• Title, Summary, Keyword: Kissinger method

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The crystallization behavior of glass made from coal bottom ash (석탄 바닥재로 제조된 유리의 결정화 거동 분석)

  • Jang, Seok-Joo;Kang, Seung-Gu
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.20 no.1
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    • pp.58-63
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    • 2010
  • The glass-ceramics made from the mixture of coal bottom ash, produced from a thermal power plant mixed with $Na_2O$ and $Li_2O$ was fabricated and their crystallization behavior was studied using a non-isothermal analyzing method. The temperature for 50% crystallization was higher than the exothermic peak temperature $T_p$ at DTA curve and the quickest crystallization temperature was much the same as $T_p$ as identified from the relationships of crystallized fraction and crystallization rate with temperature. By using Kissinger equation describing a crystallization behavior, the activation energy (262 kJ/mol), the Avrami constant (1.7) and the frequency ($5.7{\times}10^{16}/s$) for crystallization were calculated from which the nepheline crystal could be expected as showing an 1~2-dimensional surface crystallization behavior mainly with some bulk crystallization tendency at the same time. The actual observation of microstructure using SEM showed the considerable amount of surface crystals of dendrite and the bulk crystals with low fraction, so the prediction by the Kissinger equation was in accord with the crystallization behavior of glass-ceramics fabricated in this study.

Thermal Degradation Analyses of Epoxy-Silica Nano Composites (에폭시-실리카 나노 복합소재의 열화 특성 및 거동 분석)

  • Jang, Seo-Hyun;Han, Yusu;Hwang, Do Soon;Jung, Joo Won;Kim, Yeong K.
    • Composites Research
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    • v.33 no.5
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    • pp.268-274
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    • 2020
  • This paper analyzed the degradation behaviors of silica nano epoxy composite based on the isoconversional method. The size of the silica nano particle was about 12 nm and the particles were mixed by three different weight ratios to make the degradation test samples. The thermogravimetric analyses were performed under six different temperature increase rates to measure the weight changes. Four different methods, Friedman, Flynn-Wall-Ozawa, Kissinger and DAEM (Distributed Activation Energy Method), were employed to calculate the activation energies depending on the conversion ratios, and their calculation results were compared. The results represented that the activation energy was increased when the silica nano particles were mixed up to 10%, indicating the definite contribution of the particles to the degradation behavior enhancements. However, the enhancement was not proportional to the particle mixture ratio by demonstrating the similar activation energies between 10% and 18% samples. The calculation results by the different methods were also compared and discussed.

A Study of Thermal Decomposition Characteristics and Toxicity of Product on PS/SAN/ABS (PS/SAN/ABS의 열분해특성과 생성물의 독성에 관한 연구)

  • Kang Yun Jin;Lee Nae Woo;Seul Soo Duk
    • Journal of the Korean Institute of Gas
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    • v.4 no.1
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    • pp.16-25
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    • 2000
  • To estimate the thermal characteristics and toxic parameters on styrene copolymers, We have investigated the activation energy, physical features and generation possibility of toxic material like narcotic gases. The activation energy was 25${\~}$50 Kcal/mol by the Kissinger's and DSC method at high temperature decomposition. It will be good information to estimate the possibility of fire occurrence. From calculations of FED, the values of $LC_{50}$ for PS, SAN and ABS were checked as 8,580, 265 and 308 $mg/m^3$ The mechanisms of thermal decomposition were mainly estimated by main chain scission, not by side group on FT-IR analysis.

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Cure Kinetics of DGEBA/MDA/SN/HQ Thermosetting Matrix (열경화성 DGEBA/MDA/SN/HQ 매트릭스의 경화반응 속도)

  • Lee, Jae-Yeong;Sim, Mi-Ja;Kim, Sang-Uk
    • Korean Journal of Materials Research
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    • v.5 no.6
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    • pp.667-672
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    • 1995
  • Cure kinetics of DGEBA(diglycidyl ether of bisphenol A)/MDA(4, 4'-methylene dianiline)/SN(succinonitrile) system and DGEBA/MDA/SN/HQ(hydroquinone) system was studied by Kissinger equation and Fractional life method through DSC in the temperature range of 85∼150$^{\circ}C$. As cure temperature was increased, reaction rate increased and reaction order was almost constant. The reaction rate of the system with HQ as a catalyst was more higher and activation energy of that was lower about 20% than those of the system without HQ. Starting temperature of cure reaction for DGEBA/MDA/SN/HQ system decreased about 30$^{\circ}C$ than that of DGEBA/MDA/SN system.

