scholarly journals Effects of dopants on the isothermal decomposition kinetics of potassium metaperiodate

2011 ◽  
Vol 76 (8) ◽  
pp. 1129-1138
Author(s):  
Karuvanthodi Muraleedharan ◽  
Parambil Kannan ◽  
Ganga Devi
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Kinetic Model ◽  
Entire Range ◽  
Decomposition Kinetics ◽  
Isothermal Decomposition ◽  
Acceleration Period ◽  
Two Stages ◽  
Kinetics Of

The isothermal decomposition and kinetics of potassium metaperiodate (KIO4) were studied by thermogravimetry as a function of the concentration of dopants. The thermal decomposition of KIO4 proceeds mainly through two stages: an acceleration period up to ? = 0.50 and a decay stage. The thermal decomposition data for both doped and untreated KIO4 were found to be best described by the Prout-Tompkins Equation. The ? - t data of doped and untreated samples of KIO4 were subjected to isoconversional studies for the determination of the activation energy values. The isoconversional studies of the isothermal decomposition of untreated and doped samples of KIO4 indicated that the thermal decomposition of KIO4 proceeds through a single kinetic model, the Prout-Tompkins model, throughout the entire range of conversion, as opposed to earlier observations.

Thermal Decomposition Kinetics of RDX with Distributed Activation Energy Model

2013 ◽  
Vol 641-642 ◽  
pp. 144-147 ◽  
Author(s):  
Ming Hua Chen ◽  
Tao Zhang ◽  
Wen Ping Chang ◽  
Xiao Biao Jia
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Energy Model ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Distributed Activation Energy Model ◽  
Thermogravimetric Analyzer ◽  
Decomposition Stage ◽  
Decomposition Processes ◽  
Kinetics Of

The thermal decomposition kinetics of RDX at different rates was studied by thermogravimetric analyzer(TG) and the activation energy of RDX was calculated by distributed activation energy model. It is shown that the thermal decomposition processes of RDX were divided into three stages according to the TG curves, they are molten stage, thermal decomposition stage and eng stage. The activation energies of RDX are all between 124.34 and 181.48KJ•mol-1 in the thermal decomposition stage of non-monotonously increasing. The activation energy of RDX is 139.98 KJ•mol-1 in the molten stage, and the thermal decomposition stage is167.24KJ•mol-1.

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).

Characteristics and thermal decomposition kinetics of wood-SiO2 composites derived by the sol-gel process

Holzforschung ◽  
2017 ◽  
Vol 71 (3) ◽  
pp. 233-240 ◽  
Author(s):  
Ke-Chang Hung ◽  
Jyh-Horng Wu
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Apparent Activation Energy ◽  
Sol Gel ◽  
Weight Percent Gain ◽  
Weight Percent ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Sol Gel Process ◽  
Kinetics Of

Abstract Wood-SiO2 composites (WSiO2Cs) were prepared by means of the sol-gel process with methyltrimethoxysilane (MTMOS) as a reagent, and the physical properties, structure and thermal decomposition kinetics of the composites has been evaluated. The dimensional stability of the WSiO2Cs was better than that of unmodified wood, especially in terms of the weight percent gain (WPG), which achieved values up to 30%. The 29Si-NMR spectra show two different siloxane peaks (T2 and T3), which supports the theory about the formation of MTMOS network structures. Thermal decomposition experiments were also carried out in a TG analyzer under a nitrogen atmosphere. The apparent activation energy was determined according to the iso-conversional methods of Friedman, Flynn-Wall-Ozawa, modified Coats-Redfern, and Starink. The apparent activation energy between 10 and 70% conversion is 147–172, 170–291, 189–251, and 192–248 kJ mol−1 for wood and WSiO2Cs with WPGs of 10, 20, and 30%, respectively. However, the reaction order between 10 and 70% conversion calculated by the Avrami theory was 0.50–0.56, 0.35–0.45, 0.33–0.44, and 0.28–0.48. These results indicate that the dimensional and thermal stability of the wood could be effectively enhanced by MTMOS treatment.

Kinetics on the Isothermal Decomposition of Oil Shale

2012 ◽  
Vol 581-582 ◽  
pp. 112-116 ◽  
Author(s):  
Hua Qing Xue ◽  
Hong Yan Wang ◽  
Gang Yan ◽  
Wei Guo ◽  
Xiao Bo Li ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Oil Shale ◽  
Kinetics Model ◽  
Isothermal Kinetics ◽  
Temperature Error ◽  
Isothermal Decomposition ◽  
Oil Shale Pyrolysis ◽  
Two Stages ◽  
Kinetics Of ◽  
Rapid Conversion

The kinetics of the thermal decomposition of Huadian oil shale was studied at five different isothermal atmospheres of 623K, 648K, 673K, 698K, and 723K. The temperature recorded was that of the sample that the temperature error between furnace and sample will eliminate. According to conversion data, the effect of increased temperature is to decrease the pyrolysis time. The conversion data described the oil shale pyrolysis as two stages, rapid conversion and modest conversion. The Arrhenius equations of ki=1.40×105e-109828/RT and kii=1.76×106e-130463/RT were obtain by isothermal kinetics model for each stage.

