scholarly journals Thermal decomposition of mercerized linter cellulose and its acetates obtained from a homogeneous reaction

Polímeros ◽  
2011 ◽  
Vol 21 (2) ◽  
pp. 111-117 ◽  
Author(s):  
Daniella L. Morgado ◽  
Elisabete Frollini
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Quantitative Methods ◽  
Homogeneous Medium ◽  
Solvent System ◽  
Homogeneous Reaction ◽  
Reactive Site ◽  
Cellulose Decomposition ◽  
Mechanism Of Thermal Decomposition ◽  
Cellulose Acetates

Cellulose acetates with different degrees of substitution (DS, from 0.6 to 1.9) were prepared from previously mercerized linter cellulose, in a homogeneous medium, using N,N-dimethylacetamide/lithium chloride as a solvent system. The influence of different degrees of substitution on the properties of cellulose acetates was investigated using thermogravimetric analyses (TGA). Quantitative methods were applied to the thermogravimetric curves in order to determine the apparent activation energy (Ea) related to the thermal decomposition of untreated and mercerized celluloses and cellulose acetates. Ea values were calculated using Broido's method and considering dynamic conditions. Ea values of 158 and 187 kJ mol-1 were obtained for untreated and mercerized cellulose, respectively. A previous study showed that C6OH is the most reactive site for acetylation, probably due to the steric hindrance of C2 and C3. The C6OH takes part in the first step of cellulose decomposition, leading to the formation of levoglucosan and, when it is changed to C6OCOCH3, the results indicate that the mechanism of thermal decomposition changes to one with a lower Ea. A linear correlation between Ea and the DS of the acetates prepared in the present work was identified.

scholarly journals Kinetics and Mechanism of Thermal Decomposition of 1-R-Substituted bis(1,1-Dinitromethyl-3-Nitro- 1,2,4-Triazole-5-yl)

2020 ◽  
pp. 25-30
Author(s):  
Lyudmila А. Kruglyakova ◽  
Rudolf S. Stepanov ◽  
Konstantin V. Pekhotin ◽  
Oksana А. Golubtsova
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Activation Parameters ◽  
Decomposition Kinetics ◽  
Mechanism Of Thermal Decomposition ◽  
Limiting Stage ◽  
Manometric Method ◽  
Steric Constant ◽  
Kinetics Of ◽  
Constant Activation Energy

Thermal decomposition kinetics of 1-substituted bis(1,1-dinitromethyl-3-Nitro-1,2,4-triazole- 5-yl) in solution of 1,3-dinitrobenzene is studied with manometric method under isothermal conditions. The limiting stage of thermal decomposition is homolytic break of C-NO2 bond in gem-dinitromethyl group; activation parameters of this stage are calculated. The reactivity of investigated compounds is analyzed. Correlation dependences between logarithm of rate constant, activation energy and steric constant of substituent R are obtained

Application of Calculus Equation in Solving Thermal Decomposition Kinetics Parameters of Flame Retardant Wood

2014 ◽  
Vol 983 ◽  
pp. 190-193
Author(s):  
Cai Yun Sun ◽  
Yong Li Yang ◽  
Ming Gao
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Thermal Degradation ◽  
Phosphoric Acid ◽  
Flame Retardant ◽  
Kinetic Parameters ◽  
Flame Retardancy ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Kinetics Parameters

Wood has been treated with amino resins and amino resins modified with phosphoric acid to impart flame retardancy. The thermal degradation of samples has been studied by thermogravimetry (TG) in air. From the resulting data, kinetic parameters for different stages of thermal degradation are obtained following the method of Broido. For the decomposition of wood and flame retardant wood, the activation energy is found to decrease from 122 to 72 kJmol-1.

THE THERMAL DECOMPOSITION OF HEXAFLUOROAZOMETHANE

1962 ◽  
Vol 40 (5) ◽  
pp. 930-934 ◽  
Author(s):  
Elizabeth Leventhal ◽  
Charles R. Simonds ◽  
Colin Steel
Keyword(s):  
Thermal Decomposition ◽  
High Pressure ◽  
Rate Constant ◽  
Static System ◽  
Homogeneous Reaction

The pyrolysis of hexafluoroazomethane has been studied in a static system between 0.3 mm and 73 mm and 572 °K and 634 °K by measuring the rate of nitrogen formation. The rate constant of the high-pressure homogeneous reaction is given by k = 1016.17±0.15 exp (−55,200 ± 400/RT) sec−1

Activation energy in the thermal decomposition of MgH2 powders by coupled TG–MS measurements

2013 ◽  
Vol 116 (2) ◽  
pp. 865-874 ◽  
Author(s):  
Renzo Campostrini ◽  
Mahmoud Abdellatief ◽  
Matteo Leoni ◽  
Paolo Scardi
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition
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