Understanding the curing kinetics of thermosetting resins is crucial for optimizing processing, predicting performance, and guiding design. This study developed a non-isothermal kinetic analysis method using in situ FTIR to investigate the commercial benzoxazine resin (CB7100), comparing the results with those obtained from conventional DSC. Both techniques demonstrated close agreement in peak curing temperatures, confirming the reliability of FTIR. The apparent activation energies calculated using the Kissinger and Ozawa methods were comparable, with values ranging from 80 to 86 kJ·mol⁻¹ for Kissinger and approximately 90 kJ·mol⁻¹ for Ozawa. Furthermore, the Flynn–Wall–Ozawa method, along with the Friedman approach and the Málek method, was employed to further investigate the curing kinetics. Notably, FTIR offers additional insights through 2D spectral analysis, making it a valuable complement to DSC in the kinetic evaluation of benzoxazine resins.
{"title":"Establishment and validation of a non-isothermal curing kinetic calculation method for benzoxazine based on in situ FTIR spectroscopy","authors":"Chenpei Li, Weihao Qin, Shenhao Song, Sentao Lin, Hongyang Zhang, Haitao Wan, Xin Meng, Changlu Zhou","doi":"10.1016/j.tca.2025.180148","DOIUrl":"10.1016/j.tca.2025.180148","url":null,"abstract":"<div><div>Understanding the curing kinetics of thermosetting resins is crucial for optimizing processing, predicting performance, and guiding design. This study developed a non-isothermal kinetic analysis method using in situ FTIR to investigate the commercial benzoxazine resin (CB7100), comparing the results with those obtained from conventional DSC. Both techniques demonstrated close agreement in peak curing temperatures, confirming the reliability of FTIR. The apparent activation energies calculated using the Kissinger and Ozawa methods were comparable, with values ranging from 80 to 86 kJ·mol⁻¹ for Kissinger and approximately 90 kJ·mol⁻¹ for Ozawa. Furthermore, the Flynn–Wall–Ozawa method, along with the Friedman approach and the Málek method, was employed to further investigate the curing kinetics. Notably, FTIR offers additional insights through 2D spectral analysis, making it a valuable complement to DSC in the kinetic evaluation of benzoxazine resins.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"753 ","pages":"Article 180148"},"PeriodicalIF":3.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-08-30DOI: 10.1016/j.tca.2025.180127
Yves Zerega, Laurence Tortet, Véronique Wernert
A new numerical data-processing method for Thermogravimeter-Mass Spectrometer (TG/MS) coupling data is presented. It enables the determination of quantified desorption temperature distributions and the quantification of each desorbed compound targeted by the MS. Its main advantage is that no calibration of the evolved gases is required.
The mathematical formulation of the problem consists in matching the local negative derivative of the mass variation monitored by the TG with the sum of the ion counts monitored by the MS for each compound. This results in an overdetermined system of equations, with a set of delays and proportional factors as unknowns. A least-squares method is employed to solve the system. The desorption temperature distributions are then computed using the delays and proportional factors obtained when the mean square error is minimised. From the distributions, the desorbed quantities, as well as the maximum and mean desorption temperatures, can be calculated.
The numerical method was initially validated using water desorption from FAU-NaX zeolite. Assumptions made to establish the model were confirmed. The transfer of evolved gases to the MS introduces only a pure shift. After mathematical baseline correction, a linear response in the MS amplitude was observed over a sufficiently broad range for our measurements. The treated MS curve matches the -DTG curve with an uncertainty of <0.5 mg/g. The adaptability of the method to variations in MS detection sensitivity was demonstrated. A mass deviation of 10 % is considered acceptable when comparing the desorption temperature distributions of two samples.
