• Title/Summary/Keyword: glass transition temperature

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The Effect of DSC Analysis Condition on the Glass Transition Temperature of curred Epoxy This paper studies on the effect of DSC(Differential Scanning Calorimeter) analysis condition on the glass transition temperature of silica filled epoxy network polymer used for ultra-high voltage apparatus. The effects of temperature scanning rate specimen size and gas flow rate on measured glass transition temperature have been studied in order to select optimum thermal analysis condition. (에폭시 경화물 DSC에 의한 유리전이 온도 측정의 분석조건 의존성)

  • 오무원;권혁삼
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.30-33
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    • 1994
  • This paper studies on the effect of DSC(Differential Scanning Calorimeter) analysis condition on the glass transition temperature of silica filled epoxy network polymer used for ultra-high voltage apparatus. The effects of temperature scanning rate specimen size and gas flow rate on measured glass transition temperature have been studied in order to select optimum thermal analysis condition.

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Change of Glass Transition Temperature of PETG Containing Gas (가스를 포함하는 고분자 재료(PETG)의 유리전이온도 변화)

  • Cha, Seong-Un;Yun, Jae-Dong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.4
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    • pp.824-829
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    • 2000
  • The industries use polymer materials for many purposes because they have many merits. But these materials' costs take up too much proportion in overall cost of products that use these materials as their major material. So it is very economical for polymer industries to reduce these costs. Microcellular foaming process appeared in 1980's to solve this problem and it proved to be quite successful. This process uses inert gases such as CO2, N2. As these gases are dissolved into polymer matrices. many properties are changed. Glass transition temperature is one of these properties. DSC, DMA are devices that measures this temperature, but these are not sufficient to measure the temperature of polymer containing gas. In this paper, we devised a new tester that uses magnetism. We used this device to acquire data of the change of glass transition temperature and made Cha-Yoon model that can predict the change of glass transition temperature. Using this model, the change of this temperature can be estimated as a function of weight gain of gas. Cha-Yoon model proved that Chow's model is inappropriate to predict the change of glass transition temperature of polymer matrices containing gas.

The Effect of Gas Absorption Induced a Change of Glass Transition Temperature in Microcellular Foamed Plastics (초미세 발포 플라스틱의 유리전이온도를 변화시키는 가스 용해량의 영향)

  • Hwang, Yun-Dong;Cha, Seong-Un
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.5
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    • pp.816-822
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    • 2001
  • The thermoforming process is widely used in the plastics industry to produce articles for the packaging, automotive, domestic construction and leisure industries. The microcellular foaming process appeared at M.I.T. in 1980s to save a quantity of polymer materials and increase their mechanical properties. The glass transition temperature of polymer materials is one of many important process variables in appling the microcellular foaming process to the conventional thermoforming process. The goal of this research is to evaluate the relation between gas absorption and glass transition temperature in batch process using microcellular foaming process. The weight gain ratio of polymer materials has a conception of gas absorption. Polymers such as acrylonitrile-butadiene-styrene(ABS), polystyrene(PS) have been used in this experiment. According to conventional Chows model and Cha-Yoon model, it was estimated with real experimental result to predict a change of glass transition temperature as a function of the weight gain ratio of polymer materials in batch process to gain microcellular foamed plastic products.

Evaluation of Polymer Glass Transition Temperature Using HP-DSC in Hydrogen Atmosphere (수소 환경하에서의 고압시차주사 열량계를 이용한 고분자재료의 유리전이온도 평가)

  • KIM, DAEHO;LEE, SANGHYUN
    • Transactions of the Korean hydrogen and new energy society
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    • v.32 no.2
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    • pp.109-115
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    • 2021
  • Evaluation of the thermal properties of a polymer is important for application of hydrogen infrastructure. This study describes the process of measurement of the glass transition temperature using high-pressure differential scanning calorimeter (HP-DSC) in hydrogen condition. Pressure stability of HP-DSC was evaluated up to 8 MPa in hydrogen gas and temperature calibration was carried out in the range from -92℃ to 232℃ using the reference materials. Glass transition temperature of commercial EPDM polymer was measurued at 0.2, 2, 3, 5 MPa in hydrogen condition.

Relationship Between Coefficient of Thermal Expansion and Glass Transition Temperature in Phosphate Glasses (인산염유리의 선팽창계수와 유리전이온도의 관계)

  • 전재삼;차명룡;정병해;김형순
    • Journal of the Korean Ceramic Society
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    • v.40 no.11
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    • pp.1127-1131
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    • 2003
  • Phosphate glasses known for low melting temperature glasses in electrical parts has been recently used in wide area with modification of thermal properties using alkali oxides. It is our purpose to find a correlation between thermal expansion coefficient, glass transition temperature and melting temperature through investigating thermal properties in P$_2$O$\sub$5/-SnO-ZnO-SiO$_2$/B$_2$O$_3$. As a result, the product of thermal expansion coefficient and the glass transition temperature in the glasses is found to be a constant value would be a unique value for knowing one of thermal properties.

