• Title, Summary, Keyword: Ozawa method

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Evaluation of the Activation Energy of Chlorinated Poly Vinyl Chloride (CPVC) Using Thermogravimetric Analysis (TGA를 이용한 Chlorinated Poly Vinyl Chloride(CPVC)의 활성화 에너지 평가)

  • Park, Hyung-Ju
    • Fire Science and Engineering
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    • v.33 no.1
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    • pp.1-6
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    • 2019
  • The activation energy of CPVC (Chlorinated Poly Vinyl Chloride) used for non-metallic synthetic resin piping in fire-fighting was measured by thermogravimetric analysis (TGA). The activation energy was determined using by TGA kinetic methods, such as Kissinger and Flynn-Wall-Ozawa method. The calculated activation energy was 128.07 kJ/mol (Kissinger method) and 145.60 kJ/mol (Flynn-Wall-Ozawa method). The difference in activation energies calculated by the Kissinger method and Flynn-Wall-Ozawa method was not considered to be significant considering that the different analysis methods. The combustion characteristics will be tested in a future study through an evaluation of thermal deterioration using an accelerated deterioration and air oven aging test and the lifetime of CPVC will be predicted.

Characteristics of Medical Polymer Based on Epoxy Resin System -Cure Characteristics for DGEBA/MDA/PGE- DMU System by Kissinger and Ozawa Equations- (에폭시 수지계 의료용 고분자 재료의 특성 연구 - Kissinger 식과 Ozawa 식에 의한 DGEBA/MDA/PGE-DMU 계의 경화특성 -)

  • Kim, Jang-Hoon;Lee, Jae-Young;Kim, Sang-Wook;Sim, Mi-Ja
    • Korean Journal of Materials Research
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    • v.11 no.9
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    • pp.727-732
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    • 2001
  • The cure kinetics of diglycidyl ether of bisphenol A (DGEBA)/4,4'- methylene dianiline (MDA) system with synthesized phenyl glycidyl ether-dimethylurea (PGE-DMU) was studied by Kissinger and Ozawa equations with DSC analysis in the temperature range of $20~300^{\circ}C$ To investigate the reaction mechanism between epoxy group of PGE and urea group of DMU, FT-lR spectroscopy analysis was used. The epoxide group of PGE reacted with the urea group of DMU and formed a hydroxyl group which acted as a catalyst on the cure reaction of other epoxide and amine groups. The activation energy of DGEBA/MDA system without PGE-DMU was 46.5 kJ/mol and those of the system with 5 and 10 phr of PGE- DMU were 43.4 and 37.0 kJ/mol, respectively. Ozawa method also showed the same tendency.

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Characterization on Co-Combustion of Coal and Paper Mill Sludge (석탄과 제지슬러지 혼소에 따른 연소특성에 관한 연구)

  • Lee, Kamp-Du;Ryu, Tae-Uk;Park, Sang-Won
    • Journal of Environmental Science International
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    • v.22 no.3
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    • pp.331-339
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    • 2013
  • Efforts were made to determine the activation energy and the reaction order by adopting Kissinger and Flynn-Wall-Ozawa analysis methods. All the data were acquired from TGA thermograms for the mixed fuels with different temperature heating rates. It could be known that both the coal and the mixed fuels decomposed thermally at temperature ranges of $300{\sim}700^{\circ}C$. The temperature at the maximum reaction rate, Tp, could be determined by DTG method, which could be obtained by differentiation of TGA thermogram. Kissinger analysis showed the linear relationship with experimental data, showing the activation energy of $319.64{\pm}4$ kJ/mol. From Flynn-Wall-Ozawa analysis, it was shown that the activation energies and the reaction orders did not undergo any significant changes with both the conversions and the heating rates. It was considered from this facts that the combustion mechanism of the mixed fuels could not be affected by the extent of conversion and heating rate. In the present study, the activation energies showed different values according to the different analysis methods. The difference might be originated from the inconsistency of the mathematical data treatment method. In other words, while the activation energies obtained from the Kissinger method indicated the average values for overall reaction, that from Flynn-Wall-Ozawa method showed the average values for the each conversion around Tp.