{"title":"New method for quantitative thermal gravimetric analysis per compound - model and numerical processing of TG and MS data","authors":"Yves Zerega, Laurence Tortet, Véronique Wernert","doi":"10.1016/j.tca.2025.180127","DOIUrl":"10.1016/j.tca.2025.180127","url":null,"abstract":"<div><div>A new numerical data-processing method for Thermogravimeter-Mass Spectrometer (TG/MS) coupling data is presented. It enables the determination of quantified desorption temperature distributions and the quantification of each desorbed compound targeted by the MS. Its main advantage is that no calibration of the evolved gases is required.</div><div>The mathematical formulation of the problem consists in matching the local negative derivative of the mass variation monitored by the TG with the sum of the ion counts monitored by the MS for each compound. This results in an overdetermined system of equations, with a set of delays and proportional factors as unknowns. A least-squares method is employed to solve the system. The desorption temperature distributions are then computed using the delays and proportional factors obtained when the mean square error is minimised. From the distributions, the desorbed quantities, as well as the maximum and mean desorption temperatures, can be calculated.</div><div>The numerical method was initially validated using water desorption from FAU-NaX zeolite. Assumptions made to establish the model were confirmed. The transfer of evolved gases to the MS introduces only a pure shift. After mathematical baseline correction, a linear response in the MS amplitude was observed over a sufficiently broad range for our measurements. The treated MS curve matches the -DTG curve with an uncertainty of <0.5 mg/g. The adaptability of the method to variations in MS detection sensitivity was demonstrated. A mass deviation of 10 % is considered acceptable when comparing the desorption temperature distributions of two samples.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"753 ","pages":"Article 180127"},"PeriodicalIF":3.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work aims to valorize locally available plant fibers extracted from date palm, alfa, reed, and olive tree branches and to promote them as fillers for epoxy matrix composites specifically designed for thermal insulation in building envelopes. The motivation of this study lies in the urgent global demand for sustainable and eco-friendly insulation materials that can significantly reduce energy consumption in buildings and decrease greenhouse gas emissions, thereby contributing to climate change mitigation and improved energy efficiency. An exhaustive characterization of the fibers was carried out using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDS). The fibers exhibited significant porosity, enabling air entrapment and improving thermal performance. Variations in crystallinity index were observed, with alfa fibers showing the highest value at 51.76%. Chemical characterization revealed differences in oxygen-to-carbon ratios, reflecting the unique features of each fiber type. Composites were developed with a 50:50 mass ratio of fiber to epoxy resin. Thermal conductivity, measured using the guarded hot plate method, ranged between 0.059 and 0.097 W·m⁻¹·K⁻¹, confirming the crucial role of fiber internal structure, particularly the lumen, in limiting heat transfer. The specific heat capacity (Cp), evaluated using µDSC, varied from 1.343 to 1.460 J·g⁻¹·K⁻¹, indicating good thermal inertia suitable for maintaining indoor comfort. These findings highlight the strong potential of these bio-based composites as green, efficient, and locally sourced insulation materials for sustainable buildings. This study also opens perspectives for further research on fiber treatment optimization, durability assessment, and industrial-scale production to meet future demands for eco-friendly construction materials.
{"title":"Sustainable insulation materials from local plant fibers: Characterization and thermal properties of epoxy-based composites","authors":"Abderrahim Benallel , Amine Tilioua , Najma Laaroussi","doi":"10.1016/j.tca.2025.180146","DOIUrl":"10.1016/j.tca.2025.180146","url":null,"abstract":"<div><div>This work aims to valorize locally available plant fibers extracted from date palm, alfa, reed, and olive tree branches and to promote them as fillers for epoxy matrix composites specifically designed for thermal insulation in building envelopes. The motivation of this study lies in the urgent global demand for sustainable and eco-friendly insulation materials that can significantly reduce energy consumption in buildings and decrease greenhouse gas emissions, thereby contributing to climate change mitigation and improved energy efficiency. An exhaustive characterization of the fibers was carried out using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDS). The fibers exhibited significant porosity, enabling air entrapment and improving thermal performance. Variations in crystallinity index were observed, with alfa fibers showing the highest value at 51.76%. Chemical characterization revealed differences in oxygen-to-carbon ratios, reflecting the unique features of each fiber type. Composites were developed with a 50:50 mass ratio of fiber to epoxy resin. Thermal conductivity, measured using the guarded hot plate method, ranged between 0.059 and 0.097 W·m⁻¹·K⁻¹, confirming the crucial role of fiber internal structure, particularly the lumen, in limiting heat transfer. The specific heat capacity (Cp), evaluated using µDSC, varied from 1.343 to 1.460 J·g⁻¹·K⁻¹, indicating good thermal inertia suitable for maintaining indoor comfort. These findings highlight the strong potential of these bio-based composites as green, efficient, and locally sourced insulation materials for sustainable buildings. This study also opens perspectives for further research on fiber treatment optimization, durability assessment, and industrial-scale production to meet future demands for eco-friendly construction materials.