High thermodynamic stability study of PLA/LCNF composite

2018 ◽  
Vol 32 (8) ◽  
pp. 1017-1030
Author(s):  
Yang Liu ◽  
Zhaodong Ding ◽  
Xuejiao Liu ◽  
Xuan Wang ◽  
Liping Zhang
Keyword(s):  
Thermal Degradation ◽  
Cellulose Nanofibrils ◽  
Model Fitting ◽  
Degradation Process ◽  
Nitrogen Atmosphere ◽  
Stability Study ◽  
Poly Lactic Acid ◽  
Heating Rates ◽  
Isokinetic Relationship ◽  
Exponential Factor

Thermal degradation behaviors of one composite constituted by poly(lactic acid) (PLA), cellulose nanofibrils (CNF), and lignin–cellulose nanofibrils (LCNF) in a nitrogen atmosphere were studied using thermogravimetric analysis (TGA). It was found that the thermal degradation stability of the PLA/LCNF composite was improved when compared to PLA and PLA/CNF. The Flynn–Wall–Ozawa method was used to determine the apparent activation energy of the composite samples which was based on a set of TGA data obtained at different heating rates. It was shown that the conversion functions calculated by means of the Coats–Redfern method depend on a set of kinetic models, which could be concluded that using the model-fitting methods couldn’t reveal the complexity of the thermal degradation process and the isokinetic relationship method was used to estimate a model-independent pre-exponential factor (ln A) corresponding to a given degree of conversion.

scholarly journals Kinetic Analysis of Pyrolysis and Thermo-Oxidative Decomposition of Tennis String Nylon Wastes

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7564
Author(s):  
Haibo Wan ◽  
Zhen Huang
Keyword(s):  
Thermal Degradation ◽  
Kinetic Analysis ◽  
Model Fitting ◽  
Degradation Process ◽  
Nylon 6 ◽  
Reaction Model ◽  
Heating Rates ◽  
Model Free ◽  
Order Chemical Reaction ◽  
First Order Chemical Reaction

Thermal degradation of nylon-6 tennis string nylon wastes in inert nitrogen and air atmospheres was investigated by means of multiple heating-rate thermogravimetric analyses. The results obtained under the heating rates of 5–20 K/min are compared in terms of degradation feature and specific temperature for two atmospheres. Using nonisothermal data, kinetic analysis was thoroughly conducted using various isoconversional model-free methods, including Starink, Madhusudanan–Krishnan–Ninan, Tang, Coats–Redfern, and Flynn–Wall–Ozawa methods. With these kinetic analysis methods, the activation energy over the entire degradation process was successfully calculated. By means of the model-fitting master-plots method, the first-order chemical reaction model was determined to be the most appropriate mechanism function for describing pyrolysis and oxidative thermal degradation of nylon-6 waste. Using kinetic parameters, satisfactory matching against experimental data resulted using the Coats–Redfern method for both cases. Furthermore, thermodynamic parameters such as changes in entropy, enthalpy, and Gibbs free energy during thermal degradation processes were evaluated.

scholarly journals Determination of the Thermodynamic Parameters of the Pyrolysis Process of Post-Consumption Thermoplastics by Non-Isothermal Thermogravimetric Analysis

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4379
Author(s):  
Paul Palmay ◽  
Cesar Puente ◽  
Diego Barzallo ◽  
Joan Carles Bruno
Keyword(s):  
Thermogravimetric Analysis ◽  
Thermodynamic Parameters ◽  
Degradation Process ◽  
Nitrogen Atmosphere ◽  
Correlation Factor ◽  
Pyrolysis Process ◽  
Heating Rates ◽  
Exponential Factor ◽  
Isoconversional Models ◽  
The One

Currently, the pyrolysis process is an important technology for the final treatment of plastic waste worldwide. For this reason, knowing in detail the chemical process and the thermodynamics that accompany cracking reactions is of utmost importance. The present study aims to determine the thermodynamic parameters of the degradation process of conventional thermoplastics (polystyrene (PS), polyethylene terephthalate (PET), high-density polyethylene (HDPE), polypropylene (PP) and polyvinyl chloride (PVC)) from the study of their chemical kinetics by thermogravimetric analysis (TG). Non-isothermal thermogravimetry was performed at three heating rates from room temperature to 550 °C with an inert nitrogen atmosphere with a flow of 20 mL min−1. Once the TG data is obtained, an analysis is carried out with the isoconversional models of Friedman (FR), Kissinger-Akahira-Sunose (KAS), and Flynn-Wall-Ozawa (FWO) in order to determine the one that best fits the experimental data, and with this, the calculation of the activation energy and the pre-exponential factor is performed. The validation of the model was carried out using the correlation factor, determining that the KAS model is the one that best adjusts for the post-consumer thermoplastic degradation process at the three heating rates. With the use of the kinetic parameters, the variation of the Gibbs free energy is determined in each of the cases, where it is necessary that for structures containing aromatic groups a lower energy is presented, which implies a relative ease of degradation compared to the linear structures.

