scholarly journals Thermal Decomposition Behavior of Melaminium Benzoate Dihydrate

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
N. Kanagathara ◽  
M. K. Marchewka ◽  
K. Pawlus ◽  
S. Gunasekaran ◽  
G. Anbalagan
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Effective Activation Energy ◽  
Preexponential Factor ◽  
Effective Activation ◽  
Heating Rates ◽  
Monoclinic System ◽  
Model Free ◽  
Thermal Decomposition Behavior ◽  
Decomposition Behavior

Crystals of melaminium benzoate dihydrate (MBDH) have been grown from aqueous solution by slow solvent evaporation method at room temperature. Powder X-ray diffraction analysis confirms that MBDH crystallizes in the monoclinic system (C2/c). Thermal decomposition behavior of MBDH has been studied by thermogravimetric analysis at three different heating rates: 10, 15, and 20°C/min. Nonisothermal studies of MBDH revealed that the decomposition occurs in three stages. The values of effective activation energy (Ea) and preexponential factor (ln A) of each stage of thermal decomposition for all heating rates were calculated by model free methods: Arrhenius, Flynn-Wall, Friedman, Kissinger, and Kim-Park methods. A significant variation of effective activation energy (Ea) with conversion (α) indicates that the process is kinetically complex. The linear relationship between the A and Ea values was established (compensation effect). Avrami-Erofeev model (A3), contracting cylinder (R2), and Avrami-Erofeev model (A4) were accepted by stages I, II, and III, respectively. DSC has also been performed.

scholarly journals Adsorption and Decomposition of Peroxides on the Surfaces of Dispersed Oxides Fe2O3, Cr2O3 and V2O5

2019 ◽  
Vol 3 (1) ◽  
pp. 13
Author(s):  
Volodymyr Dutka ◽  
Olena Aksimentyeva ◽  
Nataliya Oschapovska ◽  
Yaroslav Kovalskyi ◽  
Halyna Halechko
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Effective Activation Energy ◽  
Equilibrium Constants ◽  
Langmuir Equation ◽  
Effective Activation ◽  
Activation Energy Of Degradation ◽  
Degradation Reaction ◽  
Desorption Equilibrium ◽  
Adsorption Desorption

The adsorption of peroxides on dispersed oxides Fe2O3, Cr2O3 and V2O5 was studied. It is shown that the adsorption of peroxides is described by the Langmuir equation. The adsorption of benzoyl peroxide grows within Fe2O3<Cr2O3<V2O5. Adsorption-desorption equilibrium constants (K) for Cr2O3 and V2O5 are the same, but for Fe2O3 this value is 6 times higher. The decomposition of peroxides is observed in the solution and on the surface of adsorbents. The effective activation energy (E) of the thermal decomposition of peroxides in the studied systems is in the range of 80–140 kJ/mol. The activation energy of degradation of peroxides on the surface (Es) of the dispersed oxides studied is lower. The degradation reaction of peroxides on the surface of Fe2O3 and V2O5 has an oxidation-reducing nature, during which free radicals are produced. On the surface of Cr2O3, there is a heterolytic decay of peroxides. The parameters of the reaction of peroxides decomposition are found. The decomposition of peroxides in the presence of Fe2O3, Cr2O3 and V2O5 in styrene is accompanied by the formation of polystyrene both in the solution and on the surface of the adsorbent.

Decomposition Kinetics of Switchgrass: Estimating Activation Energy

2014 ◽  
Vol 881-883 ◽  
pp. 726-733
Author(s):  
Gui Ying Xu ◽  
Jiang Bo Wang ◽  
Ling Ping Guo ◽  
Guo Gang Sun
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Apparent Activation Energy ◽  
High Purity ◽  
Isoconversional Methods ◽  
Decomposition Kinetics ◽  
Heating Rates ◽  
Model Free ◽  
Chemical Utilization ◽  
Kinetics Of

TG analysis was used to investigate the thermal decomposition of switchgrass, which is a potential gasification feedstock. 10 mg switchgrass sample with the particles between 0.45 and 0.70 mm was linearly heated to 873 K at heating rates of 10, 20, 30 K/min, respectively, under high-purity nitrogen. The Kissinger method and three isoconversional methods including Friedman, Flynn-wall-Ozawa, Vyazovkin and Lenikeocink methods were used to estimate the apparent activation energy of switchgrass. With the three isoconversional methods, it can be concluded that the activation energy increases with increasing conversion. The four model free methods reveal activation energies in the range of 70-460 kJ/mol. These activation energy values provide the basic data for the thermo-chemical utilization of the switchgrass.

