Thermal degradation kinetics of a lignin particle-reinforced phenolic foam

2020 ◽  
pp. 0021955X2093288
Author(s):  
Juan Carlos Domínguez ◽  
Belén Del Saz-Orozco ◽  
Mercedes Oliet ◽  
M Virginia Alonso ◽  
Francisco Rodriguez
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Kinetic Parameters ◽  
Degradation Kinetics ◽  
Degradation Process ◽  
Activation Energies ◽  
Thermal Degradation Kinetics ◽  
Model Free ◽  
Predicted Values ◽  
Kinetics Of

In the present work, the thermal degradation kinetics of a phenolic (PF) and lignin particle-reinforced phenolic (LRPF) foam and the lignin used as the reinforcement (LR) were studied. The activation energies of the degradation processes were obtained using a discrete distributed activation energy model (discrete DAEM) and the Vyazovkin model-free kinetic (MFK) method. The discrete DAEM was validated by comparing the predicted values with the data obtained at 8 °C min−1. Heating ramps of 6 and 12 °C min−1 were used to calculate the kinetic parameters through the model. The effect of the reinforcement on the kinetics of the LRPF was studied by comparison with the results obtained for the PF. For reactions with non-zero mass fractions, the activation energies of the PF were in the range between 79.9 and 177.6 kJ mol−1, and the activation energy for the LRPF ranged from 91 to 187 kJ mol−1. For the LR, the activation energy values were in a narrower range than for the foams: 150–187 kJ mol−1. The degradation process of the LRPF was modified due to the use of LR: the range of activation energy for LRPF was between the ranges for the PF and LR. The activation energy dependence on conversion was also calculated using the Vyazovkin method and compared with the DAEM results; no compensation effect for the kinetic parameters was found.

Thermal properties and thermal degradation kinetics of phenolic and wood flour-reinforced phenolic foams

2016 ◽  
Vol 51 (1) ◽  
pp. 125-138 ◽  
Author(s):  
JC Domínguez ◽  
B del Saz-Orozco ◽  
M Oliet ◽  
MV Alonso ◽  
F Rodriguez
Keyword(s):  
Thermal Stability ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Wood Flour ◽  
Activation Energies ◽  
Thermal Degradation Kinetics ◽  
Kinetic Methods ◽  
Model Free ◽  
Phenolic Foam ◽  
Kinetics Of

In the present work, the thermal stability, changes in chemical structure during thermal degradation, and the kinetics of thermal degradation of a phenolic foam were studied. An 8.5 wt% of Pinus radiata wood flour reinforcement was added to the phenolic foam. A commercial phenolic resol was used as the matrix for the foam. The wood flour-reinforced foam showed a structure similar to the phenolic foam according to the Fourier transform infrared spectroscopy results. The wood flour increased the thermal stability of the phenolic foam in the first stage of thermal degradation ( T 5%), decreased it in the second step ( T 25%), and negligibly influenced the final stage. The activation energies of the degradation processes of the studied materials were obtained by the Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa model-free kinetic methods and a 2-Gaussian distributed activation energy model. The values of the activation energies obtained by the model-free kinetic methods for the first degradation stage of the phenolic foams were in a range between 110 and 170 kJ mol−1, whereas for the wood flour it was 162 kJ mol−1 for almost all of the conversion range of its main degradation stage. The applied models showed good fits for all the materials, and the activation energies calculated were in agreement with the values found in the literature.

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.

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.

Non-isothermal crystallization and thermal degradation kinetics of MXene/linear low-density polyethylene nanocomposites

e-Polymers ◽  
2017 ◽  
Vol 17 (5) ◽  
pp. 373-381 ◽  
Author(s):  
Xinxin Cao ◽  
Mengqi Wu ◽  
Aiguo Zhou ◽  
You Wang ◽  
Xiaofang He ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Isothermal Crystallization ◽  
Degradation Kinetics ◽  
Thermal Degradation Kinetics ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Kinetics Of

AbstractA novel two-dimensional material MXene was used to synthesize nanocomposites with linear low-density polyethylene (LLDPE). The influence of MXene on crystallization and thermal degradation kinetics of LLDPE was investigated. Non-isothermal crystallization kinetics was investigated by using differential scanning calorimetry (DSC). The experimental data was analyzed by Jeziorny theory and the Mo method. It is found that MXene acted as a nucleating agent during the non-isothermal crystallization process, and 2 wt% MXene incorporated in the nanocomposites could accelerate the crystallization rate. Findings from activation energy calculation for non-isothermal crystallization came to the same conclusion. Thermal gravity (TG) analysis of MXene/LLDPE nanocomposites was conducted at different heating rates, and the TG thermograms suggested the nanocomposites showed an improvement in thermal stability. Apparent activation energy (Ea) of thermal degradation was calculated by the Kissinger method, and Ea values of nanocomposites were higher than that of pure LLDPE. The existence of MXene seems to lead to better thermal stability in composites.

