scholarly journals Synthesis and characterization of a new conjugated polymer containing bithiazole group and its thermal decomposition kinetics

2020 ◽  
Vol 39 (2) ◽  
pp. 227
Author(s):  
Adnan Kurt ◽  
Hacer Andan ◽  
Murat Koca
Keyword(s):  
Thermal Decomposition ◽  
Heating Rate ◽  
Conjugated Polymer ◽  
Three Dimensional ◽  
Heating Rates ◽  
Diffusion Type ◽  
Optimum Heating ◽  
Rate Loss ◽  
Kinetics Of

A new conjugated polymer containing a bithiazole group is prepared by the polycondensation of 2,2'-diamino-4,4'-bithiazole and terephthaldialdehyde in the presence of glacial acetic acid. The kinetics of thermal degradation of the new polymer are investigated by thermogravimetric analysis at different heating rates. The temperature corresponding to the maximum rate loss shifts to higher temperatures with increasing heating rate. The thermal decomposition activation energies of the conjugated polymer in a conversion range of 3–15 % are 288.4 and 281.1 kJ/mol by the Flynn–Wall–Ozawa and Kissinger methods, respectively. The Horowitz–Metzger method shows that the thermodegradation mechanism of the conjugated polymer proceeds over a three-dimensional diffusion type deceleration D3 mechanism. The optimum heating rate is 20 ºC/min.

scholarly journals Thermal decomposition kinetics of a coumarin based copolymer: Poly(3-benzoyl coumarin-7-yl-methacrylate:0.54-co-methyl methacrylate:0.46)

2019 ◽  
Vol 15 (2) ◽  
pp. 206-211
Author(s):  
Adnan Kurt ◽  
Ahmet Faruk Ayhan ◽  
Murat Koca
Keyword(s):  
Thermal Decomposition ◽  
Methyl Methacrylate ◽  
Heating Rate ◽  
Kinetic Equations ◽  
Three Dimensional ◽  
Diffusion Type ◽  
Optimum Heating ◽  
Coumarin 7 ◽  
Copolymer Poly ◽  
Kinetics Of

In present study, thermal decomposition studies of a copolymer based the coumarin containing monomer 3-benzoyl coumarin-7-yl-methacrylate (BCMA) and methyl methacrylate [poly(BCMA:0.54-co-MMA:0.46)] were performed by thermogravimetric analysis (TGA). The temperature for maximum rate losses was increased from 384.81 °C to 407.45 °C with the increasing in heating rate from 5 °C/min to 20°C/min. The thermal decomposition activation energies of copolymer in the conversion range of 9% - 21% were resulted to be 212.98 kJ/mol and 210.30 kJ/mol by Kissinger’s and Flynn–Wall–Ozawa methods, respectively. The study of kinetic equations such as Coats-Redfern, Tang, Madhusudanan and Van-Krevelen methods exhibited that the thermal decomposition process of the studied copolymer was followed with a D3 mechanism, a three-dimensional diffusion type deceleration solid state mechanism, at the optimum heating rate of 20 °C/min.  

scholarly journals Synthesis and characterization of a novel isocoumarin derived polymer and its thermal decomposition kinetics

2018 ◽  
Vol 37 (2) ◽  
Author(s):  
Adnan Kurt ◽  
Halil Ibrahim Avci ◽  
Murat Koca
Keyword(s):  
Thermal Decomposition ◽  
Heating Rate ◽  
Thermal Decomposition Mechanism ◽  
Diffusion Type ◽  
Positive Direction ◽  
One Dimensional ◽  
Dimensional Diffusion ◽  
Nmr Techniques ◽  
Optimum Heating