Non-isothermal TGA Analysis on Thermal Degradation Kinetics of Modified-NR Rubber Composites (비등온 TGA에 의한 개질NR고무복합재료지 열분해 Kinetics에 관한 해석)

  • Oh, Jeong-Seok;Lee, Joon-Mann;Ahn, Won-Sool
    • Polymer Korea
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    • v.33 no.5
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    • pp.435-440
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    • 2009
  • Thermal degradation behavior of CR (chloroprene) -modified NR (natural rubber) compounds, having different sulfur/accelerator compositions, was studied by non-isothermal TGA method. Data were analyzed using both Kissinger and Flynn-Wall-Ozawa analysis to assess the activation energies. Activation energy obtained from Kissinger analysis was $147.0{\pm}2.0$ kJ/mol for all samples, showing little effect of sulfur/accelerator composition changes in the samples. On the other hand, activation energy from Flynn-Wall-Ozawa analysis exhibited much variations with conversion, showing average value of $211.6{\pm}19.0$ kJ/mol. From the results, it was considered that whole thermal degradation processes of the samples were composed of complex multiple step processes, of which reaction mechanisms were different from each other.

A Study on Thermal Stability of Chlorinated Polyethylene (함염소 폴리에틸렌의 열안정성에 관한 연구)

  • Seul S. D.;Lee N. W.
    • Journal of the Korean Institute of Gas
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    • v.1 no.1
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    • pp.120-126
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    • 1997
  • The thermal decomposition of low density polyethylene(LDPE) and $25\%{\~}48\%$ chlorinated polyethylene(CPE) were studied using a dynamic thermogravimetry in the stream of nitrogen gas with 20ml/min. The mathematic method, differential (Friedman) and Integral (Ozawa) method were used to obtain value of activation energy of decomposition energy on the reaction. The activation energies evaluated by the above methods agree with each other very well. The maximum average activation energy calculated was 71.71kcal/mol. The thermal decomposition of LDPE and CPE were considered to be carried out by main chain scission and the thermogravimetric trace curve agree with the theoretical equation.

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The Potential Energy Recovery and Thermal Degradation of Used Tire Using TGA (열분석법을 이용한 사용후 타이어의 열적 특성과 포텐셜 에너지의 회수)

  • Kim, Won-Il;Kim, Hyung-Jin;Hong, In-Kwon
    • Elastomers and Composites
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    • v.34 no.2
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    • pp.135-146
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    • 1999
  • The thermal degradation kinetics of SBR and tire were studied using a conventional thermogravimetric analysis in the stream nitrogen at a heating rate of 5, 10, 15, $20^{\circ}C/min$, respectively. Thermogravimetric curves and their derivatives were analyzed using various analytical methods to determine the kinetic parameters. The degradation of the SBR and tire was found to be a complex process which has multi-stages. The Friedman method gave average activation energies for the SBR and tire of 247.53kJ/mol and 230.00kJ/mol, respectively. Mean-while, the Ozawa method Eave 254.80kJ/mol and 215.76kJ/mol. It would appear that either. Friedman's differential method or Ozawa's integral method provided satisfactory mathematical approaches to determine the kinetic parameters for the degradation of the SBR and tire. Approximately 86% and 55% of oil products were obtained at a final temperature of $700^{\circ}C$ and a heating rate of $20^{\circ}C/min$ for the SBR and tire respectively.

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Non-isothermal TGA Study on Thermal Degradation Kinetics of ACM Rubber Composites (비등온 TGA를 이용한 ACM 고무복합재료의 열분해 거동 연구)

  • Ahn, WonSool;Lee, Hyung Seok
    • Elastomers and Composites
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    • v.48 no.2
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    • pp.161-166
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    • 2013
  • Thermal degradation behavior of chlorine cure-site ACM and carboxylic cure-site ACM rubbers was studied by non-isothermal TGA thermal analysis. Carboxylic cure-site ACM rubber exhibited comparatively more thermally stable than chlorine cure-site ACM, showing higher peak temperature, at which maximum reaction rate occurred. Activation energies from Kissinger method were calculated as 118.6 kJ/mol for the chlorine cure-site ACM and 105.5 kJ/mol for the carboxylic cure-site ACM, showing similar values from Flynn-Wall-Ozawa analysis over the conversion range of 0.1~0.2. From the analysis of the reaction order change, both samples seemed thermally decomposed through the multiple reaction mechanism as is the common rubber materials.

