Using the Agrawal integral equation to study the thermal degradation of polyvinyl acetate-montmorillonite-dioctadecyl dimethyl ammonium bromide

2013 ◽  
Vol 33 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Qun Fang ◽  
Hui-wan Cui ◽  
Guan-ben Du
Keyword(s):  
Integral Equation ◽  
Thermal Degradation ◽  
Polyvinyl Acetate ◽  
Pyrolysis Temperature ◽  
Degradation Process ◽  
Ammonium Bromide ◽  
Pyrolysis Kinetics ◽  
Dimethyl Ammonium ◽  
Thermal Degradation Process ◽  
Kinetics Of

Abstract To study the pyrolysis kinetics of exfoliated nanocomposites, polyvinyl acetate (PVAc)-montmorillonite (MMT)-dioctadecyl dimethyl ammonium bromide (DOAB) was prepared through five different synthesis processes. The synthesis processes and MMT-DOAB had some effect on the thermal degradation, which was found to consist of eight phases. MMT-DOAB had no significant effect on the pyrolysis temperature, but delayed the thermal degradation process. The pyrolysis kinetics in thermal degradation were analyzed using the Agrawal integral equation.

scholarly journals Thermal degradation process of polysulfone aramid fiber

2014 ◽  
Vol 18 (5) ◽  
pp. 1637-1641 ◽  
Author(s):  
Fang-Long Zhu ◽  
Qian-Qian Feng ◽  
Qun Xin ◽  
Yu Zhou
Keyword(s):  
Thermal Degradation ◽  
Degradation Process ◽  
Aramid Fiber ◽  
Degradation Behavior ◽  
Heating Rates ◽  
Degradation Temperature ◽  
Mass Losses ◽  
Thermal Degradation Behavior ◽  
Thermal Degradation Process ◽  
Kinetics Of

Polysulfone aramid fiber is one kind of high temperature fibers. In the paper, thermal degradation behavior and kinetics of polysulfone aramid fiber were investigated by thermogravimetric analysis and differential thermogravimetric at different heating rates under nitrogen and air, respectively. The experimental results show that its initial degradation temperature is 375?C in nitrogen and 410?C in air at heating rate of 10 K/min. When temperature went to 800?C, the fiber loses all mass in air. The mass losses in the stage showed that degradation of polysulfone aramid occurs in two-step process as could be concluded by the presence of two distinct exothermic peaks in differential thermogravimetric curves.

scholarly journals Thermal Degradation Characteristics and Kinetics of Oxy Combustion of Corn Residues

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Poramate Sittisun ◽  
Nakorn Tippayawong ◽  
Darunee Wattanasiriwech
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Degradation Process ◽  
Similar Magnitude ◽  
Heating Rates ◽  
Decomposition Rates ◽  
Similar Weight ◽  
Thermal Degradation Process ◽  
Kinetics Of ◽  
Corn Residues

Thermogravimetric analysis was used to investigate oxy combustion of corncob and stover. The biomass samples were heated from ambient temperature to 900°C at different heating rates of 10, 30, and 50 K/min. Both biomass samples showed similar weight loss patterns with three zones, corresponding to dehydration, devolatilization, and char combustion, but displayed different degradation temperatures. Increasing heating rate was found to shift the degradation patterns to higher temperatures. Decomposition rates of cob and stover may have been influenced by their lignocellulosic composition. The kinetic parameters of the thermal degradation process were also determined and compared using the Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods. Both methods were found to give similar values and patterns of activation energy against conversion fraction. The average values were found to be in similar magnitude to those reported in the literature, around 170 and 148 kJ/mol for cob and stover, respectively.

Structural comparisons of pyrodextrins during thermal degradation process: The role of hydrochloric acid

2021 ◽  
Vol 349 ◽  
pp. 129174
Author(s):  
Huijia Mao ◽  
Zhijun Chen ◽  
Jie Li ◽  
Xueyang Zhai ◽  
Hongyan Li ◽  
...  
Keyword(s):  
Hydrochloric Acid ◽  
Thermal Degradation ◽  
Degradation Process ◽  
Thermal Degradation Process

Non-isothermal degradation kinetics for polycarbonate/ polymethylphenylsilsesquioxane composites

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiangbo Wang ◽  
Zhong Xin
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Flame Retardancy ◽  
Degradation Kinetics ◽  
Degradation Process ◽  
Nitrogen Atmosphere ◽  
Ozawa Method ◽  
Degradation Behaviors ◽  
Thermal Degradation Process

AbstractThe thermal degradation behaviors of PC/PMPSQ (polymethylphenylsilsesquioxane) systems were investigated by thermogravimetric analysis (TGA) under non-isothermal conditions in nitrogen atmosphere. During non-isothermal degradation, Kissinger and Flynn-Wall-Ozawa methods were used to analyze the thermal degradation process. The results showed that a remarkable decrease in activation energy ( E ) was observed in the early and middle stages of thermal degradation in the presence of PMPSQ, which indicated that the addition of PMPSQ promoted the thermal degradation of PC. Flynn-Wall-Ozawa method further revealed that PMPSQ significantly increased the activation energy of PC thermal degradation in the final stage, which illustrated that the PMPSQ stabilized the char residues and improved the flame retardancy of PC in the final period of thermal degradation process

Characterization and thermal degradation kinetics of thermoplastic polyimide based on BAPP