A Study on the Thermal Properties of Epoxy/Micro-Nano Alumina Composites, as Mixture of Surface Modified Nano Alumina (표면개질된 나노알루미나를 혼합한, 에폭시/마이크로-나노알루미나 콤포지트의 열적특성)

  • Park, Jae-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.9
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    • pp.1504-1510
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    • 2016
  • The aim of this study is to improve properties both glass transition temperature($T_g$) and coefficient of thermal expansion(CTE) using epoxy/micro-nano alumina composites with adding glycerol diglycidyl ether (GDE:1,2,3,5g). This paper deals with the effects of GDE addition for epoxy/micro alumina contents (40, 50, 60wt%)+surface modified nano alumina(1_phr) composites. 20 kinds specimen were prepared with containing micro, nano alumina and GDE as a micro composites(10, 20, 30, 40, 50, 60, 70wt%) or a nano/micro alumina composites(1phr/40, 50, 60wt%). Average particle size of nano and micro alumina used were 30nm and $1{\sim}2{\mu}m$, respectively. The micro alumina used were alpha phase with Heterogeneous and nano alumina were gamma phase particles of spherical shape. The glass transition temperature and coefficients of thermal expansion was evaluated by DSC and TMA. The glass transition temperature decreased and coefficients of thermal expansion become smaller with filled contents of epoxy/micro alumina composites. On the other hand, $T_g$ and CTE as GDE addition variation(1,2,3,5g) of epoxy/micro-nano alumina composites decreased and increased respectively.

Effect of Thermal Aging Temperature on Weight Loss and Glass Transition Temperature of Epoxy Adhesives (열화 온도가 에폭시 접착제의 질량변화 및 유리전이온도에 미치는 영향)

  • Park, Soo-Jin;Kim, Jong-Hak;Joo, Hyeok-Jong;Kim, Joon-Hyung;Jin, Fan-Long
    • Elastomers and Composites
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    • v.41 no.1
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    • pp.19-26
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    • 2006
  • In this study, the effect of thermal aging temperature on the weight loss, glass transition temperature, and morphology of epoxy adhesives cured with amine (D-230), amide (G-5022), and anhydride (HN-2200) was investigated. As a result, the weight loss of three specimens was increased with increasing the thermal aging temperature. The result was attributed to the thermal aging which was occurred at the surface of adhesive specimens at high aging temperature, resulting in increasing the weight loss of the specimens. According to the DSC result, the glass transition temperature of DGEBA/D-230 and DGEBA/G-5022 samples war increased as the aging temperature increased, whereas the glass transition temperature of DGEBA/HN-2200 samples was constant above aging temperature of $150^{\circ}C$ and aging tine of 7 days. The SEM result indicated that the surface of DGEBA/G-5022 specimen showed more rough topography than that of DGEBA/D-230 or DGEBA/HN-2200 specimen after thermal aging. This could be correlated with the result of weight loss.

Effect of Glass Transition Temperature on Strength Properties of Polymer-Modified Mortar Using Polymer Dispersion (폴리머 분산계 혼입 폴리머 시멘트 모르타르의 강도에 대한 유리전이온도의 효과)

  • 송해룡;형원길;김완기;소양섭
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.1011-1016
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    • 2001
  • The purpose of this study is to find out the effect of polymer glass transition temperature on mechanical properties of polymer latex-modified mortars in comparison with ordinary cement mortar. The Polymer latex-modified mortars are prepared with 5, 10, 15 and 20% of polymer cement ratio respectively, and properties of modified mortars such as air content, compressive, flexural and tensile strengths are tested. The test results indicate that the types of polymer dispersion and the polymer-cement ratio are very important factors to characterize the properties of polymer-modified mortars, and also the glass transition temperature of polymer dispersions has an important effect on the performance of polymer-modified mortars. The modifying effects of two kinds of polymer dispersion, St/BA-1 and SBR, are evaluated.

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AC Insulation Breakdown Properties of the EMNC to Application of Distribution Molded Transformer (배전용 몰드변압기 적용을 위한 EMNC의 교류절연파괴특성 연구)

  • Park, Jae-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.5
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    • pp.649-656
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    • 2013
  • A conventional epoxy-microsilica composite (EMC) and an epoxy-microsilica-nanosilicate composite (EMNC) were prepared in order to apply them to mold-type transformers, current transformers (CT) and potential transformers (PT). Nanosilicate was exfoliated in a epoxy resin using our electric field dispersion process and AC insulation breakdown strength at $30{\sim}150^{\circ}C$, glass transition temperature and viscoelasticity were studied. AC insulation breakdown strength of EMNC was higher than that of EMC and that value of EMNC was far higher at high temperature. Glass transition temperature and viscoelasticity property of EMNC was higher than those of EMC at high temperature. These results was due to the even dispersion of nanosilicates among the nanosilicas, which could be observed using transmission electron microscopy (TEM). That is, the nanosilicates interrupt the electron transfer and restrict the mobility of the epoxy chains.

Effect of Acrylonitrile Content on the Glass Transition Temperature and Melt Index of PVC/SAN Blends

  • Liu Wang;Kim Hwan-Chul;Pak Pyong-Ki;Kim Jong-Chun
    • Fibers and Polymers
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    • v.7 no.1
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    • pp.36-41
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    • 2006
  • PVC and SAN are often mixed to compensate for the disadvantages of each polymer. Miscibility and thermal stability of PVC/SAN blend were investigated in this study by blending SAN polymer having 20, 24, 28, 32 % of acrylonitrile contents. Two polymers were mixed using a melt blending method with a single screw extruder. DSC thermogram was used to evaluate miscibility of the two polymers. SAN having 24 % of acrylonitrile showed the best miscibility with PVC. In order to evaluate degradation behavior, blended polymer was heat treated in DSC furnace and glass transition temperature was measured consecutively. Glass transition temperature increased continuously with annealing time due to degradation and cross-linking of polymer chains. Melt index of blended polymer was always higher than that of PVC.