• Title, Summary, Keyword: Thermogravimetric technique

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COMBUSTION KINETICS OF POLYETHYLENE TEREPHTHALATE

  • Oh, Sea-Cheon;Lee, Dong-Gyu;Kwak, Hyun;Bae, Seong-Youl
    • Environmental Engineering Research
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    • v.11 no.5
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    • pp.250-256
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    • 2006
  • The combustion kinetics of poly(ethylene terephthalate) (PET) was studied by the dynamic model which accounts for the thermal decomposition of polymer at any time. The kinetic analysis was performed by a conventional nonisothermal thermogravimetric (TG) technique at several heating rates between 10 and 40 K/min in air atmosphere. The thermal decomposition of PET in air atmosphere was found to be a complex process composed of at least two stages for which kinetic values can be calculated. The combustion kinetic analysis of PET gave apparent activation energy for the first stage of $257.3{\sim}269.9\;kJ/mol$, with a value of $140.5{\sim}213.8\;kJ/mol$ for the second stage. To verify the effectiveness of the kinetic analysis method used in this work, the kinetic analysis results were compared with those of various analytical methods. The kinetic parameters were also compared with values of the pyrolysis of PET in nitrogen atmosphere.

Lifetime Prediction of PTFE Electrical Insulation Material Using Thermal Analysis Technique (열분석장치를 적용한 PTFE 전기절연재의 수명 예측 연구)

  • Yoon, Sung-Ho
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.296-297
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    • 2011
  • A series of thermogravimetric analysis tests were conducted to predict the lifetime of the PTFE electrical insulation material. The prepared PTFE samples were heated from $25^{\circ}C$ to $700^{\circ}C$ at different heating rates. The kinetic energy of the PTFE was calculated from the logarithmic heating rate versus reciprocal temperature curves at constant conversion levels. Also, the lifetime of the PTFE for a given operating temperature can be predicted using the relationship between the activation energy and the estimated lifetime proposed by Toop.

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Thermal Characteristics of Polypropylene in Combustion Reaction Using TGA (TGA를 이용한 폴리프로필렌의 연소반응에서의 열적 특성 연구)

  • Kang, Yun-Jin;Seo, Su-Eun;Seo, Gyu-Suk;Kang, Kyung-Sik
    • Journal of the Korea Safety Management and Science
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    • v.10 no.4
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    • pp.111-120
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    • 2008
  • The combustion reaction of polypropylene was investigated using a thermogravimetric technique under an air atmosphere condition at several heating rates from 10 to $50^{\circ}C/min$. To obtain information on the kinetic parameters, the dynamic thermogravimetric analysis curve and its derivative were analyzed by a variety of analytical methods such as Kissinger, Friedman, Freeman-Carroll, Chatterjee-Conrad, Ozawa and Coats-Redfern methods. The comparative works for the kinetic results obtained from various methods should be performed to determine the kinetic parameters, because there are tremendous differences in the calculated kinetic parameters depending upon the mathematical method taken in the analysis.

Thermal Degradation of High Molecular Components Obtained from Pyrolysis of Mixed Waste Plastics (혼합폐플라스틱의 열분해로부터 생성된 고분자성분의 열적분해)

  • Oh, Sea Cheon;Ryu, Jae Hun;Kwak, Hyun;Bae, Seong-Youl;Lee, Kyong-Hwan
    • Applied Chemistry for Engineering
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    • v.19 no.2
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    • pp.191-198
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    • 2008
  • The thermal degradation characteristics of high molecular components obtained from pyrolysis of mixed waste plastics have been studied by thermogravimetric analysis (TGA) and gas chromatography spectrometry (GC-MS). The kinetics of thermal degradation has been studied by a conventional nonisothermal thermogravimetric technique at several heating rates between 10 and $50^{\circ}C/min$. The dynamic thermogravimetric analysis curve and its derivative have been analyzed using a variety of analytical methods reported in the literature to obtain information on the kinetic parameters such as activation energies and reaction orders. The yields of liquid products have been monitored by batch pyrolysis reactor under various reaction temperatures and reaction times. And the characteristic of liquid products with the increase in reaction temperature has been performed by GC-MS.

Sulfation Reaction Kinetics of Pulverized Korean Dolomite and Limestone using Thermogravimetric Analyses (열중량분석을 이용한 국내산 미분 백운석과 석회석의 황화 반응 특성 연구)

  • 박영철
    • Journal of Energy Engineering
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    • v.7 no.2
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    • pp.216-222
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    • 1998
  • Thermogravimetric analyses were conducted by isothermal technique in order to characterize the sulfation reaction of calcined sorbents such as Tanyang dolomite, Yongwol dolomite, Tanyang limestone, and Yongwol limestone. Sulfation reaction for 0.08 mm in particle diameter were carried out with respect to various factors.; isothermal reaction temperatures (650~85$0^{\circ}C$), SO$_2$ concentration (0.38~1%), and oxygen concentration (1.2~6.7%). Measured reaction orders of SO$_2$ concentration, oxygen concentration, and activation energy were 0.3~2.2, 0.22~0.51 and 23.6~36 kJ/mol, respectively. The kinetic equations of sulfation reaction of calcined dolomites were correlated with various factors.