Photoisomerization and thermal degradation kinetics of poly(ether–ester)s containing azomethine moiety in the main chain

2019 ◽  
Vol 32 (1) ◽  
pp. 47-58 ◽  
Author(s):  
R Vini ◽  
SC Murugavel
Keyword(s):  
Thermal Degradation ◽  
Main Chain ◽  
Degradation Kinetics ◽  
Uv Spectroscopy ◽  
Thermal Degradation Kinetics ◽  
Spectroscopic Techniques ◽  
Isothermal Model ◽  
Model Free ◽  
Kinetics Of ◽  
Ether Ester

Poly(ether–ester)s containing azomethine group in the main chain were synthesized by solution polycondensation of 4,4′-bis(3-hydroxypropyloxy)- N-benzylidene aniline with adipoyl and terephthaloyl diacid chlorides. The synthesized poly(ether–ester)s were characterized by Fourier transform infrared and proton, and carbon-13 nuclear magnetic resonance spectroscopic techniques. Thermal properties were studied using thermogravimetric analysis (TGA) and differential scanning calorimetry. Thermal degradation kinetics of poly(ether–ester)s were characterized by TGA at various heating rates (5°C min−1, 10°C min−1, and 20°C min−1). The apparent activation energy for the degradation of both the polymers was determined by three different non-isothermal model-free kinetics methods (Friedmann, Flynn–Wall Ozawa, and Kissinger–Akahira–Sunose). The photoisomerization property was examined with ultraviolet (UV) spectroscopy, and the polymer PEE1 showed a rate of trans to cis isomerization ranging 10–20 s, whereas reverse process took around 100 min in solution. UV studies suggested that this material may be used in the field of rewritable applications.

Effect of Pd Nanoparticle on the Thermal Degradation Kinetics of Nylon 6/Pd Nanocomposite Prepared by a Dry Process

2012 ◽  
Vol 486 ◽  
pp. 27-33 ◽  
Author(s):  
Jae Young Lee ◽  
Sung Wan Hong ◽  
Kyeong Sik Han ◽  
Taeck Hong Lee ◽  
Hong Ki Lee
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Pd Nanoparticles ◽  
Nylon 6 ◽  
Thermal Degradation Kinetics ◽  
Heating Rates ◽  
Dry Process ◽  
Effect Of Pd ◽  
Kinetics Of

Palladium (Pd) nanoparticles were incorporated into a nylon 6 film via a dry process which consisted of simultaneous vaporization, penetration and reduction processes of palladium (II) bis (acetylacetonate, Pd (acac)2) at 180°C for various exposure time. The even dispersion of the generated Pd nanoparticles were observed by transmission electron microscope (TEM) and the Pd loading weight of about 15~43 wt% was measured by thermogravimetric analysis (TGA). In order to study the catalytic effect of Pd nanoparticles on the thermal degradation kinetics of nylon 6, TGA data at various heating rates were introduced to Flynn & Wall equation. The thermal degradation activation energy for neat nylon 6 was ca. 162~178 kJ/mol over the thermal degradation fraction of 0.05~0.40 while that of the nylon 6/Pd (26.5 wt%) nanocomposite was ca. 110~169 kJ/mol over the same fraction range. It meant the Pd nanoparticles were acted as a catalyst on the depolymerization of amide group in nylon 6. It was also found that the activation energy decreased slightly with the increasing Pd loading weight.

scholarly journals Thermomechanical and Morphological Studies of CFRP Tested in Different Environmental Conditions

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 63 ◽  
Author(s):  
Claudia Barile ◽  
Caterina Casavola ◽  
Paramsamy Vimalathithan ◽  
Marco Pugliese ◽  
Vincenzo Maiorano
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Mass Loss ◽  
Environmental Conditions ◽  
Degradation Kinetics ◽  
Fiber Reinforced Polymers ◽  
Thermal Degradation Kinetics ◽  
Morphological Studies ◽  
Significant Difference ◽  
Kinetics Of

