Pub Date : 2026-04-01Epub Date: 2026-02-07DOI: 10.1016/j.tca.2026.180244
Xudong Song , Dongbin Mai , Linmin Zhang , Juntao Wei , Qinghua Guo , Lipeeka Rout , Yan Gong , Yonghui Bai , Peng Lv , Weiguang Su , Guangsuo Yu
This study investigated biomass gasification using a self-built visual drop tube furnace and high-speed imaging, focusing on the effects of heat carrier temperature and oxygen concentration. Findings revealed that biomass particle position within the heat carrier layer significantly impacted gasification time. Placement on the bed surface reduced bed resistance, shortening the gasification time from 170 ms to 126 ms. While no distinct volatile flame was observed, the thermal storage of heat carriers stabilized the biomass flame. Increasing the oxygen concentration from 0.10 to 0.20 markedly enhanced flame characteristics, boosting the maximum flame luminosity and flame area by 2.72 and 4.69 times, respectively. This study aims to enhance thermal management within the gasifier through a solid heat carrier. The research objectives are twofold: to investigate the influence of the carrier’s thermal storage capacity on the biomass gasification reaction rate, and to examine the evolution of flame luminosity under controlled oxygen addition. Both factors are critical for maintaining a stable gasification process.
{"title":"Influence of heat carrier temperature and oxygen concentration on biomass gasification and flame characteristics","authors":"Xudong Song , Dongbin Mai , Linmin Zhang , Juntao Wei , Qinghua Guo , Lipeeka Rout , Yan Gong , Yonghui Bai , Peng Lv , Weiguang Su , Guangsuo Yu","doi":"10.1016/j.tca.2026.180244","DOIUrl":"10.1016/j.tca.2026.180244","url":null,"abstract":"<div><div>This study investigated biomass gasification using a self-built visual drop tube furnace and high-speed imaging, focusing on the effects of heat carrier temperature and oxygen concentration. Findings revealed that biomass particle position within the heat carrier layer significantly impacted gasification time. Placement on the bed surface reduced bed resistance, shortening the gasification time from 170 ms to 126 ms. While no distinct volatile flame was observed, the thermal storage of heat carriers stabilized the biomass flame. Increasing the oxygen concentration from 0.10 to 0.20 markedly enhanced flame characteristics, boosting the maximum flame luminosity and flame area by 2.72 and 4.69 times, respectively. This study aims to enhance thermal management within the gasifier through a solid heat carrier. The research objectives are twofold: to investigate the influence of the carrier’s thermal storage capacity on the biomass gasification reaction rate, and to examine the evolution of flame luminosity under controlled oxygen addition. Both factors are critical for maintaining a stable gasification process.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"758 ","pages":"Article 180244"},"PeriodicalIF":3.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190921","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 : 2026-04-01Epub Date: 2026-02-07DOI: 10.1016/j.tca.2026.180243
Mohammed el Amine Facih, Moulai Karim Boulkadid, Sabri Touidjine, Samir Belkhiri, Hichem Fettaka
Pyrotechnic formulations are widely applied in military and civilian domains for functions including illumination, signaling, smoke generation, and the initiation or enhancement of impulse devices. Fuel-rich alloys are particularly important for modulating ignition delay, combustion temperature, and heat output. Commonly composed of metallic powders and oxidizers, such systems ensure reliable ignition in applications ranging from fireworks to emergency initiators. Alloys of magnesium and aluminum combined with potassium perchlorate are favored for their low ignition thresholds and high enthalpy release. This study investigates the effect of sodium azide (NaN₃) surface coatings on the thermal and combustion behavior of fuel-rich ignition compositions. Al–Mg powders were coated with NaN₃ and characterized by SEM, thermogravimetry, and combustion tests. Kinetic parameters were derived via isoconversional methods, while calorimetry quantified energetic output. Findings reveal significant gains in thermal stability, energy release, and combustion efficiency, highlighting NaN₃-coated metallic fuels as promising candidates for next-generation pyrotechnic systems.
