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Piotr ścigalski - One of the best experts on this subject based on the ideXlab platform.
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thermal behavior of cinnamyl diesters studied by the tg ftir qms in inert atmosphere
Journal of Analytical and Applied Pyrolysis, 2014Co-Authors: Marta Worzakowska, Piotr ścigalskiAbstract:Abstract The thermal behavior of cinnamyl diesters in inert atmosphere was studied by the TG/FTIR/QMS coupled method. The results confirmed that diesters decomposed through the main two Step process. The first, main Decomposition Step was characterized by an asymmetric, non-well separated peak which indicates on multi-Step processes during the pyrolytic cracking of diesters. It was observed between ca. 200 and 460–525 °C with significant mass loss from 85.7% to 90.9%. The TG/FTIR/QMS and additional performed DSC analysis showed that in the first Step of Decomposition cis elimination reactions, partial decarboxylation of formed dicarboxylic acids, condensation process of two carboxyl groups and polymerization process allene (benzene-1,2-propadienyl) in gaseous phase were expected. As a consequence, the production of CO2, H2O and CO as the main gases and also small amounts of organic compounds like carboxylic acids, cyclic ketones, aldehydes, allene, styrene, ethylbenzene, toluene and benzene are indicated. The second Step of Decomposition occurred at higher temperatures (above 460–525 °C) with the mass loss from 1.6% to 7.8%. The release of mainly CO2 and H2O as main gaseous products was ascribed. It was probably the result of the carbonization process of polymeric residue formed after the first Decomposition Step.
Marta Worzakowska - One of the best experts on this subject based on the ideXlab platform.
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thermal behavior of cinnamyl diesters studied by the tg ftir qms in inert atmosphere
Journal of Analytical and Applied Pyrolysis, 2014Co-Authors: Marta Worzakowska, Piotr ścigalskiAbstract:Abstract The thermal behavior of cinnamyl diesters in inert atmosphere was studied by the TG/FTIR/QMS coupled method. The results confirmed that diesters decomposed through the main two Step process. The first, main Decomposition Step was characterized by an asymmetric, non-well separated peak which indicates on multi-Step processes during the pyrolytic cracking of diesters. It was observed between ca. 200 and 460–525 °C with significant mass loss from 85.7% to 90.9%. The TG/FTIR/QMS and additional performed DSC analysis showed that in the first Step of Decomposition cis elimination reactions, partial decarboxylation of formed dicarboxylic acids, condensation process of two carboxyl groups and polymerization process allene (benzene-1,2-propadienyl) in gaseous phase were expected. As a consequence, the production of CO2, H2O and CO as the main gases and also small amounts of organic compounds like carboxylic acids, cyclic ketones, aldehydes, allene, styrene, ethylbenzene, toluene and benzene are indicated. The second Step of Decomposition occurred at higher temperatures (above 460–525 °C) with the mass loss from 1.6% to 7.8%. The release of mainly CO2 and H2O as main gaseous products was ascribed. It was probably the result of the carbonization process of polymeric residue formed after the first Decomposition Step.
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Thermal behavior of cinnamyl diesters studied by the TG/FTIR/QMS in inert atmosphere
Journal of Analytical and Applied Pyrolysis, 2014Co-Authors: Marta Worzakowska, Piotr ŚcigalskiAbstract:Abstract The thermal behavior of cinnamyl diesters in inert atmosphere was studied by the TG/FTIR/QMS coupled method. The results confirmed that diesters decomposed through the main two Step process. The first, main Decomposition Step was characterized by an asymmetric, non-well separated peak which indicates on multi-Step processes during the pyrolytic cracking of diesters. It was observed between ca. 200 and 460–525 °C with significant mass loss from 85.7% to 90.9%. The TG/FTIR/QMS and additional performed DSC analysis showed that in the first Step of Decomposition cis elimination reactions, partial decarboxylation of formed dicarboxylic acids, condensation process of two carboxyl groups and polymerization process allene (benzene-1,2-propadienyl) in gaseous phase were expected. As a consequence, the production of CO 2 , H 2 O and CO as the main gases and also small amounts of organic compounds like carboxylic acids, cyclic ketones, aldehydes, allene, styrene, ethylbenzene, toluene and benzene are indicated. The second Step of Decomposition occurred at higher temperatures (above 460–525 °C) with the mass loss from 1.6% to 7.8%. The release of mainly CO 2 and H 2 O as main gaseous products was ascribed. It was probably the result of the carbonization process of polymeric residue formed after the first Decomposition Step.
