scholarly journals Thermal Decomposition of Brominated Butyl Rubber

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6767
Author(s):  
Wei Zhang ◽  
Yang Zang ◽  
Yanli Lu ◽  
Weisheng Lin ◽  
Shengyun Zhao ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Isoconversional Method ◽  
Butyl Rubber ◽  
Heating Rates ◽  
Excellent Thermal Stability ◽  
Small Peak ◽  
Air Atmosphere ◽  
Brominated Butyl Rubber ◽  
Derivative Thermogravimetry

The thermal decomposition of brominated butyl rubber under air atmosphere was investigated by thermogravimetry (TG) and derivative thermogravimetry (DTG) at various heating rates. The kinetic parameters were evaluated by TG and the isoconversional method developed by Ozawa. One prominent decomposition stage was observed in the DTG curves at high heating rates, while an additional small peak was observed at low heating rates. The apparent activation energy determined using the TG method ranged from 219.31 to 228.13 kJ·mol−1 at various heating rates. The non-isothermal degradation was found to be a first-order reaction, and the activation energy, as determined by the isoconversional method, increased with an increase in mass loss. The kinetic data suggest that brominated butyl rubber has excellent thermal stability. This study can indirectly aid in improving rubber pyrolysis methods and in enhancing the heat resistance of materials.

scholarly journals Thermal Decomposition of Brominated Butyl Rubber

2021 ◽  
Author(s):  
Wei Zhang ◽  
Jinping Xiong ◽  
Yang Zang ◽  
Yanli Lu ◽  
Weisheng Lin ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Isoconversional Method ◽  
Butyl Rubber ◽  
Heating Rates ◽  
Excellent Thermal Stability ◽  
Small Peak ◽  
Air Atmosphere ◽  
Brominated Butyl Rubber ◽  
Derivative Thermogravimetry

The thermal decomposition of brominated butyl rubber under air atmosphere was investigated by thermogravimetry (TG) and derivative thermogravimetry (DTG) at various heating rates. The kinetic parameters were evaluated by TG and the isoconversional method developed by Ozawa. One prominent decomposition stage was observed in the DTG curves at high heating rates while an additional small peak was observed at low heating rates. The apparent activation energy determined using the TG method ranged from 219.31–228.13 kJ·mol-1 at various heating rates. The non-isothermal degradation was found to be a first order reaction, and the activation energy, as determined by the isoconversional method, increased with an increase in mass loss. The kinetic data suggested that brominated butyl rubber had excellent thermal stability. This study will indirectly aid in improving rubber pyrolysis methods and in enhancing the heat resistance of materials.

scholarly journals Non-isothermal kinetic analysis of the thermal decomposition of spruce wood in air atmosphere

2018 ◽  
Vol 64 (No. 1) ◽  
pp. 41-46 ◽  
Author(s):  
Ondro Tomáš ◽  
Vitázek Ivan ◽  
Húlan Tomáš ◽  
Lawson Michael K
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Picea Abies ◽  
Heating Rates ◽  
Air Atmosphere ◽  
Spruce Wood ◽  
Lignin Decomposition ◽  
Main Decomposition ◽  
Isothermal Kinetic Analysis ◽  
Isothermal Kinetic

Thermal decomposition of spruce wood (Picea abies) was studied using the thermogravimetric (TG) analysis in air atmosphere from 30°C to 600°C with the heating rates of 5, 10, 15, 20, 25 and 30°C.min<sup>–1</sup>. The TG results show that the main decomposition region is in the temperature range of 250–360°C, where a total disintegration of hemicellulose and cellulose with partial lignin decomposition can be observed. The values of apparent activation energy for this process are between 168.6–196.5 kJ·mol<sup>–1</sup>, 179.8–188.1 kJ·mol<sup>–1</sup> and 170.1–178.7 kJ·mol<sup>–1</sup> determined by the Friedman, Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods, respectively. 