2017 ◽  
Vol 30 (7) ◽  
pp. 787-793 ◽  
Author(s):  
Xu Su ◽  
Yong Xu ◽  
Linshuang Li ◽  
Chaoran Song
Keyword(s):  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Degradation Process ◽  
Thermal Degradation Kinetics ◽  
Heating Rates ◽  
Step Method ◽  
Nitrogen Derivative ◽  
Degradation Reaction ◽  
Kinetics Of

Two kinds of thermoplastic polyimides (PIs) were synthesized via a two-step method with 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 4,4′-oxydianiline (ODA) diamine, and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), and their thermal degradation kinetics was studied by thermogravimetric analysis at different heating rates under nitrogen. Derivative thermogravimetric analysis curves indicated a simple, single-stage degradation process in PI BTDA-BAPP and a two-stage degradation process in PI BTDA-ODA-BAPP. The activation energies ( Eas) of the thermal degradation reaction were determined by the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose methods without a knowledge of the kinetic reaction mechanism. By comparing the values of Ea and weight loss temperatures, it was demonstrated that the thermal stability of PI BTDA-ODA-BAPP was superior to that of PI BTDA-BAPP.

scholarly journals A thermal degradation study of Y and La methanesulfonates

2006 ◽  
Vol 71 (8-9) ◽  
pp. 905-915
Author(s):  
Moura de ◽  
Jivaldo Matos ◽  
Farias de
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Differential Thermal Analysis ◽  
Thermal Degradation ◽  
Degradation Process ◽  
Oxide Formation ◽  
Scanning Calorimetry ◽  
Degradation Study ◽  
Thermogravimetric Data ◽  
Thermal Degradation Process

The synthesis, characterization and thermal degradation of yttrium and lanthanum methanesulfonates is reported. The prepared salts were characterized by elemental analysis and infrared spectroscopy. The thermal degradation study was performed using thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC).Using the thermogravimetric data, a kinetic study of the dehydration ofY and Lamethanesulfonates was performed employing the Coats-Redfern and Zsak?methods. It was verified that under heating, yttrium and lanthanum methanesulfonates undergo three main processes: dehydration, thermal degradation and oxide formation. Furthermore, depending on the nature of the atmosphere, i.e., inert or oxidant, the thermal degradation process could be endothermic (N2) or exothermic (air).

Adsorption Kinetics of Reactive Dyes on Silk with Octyl Butyl Dimethyl Ammonium Bromide as Accelerant

2012 ◽  
Vol 549 ◽  
pp. 278-282 ◽  
Author(s):  
Cheng Chen ◽  
Guang Xian Zhang ◽  
Feng Xiu Zhang ◽  
Hui Zheng
Keyword(s):  
Adsorption Kinetics ◽  
Dye Adsorption ◽  
Reactive Dyes ◽  
Second Order ◽  
Ammonium Bromide ◽  
Order Kinetic ◽  
Dye Uptake ◽  
Dimethyl Ammonium ◽  
Adsorption Rates ◽  
Kinetics Of

With octyl butyl dimethyl ammonium bromide (OBDAB) as accelerant, adsorption kinetics of dyeing silk with three reactive dyes was studied in this paper. As concentration of OBDAB increased, the dye-uptake rate increased. The highest dye-uptake rates of three reactive dyes could reach to 89.40%~98.98% and the concentration of OBDAB was only 6-8g/L. This showed OBDAB was an effective accelerant. Pseudo first- and second-order kinetic models were used to analyze the adsorption kinetic data. The experimental data were found to follow the second-order kinetic model. Meanwhile, the initial dye adsorption rates of reactive red dye B-3BF, reactive yellow dye B-4RFN and reactive orange dye B-2RLN increased as temperature increased, and the activation energy of them were found respectively to be 28.42,13.14,32.90 kJ/mol.The positive values of and obtained indicated that reactive dyes adsorption with OBDAB as accelerant was an endothermic process. The conclusion showed OBDAB was a potential accelerant.

scholarly journals Thermal degradation of the anthocyanins extracts from jabuticaba peels and red cabbage leaves

2020 ◽  
Vol 16 (6) ◽  
Author(s):  
Priscila Pereira Souza ◽  
Weber Silva Robazza ◽  
Alessandro Cazonatto Galvão
Keyword(s):  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Degradation Process ◽  
Differential Method ◽  
Red Cabbage ◽  
Average Value ◽  
Extraction And Purification ◽  
Different Temperatures ◽  
Thermal Degradation Process ◽  
Experimental Values

Anthocyanins are phenolic compounds with tinctorial capacity. Their successful extraction and purification depends on information associated with their thermal stability. This work presents a study on the degradation kinetics of the anthocyanins in the peels of the jabuticaba fruits and the leaves of red cabbage through assays performed at different temperatures (ranging from 323.15 K to 363.15 K) and degradation times (up to 10 hours for jabuticaba and 30 hours for red cabbage). Total monomeric anthocyanins were determined through the pH differential method. Regarding the extraction, it was observed a larger quantity of anthocyanins from red cabbage extracts, with an average value of 1.3774 mg‧gdb-1, when compared to jabuticaba extracts, with an average value of 1.0479 mg‧gdb-1. The results suggest that the anthocyanins in the red cabbage leaves are much more thermally stable than the anthocyanins in the jabuticaba peels. The experimental assays suggest that the thermal degradation reaction proceeds according to a first-order kinetics model for the anthocyanins in both sources under study. The experimental values were treated according to their thermodynamic relations, which indicated that the thermal degradation process of the evaluated anthocyanins is endothermic and not spontaneous, with similar values of 64.8 kJ‧mol-1 for the red cabbage and 70.2 kJ‧mol-1 for the jabuticaba. 

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