INVESTIGATION OF THERMAL DEGRADATION OF POULTRY PROCESSING DEWATERED SLUDGE USING THERMOGRAVIMETRIC ANALYSIS METHOD

2015 ◽  
Vol 76 (5) ◽  
Author(s):  
N. Aniza ◽  
S. Hassan ◽  
M. F. M. Nor ◽  
K. E. Kee ◽  
Aklilu T.
Keyword(s):  
Particle Size ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Heating Rate ◽  
Degradation Process ◽  
Heating Rates ◽  
Initial Stage ◽  
Poultry Processing ◽  
Effect Of Particle Size ◽  
Dewatered Sludge

Thermal degradation of Poultry Processing Dewatered Sludge (PPDS) was studied using thermogravimetric analysis (TGA) method. The effect of particle size on PPDS samples and operational condition such as heating rates were investigated. The non-isothermal TGA was run under a constant flow of oxygen at a rate of 30 mL/min with temperature ranging from 30ºC to 800ºC. Four sample particle sizes ranging between 0.425 mm to 2 mm, and heating rate between 5 K/min to 20 K/min were used in this study. The TGA results showed that particle size does not have any significant effect on the thermogravimetry (TG) curves at the initial stage, but the TG curves started to separate explicitly at the second stage. Particle size may affect the reactivity of sample and combustion performance due to the heat transfer and temperature gradient. The TG and peak of derivative thermogravimetry (DTG) curves tend to alter at high temperature when heating rate is increased most likely due to the limitation of mass transfer and the delay of 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 Kinetic Analysis of the Thermal Degradation of Recycled Acrylonitrile-Butadiene-Styrene by non-Isothermal Thermogravimetry

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 281 ◽  
Author(s):  
Rafael Balart ◽  
David Garcia-Sanoguera ◽  
Luis Quiles-Carrillo ◽  
Nestor Montanes ◽  
Sergio Torres-Giner
Keyword(s):  
Thermal Degradation ◽  
Kinetic Analysis ◽  
Acrylonitrile Butadiene Styrene ◽  
Isoconversional Methods ◽  
Reaction Model ◽  
Integral Model ◽  
Heating Rates ◽  
Exponential Factor ◽  
Model Free ◽  
Butadiene Styrene

This work presents an in-depth kinetic study of the thermal degradation of recycled acrylonitrile-butadiene-styrene (ABS) polymer. Non-isothermal thermogravimetric analysis (TGA) data in nitrogen atmosphere at different heating rates comprised between 2 and 30 K min−1 were used to obtain the apparent activation energy (Ea) of the thermal degradation process of ABS by isoconversional (differential and integral) model-free methods. Among others, the differential Friedman method was used. Regarding integral methods, several methods with different approximations of the temperature integral were used, which gave different accuracies in Ea. In particular, the Flynn-Wall-Ozawa (FWO), the Kissinger-Akahira-Sunose (KAS), and the Starink methods were used. The results obtained by these methods were compared to the Kissinger method based on peak temperature (Tm) measurements at the maximum degradation rate. Combined Kinetic Analysis (CKA) was also carried out by using a modified expression derived from the general Sestak-Berggren equation with excellent results compared with the previous methods. Isoconversional methods revealed negligible variation of Ea with the conversion. Furthermore, the reaction model was assessed by calculating the characteristic and functions and comparing them with some master plots, resulting in a nth order reaction model with n = 1.4950, which allowed calculating the pre-exponential factor (A) of the Arrhenius constant. The results showed that Ea of the thermal degradation of ABS was 163.3 kJ mol−1, while ln A was 27.5410 (A in min−1). The predicted values obtained by integration of the general kinetic expression with the calculated kinetic triplet were in full agreement with the experimental data, thus giving evidence of the accuracy of the obtained kinetic parameters.

scholarly journals Thermogravimetric kinetic study of solid recovered fuels pyrolysis

2018 ◽  
Vol 72 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Milos Radojevic ◽  
Martina Balac ◽  
Vladimir Jovanovic ◽  
Dragoslava Stojiljkovic ◽  
Nebojsa Manic
Keyword(s):  
Thermal Analysis ◽  
Kinetic Parameters ◽  
Simultaneous Thermal Analysis ◽  
Experimental Tests ◽  
Nitrogen Atmosphere ◽  
Cement Industry ◽  
Thermochemical Conversion ◽  
Gravimetric Analysis ◽  
Heating Rates ◽  
Exponential Factor