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"753 ","pages":"Article 180146"},"PeriodicalIF":3.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-08-24DOI: 10.1016/j.tca.2025.180109
Hua Fei , Jianmin Tong , Yuanlin Li , Ximei Liang , Xi Dai , Min Fang
In this work, modified biomass carbon carriers with interconnected three-dimensional porous structures capable of encapsulating phase change materials were prepared using cassava, which is rich in high amylose, and chayote, which is rich in cellulosic/hemicellulosic constituents. Six modified carbon carriers with different pore structures were prepared by a combination of vacuum drying and tube furnace carbonization with different carbonization temperatures. CAB1000 and CHB900, which have the most abundant pore structures, were used as the best carriers to adsorb LAPW phase change materials. Two composite phase change materials of LAPW/CAB1000 and LAPW/CHB900 with 65 % loading were obtained by vacuum adsorption, and the binding of CAB1000 and CHB900 to LA-PW was purely physical without chemical reaction. The phase change enthalpy of LAPW/CAB1000 and LAPW/CHB900 are 112.68 J/g and 83.30 J/g, and the phase transition temperatures are 35.79 °C and 34.08 °C, respectively. After 500 cycles, both LAPW/CAB1000 and LAPW/CHB900 maintain a phase transition peak and a stable phase transition temperature. The thermal conductivity of LAPW/CAB1000 and LAPW/CHB900 are 0.45 W/(m·k) and 0.42 W/(m·k), respectively, which are 45.52 % and 34.32 % higher than LA-PW. Therefore, the LAPW/CAB1000 and LAPW/CHB900 prepared in this work have high thermal conductivity and good phase change energy storage properties.
{"title":"The thermal conductivity enhancement of binary eutectic adsorbed into modified cassava and chayote based in vacuum environment","authors":"Hua Fei , Jianmin Tong , Yuanlin Li , Ximei Liang , Xi Dai , Min Fang","doi":"10.1016/j.tca.2025.180109","DOIUrl":"10.1016/j.tca.2025.180109","url":null,"abstract":"<div><div>In this work, modified biomass carbon carriers with interconnected three-dimensional porous structures capable of encapsulating phase change materials were prepared using cassava, which is rich in high amylose, and chayote, which is rich in cellulosic/hemicellulosic constituents. Six modified carbon carriers with different pore structures were prepared by a combination of vacuum drying and tube furnace carbonization with different carbonization temperatures. CAB1000 and CHB900, which have the most abundant pore structures, were used as the best carriers to adsorb LAPW phase change materials. Two composite phase change materials of LAPW/CAB1000 and LAPW/CHB900 with 65 % loading were obtained by vacuum adsorption, and the binding of CAB1000 and CHB900 to LA-PW was purely physical without chemical reaction. The phase change enthalpy of LAPW/CAB1000 and LAPW/CHB900 are 112.68 J/g and 83.30 J/g, and the phase transition temperatures are 35.79 °C and 34.08 °C, respectively. After 500 cycles, both LAPW/CAB1000 and LAPW/CHB900 maintain a phase transition peak and a stable phase transition temperature. The thermal conductivity of LAPW/CAB1000 and LAPW/CHB900 are 0.45 W/(m·k) and 0.42 W/(m·k), respectively, which are 45.52 % and 34.32 % higher than LA-PW. Therefore, the LAPW/CAB1000 and LAPW/CHB900 prepared in this work have high thermal conductivity and good phase change energy storage properties.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"753 ","pages":"Article 180109"},"PeriodicalIF":3.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144906946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Iron ore sintering is essential in steelmaking, but traditional fluxes like limestone contribute to CO2 emissions. Alternative calcium-based fluxes such as carbide slag (CS) and white mud (WM) offer environmental benefits, though their melting behaviors are less understood. This study investigates the effects of flux type, magnetite concentrate addition, and reducing atmosphere on the melting characteristics of sintering mixtures using high-temperature microscopic heating and thermal analysis. At basicity 4.0, mixtures with CS and WM showed critical melting temperatures (Tcm) 1.6 % and 3.8 % higher than those with limestone. Adding 20–30 % magnetite raised Tcm by 25–35 K, and 6–10 % CO further increased Tcm by 15–20 K. Microstructural analysis showed more dendritic and needle-like crystals with CS and WM. While CS and WM are viable alternatives, their inferior melting performance requires further optimization for industrial use.