Antonio Marcilla - One of the best experts on this subject based on the ideXlab platform.
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Characterization of styrene–butadiene copolymers by catalytic pyrolysis over Al-MCM-41
Journal of Analytical and Applied Pyrolysis, 2009Co-Authors: Antonio Marcilla, Amparo Gómez-siurana, J.c. García Quesada, D. BerenguerAbstract:Abstract In this work, the Al-MCM-41 catalytic pyrolysis of styrene–butadiene copolymers in a thermobalance has been studied. The behaviour of such copolymers and the corresponding to high impact polystyrene (HIPS), physical blend of PS and PB with a given grafting degree, has been compared, and the importance of the degree of contact between the catalyst and the different polymer domains has been pointed out. Different particle size copolymer particles have been mixed with the catalyst, and in addition, samples have been prepared by solving the copolymer and mixing it with the catalyst, thus assuring an intimate contact. Different Decomposition Steps which can be related to the degradation of the different domains of the copolymer (polystyrene (PS) and polybutadiene (PB)) have been observed, despite the Decomposition processes of the PB and PS domains are not completely independent, showing certain interaction. The importance of to carefully controlling, defining and characterizing the experimental conditions of catalytic pyrolysis of PS–PB experiments in order to generalize or to extend the results obtained in such experiments is clearly demonstrated, and pseudokinetic models capable of reproducing the amount of material evolving trough each Decomposition Step have been suggested. The possibility of combining the two criteria: (1) the assignment of each Decomposition Step and (2) the application of a pseudokinetic model is suggested as a potential tool for the characterization of the composition of commercial copolymers or mixtures of PB and PS, once the adequate calibration runs have been performed.
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Study of the early deactivation in pyrolysis of polymers in the presence of catalysts
Journal of Analytical and Applied Pyrolysis, 2007Co-Authors: Antonio Marcilla, Amparo Gómez-siurana, D. BerenguerAbstract:Abstract In this work, the early degradation Step of the pyrolysis of some polymers in the presence of certain catalysts has been studied using thermogravimetric analysis (TGA). Three commercial polymers (PE, PP and EVA) and three catalysts were studied (ZSM-5, MCM-41a, and MCM-41b), and the MCM-41a catalyst has been selected for the analysis of the earlier Steps of the pyrolysis process carried out in the presence of catalysts. Several cycles of heating–cooling were performed using a thermobalance, in order to analyze the influence of the first stages of Decomposition on the activity of the more accessible active sites involved. In this way, the behaviour of the polymer–catalyst mixtures (20% (w/w) of catalyst) was studied and compared with that observed in the corresponding thermal degradation as well as in the pyrolysis in the presence of catalysts, in a single heating cycle. The results obtained clearly show the existence of an early degradation Step. For a polymer–catalyst system with low steric hindrances such as PE-MCM-41, this early degradation Step causes a noticeable decrease of the catalyst activity for the main Decomposition Step (i.e., cracking of the chain). The decrease of the catalytic activity is lower for a polymer–catalyst system with higher steric restrictions, as occurs in the EVA-MCM-41 degradation process. However, in this case, the catalyst activity in the first Decomposition Step (i.e., the loss of the acetoxi groups) is noticeable decreased after one pyrolysis run, thus reflecting that the active sites involved are mainly the most accessible ones.
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Oxidativedegradation of EVA copolymers in the presence of catalysts
Journal of Thermal Analysis and Calorimetry, 2007Co-Authors: Antonio Marcilla, Amparo Gómez-siurana, S. MenarguesAbstract:A study of the catalytic degradation of EVA copolymers under air atmosphere has been carried out using thermogravimety (TG). Three commercial EVA copolymers and five zeolites and related materials catalysts have been selected. The degradation process in air atmosphere involves four main Decomposition Steps (as observed in TG), being more complex than the corresponding process in inert atmosphere. The presence of MCM-41, HY and H-β does not seem to noticeably affect to the overall degradation temperature, despite the temperature of maximum reaction rate for the second Decomposition Step being slightly displaced towards lower temperatures. Contrarily, the presence of HZSM-5 and HUSY zeolites seems to displace the main stage of the oxidative degradation process towards higher temperatures. Moreover, the relative importance of the second and third Decomposition Step is different depending on the amount and the nature of the zeolite mixed with the EVA sample. The results obtained show that the presence of the catalyst also enhances the formation of the carbonous residue.
