• International Journal of Industrial Entomology and Biomaterials
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• v.33 no.2
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• pp.108-112
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• 2016

Silk has been used extensively in textile applications because of its good luster and feel. However, the low elongation and elastic recovery of silk has limited its use in a wider variety of textile applications. In this study, silk textile samples were made with a highly twisted silk/polyurethane core-spun yarn. They were immersed in water and dried at different temperatures, and the effect of treatment temperature on the mechanical properties of the silk textile was examined. It was found that the water temperature strongly affected the morphology and mechanical properties of the silk textile, whereas the drying temperature did not. As the water temperature was increased, the weft silk yarn became tangled and the interval between warp yarns decreased, resulting in shrinkage of the silk textile. When the silk textile was immersed in water at high temperature (i.e., $100^{\circ}C$), the elongation of the textile increased eight-fold as compared to an untreated silk textile. The maximum elastic recovery ratio of the silk textile was 96.7%.

• Textile Coloration and Finishing
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• v.22 no.3
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• pp.239-245
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• 2010

Breathable waterproof PET fabrics were prepared by the UV coating of UV-curable polyurethaneacrylate(PUA) formulation mixed with polyethyleneglycol(PEG) as a water soluble pore former. The dispersed PEG in the UV-cured coating was extracted by warm water, which can generate individual circular pores uniformly distributed all over the coating instead of pore channels. Accordingly the moisture permeability of the microporously coated fabrics increased substantially with increasing PEG addition without significant reduction of hydrostatic pressure. Also the silicone diacrylate addition in the formulation was beneficial in increasing the hydrostatic pressure. The UV-based microporous coating can be an alternative to conventional thermal curing of solventborne polyurethane coating owing to the enhanced environment friendliness and energy saving.

• Journal of the Korean Applied Science and Technology
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• v.39 no.2
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• pp.161-168
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• 2022

Unmodified castor oil (CO) was used to obtain a castor-based aqueous polyurethane (CPUD) and isophorone diisocyanate (IPDI) was used to obtain a transparent film. The mixing effect of polypropyleneglycole (PPG) was analyzed to increase flexibility. In addition, ethylenediamine (EDA) was used as a chain extender. Tensile strength, elongation, and abrasion resistance were measured according to the change according to the castor oil content and the change in the chain extender, respectively. The tensile strength of the sample containing a lot of castor oil was 1.112 kgf/㎟, and the elongation was 88%. The tensile strength of the sample containing a lot of chain extender was 3.33kgf/㎟, and the elongation was 99%. The surface strength was visually confirmed through SEM. The surface strength was visually confirmed through SEM.

• International Journal of Industrial Entomology and Biomaterials
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• v.33 no.2
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• pp.132-137
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• 2016

Although silk textile shows excellent performance when used in clothing over a long period, its limited elongation and elasticity have restricted its extension to other textile and non-textile applications. In the present study, silk textile was produced using silk/polyurethane core-spun yarn and degummed to enhance its elongation and elasticity. The effects of degumming on the structure and mechanical properties of the silk textile were examined. Scanning electron microscopy observation revealed that the silk filaments became finer and more flexible with degumming, resulting in increased tangling of weft yarns and a highly shrunk textile structure in the weft direction. Although the strength of the degummed silk textile was decreased, its elongation greatly increased by 383% (a 16-fold increase) because of the degumming treatment. In particular, the elasticity of the silk textile was greatly improved. The silk textile exhibited ~30% reduction in the elongation after the second extension; however, the elongation almost did not change after 18 additional extension-recovery tests.

• Microbiology and Biotechnology Letters
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• v.41 no.2
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• pp.215-220
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• 2013

Biofilters for the removal of methane using tobermolite, perlite and polyurethane as packing materials have been undergoing recent development. The effects of these packing materials on methane oxidation activity were evaluated in this study. Mixed methanotrophs (consortia A, B, C and D) from wetland and landfill soils were used as the inoculum sources. The influences of packing materials, consisting of tobermolite, perlite, and polyurethane, on the methane oxidation rate and methanotrophic bio-mass, were estimated. When perlite was added into the methanotrophic cultures, the methane oxidation rate was more than twice that of the control (without packing materials), and the methanotrophic biomass increased more than 10 fold. The ratio of methanotrophic bacteria to total bacteria under with tobermolite packing material was higher than the control and the other packing materials, indicating that tobermolite can serve as a specific packing material where dominance of methanotrophs is desired. Therefore, perlite and tobermolite provide habitats which increase the activity of methanotrophic bacteria, and these packing materials are promising for use in methane oxidation processes.