{"title":"Study on the melting characteristics of iron ore sintering mixtures using spent carbide slag and white mud as calcium-based fluxes","authors":"Laiquan Lv, Hanxiao Meng, Jiankang Wang, Jianguo Zhao, Hao Zhou","doi":"10.1016/j.tca.2025.180131","DOIUrl":"10.1016/j.tca.2025.180131","url":null,"abstract":"<div><div>Iron ore sintering is essential in steelmaking, but traditional fluxes like limestone contribute to CO<sub>2</sub> emissions. Alternative calcium-based fluxes such as carbide slag (CS) and white mud (WM) offer environmental benefits, though their melting behaviors are less understood. This study investigates the effects of flux type, magnetite concentrate addition, and reducing atmosphere on the melting characteristics of sintering mixtures using high-temperature microscopic heating and thermal analysis. At basicity 4.0, mixtures with CS and WM showed critical melting temperatures (<em>T</em><sub>cm</sub>) 1.6 % and 3.8 % higher than those with limestone. Adding 20–30 % magnetite raised <em>T</em><sub>cm</sub> by 25–35 K, and 6–10 % CO further increased <em>T</em><sub>cm</sub> by 15–20 K. Microstructural analysis showed more dendritic and needle-like crystals with CS and WM. While CS and WM are viable alternatives, their inferior melting performance requires further optimization for industrial use.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"753 ","pages":"Article 180131"},"PeriodicalIF":3.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-08-31DOI: 10.1016/j.tca.2025.180128
Lucie Kořená , Václav Slovák , Samantha L. Flores-López , Ana Arenillas
The individual effect of pore size on the melting behaviour of probe liquid confined in material pores, as well as on parameters used to convert differential scanning calorimetry (DSC) data into pore size distribution (PSD) was systematically investigated. For thermoporometric testing, a tailored series of carbon xerogels with uniform pore shape and surface chemistry but varying pore sizes (10 - 50 nm) was prepared, and water was chosen as a probe liquid. The observed decreasing relation between water melting point depression and carbon xerogels pore radius confirmed the suitability of modified Gibbs-Thomson equation for PSD determination. A good linear correlation was established between the DSC peak area (representing heat of fusion of pore-confined ice) and pore volume, with the relation notably affected by pore size. The experimentally derived Gibbs-Thomson constant (39 nm K) deviated significantly from the commonly accepted one, and the non-freezable layer width (the delta layer) increased with increasing pore size.
{"title":"Systematic DSC analysis of the melting point depression and the non-freezable layer width in different mesopore sizes in carbon xerogels","authors":"Lucie Kořená , Václav Slovák , Samantha L. Flores-López , Ana Arenillas","doi":"10.1016/j.tca.2025.180128","DOIUrl":"10.1016/j.tca.2025.180128","url":null,"abstract":"<div><div>The individual effect of pore size on the melting behaviour of probe liquid confined in material pores, as well as on parameters used to convert differential scanning calorimetry (DSC) data into pore size distribution (PSD) was systematically investigated. For thermoporometric testing, a tailored series of carbon xerogels with uniform pore shape and surface chemistry but varying pore sizes (10 - 50 nm) was prepared, and water was chosen as a probe liquid. The observed decreasing relation between water melting point depression and carbon xerogels pore radius confirmed the suitability of modified Gibbs-Thomson equation for PSD determination. A good linear correlation was established between the DSC peak area (representing heat of fusion of pore-confined ice) and pore volume, with the relation notably affected by pore size. The experimentally derived Gibbs-Thomson constant (39 nm K) deviated significantly from the commonly accepted one, and the non-freezable layer width (the delta layer) increased with increasing pore size.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"753 ","pages":"Article 180128"},"PeriodicalIF":3.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-08-26DOI: 10.1016/j.tca.2025.180114
Saurav Bhattacharjee , Syam Nair
Durability loss of calcium silicate hydrate (C-S-H) phases due to carbonation in cementitious materials is major concern for practicing civil engineers. Study attempts to quantify the time dependent changes in carbonate phases and residual lime content in C-S-H phases due to long term carbonation in cementitious materials. Synthesized C-S-H phases were subjected to varying carbon dioxide exposure conditions to simulate long term behaviour of hydration products in field conditions. Thermogravimetric analysis was used in tandem with stoichiometric equations of precipitation and dissolution of various ionic species for quantification of precipitated phases. Observations show that prolonged carbonation can lead to decalcification of cementing materials and degradation of C-S-H to non-cementing phases like silica gel. Even though the concentration of residual lime in the matrix was found to increase with carbonation, the pH levels of cementitious matrix decreased with time due to buffering action by carbonic acid-bicarbonate equilibria created during carbonation process.
