• Title/Summary/Keyword: thermal $T_g$

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The Effect of Drawing and Annealing Condition on the Fine Structure of PET Film (연신 및 열처리 조건이 PET film의 미세구조에 미치는 영향)

  • Park, Jong-Bum;Choi, Suk-Chui;Cho, Hyun-Hok
    • Textile Coloration and Finishing
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    • v.3 no.1
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    • pp.8-16
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    • 1991
  • In order to investigate the fine structure of PET films, PET films were stretchd at various draw ratios (2, 3, 4, 5) below $T_g$ ($72^{\circ}C$) and then annealed at various temperatures (125, 150, 175, $200^{\circ}C$) under free-annealed (FA) and taut-annealed (TA) conditions. Such changes as thermal shrinkage, crystallinity, crystallite size, dynamic viscoelasticity and thermal behaviour were measured in relation to the draw ratio and annealing condition.The following results were obtained. 1. Thermal shirinkage increased with increasing annealing temperature and draw ratio, but decreased in case of draw ratio 4 (draw ratio 3 at $200^{\circ}C$) and above it. 2. The degree of crystallinity of FA samples were higher than those of TA samples. 3. Tan 5 of TA samples were less than those of FA samples, and storage moduli (E') and loss moduli (E") of FA samples were less than those of TA samples; moreover, maximum tan '||'&'||' temperature of FA samples were shifted toward higher temperature than those of TA samples. 4. The melting endotherm ($T_m$) and heat of fusion $(\DeltaH)$ of the PET film increased with the draw ratio and annealing temperature; in addition, premelting endotherm ($T_m$) and heat of fusion $(\DeltaH)$ of the local crystallization in the FA samples were larger than those of TA samples. 5. The X-ray diffraction pattern displayed sharp peaks gradually with the draw ratio and annealing temperature. 6. Crystallite sizes of FA samples were larger than those of TA samples.

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Effect of Heating Rates on the Thermal Denaturation of Pork Loin Muscle (가열속도가 돈육 등심 근육의 열변성에 미치는 영향)

  • Kim, Cheon-Jei;Song, Min-Seok;Lee, Chang-Hyun;Lee, Eui-Soo;Cho, Jin-Kook;Choi, Do-Young
    • Korean Journal of Food Science and Technology
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    • v.31 no.3
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    • pp.678-681
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    • 1999
  • The objective of this study was to evaluate the effect of different heating rates on the thermal properties of pork loin muscle by DSC. Pork loin muscle was subjected to programmed heating at the following heating rate: 5, 10, 20, 30 and $40^{\circ}C/min$. Peaks were progressively shifted to right side as the heating rate was increased. $T_0$ was $50.39^{\circ}C$ at $5^{\circ}C/min$ and it was increased to $57.45^{\circ}C$ at $40^{\circ}C/min$ (p<0.05). Total enthalpy was 3.52 J/g at $5^{\circ}C/min$ and total enthalpy was increased to 3.60, 4.14, 4.54 and 4.61 J/g by degrees at heating rate 10, 20, 30 and $40^{\circ}C/min$ respectively.

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A Study on the Electrical and Mechanical Properties of a Epoxy Powder for Compact Bus Duct (콤팩트 부스덕트용 에폭시분체도료의 전기적.기계적 특성연구)

  • Kim, Sang-Hyun;Choi, Jin-Wook;Kim, Dong-Wook;Kim, Hyun-Hee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.3
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    • pp.210-217
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    • 2009
  • Insulated methods of compact bus duct has been applied a way of coating Epoxy powder. The problem which is caused by degradation during operation is very important in severe environment. Therefore, this study compared and verified many kind of properties ; electrical breakdown by thermal and water aging, v-t characteristic, arc discharge, mechanical properties, bending test and cross cut. Sample D was stable before the $T_g$ to be about $7{\sim}10 %$ decrease in the breakdown test according to temperature change. In case of V-t and arc discharge, it had been kept up suitable characteristic. Also, in case of electrical and mechanical characteristic, both sample D and A have excellent capacity.

Synthesis and Characteristics of New Poly(p-phenylenevinylene) with Bulky t-Octylphenoxy Group

  • Kim, Yun-Hi;Lee, Hyun-Ouk;Jung, Sung-Ouk;Kwon, Soon-Ki
    • Macromolecular Research
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    • v.11 no.3
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    • pp.194-197
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    • 2003
  • A new 2,5-di(t-octylphenoxy) group substituted poly(p-phenylenevinylene) derivative was synthesized by Gilch polymerization. The obtained polymer was characterized by NMR, FT-IR, and chemical analysis and completely soluble in common organic solvents. The polymer showed good thermal stability with T$_{g}$ of 105$^{\circ}C$. The polymer dissolved in chloroform showed maximum emission at 514 nm with a shoulder peak at around 560 nm. The EL spectrum of the ITO/PEDOT/TOP-PPV/Al device was observed maximum emission at 545 nm with a shoulder peak at around 585 nm.m.

Structure and Optical Properties of the Ca/Ag Double Layer for Transparent Cathode in TEOLED

  • Kim, Boo-Kyung;Moon, D.G.;Ahn, B.T.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1071-1074
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    • 2006
  • Ca/Ag double layer which is fabricated by thermal evaporation exists as the double layer of (Ca+O)/(Ag+Ca). In Ca layer, are crystalline Ca(OH)2 and amorphous Ca and in Ag layer, are crystalline Ag and amorphous Ca. And for the certain thickness of Ag, in the Ca/Ag double layer, the thicker Ca is, the higher transmittance is.

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