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TG/FTIR study of the thermal pyrolysis of EVA copolymers
Journal of Analytical and Applied Pyrolysis, 2005Co-Authors: Antonio Marcilla, A. Gómez, S. MenarguesAbstract:Abstract In this work, the evolution of the gas evolved during the thermal pyrolysis of three commercial ethylene-vinyl acetate copolymers (EVA) has been studied. The Decomposition of the copolymers has been carried out in a thermobalance connected to a Fourier transform infrared spectrometry (FTIR) spectrometer through a heated line. The experiments have been performed under N2 atmosphere at several heating rates, and the results obtained showed that, from the quality of the FTIR data obtained, the higher heating rates produced the best results. The evolution of the spectrograms obtained along the pyrolysis process reveals two events of generation of volatile products, related to the stages of EVA Decomposition already described in the bibliography. On the other hand, the TG and Gram–Schmidt curves show the existence of two different stages for the second Step of the pyrolysis of EVA, which can be associated to the Decomposition of the different domains which appear in the polymeric chain after the first Decomposition Step. The interpretation of the FTIR spectrograms corresponding to the temperatures of maximum Decomposition rate for each Decomposition Step shows the formation of acetic acid, CO and CO2 in the first Decomposition Step (elimination of the acetoxi groups), and the formation of a complex hydrocarbon mixture in the second Decomposition Step (cracking of the polymeric chain) including alkanes, alkenes and mononuclear aromatic compounds. The evolution of the ratio of the absorbance of bands at 3015 cm−1 (olefinic C H stretching) and 2925 cm−1 (asymmetric stretching of CH2 ), representative of the evolution of the ratio 1-alkenes/alkanes, shows a minimum, for the second Decomposition Step, close to the temperature of maximum Decomposition rate, which reflects the differences in the evolution of the alkanes and alkenes in the two stages of the second Decomposition Step.
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Catalytic cracking of ethylene-vinyl acetate copolymers: comparison of different zeolites
Journal of Analytical and Applied Pyrolysis, 2003Co-Authors: Antonio Marcilla, A. Gómez, S. Menargues, Javier Garcia-martinez, Diego Cazorla-amorósAbstract:Abstract In this work, five catalysts (three zeolites and two ordered mesoporous aluminosilicates, MCM-41) were tested for the pyrolysis of two samples of commercial ethylene-vinyl acetate (EVA) copolymers with different vinyl acetate percentage and different melt flow index. This study was carried out by using a thermobalance under nitrogen atmosphere and with a heating rate of 10 °C min −1 . As can be expected, the preliminary analysis of TG curves shows differences depending on the chemical and structural characteristics of the polymer and of the catalyst used: (i) despite that the temperature of maximum Decomposition rate is always the same for the first Decomposition Step (acetic acid loss), the presence of catalyst makes this Step less selective, thus occurring within a wider range of temperatures, especially for those catalysts with high external surface areas; (ii) the catalysts produce a reduction of the temperature of the second Decomposition Step (cracking of the residue from the first Step) which is always lower than that of the thermal process; (iii) it seems that the greater decrease of the maximum Decomposition rate temperature occurs when Hβ zeolite is added and is followed by the addition of Al-MCM-41 (however, the effect of the addition of catalyst depends on its percentage); and (iv) the comparison of TG curves corresponding to the addition of Hβ and Al-MCM-41 (which have high external surface areas), and of HY and H-ZSM-5 (with much lower external surface areas) reveals the importance of the accessibility to the active sites in the behavior of the catalyst.
S. Menargues - One of the best experts on this subject based on the ideXlab platform.
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Oxidativedegradation of EVA copolymers in the presence of catalysts
Journal of Thermal Analysis and Calorimetry, 2007Co-Authors: Antonio Marcilla, Amparo Gómez-siurana, S. MenarguesAbstract:A study of the catalytic degradation of EVA copolymers under air atmosphere has been carried out using thermogravimety (TG). Three commercial EVA copolymers and five zeolites and related materials catalysts have been selected. The degradation process in air atmosphere involves four main Decomposition Steps (as observed in TG), being more complex than the corresponding process in inert atmosphere. The presence of MCM-41, HY and H-β does not seem to noticeably affect to the overall degradation temperature, despite the temperature of maximum reaction rate for the second Decomposition Step being slightly displaced towards lower temperatures. Contrarily, the presence of HZSM-5 and HUSY zeolites seems to displace the main stage of the oxidative degradation process towards higher temperatures. Moreover, the relative importance of the second and third Decomposition Step is different depending on the amount and the nature of the zeolite mixed with the EVA sample. The results obtained show that the presence of the catalyst also enhances the formation of the carbonous residue.