Determination of Chemical Kinetic Parameters of Surrogate Solid Wastes

2004 ◽  
Vol 126 (4) ◽  
pp. 685-692 ◽  
Author(s):  
D. Jinno ◽  
Ashwani K. Gupta ◽  
K. Yoshikawa
Keyword(s):  
Thermal Decomposition ◽  
Heat Flow ◽  
Kinetic Parameters ◽  
Heating Rate ◽  
Chemical Kinetic ◽  
Solid Wastes ◽  
Heating Rates ◽  
Kinetics Parameters ◽  
Thermal Decomposition Behavior ◽  
Decomposition Behavior

Results on the thermal decomposition behavior of several important components in solid wastes are presented under controlled chemical and thermal environments. Thermogravimetry (TGA) tests were conducted on the decomposition of cellulose, polyethylene, polypropylene, polystyrene and polyvinyl chloride in inert (nitrogen), and oxidative (air) atmospheres. Inert condition tests were performed at heating rates of 5, 10, 30, and 50°C/min while the oxidative condition tests were performed at one heating rate of 5°C/min. Differential scanning calorimetry (DSC) was also used to measure the heat flow into and out of the sample during thermal decomposition of the material. The TGA results on the mass evolution of the materials studied as a function of temperature showed that the cellulose contained a small amount of moisture whereas no moisture was found in the other materials examined. The DSC curve showed the heat flow into and out of the sample during the process of pyrolysis and oxidative pyrolysis. The temperature dependence and mass loss characteristics of materials were used to evaluate the Arrhenius kinetic parameters. The surrounding chemical environment, heating rate, and material composition and properties affect the overall decomposition rates under defined conditions. The composition of these materials was found to have a significant effect on the thermal decomposition behavior. Experimental results show that decomposition process shifts to higher temperatures at higher heating rates as a result of the competing effects of heat and mass transfer to the material. The results on the Arrhenius chemical kinetic parameters and heat of pyrolysis obtained from the thermal decomposition of the sample materials showed that different components in the waste have considerably different features. The thermal decomposition temperature, heat evolved and the kinetics parameters are significantly different various waste components examined. The amount of thermal energy required to destruct a waste material is only a small faction of the energy evolved from the material. These results assist in the design and development of advanced thermal destruction systems.

The Thermal Decomposition Behavior of Graphene Oxide/HMX Composites

2015 ◽  
Vol 645-646 ◽  
pp. 110-114 ◽  
Author(s):  
Gui Yu Zeng ◽  
Jian Hua Zhou ◽  
Cong Mei Lin
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Graphene Oxide ◽  
Interlayer Space ◽  
Decomposition Process ◽  
Thermal Decomposition Process ◽  
Hummers Method ◽  
Thermal Decomposition Behavior ◽  
Decomposition Behavior ◽  
Decomposition Activation Energy

Graphene oxide (GO) was prepared by Hummers method and GO/1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) composite was prepared via an ultrasonic compounding method. The structure of GO was characterized using XRD and SEM, the thermal decomposition of HMX and GO/HMX composite was analyzed by DSC/TG test. The results show that interlayer space of GO increases markedly, the thermal decomposition process of HMX can be promoted with the nanolayer structure of GO, resulting the reduced thermal decomposition activation energy of about 50 kJ/mol with 1% GO.

scholarly journals Thermal decomposition behavior and kinetics for pyrolysis and catalytic pyrolysis of Douglas fir

RSC Advances ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 2196-2202 ◽  
Author(s):  
Lu Wang ◽  
Hanwu Lei ◽  
Jian Liu ◽  
Quan Bu
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Thermogravimetric Analysis ◽  
Catalytic Pyrolysis ◽  
Douglas Fir ◽  
Thermal Decomposition Behavior ◽  
Decomposition Behavior

Investigation of non-catalytic and catalytic pyrolysis of DF by thermogravimetric analysis revealed that the application of ZSM-5 reduced the activation energy.

scholarly journals Study on Blending of Wall Material of the Nonel Tube by CSW/PE-g-MAH

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Hong-wei Li ◽  
Bin-bin Zhang ◽  
Ji-nian Yang ◽  
Huan Li ◽  
Ji-chang Gui ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Composite System ◽  
Interfacial Structure ◽  
Wall Material ◽  
Thermal Decomposition Behavior ◽  
Decomposition Behavior ◽  
Calcium Sulfate Whiskers ◽  
Melting And Crystallization ◽  
Decomposition Activation Energy

