시험을 통해 기능성 원사의 염색 조건을 선정하는 시험을 실시하였다.