{"title":"Impact of carbonation on calcium silicate hydrate phases in cementitious materials: Quantification of carbonate phases and residual lime content","authors":"Saurav Bhattacharjee , Syam Nair","doi":"10.1016/j.tca.2025.180114","DOIUrl":"10.1016/j.tca.2025.180114","url":null,"abstract":"<div><div>Durability loss of calcium silicate hydrate (C-S-H) phases due to carbonation in cementitious materials is major concern for practicing civil engineers. Study attempts to quantify the time dependent changes in carbonate phases and residual lime content in C-S-H phases due to long term carbonation in cementitious materials. Synthesized C-S-H phases were subjected to varying carbon dioxide exposure conditions to simulate long term behaviour of hydration products in field conditions. Thermogravimetric analysis was used in tandem with stoichiometric equations of precipitation and dissolution of various ionic species for quantification of precipitated phases. Observations show that prolonged carbonation can lead to decalcification of cementing materials and degradation of C-S-H to non-cementing phases like silica gel. Even though the concentration of residual lime in the matrix was found to increase with carbonation, the pH levels of cementitious matrix decreased with time due to buffering action by carbonic acid-bicarbonate equilibria created during carbonation process.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"753 ","pages":"Article 180114"},"PeriodicalIF":3.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144917849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-09-30DOI: 10.1016/j.tca.2025.180149
Shunsuke Fukunaga, Mito Hotta, Nobuyoshi Koga
The thermal dehydration of sodium acetate trihydrate (SA-TH) and the hydration of its anhydride form a potential thermochemical energy storage system. A comprehensive understanding of the thermal dehydration kinetics of SA-TH is imperative for evaluating its thermal stability and optimizing the thermal dehydration conditions. However, the kinetic characterization of the solid-state thermal dehydration of SA-TH is complicated due to the efflorescence of SA-TH at ambient temperature and its melting slightly above room temperature. The purpose of this study was to provide a comprehensive description of the kinetics across a range of varying temperatures and partial pressures of water vapor (p(H2O)), exploring the physico-chemical and physico-geometrical perspectives. As the initial report, this article presents the physico-geometrical kinetic behavior of the thermal dehydration of the SA-TH samples with varying particle sizes in flowing dry N2. A low-temperature thermogravimetry (TG) system was utilized to monitor the complete process of the thermal dehydration. The TG curves, systematically recorded under various heating conditions, were subjected to the formal kinetic analysis via the isoconversional plot and master plot methods. The kinetic results of the formal kinetic analysis, as well as in situ microscopic observation, revealed the physico-geometrical feature of the consecutive surface reaction (SR) and phase boundary-controlled reaction (PBR). The overall reaction process under isothermal conditions was successfully described by the SR–PBR model. However, the substantial impact of the self-generated p(H2O) on the kinetics was predicted in the results of both the formal kinetic analysis and physico-geometrical modeling using the SR–PBR model.
{"title":"Physico-geometrical kinetics of the solid-state thermal dehydration of sodium acetate trihydrate in flowing dry N2","authors":"Shunsuke Fukunaga, Mito Hotta, Nobuyoshi Koga","doi":"10.1016/j.tca.2025.180149","DOIUrl":"10.1016/j.tca.2025.180149","url":null,"abstract":"<div><div>The thermal dehydration of sodium acetate trihydrate (SA-TH) and the hydration of its anhydride form a potential thermochemical energy storage system. A comprehensive understanding of the thermal dehydration kinetics of SA-TH is imperative for evaluating its thermal stability and optimizing the thermal dehydration conditions. However, the kinetic characterization of the solid-state thermal dehydration of SA-TH is complicated due to the efflorescence of SA-TH at ambient temperature and its melting slightly above room temperature. The purpose of this study was to provide a comprehensive description of the kinetics across a range of varying temperatures and partial pressures of water vapor (<em>p</em>(H<sub>2</sub>O)), exploring the physico-chemical and physico-geometrical perspectives. As the initial report, this article presents the physico-geometrical kinetic behavior of the thermal dehydration of the SA-TH samples with varying particle sizes in flowing dry N<sub>2</sub>. A low-temperature thermogravimetry (TG) system was utilized to monitor the complete process of the thermal dehydration. The TG curves, systematically recorded under various heating conditions, were subjected to the formal kinetic analysis via the isoconversional plot and master plot methods. The kinetic results of the formal kinetic analysis, as well as in situ microscopic observation, revealed the physico-geometrical feature of the consecutive surface reaction (SR) and phase boundary-controlled reaction (PBR). The overall reaction process under isothermal conditions was successfully described by the SR–PBR model. However, the substantial impact of the self-generated <em>p</em>(H<sub>2</sub>O) on the kinetics was predicted in the results of both the formal kinetic analysis and physico-geometrical modeling using the SR–PBR model.