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The Study on Thermal Analysis and Thermodynamic Characteristics of Spinel Compounds(ZnCo2O4, NiCo2O4) (스피넬 구조를 가지는 전이금속화합물(ZnCo2O4, NiCo2O4)의 열적 분석 및 열역학적 특성 연구)

  • Kim, Jae-Uk;Ji, Myoung-Jin;Cha, Byung-Kwan;Kim, Chul-Hyun;Jang, Won-Cheoul;Kim, Jong-Gyu
    • Journal of the Korean Chemical Society
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    • v.54 no.2
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    • pp.192-197
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    • 2010
  • The spinel compound was obtained by the thermal decomposition of Zn-Co and Zn-Ni gel prepared by sol-gel method using oxalic acid as a chelating agent. The formation of spinel compound has been comfirmed by thermogravimetric analysis (TGA), x-ray powder diffraction (XRD) and infrared spectroscopy (IR). The particle size of 13 nm~16 nm was calculated by Scherrer's equation. The sol-gel method provides a practicable and effective route for the synthesis of the spinel compound at low temperature ($350^{\circ}C$). The kinetic parameters such as activation energy (Ea) and pre-exponential factor (A) for each compound were found by means of the Kissinger method and Arrhenius equation. The decomposition of spinel compound has an activation energy about 155 kJ/mol. Finally, the thermodynamic parameters (${\Delta}G^{\varphi}$, ${\Delta}H^{\varphi}$, ${\Delta}S^{\varphi}$) for decomposition of spinel compound was determined.

Study on Thermal Decomposition of Korean Diaspore (국내산 다이아스포아의 열분해에 관한 연구)

  • 이헌수;손명모;박희찬
    • Journal of the Korean Ceramic Society
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    • v.24 no.4
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    • pp.307-312
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    • 1987
  • The investigation has been performed to study thermal dehydration of Song-sug, Pyung-il-do and Chung-mu diapore in Korea. Thermal analysis of Korean diaspore showed two steps of dehydration by dispore and kaolinite. The activation energy of dehydration reation of each diaspore was calculated by kissinger's method, and the results obtained were 63.608, 37.867 and 54.885Kcal/mol, respectively.

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Synthesis and Characterization of UV-curable Aliphatic Epoxy Acrylate (자외선 경화형 지방족 에폭시 아크릴레이트의 합성 및 특성분석)

  • Kim, Young Chul;Lee, Byung-Hoon
    • Journal of Adhesion and Interface
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    • v.10 no.4
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    • pp.191-198
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    • 2009
  • UV-curable aliphatic epoxy acrylates were prepared by the reaction of glycerol diglycidyl ether (GDE) with 2-carboxyethyl acrylate (2-CEA) or 2-hydroxyethyl acrylate (2-HEA). The structures of the epoxy acrylates were characterized by FT-IR, $^1H$-NMR, and $^{13}C$-NMR and the yield was obtained by prep-LC. The UV- and the thermal-curing behaviors of the product were investigated using photo-DSC and DSC, respectively. The reactivity of 2-CEA was higher than 2-HEA and the yield of the product (GEA-C) which was prepared using 2-CEA was about 83%. The maximum UV-curing time ($T_{max}$) of the GEA-C contained non-reactive components and by-product was about 10 seconds. The GEA-C showed low color difference (${\Delta}E^*$), low viscosity, and good thermal stability - its value was 2.51, 192 cps, and $299^{\circ}C$ (at 5% weight loss), respectively. The activation energies ($E_a$) of thermal-curing reaction calculated from Kissinger and Ozawa-Flynn-Wall method were 91~92 kJ/mol.