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

  • 박형주;김기환;김홍
    • Fire Science and Engineering
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    • v.18 no.3
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    • pp.45-50
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    • 2004
  • Thermal degradation of PVC which used for insulator of 600V vinyl insulated wire has been studied by thermo gravimetry analysis and accelerated thermal aging test. The activation energy using thermo gravimetry analysis was determined by the kinetic methods, such as Kissinger and Flynn-Wall-Ozawa. The activation energy was determined to from 89.29 kJ/mol to 111.39 kJ/mol in 600V PVC insulated wire and from 97.80 kJ/mol to 119.25 kJ/mol in 600v heat-resistant PVC insulated wire. And also, the activation energy through a long-term thermal aging test was calculated by using Arrhenius equation In the low temperature of 8$0^{\circ}C$, 9$0^{\circ}C$, 10$0^{\circ}C$. The results showed that 600V PVC insulated wire was 92.16 kJ/mol, and 600v heat-resistant PVC insulated wire was 97.52 kJ/mol. Consequently, the activation energy of 600V heat-resistant PVC insulated wire is larger than 600V PVC insulated wire. Therefore, it can be predicted that 600V heat-resistant PVC insulated wire has a long-term stability relatively.

Non-isothermal Crystallization Behavior of Poly(glycolide-co-ε-caprolactone-co-L-lactide) Block Copolymer (생체분해성 Poly(glycolide-co-ε-caprolactone-co-L-lactide) 블록 공중합물의 비등온 결정화 거동에 관한 연구)

  • Choi, Sei-Young;Song, Seung-Ho
    • Elastomers and Composites
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    • v.49 no.1
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    • pp.13-23
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    • 2014
  • In this work, glycolide, L-lactide and ${\varepsilon}$-caprolactone monomers were polymerized into the triblock copolymers by two step polymerization method and their non-isothermal crystallization behaviors were studied by combination of modified Avrami and Ozawa formula for further analysis of their behaviors. The result showed that PGCLA21 gave the highest value for supercooling analysis and super cooling degree increased with L-lactide content. Crystallization velocity constant, however, showed no significant change. The result of cooling function in specific relative crystallization degree showed that the increase of L-lactide content made an effect on the more enhancement of crystallization velocity of the PGCLA than PGCL. The result of big logF(T) value with the L-lactide content above critical point for PGCLA41 and PGCLA21 showed that bigger cooling velocity needed to gain same crystal size compared with PGCL. This means that it gives negative effect in the increase of crystallization velocity.

Crystallization Behavior and Mechanical Properties of Carbon Nanotube Reinforced Poly(ethylene terephthalate) (탄소나노튜브 충진 폴리에틸렌테레프탈레이트의 결정화거동 및 기계적 물성)

  • Park, Hawe-Soo;Kim, Jun-Young;Kim, Seong-Hun
    • Textile Science and Engineering
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    • v.44 no.1
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    • pp.28-37
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    • 2007
  • Polymer nanocomposites based on multiwall carbon nanotube (MWCNT) and poly(ethylene terephthalate) (PET) were prepared by a melt blending process in a twin-screw extruder. The non-isothermal crystallization behavior of the PET/MWCNT nanocomposites was investigated by employing the Ozawa, the Avrami, and the combined method. The non-iso-thermal crystallization behavior of the PET/MWCNT nanocomposites significantly depends on cooling rate and MWCNT content. The incorporation of MWCNT accelerates the nucleation and crystal growth mechanisms of PET, and this effect being more appreciable at lower MWCNT content. The combined Avrami and Ozawa method was found to be more effective in describing the non-isothermal crystallization process of PET/MWCNT nanocomposites. The nucleation activity of PET/MWCNT nanocomposites was increased with the incorporation of MWCNT. The activation energy for crystallization of PET/MWCNT nanocomposites was higher than that of PET. The incorporation of MWCNT improved the thermal stability and mechanical properties of PET/MWCNT nanocomposites.