• Title, Summary, Keyword: Kissinger method

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A Study on Formation and Thermal Decomposition Kinetics of PU Elastomers by Dynamic DSC and TGA Analysis (Dynamic DSC 및 TGA 열분석을 이용한 PU Elastomer의 중합반응 및 열분해 반응 Kinetics에 관한 연구)

  • Yoon, Soo-Koong;Ahn, Won-Sool
    • Elastomers and Composites
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    • v.42 no.1
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    • pp.47-54
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    • 2007
  • Reaction kinetics of polyurethane elastomers (PU) were studied using dynamic DSC and TGA for three PU samples of general purpose (Sample A), high temperature cross-likable CASE purpose with MOCA (Sample B), and RT cross-likable CASE purpose grade (Sample C). From DSC results, sample with MOCA(Sample B) showed lower shift of peak temperature, while showing broader thermograms than those of general purpose grade (Sample A). On the other hand, RT cross-linkable PU grade (Sample C) showed an interesting double mode reaction patterns, i.e., a lower temperature reaction at about $70\;^{\circ}C$, and a higher temperature reaction in the range of $140{\sim}170\;^{\circ}C$, indicating that it requires 2-step reaction process in order to complete the reaction. Once the cross-linking reaction completed, however, TGA results showed that all the samples would be considered to have similar chemical structures, showing similar decomposition processes. Sample C, especially, had showed decomposition properties of both Sample A and Sample B. Formation activation energies calculated from Kissinger method showed 10.39, 65.85, 36.52(Low $T_p$) and 18.21(High $T_p$) kcal/mol, while decomposition activation energies were 31.94, 30.84, 24.16 kcal/mol, respectively.

Cure Kinetics of Diglycidyl ether of bisphenol A-Methylene dianiline-Succlnonitrile System (Diglycidyl ether of bisphenol A/Methylene dianiline/Succinonitrile계의 경화반응 속도론)

  • Jo, Seong-U;Sim, Mi-Ja;Kim, Sang-Ok
    • Korean Journal of Materials Research
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    • v.2 no.4
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    • pp.257-262
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    • 1992
  • The cure kinetics of a diglycidyl ether of bisphenol A (DGEBA) with 4, 4'-methylene dianiline (MDA) added succinonitrile was studied through the dynamic run method by applying the data to the Kissinger equation which analyses the effect of the heating rate on the temperature at maximum reaction rate using Differential Scanning Calorimetry (DSC) analyzer in the range of 3$0^{\circ}C$-35$0^{\circ}C$. In the DGEBA/MDA system with SN, the activation energy ($E_a$) and the pre-exponential factor (A) were calculated. From these results, the rate constants (k) were obtained according to the different SN contents.

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Kinetic Studies of the Catalytic Low Rank Coal Gasification under CO2 Atmosphere (CO2분위기하에서 저급석탄 촉매가스화 반응 특성 연구)

  • Park, Chan Young;Park, Ji Yun;Lee, Si Hoon;Rhu, Ji Ho;Han, Moon Hee;Rhee, Young Woo
    • Korean Chemical Engineering Research
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    • v.50 no.6
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    • pp.1086-1092
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    • 2012
  • In this study, kinetic studies and analysis of the produced syngas were conducted for low rank coal gasification under $CO_2$ atmosphere. 6 coals were analyzed to measure amount of sulfur and ash by proximate and ultimate analyses. And then they were analyzed to select suitable sample by using Thermogravimetric analyzer (TGA). Selected coal sample Samhwa was mixed with catalysts. Mixed samples with catalysts were used to get activation energy under $CO_2$ atmosphere by using Kissinger's method and shrinking core model (SCM). Also, analysis of produced syngas was performed by Gas Chromatography (GC). In this experiment, activation of the $K_2CO_3$ was the best performance, and result of the analysis of the syngas showed similar trend with result of the activation energy.

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.

A Study on Effects of Vulcanization Systems on Cross-linking and Degradation Reactions of NR/CR Blends Using Dynamic DSC and TGA (Dynamic DSC와 TGA를 이용한 NR/CR 고무블렌드의 가황시스템이 가교 및 열화반응에 미치는 영향 연구)

  • Min, Byung-kwon;Park, DongRyul;Ahn, WonSool
    • Korean Chemical Engineering Research
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    • v.47 no.2
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    • pp.169-173
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    • 2009
  • Effects of variations sulfur/accelerator ratio on cross-linking and thermal degradation behavior of NR/CR rubber compounds were studied using both dynamic DSC and non-isothermal TGA. DSC thermograms of the given samples were obtained with several different heating rates, and after cross-liked in DSC, TGA thermograms with the same samples also obtained. Kissinger analysis was applied to assess the activation energies for the cross-linking and thermal decomposition processes. Results showed that the formation and thermal decomposition reaction of the samples occurred in the overall temperature range of $120{\sim}180^{\circ}C$ and $350{\sim}450^{\circ}C$, respectively, exhibiting that data could be well-fittable by Kissinger method. Furthermore, formation activation energy by DSC was estimated as $83.0{\pm}5.0kJ/mol$, which was much smaller than that of degradation by TGA, $147.0{\pm}2.0kJ/mol$. From these results, it was considered that, although variations of sulfur/accelerator ratio in the present experiments affected little on the formation mechanism and/or thermal degradation, they could play roles as the catalysts which lower the activation energy of formation. Because of stabilization after formation reaction, however, they have no more effects on the lowering the activation energy, showing higher values when decomposition, caused by main-chain scissions.

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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