In the Republic of Serbia there are significant quantities of coffee and tire wastes that can be utilized as Solid Recovered Fuel (SRF) and used as an additional fuel for co?combustion with coal and biomass in energy production and cement industry sectors. Differences between SRF and base fuel are a cause of numerous problems in design of burners. The objective of this study was to determine the kinetic parameters for the thermochemical conversion of selected SRF using Simultaneous Thermal Analysis (STA). Samples of coffee and tire waste were used for the experimental tests. Thermal analysis was carried out in nitrogen atmosphere at three different heating rates 10, 15 and 20 K/min for each sample, while it was heated from room temperature up to 900?C. Two sample sizes x <0.25 mm and 0.25 < x <0.5 mm of each SRF were used in experiments, in order to obtain reliable Thermal Gravimetric Analysis (TGA) data for estimation of kinetic parameters for SRF pyrolysis. Experimental results were used for determination of pre-exponential factor and activation energy according to methods presented in the literature. Presented research provides valuable data of coffee and tire waste that can be used for the burners design.

scholarly journals Thermal decomposition of potassium titanium oxalate

2011 ◽  
Vol 76 (7) ◽  
pp. 1015-1026 ◽  
Author(s):  
Karuvanthodi Muraleedharan ◽  
Labeeb Pasha
Keyword(s):  
Carbon Dioxide ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Model Fitting ◽  
Nitrogen Atmosphere ◽  
Single Step ◽  
Heating Rates ◽  
Decomposition Stage ◽  
Model Free ◽  
Good Agreement

The thermal decomposition of potassium titanium oxalate (PTO) was studied using non-isothermal thermogravimetry at different heating rates under a nitrogen atmosphere. The thermal decomposition of PTO proceeds mainly through five stages forming potassium titanate. The theoretical and experimental mass loss data are in good agreement for all stages of the thermal decomposition of PTO. The third thermal decomposition stage of PTO, the combined elimination of carbon monoxide and carbon dioxide, were subjected to kinetic analyses both by the method of model fitting and by the model free approach, which is based on the isoconversional principle. The model free analyses showed that the combined elimination of carbon monoxide and carbon dioxide and formation of final titanate in the thermal decomposition of PTO proceeds through a single step with an activation energy value of about 315 kJ mol-1.

Thermal degradation kinetics of oxo-degradable PP/PLA blends

2018 ◽  
Vol 39 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Dev K. Mandal ◽  
Haripada Bhunia ◽  
Pramod K. Bajpai
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Kinetic Parameters ◽  
Degradation Kinetics ◽  
Nitrogen Atmosphere ◽  
Thermal Degradation Kinetics ◽  
Heating Rates ◽  
Kinetics Of

AbstractIn this article, the influence of polylactide and pro-oxidant on the thermal stability, degradation kinetics, and lifetime of polypropylene has been investigated using thermogravimetric analysis under nitrogen atmosphere at four different heating rates (i.e. 5, 10, 15, and 20°C/min). The kinetic parameters of degradation were studied over a temperature range of 30–550°C. The derivative thermogravimetric curves have indicated single stage and two stage degradation processes. The activation energy was evaluated by using the Kissinger, Kim-Park, and Flynn-Wall methods under the nitrogen atmosphere. The activation energy value of polypropylene was much higher than that of polylactide. Addition of polylactide and pro-oxidant in polypropylene decreased the activation energy. The lifetime of polypropylene has also decreased with the addition of polylactide and pro-oxidant.

Kinetic Studies on the Thermal Synthesis of Fluorapatite: Model Free and Model-Fitting Methods

2018 ◽  
Vol 28 ◽  
pp. 75-89
Author(s):  
Hamid Reza Javadinejad ◽  
Sayed Ahmad Hosseini ◽  
Mohsen Saboktakin Rizi ◽  
Eiman Aghababaei ◽  
Hossein Naseri
Keyword(s):  
Activation Energy ◽  
Model Fitting ◽  
Kinetic Studies ◽  
Isoconversional Methods ◽  
Reaction Model ◽  
Heating Rates ◽  
Thermal Synthesis ◽  
Exponential Factor ◽  
Model Free ◽  
Master Plots

The kinetic study for the synthesis of Fluorapatite has been done using the thermogravimetric technique under non-isothermal conditions and at four heating rates of 5, 10, 15 and 20 °C. Both model free and model-fitting methods were used to investigate kinetic parameters. Calcium oxide, phosphorus pentoxide and calcium fluoride were used as the precursor materials. The activation energy values were calculated through model-fitting and isoconversional methods and were used to predict the reaction model and pre-exponential factor. In this case several techniques were considered such as master plots and compensation effects. The results indicated that the reaction mechanism was chemically controlled with second and third order reaction models in the whole range of conversion which the activation energy varied from 25 to 43 kJ/mol.

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