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Thermal Characteristics of Polyvinylchloride in Combustion Reaction Using TGA (TGA를 이용한 폴리염화비닐의 연소반응에서의 열적 특성 연구)

  • Seo, Su-Eun;Kang, Yun-Jin;Min, Cho-Young;Bae, Dong-Chul;Kang, Kyung-Sik
    • Journal of the Korea Safety Management and Science
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    • v.11 no.3
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    • pp.217-226
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    • 2009
  • The combustion reaction of polyvinylchloride(PVC) was investigated using a thermogravimetric technique under an air atmosphere condition at several heating rates from 10 to $50^{\circ}C$/min. To obtain information on the kinetic parameters, the dynamic thermogravimetric analysis curve and its derivative were analyzed by a variety of analytical methods such as Kissinger, Friedman, Chatterjee-Conrad, Ozawa and Coats-Redfern methods. The combustion reaction of PVC proceeded in two steps; the first step was caused by the dehydrochlorination process in PVC, and the second step by the combustion of polyene. The comparative works for the kinetic results obtained from various methods should be performed to determine the kinetic parameters, because there are tremendous differences in the calculated kinetic parameters depending upon the mathematical method taken in the analysis.

Non-isothermal Pyrolysis Characteristics of the Mixture of Waste Automobile Lubricating Oil and Polystyrene (폐윤활유와 Polystyrene 혼합물의 비등온 열분해반응 특성)

  • Kim, Seung-Soo;Chun, Byung-Hee;Park, Chan Jin;Kim, Sung Hyun
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.6
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    • pp.1063-1072
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    • 2000
  • Kinetic tests on pyrolysis of the mixture of waste automobile lubricating oil and polystyrene were carried out with thermogravimetric technique at the heating rates of 0.5, 1.0, $2.0^{\circ}C/min$ in a stirred batch reactor. The activation energy and the reaction order were determined at conversions of 1 to 100% using differential method. The mixture of waste automobile lubricating oil and polystyrene was pyrolyzed at lower temperature rather than waste automobile lubricating oil and polystyrene. respectively. Also, the thermal decomposition took place in two broad reaction steps. The pyrolyzed oil of mixture represented high selectivity of styrene monomer and dimer like that of polystyrene pyrolyzed products.

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Synthesis, Characterization and Enhanced Selectivity in RP-HPLC of Polar Carbonyl Group Embedded Poly (Vinyl Octadecanoate) Grafted Stationary Phase by Simple Heterogeneous "Graft from" Technique

  • Rana, Ashequl A.;Karim, Mohammad Mainul;Takafuji, Makoto
    • Bulletin of the Korean Chemical Society
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    • v.32 no.1
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    • pp.77-82
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    • 2011
  • A new high performance liquid chromatograpgy (HPLC) stationary phase that possesses an internal carbonyl functional group is synthesized by heterogeneous "graft from" method. This new stationary phase, poly (vinyl octadecanoate) grafted silica (Sil-2) is then characterized by different physico-chemical methods such as diffuse reflectance infrared fourier transform, suspension state $^1H$ NMR, solid state $^{13}C$ CP/MAS NMR, $^{29}Si$ CP/MAS NMR, elemental analysis and thermogravimetric analysis. Chromatographic properties of Sil-2 were evaluated under reversed phase condition by separating polycyclic aromatic hydrocarbons (PAHs) and comparing the chromatographic results with those on polymeric as well as monomeric octadecylated silica stationary phases.

Preparation and characterization of eggshell membrane/PVA hydrogel via electron beam irradiation technique

  • Choi, Jawun;Pant, Bishweshwar;Lee, Chohye;Park, Mira;Park, Soo-Jin;Kim, Hak-Yong
    • Journal of Industrial and Engineering Chemistry
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    • v.47
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    • pp.41-45
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    • 2017
  • Eggshell membrane (ESM), which locates between the egg white and the inner surface of the eggshell, is generally considered as waste; however, it can be utilized in various fields. In this contribution, we report a fabrication of ESM based hydrogel by incorporating with polyvinyl alcohol (PVA) via an electron beam irradiation technique. A hydrogel with porous structure along with homogeneous networks was obtained by this ecofriendly approach. The resulting ESM based hydrogels were characterized by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The swelling analysis of the produced hydrogel showed a super absorption property. This cost effective method eliminates the use of sophisticated equipment's and toxic chemicals used to fabricate hydrogel for various applications.

Synthesis of Pentadentate Schiff Base Molybdenum(Ⅴ) Complexes and Their Electrochemical Properties in Aprotic Solvents (다섯자리 Schiff Base Molybdenum(Ⅴ) 착물들의 합성과 비수용매에서의 전기화학적 성질)

  • Kim, Seon Suk;Choe, Ju Hyeong;Choe, Yong Guk;Jeong, Byeong Gu
    • Journal of the Korean Chemical Society
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    • v.38 no.2
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    • pp.160-168
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    • 1994
  • Pentadentate Schiff base molybdenum(Ⅴ) complexes such as [Mo(Ⅴ)O(Sal-DET)(NCS)] and [Mo(Ⅴ)O(Sal-DPT)(NCS)] were synthesized by Sabat method. The structure of these complexes were identified by elemental analysis, spectroscopy, and thermogravimetric analysis(T.G.A.). It was found that the mole ratio of Schiff base ligand to the complexes was found to be 1 : 1. The redox processes of the complexes were investigated by cyclic voltammetric and differential pulse polarographic technique in nonaqueous solvent containing 0. 1 M tetraethyl ammonium perchlorate(TEAP) as supporting electrolyte at glassy carbon electrode. It was found that diffusion controlled reduction processes of four steps with one electron were 2Mo(Ⅴ)$\rightleftarrow^{e-}$ Mo(Ⅴ)Mo(Ⅳ) $\longrightarrow^{e-}$ 2Mo(Ⅳ), Mo(Ⅳ) $\longrightarrow^{e-}$ Mo(Ⅲ) $\longrightarrow^{e-}$ Mo(Ⅱ)

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