• KSBB Journal
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• v.20 no.6
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• pp.458-463
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• 2005

[ $H_2$ ] from CO and water was continuously produced in a trickle bed reactor(TBR) using Citrobacter amalonaticus Y19. When the strain C. was cultivated in a stirred-tank reactor under a chemoheterotrophic and aerobic condition, the high final cell concentration of 13 g/L was obtained at 10 hr. When the culture was switched to an anaerobic condition with the continuous supply of gaseous CO, CO-dependent hydrogenase was fully induced and its hydrogen production activity approached 16 mmol/g cell/hr in 60 hr. The fully induced C. amalonaticus Y19 cells were circulated through a TBR packed with polyurethane foam, and the TBR was operated for more than 20 days for $H_2$ production. As gas retention time decreased or inlet CO partial pressure increased, $H_2$ production rate increased but the conversion from CO to $H_2$ decreased. The maximum $H_2$ production rate obtained was 16 mmol/L/hr at the gas retention time of 25 min and the CO inlet partial pressure of 0.4 atm. The high $H_2$ production rate was attributed to the high cell density in the liquid phase circulating the TBR as well as the high surface area of polyurethane foam used as packing material of the TBR.

• Journal of Adhesion and Interface
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• v.12 no.2
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• pp.47-55
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• 2011

UV-curable coatings have been used in various industries due to their advantages such as high mechanical property, good solvent resistance, fast curing process and low volatile organic compounds. However, a lack of flexibility of UV-cured films is a weak point for the pre-coated system of roll-to-roll process. In this study, UV-curable polycarbonate-based methacrylates were synthesized with polycarbonate diol, isophorone diisocyanate and 2-hydroxyethylmethacrylate to improve flexibility of the UC-cured films. The effects of polyol molecular weight, content of photoinitiator and monomers on the UV-curing behavior, flexibility and properties were investigated. The UV-curing behavior was measured by a photo-DSC, the pendulum hardness, tensile strength, viscoelastic properties were also evaluated.

• The Research Journal of the Costume Culture
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• v.15 no.5
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• pp.852-862
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• 2007

This study was to investigate the physical properties and the external characteristics of denim fabrics(100% cotton non-spun denim, 98% cotton/2% polyurethane spun denim) such as tensile strength, thickness and weight, flex stiffness, surface color and shrinkage. The results of the study were as follows. After examining the change of external characteristics of before and after washing finishing for denim fabrics, denim with bio washing had increased pliability compared to denim without washing finishing but the pliability of the denim did not increase according to the intensity or frequency of washing. The luminance change according to washing finishing was high in the order of bio stone bleach washing, bio stone washing, bio washing and denim without washing finishing and the surface color became brighter in accordance with the increase of intensity and frequency of washing finishing.

• Elastomers and Composites
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• v.48 no.3
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• pp.195-200
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• 2013

The main objective of this study is to improve abrasion resistance and wet slip resistance of thermoplastic polyurethane (TPU) by blending with ethylene-propylene-diene monomer rubber (EPDM) or polybutadiene rubber (BR) for the application of the footwear outsole materials. With addition of 10 wt% of EPDM or BR, TPU/EPDM and TPU/BR blends exhibited higher NBS abrasion resistance, tensile properties and wet slip resistance than TPU. However, with further increasing content of EPDM and BR, abrasion resistance and tensile properties of the blends decreased. Improvement in abrasion resistance and tensile properties with 10 wt% of addition of EPDM or BR may be due to better microphase separation of TPU.

• Journal of the Korean Applied Science and Technology
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• v.39 no.6
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• pp.924-931
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• 2022

Undenatured castor oil and trimethylolpropane (TMP) were used to obtain bio-based water-based polyurethane. Isophorone diisocyanate (IPDI) was incorporated into the formulation to obtain a transparent film, and ethylenediamine (EDA) was used for chain extension. In order to measure the change in physical properties according to the contents of castor oil and TMP, each tensile strength, elongation, and abrasion resistance test was conducted. As the contents of castor oil and TMP increased, the tensile strength increased, the elongation decreased, and the surface hardened strongly as the respective contents increased.