• 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.

• Clean Technology
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• v.25 no.2
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• pp.114-122
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• 2019

The synthesis of bio polyol from renewable resources has attracted attention in recent years. In particular, it is important to take advantage of bio polyols in the synthesis of polymers. In this study, a series of dimethylformamide (DMF) based polyurethanes were synthesized using polycarbonate polyol/bio polyol (PO3G: polytrimethylene ether glycol prepared from 1, 3-propanediol produced by fermentation from corn sugar), methylene diphenyl diisocyanate (MDI) and 1,4-butandiol (BD). The properties of prepared polyurethane films and the cell structure of wet type artificial leather were investigated. As the bio polyol content increased, the tensile strength of polyurethane films decreased, however, the elongation at break increased significantly. As a result of thermal characteristics analysis, the glass transition temperature of polyurethanes increased when increasing the content of polycarbonate polyol. As a result of comparing the cell characteristics of wet type artificial leathers prepared in this study, it was found that the number and uniformity of cells formed in the artificial leather samples increased when increasing the content of polycarbonate polyol in polycarbonate polyol/bio polyol. From these results, it was found that DMF-based polyurethane containing an appropriate amount of bio polyol could be used for wet type artificial leather. The bio textile analysis system according to ASTM standard was used to measure the bio carbon content of polyurethane. The content of bio carbon increased proportionally with the increase of bio polyol content used in polyurethane synthesis.

• Polymer Science and Technology
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• v.4 no.6
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• pp.439-443
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• 1993

• Proceedings of the Korean Fiber Society Conference
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• 1989.06a
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• pp.57-57
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• 1989

• Proceedings of the Korean Fiber Society Conference
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• 1991.06b
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• pp.72-72
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• 1991

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.10a
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• pp.22-23
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• 2003

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 1999.02a
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• pp.30-30
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• 1999

• Macromolecular Research
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• v.9 no.4
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• pp.228-237
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• 2001

The evolution of conformational constraints in bisphenol-A polycarbonate (BAPC) upon quiescent bulk crystallization was quantitatively analyzed from calorimetric study employing a rigid amorphous fraction (RAF) as an indicator of the level of conformational constraints. From the correlation between corrected crystallinity (X$\sub$c/) and total rigid fraction (f$\sub$r/), it was found that, regardless of molar mass distribution and thermal treatment conditions, semicrystalline BAPC always exhibits greater f$\sub$r/ than X$\sub$c/ maintaining a quantitative relationship of f$\sub$r/〓2X$\sub$c/ in the range of 0.0 $\sub$c/< 0.4. This directly indicates the evolution of approximately the same amount of RAF as X$\sub$c/, (i.e., RAF〓X$\sub$c/) upon bulk crystallization of BAPC. It was also found that T$\sub$g/ per se and T$\sub$g/ broadening enhance as RAF increases, and there appears to be a critical level of RAF (>0.2) needed to initiate significant changes in both quantities.

• Fibers and Polymers
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• v.2 no.3
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• pp.129-134
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• 2001

Liquid crystalline (LC) poly(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate) (50/50, mole/mole) [PECPT] was synthesized and blended with polycarbonate (PC). LC properties of PECPT and thermal, morphological, and rheological behaviors of the PECPT/PC blend were studied. PECPT showed the nematic LC phase and much longer relaxation time than poly(ethylene terephthalate) (PET). The apparent melt viscosity of PECPT was one third of that of FET. An abrupt torque change was observed during the blending process due to the orientation of LC domains. For the blends containing 10~30 wt% of PECPT, the complex viscosities were higher than that of PC. As PECPT content increases above 40 wt%, shear thinning was observed. The lowest complex viscosity was obtained at 40~50 wt%. Transesterification of PECPT and PC was confirmed by the selective chemical degradation of carbonate groups in PC.

• KIEAE Journal
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• v.15 no.1
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• pp.83-88
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• 2015

This study aims to develope the light-weight PV blinds with windows and to investigate the shading analysis by the control conditions. For the study, the polycarbonate characteristics and coating methods are analyzed and the PV blind design for a small office is suggested. Also, the mock-up model of a suggesting system was made. The field tests were controled based on a solar altitude under clear sky conditions. As results, it is necessary to use a polycarbonate instead of a tempered glass for a light-weight PV. The shading effects of blind systems are high in slat angle $30^{\circ}$ and low in $0^{\circ}$. Also, the shading ratio is more affected by solar latitude than solar altitude. The shading change rate is relevantly constant on the solar altitude.