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"753 ","pages":"Article 180149"},"PeriodicalIF":3.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-08-22DOI: 10.1016/j.tca.2025.180111
Shuai Zhao , Chunyun Xu , Wanfen Pu , Haolong He , Chengdong Yuan , Mikhail A. Varfolomeev
A lack of research existed on the in-situ combustion (ISC) characteristics and produced oil properties in steam-injected heavy oil reservoirs. This study focused on investigating combustion characteristics in steam-developed (steam huff-and-puff and steam flooding) heavy oil reservoirs by the combustion tube (CT) and experimental schemes, followed by a thorough characterization of the produced oils. The results indicated that as the secondary water body (SWB) was situated in the initial segment of CT, the combustion front propagated through the SWB region with oxygen concentration below 2 % and CO2 concentration of 11 %-13 %. In contrast, when SWB was positioned in the second half of CT, the peak temperatures at thermocouples 5 and 6 dipped below 300°C, failing to achieve the stable propagation of combustion front. The location of SWB significantly influenced combustion front propagation. Notably, three key indicators were found to assess the ISC effectiveness.
{"title":"In-situ combustion within steam-injected heavy oil reservoirs: Combustion characteristics and produced oil properties","authors":"Shuai Zhao , Chunyun Xu , Wanfen Pu , Haolong He , Chengdong Yuan , Mikhail A. Varfolomeev","doi":"10.1016/j.tca.2025.180111","DOIUrl":"10.1016/j.tca.2025.180111","url":null,"abstract":"<div><div>A lack of research existed on the in-situ combustion (ISC) characteristics and produced oil properties in steam-injected heavy oil reservoirs. This study focused on investigating combustion characteristics in steam-developed (steam huff-and-puff and steam flooding) heavy oil reservoirs by the combustion tube (CT) and experimental schemes, followed by a thorough characterization of the produced oils. The results indicated that as the secondary water body (SWB) was situated in the initial segment of CT, the combustion front propagated through the SWB region with oxygen concentration below 2 % and CO<sub>2</sub> concentration of 11 %-13 %. In contrast, when SWB was positioned in the second half of CT, the peak temperatures at thermocouples 5 and 6 dipped below 300°C, failing to achieve the stable propagation of combustion front. The location of SWB significantly influenced combustion front propagation. Notably, three key indicators were found to assess the ISC effectiveness.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"753 ","pages":"Article 180111"},"PeriodicalIF":3.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144895042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01Epub Date: 2025-10-08DOI: 10.1016/j.tca.2025.180155
Tomasz M. Majka , Szczepan Bednarz , Krzysztof Pielichowski
This work demonstrates that green deep eutectic solvents can act as efficient thermal stabilizers and flame retardants for an important biopolymer - polylactide. This important bioplastic is a flammable material and this feature limits its application potential in replacing synthetic polymers. In our work, selected Deep Eutectic Solvents (DESs), such as magnesium stearate:eugenol (MS:EU), zinc stearate:eugenol (ZS:EU), oxalic acid:choline chloride (OA:CCl), were adsorbed onto the surface of montmorillonite (MMT). The obtained MMT-DES hybrids were then applied as additives for polylactide (PLA) utilizing an easily upscaled extrusion process. Notably, among the MMT-DES hybrids, the MMT-OA:CCl hybrid exhibited the greatest thermal stability, as well as it showed 93 % lower flammability than pure filler. Thermogravimetric analysis of PLA/DES and PLA/MMT-DES composites allowed us to rank these materials in terms of thermal stability using two different criteria - indices comparison and Overall Thermal Stabilization Effect (OSE). In both cases, the highest thermal stability was achieved by PLA/OA:CCl. Finally, a 34 % reduction in flammability was achieved with the MMT-DES hybrid, while the use of DES alone resulted in a still remarkable 20 % reduction. The obtained results show the vast potential of green DES to improve the performance of biopolymers that play a growing role in sustainable development.
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