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 Hydrothermal Synthesis of Hematite Nanoparticles Decorated on Carbon Mesospheres and Their Synergetic Action on the Thermal Decomposition of Nitrocellulose

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 968 ◽  
Author(s):  
Abdenacer Benhammada ◽  
Djalal Trache ◽  
Mohamed Kesraoui ◽  
Salim Chelouche
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Analytical Techniques ◽  
Decomposition Reaction ◽  
Decomposition Temperature ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Nano Catalyst ◽  
Average Size ◽  
A Minor

In this study, carbon mesospheres (CMS) and iron oxide nanoparticles decorated on carbon mesospheres (Fe2O3-CMS) were effectively synthesized by a direct and simple hydrothermal approach. α-Fe2O3 nanoparticles have been successfully dispersed in situ on a CMS surface. The nanoparticles obtained have been characterized by employing different analytical techniques encompassing Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The produced carbon mesospheres, mostly spherical in shape, exhibited an average size of 334.5 nm, whereas that of Fe2O3 supported on CMS is at around 80 nm. The catalytic effect of the nanocatalyst on the thermal behavior of cellulose nitrate (NC) was investigated by utilizing differential scanning calorimetry (DSC). The determination of kinetic parameters has been carried out using four isoconversional kinetic methods based on DSC data obtained at various heating rates. It is demonstrated that Fe2O3-CMS have a minor influence on the decomposition temperature of NC, while a noticeable diminution of the activation energy is acquired. In contrast, pure CMS have a slight stabilizing effect with an increase of apparent activation energy. Furthermore, the decomposition reaction mechanism of NC is affected by the introduction of the nano-catalyst. Lastly, we can infer that Fe2O3-CMS may be securely employed as an effective catalyst for the thermal decomposition of NC.

Studies on the Thermal Decomposition Kinetic of an Nitrate Ester

2012 ◽  
Vol 182-183 ◽  
pp. 1575-1580 ◽  
Author(s):  
Juan Wang ◽  
Da Bin Liu ◽  
Xin Li Zhou
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Decomposition Mechanism ◽  
Thermal Decomposition Mechanism ◽  
Decomposition Kinetic ◽  
Heating Rates ◽  
Exponential Factor ◽  
Nitrate Ester ◽  
Dynamic Function ◽  
Thermal Decomposition Kinetic

The certain nitrate ester explosive has been tested by TG at the heating rates of 10, 15, 20, 25K•min-1. Basing on the TG experiment results the thermal decomposition activation energy has been calculated by the methods of Ozawa, KAS and iteration. And the thermal decomposition mechanism function of the explosive with 38 kinds of dynamic function was deduced by the method of integration. The results show that the thermal decomposition mechanism of the nitrate ester is chemical reaction mechanism. The thermal decomposition kinetic parameters such as average activation energy Ea and pre-exponential factor A are 133.23×103 J•mol-1 and 3.191×107 s-1 respectively.

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.

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.

scholarly journals Analysis of Thermal Decomposition of Solid Rocket Propellants

2019 ◽  
Vol 10 (2) ◽  
pp. 43-54 ◽  
Author(s):  
Marcin CEGŁA ◽  
Janusz ZMYWACZYK ◽  
Piotr KONIORCZYK
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Energetic Materials ◽  
Decomposition Analysis ◽  
Simultaneous Thermal Analysis ◽  
Analytical Techniques ◽  
Heating Rates ◽  
Rocket Propellants ◽  
Solid Rocket ◽  
Solid Rocket Propellants

The paper presents results of thermal decomposition analysis of selected solid rocket propellants. Homogeneous propellant PAC and heterogeneous propellant H2 were subjected to simultaneous thermal analysis with the use of NETZSCH STA 2500 Regulus device with five heating rates of 2.5, 5, 7.5, 10 and 15 K/min. The method combines TG, DTG and DTA analytical techniques in a single measurement. The aim of the conducted experiments was to study thermal decomposition of these energetic materials as well as to determine activation energy of the decomposition process and the preconditioning factor from the TG curves. The tested materials properties and chemical composition along with a brief description of the experimental procedure are described. The inverse procedure of calculating the activation energy, based on the Ozawa-Flynn-Wall model is described. Finally, the results of thermal decomposition of two tested solid rocket propellants are presented along with maximum decomposition rates and percentage of mass loss.

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.

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.

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