Synthesis and Determination of the Kinetic Parameters for Non-Isothermal Decomposition of Complexes Ln(thd)3phen

2006 ◽  
Vol 530-531 ◽  
pp. 506-512 ◽  
Author(s):  
Wilton Silva Lopes ◽  
Crislene Rodrigues da Silva Morais ◽  
A.G. de Souza
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Lanthanide Complexes ◽  
Reaction Order ◽  
Decomposition Reaction ◽  
Cylindrical Symmetry ◽  
Boundary Reaction ◽  
Phase Boundary Reaction ◽  
Kinetics Of

In this work the kinetics of the thermal decomposition of two ß-diketone lanthanide complexes of the general formula Ln(thd)3phen (where Ln = Nd+3 or Tm+3, thd = 2,2,6,6- tetramethyl-3,5-heptanodione and phen = 1,10-phenantroline) has been studied. The powders were characterized by several techniques. Thermal decomposition of the complexes was studied by non-isothermal thermogravimetry techniques. The kinetic model that best describes the process of the thermal decomposition of the complexes it was determined through the method proposed by Coats-Redfern. The average values the activation energy obtained were 136 and 114 kJ.mol-1 for the complexes Nd(thd)3phen and Tm(thd)3phen, respectively. The kinetic models that best described the thermal decomposition reaction the both complexes were R2. The model R2 indicating that the mechanism is controlled by phase-boundary reaction (cylindrical symmetry) and is defined by the function g(α) = 2[1-(1-a)1/2], indicating a mean reaction order. The values of activation energy suggests the following decreasing order of stability: Nd(thd)3phen > Tm(thd)3phen.

scholarly journals Modelling of Thermal Decomposition Kinetics of Proteins, Carbohydrates and Lipids Using Scenedesmus microalgae thermal Data

2020 ◽  
Vol 32 (11) ◽  
pp. 2921-2926
Author(s):  
BOTHWELL NYONI ◽  
PHUTI TSIPA ◽  
SIFUNDO DUMA ◽  
SHAKA SHABANGU ◽  
SHANGANYANE HLANGOTHI
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Bulk Material ◽  
Decomposition Kinetics ◽  
Second Order ◽  
Thermal Decomposition Kinetics ◽  
Heating Rates ◽  
High Heating ◽  
The Individual ◽  
Kinetics Of

In present work, the thermal decomposition behaviour and kinetics of proteins, carbohydrates and lipids is studied by use of models derived from mass-loss data obtained from thermogravimetric analysis of Scenedesmus microalgae. The experimental results together with known decomposition temperature range values obtained from various literature were used in a deconvolution technique to model the thermal decomposition of proteins, carbohydrates and lipids. The models fitted well (R2 > 0.99) and revealed that the proteins have the highest reactivity followed by lipids and carbohydrates. Generally, the decomposition kinetics fitted well with the Coats-Redfern first and second order kinetics as evidenced by the high coefficients of determination (R2 > 0.9). For the experimental conditions used in this work (i.e. high heating rates), the thermal decomposition of protein follows second order kinetics with an activation energy in the range of 225.3-255.6 kJ/mol. The thermal decomposition of carbohydrate also follows second order kinetics with an activation energy in the range of 87.2-101.1 kJ/mol. The thermal decomposition of lipid follows first order kinetics with an activation energy in the range of 45-64.8 kJ/ mol. This work shows that the thermal decomposition kinetics of proteins, carbohydrates and lipids can be performed without the need of experimentally isolating the individual components from the bulk material. Furthermore, it was shown that at high heating rates, the decomposition temperatures of the individual components overlap resulting in some interactions that have a synergistic effect on the thermal reactivity of carbohydrates and lipids.

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.

The Application of Thermal Analysis to Research on Energetic Materials

2013 ◽  
Vol 750-752 ◽  
pp. 1180-1183
Author(s):  
Tao Zhang ◽  
Ming Hua Chen ◽  
Xiao Biao Jia ◽  
Hao Nan Jia ◽  
Yong Kang Chen
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
High Precision ◽  
Energetic Materials ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Physical Constants ◽  
Kinetics Of

This paper introduces briefly the application of thermal analysis in energetic materials and its importance. Thermal analysis has many advantages: operation is simple and quick, wide fields fit to, the characteristic of the high precision and so on. It plays an important role in the thermal decomposition kinetics of energetic materials, stability and compatibility, and the determination of thermal physical constants.

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