In order to improve the strength and resistance of ordinary nonel tubes, calcium sulfate whiskers (CSW, treated with silane coupling agent) and maleic anhydride grafted polyethylene (PE-g-MAH) are used to control the wall material of the nonel tube that the blending of the low-density polyethylene was enhanced. The effects of mass fraction of CSW or PE-g-MAH on the tensile properties, interfacial structure, melting and crystallization characteristics, and thermal decomposition behavior of the composite system were studied, and the thermal decomposition kinetics were calculated. The results show that, relative to pure LDPE, the strength of LDPE/CSW (85/15) is increased by 7.58%, and the strength of LDPE/CSW/PE-g-MAH (84/15/1) is increased by 7.58%. The addition of CSW or PE-g-MAH has gradually changed the fracture mode of the LDPE matrix. Thermal analysis shows that CSW can reduce the crystallinity of LDPE. The melting and crystallization characteristics of LDPE/CSW/PE-g-MAH composites have little effect, but the thermal decomposition stability is improved. The kinetic analysis showed that the reaction order (n) was around 1, CSW could improve LDPE/CSW thermal decomposition activation energy, and PE-g-MAH increased the thermal decomposition activation energy of LDPE/CSW/PE-g-MAH.

scholarly journals Thermal Decomposition Kinetics of Poly(L-lactic acid) after Heat Treatment

2015 ◽  
Vol 9 (1) ◽  
pp. 28-32
Author(s):  
Yan-Hua Cai ◽  
Yun-Chen Xie ◽  
Ying- Tang ◽  
Li-Sha Zhao
Keyword(s):  
Heat Treatment ◽  
Activation Energy ◽  
Thermal Decomposition ◽  
Lactic Acid ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Isothermal Heat Treatment ◽  
Order Kinetic ◽  
Thermal Decomposition Behavior ◽  
Decomposition Behavior

Thermal decomposition behavior of Poly(L-lactic acid) (PLLA) and PLLA composites after different heat treatment were investigated using thermogravimetric analysis. Firstly, the thermal decomposition results of neat PLLA showed that the decomposition of PLLA was a first-order kinetic reaction, and thermal decomposition kinetics indicated that the heat treatment significantly affected activation energy of thermal decomposition of PLLA. The measurement results also exhibited that the onset decomposition temperature of PLLA treated below 115°C was lower than that of the pristine PLLA. Then, the effect of additive CaCo3 on the thermal decomposition behavior of PLLA was evaluated. The addition of CaCo3 could significantly improve the crystallization performance of PLLA, but the CaCo3 did not change the decomposition trend of PLLA, and the thermal decomposition behavior of PLLA/CaCo3 composites after isothermal heat treatment was similar to that of PLLA. However, the thermal decomposition activation energy of PLLA/CaCo3 is lower than that of PLLA.

Influence of thermal decomposition behavior of titanium precursors on (Ba,Sr)TiO3 thin films

2001 ◽  
Vol 11 (PR3) ◽  
pp. Pr3-675-Pr3-682 ◽  
Author(s):  
Y. S. Min ◽  
Y. J. Cho ◽  
D. Kim ◽  
J. H. Lee ◽  
B. M. Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Decomposition ◽  
Thermal Decomposition Behavior ◽  
Decomposition Behavior

Thermo-catalytic decomposition of polystyrene waste: Comparative analysis using different kinetic models

2019 ◽  
Vol 38 (2) ◽  
pp. 202-212 ◽  
Author(s):  
Ghulam Ali ◽  
Jan Nisar ◽  
Munawar Iqbal ◽  
Afzal Shah ◽  
Mazhar Abbas ◽  
...  
Keyword(s):  
Activation Energy ◽  
Copper Oxide ◽  
Solid Waste ◽  
Thermodynamic Parameters ◽  
Model Fitting ◽  
Catalytic Decomposition ◽  
Decomposition Reaction ◽  
Inert Atmosphere ◽  
Heating Rates ◽  
Model Free

Due to a huge increase in polymer production, a tremendous increase in municipal solid waste is observed. Every year the existing landfills for disposal of waste polymers decrease and the effective recycling techniques for waste polymers are getting more and more important. In this work pyrolysis of waste polystyrene was performed in the presence of a laboratory synthesized copper oxide. The samples were pyrolyzed at different heating rates that is, 5°Cmin−1, 10°Cmin−1, 15°Cmin−1 and 20°Cmin−1 in a thermogravimetric analyzer in inert atmosphere using nitrogen. Thermogravimetric data were interpreted using various model fitting (Coats–Redfern) and model free methods (Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose and Friedman). Thermodynamic parameters for the reaction were also determined. The activation energy calculated applying Coats–Redfern, Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose and Friedman models were found in the ranges 105–148.48 kJmol−1, 99.41–140.52 kJmol−1, 103.67–149.15 kJmol−1 and 99.93–141.25 kJmol−1, respectively. The lowest activation energy for polystyrene degradation in the presence of copper oxide indicates the suitability of catalyst for the decomposition reaction to take place at lower temperature. Moreover, the obtained kinetics and thermodynamic parameters would be very helpful in determining the reaction mechanism of the solid waste in a real system.

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