A novel isocumarin derived polymer poly(2-(isocoumarin-3-yl)-2-oxoethyl methacrylate) poly(ICEMA) was synthesized by free radical polymerization. The spectral characterization was performed with FTIR and 1H,13C-NMR techniques. The glass transition temperature of poly(ICEMA) was measured to be 161.69 °C by DSC technique. The initial decomposition temperatures obtained from TGA showed a change in the positive direction from 256.59 °C to 286.10 °C as the heating rate increased to 20 °C/min. Thermal decomposition activation energies of poly(ICEMA) in the conversion range of 7% - 19% were found to be 136.12 kJ/mol and 134.83 kJ/mol by Flynn–Wall–Ozawa and Kissinger’s models, respectively. In addition, various integral models such as Coats-Redfern, Tang, Madhusudanan and Van-Krevelen models were used to determine the thermal decomposition mechanism of poly(2-(isocoumarin-3-yl)-2-oxoethyl methacrylate)which showed that it proceeded at the optimum heating rate of 5 ºC/min over the D1 one-dimensional diffusion type deceleration mechanism

Study on the Pyrolysis Kinetics of HCl-Pretreated Soybean Stalk

2014 ◽  
Vol 953-954 ◽  
pp. 261-266
Author(s):  
Dong Yu Chen ◽  
Yan Qing Hu ◽  
Qing Yu Liu
Keyword(s):  
Heating Rate ◽  
Temperature Increase ◽  
Loss Rate ◽  
High Efficiency ◽  
Three Dimensional ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Acid Washing ◽  
Shoulder Peak ◽  
Kinetics Of

To study the influences of the acid-washing on the characteristics of soybean stalk pyrolysis , and search the high-efficiency catalyst for biomass pyrolysis, pyrolysis experiments of soybean stalk pretreated by 0.1mol/L HCl acid solution were performed by nonisothermal thermogravimetric analysis (TGA) at five different heating rates. The results showed the pyrolysis process of HCl-washed soybean stalk can be separated into four stages (water loss, depolymeri-zation and vitrification, thermal decomposition, and carbonization). At the same heating rate, the maximum pyrolysis rate of HCl-washed is larger than untreated soybean stalk, but the corresponding temperature is higher. All the DTG (differential thermogravimetric) curveas appear a smaller shoulder peak respectively. With the heating rate increasing, the main pyrolysis zone of the TG (thermogravimetric) and DTG curves move to the high-temperature direction, and the maximum pyrolysis rate and its corresponding temperature increase too. HCl-wahsed makes the weight loss rate of the final temperature increase 5% approximately. The value area of activation energy of the main pyrolysis area is 140.19~174.59 kJ/mol calculated by the method of Ozawa. The Šatava method inferred the most possible mechanism function of HCl-wahsed soybean stalk is Zhuralev-Lesakin-Tempelman equation, which is three-dimensional diffusion.

scholarly journals Kinetic study of Mongolian coals by thermal analysis

2018 ◽  
Vol 18 (44) ◽  
pp. 20-23
Author(s):  
Jargalmaa S ◽  
Tsatsral G ◽  
Battsetseg M ◽  
Batkhishig D ◽  
Ankhtuya A ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Thermal Characterization ◽  
Low Rank ◽  
Weight Changes ◽  
Heating Rates ◽  
Weight Losses ◽  
Brown Coals ◽  
Temperature Ranges ◽  
Kinetics Of

Thermal analysis was used for the thermal characterization of the coal samples. The experiments were performed to study the pyrolysis and gasification kinetics of typical Mongolian brown coals. Low rank coals from Shivee ovoo, Ulaan ovoo, Aduun chuluun and Baganuur deposits have been investigated. Coal samples were heated in the thermogravimetric apparatus under argon at a temperature ranges of 25-1020ºC with heating rates of 10, 20, 30 and 40ºC/min. Thermogravimetry (TG) and derivative thermogravimetry (DTG) were performed to measure weight changes and rates of weight losses used for calculating the kinetic parameters. The activation energy (Ea) was calculated from the experimental results by using an Arrhenius type kinetic model.

