• Title/Summary/Keyword: Ozawa

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Cure and Thermal Degradation Kinetics of Epoxy/Organoclay Nanocomposite

  • Park, Jae-Jun
    • Transactions on Electrical and Electronic Materials
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    • 제13권4호
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    • pp.204-207
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    • 2012

  • Epoxy nanocomposite was synthesized through the exfoliation of organoclay in an epoxy matrix, which was composed of diglycidyl ether of bisphenol A (DGEBA), 4,4'-methylene dianiline (MDA) and malononitrile (MN). Organoclay was prepared by treating the montmorillonite with octadecyl trimethyl ammonium bromide (ODTMA). The exfoliation of the organoclay was estimated by wide angle X-ray diffraction (WAXD) analysis. In order to measure the cure rate of DGEBA/MDA (30 phr)/MN (5 phr)/organoclay (3 phr), differential scanning calorimetry (DSC) analysis was performed at various heating rates, and the data were interpreted by Kissinger equation. Thermal degradation kinetics of the epoxy nanocomposite were studied by thermogravimetric analysis (TGA), and the data were introduced to the Ozawa equation. The activation energy for cure reaction was 45.8 kJ/mol, and the activation energy for thermal degradation was 143 kJ/mol.

  • https://doi.org/10.4313/TEEM.2012.13.4.204 인용 PDF KSCI

열분석에 의한 $CaO.Al_2O_3.2SiO_2$ 유리의 결정화 고찰 (Crystallization Behavior of $CaO.Al_2O_3.2SiO_2$ Glass with Kinetic Parameters)

  • 이승한;류봉기;박희찬
    • 한국세라믹학회지
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    • 제31권12호
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    • pp.1545-1551
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    • 1994

  • Various kinetic parameters of the nucleation and crystallization in anorthite glass (CaO.Al2O3.2SiO2) were calculated by nonisothermal differential thermal analysis. Base glass and glass with TiO2 were prepared by melting. In base glass, the temperature where nucleation can occur ranges from 85$0^{\circ}C$ to 9$25^{\circ}C$ and the temperature for maximum nucleation was 900$\pm$5$^{\circ}C$. In glass with TiO2, the nucleation temperature range was 800~875$^{\circ}C$ and the maximum nucleation temperature was 850$\pm$5$^{\circ}C$. Kissinger equation, Bansal equation, and modified Ozawa equation were used for calculating activation energy for crystallization, Ec. The results showed the same activation energies for both glasses with and without TiO2 in the different equations. The shape of maximum exotherm peak and Ozawa equation were used for Avrami exponent, n. The n value for each glass was 2, indicating that each glass crystallized primarily by bulk crystallization.

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열경화성 액정 에폭시 수지의 열분해 활성화에너지 (Thermal Decomposition Energy of Liquid Crystalline Epoxy)

  • 조승현
    • Composites Research
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    • 제37권1호
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    • pp.1-6
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    • 2024

  • 합성한 Diglycidyl ether of 4,4'-dihydroxy-α-methylstilbene (DGE-DHMS)에 1-Methyl Imidazole을 2:1의 비율로 첨가하여 새로운 액정 에폭시 올리고머인 DDA를 합성하여 열안정성을 평가하였다. TGA분석을 통해 얻어진 결과로 볼 때 액정상과 isotropic상에서 열안정성의 차이는 관찰되지 않았고, Flynn-Wall-Ozawa method와 Kissinger method를 이용하여 계산한 열분해 활성화 에너지값의 비교 결과 열분해가 진행되는 동안 일정한 메커니즘이 작용함을 확인할 수 있었다.

  • https://doi.org/10.7234/composres.2024.37.1.001 인용 PDF HTML

TGA와 가속열화를 이용한 전선 피복용 PVC의 열적 열화평가 (Evaluation of Thermal Aging on PVC Using Thermo Gravimetry Analysis and Accelerated Thermal Aging Test)

  • 박형주;김기환;김홍
    • 한국화재소방학회논문지
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    • 제18권3호
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    • pp.45-50
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    • 2004

  • 600V용 비닐절연전선의 절연체로 사용되는 PVC의 열적 열화 특성을 열중량분석과 가속열화시험을 이용하여 연구하였다. TGA를 이용한 활성화에너지는 Kissinger method와 Flynn-Wall-Ozawa method를 이용하여 측정하였다. 활성화에너지를 계산한 결과 600V용 PVC 절연전선은 89.29 kJ/mol～111.39 kJ/mol, 내열 PVC절연전선은 97.80 kJ/mol～119.25 kJ/mol로 나타났다. 또한, 저온인 80, 90, 10$0^{\circ}C$에서 장기가속열화를 통한 활성화에너지를 아레니우스 방정식을 이용하여 계산하였다. 그 결과 PVC 절연전선은 92.16 kJ/mol,내열 PVC절연전선은 97.52kJ/mol로 나타났다. 연구결과에 있어 600V내열 PVC절연 전선이 PVC 절연전선에 비해 활성화에너지가 큼을 알 수 있었으며, 사용 수명을 예측함에 있어서도 장기적으로 안정함을 예측할 수 있다.

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