The present work describes the mechanical characterization combined with the thermal degradation kinetics of Carbon Fiber Reinforced Polymers (CFRP). The thermal degradation kinetics of CFRP have never been studied in the past. In that regard, the present work focuses on studying the thermal degradation kinetics of CFRP tested mechanically at different environmental conditions. Tensile tests were performed on the specimens with different lay-ups at room temperature, elevated temperature (71 °C), and cryogenic conditions (−54 °C), and the same specimens were used for thermal degradation kinetic studies. Mechanical tests show different responses respect to the different environmental conditions and different fibers orientation. On the other hand, the thermogravimetric results, mass loss, and derivative mass loss, show no significant difference in the degradation of CFRP tested at different temperatures. However, the thermal degradation kinetics shows more insight into the degradation pattern of the materials. The activation energy of degradation shows that the degradation of materials subjected to elevated conditions increases rapidly in the later stages of degradation, suggesting the formation of high char yield. The varying activation energy has been related to different degradation mechanisms. Lastly, the morphology of the materials was studied under SEM to understand the structural change in the material after tested in different weather conditions.

Thermal Degradation Kinetics of Poly (vinyl chloride)

2010 ◽  
Vol 96 ◽  
pp. 245-249 ◽  
Author(s):  
Bin Han ◽  
Yu Long Wu ◽  
Guo Rui ◽  
Wei Feng ◽  
Zhen Chen ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Mass Conservation ◽  
Thermal Degradation Kinetics ◽  
Pyrolysis Mechanism ◽  
Second Stage ◽  
Volatile Products ◽  
Infrared Spectrometer ◽  
Kinetics Of

The thermal degradation of PVC resin was examined by the thermogravimetric analysis (TGA). The pyrolysis volatile products were analyzed by Fourier transform infrared spectrometer synchronized with TG test (TG-FTIR). Based on the TG results, the kinetics of thermal degradation was studied by Friedman method. The pyrolysis mechanism was discussed also. The results indicate that the pyrolysis process of PVC can be divided into two main stages: 220°C - 380°C and 380°C - 560°C. By the calculation of mass conservation and TG-FTIR results, it can be supposed that not only HCl, but also some unsubstituted aromatics such as benzene were released during the first stage. The comparison of activation energy shows that the second stage exhibited higher activation energy than the first stage. Two activation energy values in the first stage confirm that there arose two reactions in the first stage.

Thermal degradation kinetics and lifetime of HDPE/PLLA/pro-oxidant blends

2016 ◽  
Vol 36 (9) ◽  
pp. 917-931 ◽  
Author(s):  
Gaurav Madhu ◽  
Dev K. Mandal ◽  
Haripada Bhunia ◽  
Pramod K. Bajpai
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
Model Fitting ◽  
Frequency Factor ◽  
Thermal Degradation Kinetics ◽  
Heating Rates ◽  
Model Free ◽  
Calculation Technique ◽  
Thermal Degradation Behavior

Abstract The effect of adding poly(L-lactic acid) (PLLA) with and without a pro-oxidant additive cobalt stearate (CoSt) and compatibilizer maleic anhydride grafted polyethylene (MA-g-PE) on the thermal degradation and stability of high-density polyethylene (HDPE) films was analyzed using thermogravimetric analysis (TGA). The kinetic parameters [i.e. activation energy (Ea), order of reaction (n), and frequency factor ln(A)] of the samples were studied over a temperature range of 25°C–600°C at four heating rates (i.e. 5, 10, 15, and 20°C/min) through model-free techniques (e.g. Friedman, second Kissinger, and Flynn-Wall-Ozawa) and model-fitting techniques (e.g. Freeman-Carroll and Kim-Park). The value of Ea for neat HDPE was found to be much higher than PLLA; for the HDPE/PLLA blend, it was nearer to that of HDPE. An increase in the activation energy of 80/20 (HDPE/PLLA) blend was noticed by the addition of MA-g-PE. The TGA data and degradation kinetics were also used to predict the lifetime of the film samples. The lifetime of HDPE was found to decrease with the increase in the concentration of CoSt, thereby revealing its pro-oxidative ability. Minimum lifetime was noted for the HDPE/PLLA (80/20) sample blended with CoSt, which increased slightly in the presence of MA-g-PE. Studies indicated that the thermal degradation behavior and lifetime of the investigated film samples depends not only on the fractions of their constituents but also on the heating rates and calculation technique.

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