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TG/FTIR study of the thermal pyrolysis of EVA copolymers
Journal of Analytical and Applied Pyrolysis, 2005Co-Authors: Antonio Marcilla, A. Gómez, S. MenarguesAbstract:Abstract In this work, the evolution of the gas evolved during the thermal pyrolysis of three commercial ethylene-vinyl acetate copolymers (EVA) has been studied. The Decomposition of the copolymers has been carried out in a thermobalance connected to a Fourier transform infrared spectrometry (FTIR) spectrometer through a heated line. The experiments have been performed under N2 atmosphere at several heating rates, and the results obtained showed that, from the quality of the FTIR data obtained, the higher heating rates produced the best results. The evolution of the spectrograms obtained along the pyrolysis process reveals two events of generation of volatile products, related to the stages of EVA Decomposition already described in the bibliography. On the other hand, the TG and Gram–Schmidt curves show the existence of two different stages for the second Step of the pyrolysis of EVA, which can be associated to the Decomposition of the different domains which appear in the polymeric chain after the first Decomposition Step. The interpretation of the FTIR spectrograms corresponding to the temperatures of maximum Decomposition rate for each Decomposition Step shows the formation of acetic acid, CO and CO2 in the first Decomposition Step (elimination of the acetoxi groups), and the formation of a complex hydrocarbon mixture in the second Decomposition Step (cracking of the polymeric chain) including alkanes, alkenes and mononuclear aromatic compounds. The evolution of the ratio of the absorbance of bands at 3015 cm−1 (olefinic C H stretching) and 2925 cm−1 (asymmetric stretching of CH2 ), representative of the evolution of the ratio 1-alkenes/alkanes, shows a minimum, for the second Decomposition Step, close to the temperature of maximum Decomposition rate, which reflects the differences in the evolution of the alkanes and alkenes in the two stages of the second Decomposition Step.
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Catalytic cracking of ethylene-vinyl acetate copolymers: comparison of different zeolites
Journal of Analytical and Applied Pyrolysis, 2003Co-Authors: Antonio Marcilla, A. Gómez, S. Menargues, Javier Garcia-martinez, Diego Cazorla-amorósAbstract:Abstract In this work, five catalysts (three zeolites and two ordered mesoporous aluminosilicates, MCM-41) were tested for the pyrolysis of two samples of commercial ethylene-vinyl acetate (EVA) copolymers with different vinyl acetate percentage and different melt flow index. This study was carried out by using a thermobalance under nitrogen atmosphere and with a heating rate of 10 °C min −1 . As can be expected, the preliminary analysis of TG curves shows differences depending on the chemical and structural characteristics of the polymer and of the catalyst used: (i) despite that the temperature of maximum Decomposition rate is always the same for the first Decomposition Step (acetic acid loss), the presence of catalyst makes this Step less selective, thus occurring within a wider range of temperatures, especially for those catalysts with high external surface areas; (ii) the catalysts produce a reduction of the temperature of the second Decomposition Step (cracking of the residue from the first Step) which is always lower than that of the thermal process; (iii) it seems that the greater decrease of the maximum Decomposition rate temperature occurs when Hβ zeolite is added and is followed by the addition of Al-MCM-41 (however, the effect of the addition of catalyst depends on its percentage); and (iv) the comparison of TG curves corresponding to the addition of Hβ and Al-MCM-41 (which have high external surface areas), and of HY and H-ZSM-5 (with much lower external surface areas) reveals the importance of the accessibility to the active sites in the behavior of the catalyst.
E Bilgen - One of the best experts on this subject based on the ideXlab platform.
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an improved process for h2so4 Decomposition Step of the sulfur iodine cycle
Energy Conversion and Management, 1995Co-Authors: Ilhan Ozturk, A Hammache, E BilgenAbstract:This study presents a new design, and thermodynamic and engineering analyses of the H2SO4 Decomposition section (Section II of the GA sulfur-iodine process flow sheet) of the thermochemical hydrogen producing cycle. Thermodynamic (energy and exergy) and cost analyses have been carried out using thermodynamic data and costs in the literature. The results show that energetic and exergetic efficiencies are 76.0 and 75.6%, respectively, and the typical cost is 2.2S (1990) per kmol SO2 for 4S (1990)/GJ nuclear heat cost.