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Analysis of Environmental Process for Commercial Rubbers using Thermal Degradation (열분해를 이용한 범용고무의 환경친화적 처리공정 해석)

  • Kim, Won-Il;Lee, Seung-Bum;Hong, In-Kwon
    • Elastomers and Composites
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    • v.35 no.4
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    • pp.272-280
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    • 2000
  • The experimental kinetics was analyzed for commercial rubbers such as NR, IR, BR, SBR 1500, and SBR 1700. Kinetic analysis for the commercial rubbers was performed using a thermogravimetric method, which the activation energies of NR obtained by Kissinger, Friedman, ana Ozawa's method were 195.0, 198.3, and 186.3 kJ/mol, respectively. whereas that of SBR 1500 were 246.4, 247.5, and 254.8 kJ/mol, respectively. It was shown that the yield of pyrolytic oil was generally increased with increasing the final temperature. Considering the effect of heating rate. it was found that the yield of pyrolytic oil was not consistent for each sample. The number average molecular weight of pyrolitic oil of SBR 1500 was in the range of 740-2486. The calorific value of SBR 1500 was 39-40 kJ/g, and it might be a considerable energy potential although it was lower than the conventional fuel such as kerosene, diesel, light fuel, and heavy fuel.

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A Study of Crystallization and Fracture Toughness of Glass Ceramics in the ZrO2·SiO2 Systems Prepared by the Sol-Gel Method (졸-겔법으로 제조한 ZrO2·SiO2계 결정화 유리의 결정화 및 파괴인성에 관한 연구)

  • Shin, Dae-Yong;Han, Sang-Mok;Kang, Wie-Soo
    • Journal of Industrial Technology
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    • v.20 no.A
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    • pp.247-256
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    • 2000
  • Precursor gels with the composition of $xZrO_2{\cdot}(100-x)SiO_2$ systems (x=10, 20 and 30 mol%) were prepared by the sol-gel method. Kinetic parameters, such as activation energy, Avrami's exponent, n, and dimensionality crystal growth value, m, have been simultaneously calculated from the DTA data using Kissinger and Matusita equations. The crystallite size dependence on tetragonal to monoclinic transformation of $ZrO_2$ was investigated using XRD, in relation to the fracture toughness. The crystallization of tetragonal $ZrO_2$ occurred through 3-dimensional diffusion controlled growth(n=m=2) and the activation energy for crystallization was calculated using Kissinger and Matusita equations, as about $310{\sim}325{\pm}10kJ/mol$. The growth of $t-ZrO_2$, in proportion to the cube of radius, increased with increasing heating temperature and heat-treatment time. It was suggested that the diffusion of Zr4+ions by Ostwald ripening was rate-limiting process for the growth of $t-ZrO_2$ crystallite size. The fracture toughness of $xZrO_2{\cdot}(100-x)SiO_2$ systems glass ceramics increased with increasing crystallite size of $t-ZrO_2$. The fracture toughness of $30ZrO_2{\cdot}70SiO_2$ system glass ceramics heated at $1,100^{\circ}C$ for 5 h was $4.84Mpam^{1/2}$ at a critical crystaliite size of 40 nm.

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Rheological Properties and Cure Kinetics of Cycloaliphatic/DGEBA Epoxy Blend System Initiated by Cationic Latent Curing Agent (잠재성 경화제를 이용한 Cycloaliphatic/DGEBA계 에폭시 블렌드 시스템의 유변학적 특성 및 경화 동력학)

  • 곽근호;박수진;이재락;김영근
    • The Korean Journal of Rheology
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    • v.10 no.4
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    • pp.227-233
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    • 1998
  • The effects of 1 mol% N-benzylpyrazinium hexafluoroantimonate(BPH) as a thermal latent initiator and blend compositions composed of cycloaliphatic and DGEBA epoxies were investigated in the rheological properties and cure kinetics. Latent properties were performed by measurement of the conversion as a function of reaction time using isothermal DSC at $150^{\circ}C$ and $50^{\circ}C$ Rheological properties of the blend systems were investigated in terms of isothermal experiments using a rheometer. The gelation time was obtained from the evaluation of storage modulus (G'), loss modulus (G") and damping factor (tan$\delta$)). Cross-linking activation energy ($E_c$) was also determined from the Arrhenius equation based on gel time and curing temperature. As a result, the gel time and cross-linking activation energy increased with increasing DGEBA composition. The cure activation energies ($E_a$) were obtained by Kissinger method using dynamic DSC thermograms. In this work, the cure activation energy decreased with increasing CAE concentration, which might be resulted from the short repeat units, simple side-groups and viscosity of reaction media.edia.

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