Thermal Decomposition Kinetics of Flame Retardant Polybutylene Terephthalate Matrix Composites

2019 ◽  
Vol 956 ◽  
pp. 181-191
Author(s):  
Jian Lin Xu ◽  
Bing Xue Ma ◽  
Cheng Hu Kang ◽  
Cheng Cheng Xu ◽  
Zhou Chen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Flame Retardant ◽  
Mass Loss Rate ◽  
Decomposition Reaction ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Heating Rates ◽  
Polybutylene Terephthalate ◽  
Kinetics Of

The thermal decomposition kinetics of polybutylene terephthalate (PBT) and flame-retardant PBT (FR-PBT) were investigated by thermogravimetric analysis at various heating rates. The kinetic parameters were determined by using Kissinger, Flynn-Wall-Ozawa and Friedman methods. The y (α) and z (α) master plots were used to identify the thermal decomposition model. The results show that the rate of residual carbon of FR-PBT is higher than that of PBT and the maximum mass loss rate of FR-PBT is lower than that of PBT. The values of activation energy of PBT (208.71 kJ/mol) and FR-PBT (244.78 kJ/mol) calculated by Kissinger method were higher than those of PBT (PBT: 195.54 kJ/mol) and FR-PBT (FR-PBT: 196.00 kJ/mol) calculated by Flynn-Wall-Ozawa method and those of PBT and FR-PBT (PBT: 199.10 kJ/mol, FR-PBT: 206.03 kJ/mol) calculated by Friedman methods. There is a common thing that the values of activation energy of FR-PBT are higher than that of PBT in different methods. The thermal decomposition reaction models of the PBT and FR-PBT can be described by Avarami-Erofeyev model (A1).

scholarly journals Nonisothermal Thermogravimetric Analysis of Thai Lignite with High CaO Content

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Pakamon Pintana ◽  
Nakorn Tippayawong
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Thermogravimetric Analysis ◽  
Combustion Kinetics ◽  
Heating Rates ◽  
Thermogravimetric Method ◽  
Degradation Behaviors ◽  
Fwo Method ◽  
Free Cao ◽  
Kinetics Of

Thermal behaviors and combustion kinetics of Thai lignite with different SO3-free CaO contents were investigated. Nonisothermal thermogravimetric method was carried out under oxygen environment at heating rates of 10, 30, and 50°C min−1from ambient up to 1300°C. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods were adopted to estimate the apparent activation energy (E) for the thermal decomposition of these coals. Different thermal degradation behaviors were observed in lignites with low (14%) and high (42%) CaO content. Activation energy of the lignite combustion was found to vary with the conversion fraction. In comparison with the KAS method, higherEvalues were obtained by the FWO method for all conversions considered. High CaO lignite was observed to have higher activation energy than the low CaO coal.

Kinetics of Thermal Decomposition of Group-Hi Metal Alkyls on GaAs(100)

1990 ◽  
Vol 204 ◽  
Author(s):  
V. M. Donnelly ◽  
J. A. Mccaulley ◽  
R. J. Shul
Keyword(s):  
Thermal Decomposition ◽  
Low Temperature ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Semiconductor Films ◽  
Heating Rates ◽  
Kinetics Of Thermal Decomposition ◽  
Cracking Pattern ◽  
Kinetics Of ◽  
Metal Alkyls

ABSTRACTWe report studies of the kinetics of thermal decomposition of triethylgallium (TEGa), trimethylgallium (TMGa), and trimethylindium (TMIn) adsorbed on GaAs(100) in ultrahigh vacuum. The adsorbed layers were prepared by dosing GaAs(100) at room temperature, to either saturated coverage or coverages below saturation. Subsequent heating leads to loss of adsorbed hydrocarbons. The relative coverage of carbon was monitored by X-ray photoelectron spectroscopy (XPS), and products were detected with a differentially pumped quadrupole mass spectrometer. The kinetic analysis also includes measurements of laser-induced, rapid thermal decomposition (heating rates of ∼1011°C/s).TEGa dissociatively chemisorbs on GaAs(100). Heating the substrate results in desorption of diethylgallium radicals at low temperature and C2H4 (and some C2H5) at higher temperatures, after most of the diethylgallium has desorbed. TMGa decomposes to yield a Ga-alkyl desorption product (either dimethylgallium, or a mixture of dimethylgallium and TMGa) at low temperature and CH3 at higher temperature. TMIn undergoes a methyl exchange reaction on GaAs(100) where a Ga-alkyl desorbs with the same cracking pattern as in TMGa decomposition. Decomposition mechanisms for these group-III metal alkyls are proposed, Arrhenius parameters are presented, and some implications are discussed for growth of Ga-containing III-V compound semiconductor films from these precursors by chemical vapor deposition and molecular beam techniques.

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