{"title":"New insights in the influence of sodium azide on thermal, energetic and combustion properties of ignition pyrotechnic composition","authors":"Mohammed el Amine Facih, Moulai Karim Boulkadid, Sabri Touidjine, Samir Belkhiri, Hichem Fettaka","doi":"10.1016/j.tca.2026.180243","DOIUrl":"10.1016/j.tca.2026.180243","url":null,"abstract":"<div><div>Pyrotechnic formulations are widely applied in military and civilian domains for functions including illumination, signaling, smoke generation, and the initiation or enhancement of impulse devices. Fuel-rich alloys are particularly important for modulating ignition delay, combustion temperature, and heat output. Commonly composed of metallic powders and oxidizers, such systems ensure reliable ignition in applications ranging from fireworks to emergency initiators. Alloys of magnesium and aluminum combined with potassium perchlorate are favored for their low ignition thresholds and high enthalpy release. This study investigates the effect of sodium azide (NaN₃) surface coatings on the thermal and combustion behavior of fuel-rich ignition compositions. Al–Mg powders were coated with NaN₃ and characterized by SEM, thermogravimetry, and combustion tests. Kinetic parameters were derived via isoconversional methods, while calorimetry quantified energetic output. Findings reveal significant gains in thermal stability, energy release, and combustion efficiency, highlighting NaN₃-coated metallic fuels as promising candidates for next-generation pyrotechnic systems.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"758 ","pages":"Article 180243"},"PeriodicalIF":3.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190919","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 : 2026-04-01Epub Date: 2026-02-02DOI: 10.1016/j.tca.2026.180239
Yang Chen , Qilong Huang , Zeyu Ren , Yanchun Li , Dongming Song , Yingyi Wu
To precisely tailor the combustion performance of Al/KClO4 for diverse applications, this study systematically investigates the decisive role of oxygen balance (η) in its reaction behavior. Closed bomb tests, calorimeter, and sensitivity tests were used to evaluate the performance of Al/KClO4, while TG-DSC, XRD, and SEM were used to investigate the reaction mechanism. Results show oxygen balance significantly alters the reaction pathway and energy release mode. At η ≥ −5, combustion transitions to deflagration for instantaneous energy release, whereas stable combustion dominates under significantly negative oxygen balance. Maximum heat of reaction (7927 J·g⁻¹) occurs at η = −20, and significant ignition delay appears at η ≤ −25. The sensitivity of Al/KClO4 (η = -20) is lower than that of traditional energetic materials such as black powder. In conclusion, the operational mode and combustion performance of the Al/KClO4 can be effectively regulated by adjusting the oxygen balance, thereby meeting the technical demands of diverse application scenarios.
{"title":"A study on the regulation of combustion characteristics in aluminum/potassium perchlorate through oxygen balance","authors":"Yang Chen , Qilong Huang , Zeyu Ren , Yanchun Li , Dongming Song , Yingyi Wu","doi":"10.1016/j.tca.2026.180239","DOIUrl":"10.1016/j.tca.2026.180239","url":null,"abstract":"<div><div>To precisely tailor the combustion performance of Al/KClO<sub>4</sub> for diverse applications, this study systematically investigates the decisive role of oxygen balance (η) in its reaction behavior. Closed bomb tests, calorimeter, and sensitivity tests were used to evaluate the performance of Al/KClO<sub>4</sub>, while TG-DSC, XRD, and SEM were used to investigate the reaction mechanism. Results show oxygen balance significantly alters the reaction pathway and energy release mode. At η ≥ −5, combustion transitions to deflagration for instantaneous energy release, whereas stable combustion dominates under significantly negative oxygen balance. Maximum heat of reaction (7927 J·g⁻¹) occurs at η = −20, and significant ignition delay appears at η ≤ −25. The sensitivity of Al/KClO<sub>4</sub> (η = -20) is lower than that of traditional energetic materials such as black powder. In conclusion, the operational mode and combustion performance of the Al/KClO<sub>4</sub> can be effectively regulated by adjusting the oxygen balance, thereby meeting the technical demands of diverse application scenarios.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"758 ","pages":"Article 180239"},"PeriodicalIF":3.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190923","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 : 2026-04-01Epub Date: 2026-01-24DOI: 10.1016/j.tca.2026.180234
Hongfeng Ji , Yufu Chen , Ju Tang , Wei Jiang , Yufei Gao , Fengnan Guo
Ammonium perchlorate (AP) possesses a unique molecular crystalline solid structure, giving rise to multi-channel coupled thermal transport characteristics. These properties are closely related to its thermolysis behavior, which has attracted extensive attention due to its role as an oxidizer. Based on this, the present study employs molecular dynamics simulation to analyze the distinctive thermal properties of AP from a microscopic perspective, and further investigates the influence of a copper substrate on its thermal behavior. Our results show that the thermal conductivity (TC) of AP is dominated by convective heat transport arising from molecular rotations, whereas the solid TC contributed by atomic vibrations and the cross TC arising from fluid-solid interactions are both much lower than the convective component. This unique mode of thermal transport causes the overall TC of AP to exhibit fluid-like behavior under varying temperatures and solid-like behavior under varying pressures. In addition, our study reveals several unique phenomena: molecular rotation in AP abnormally enhances the overall heat transport; after introducing a copper substrate, the overall TC of the system abnormally decreases due to interfacial effects combined with the dominant convective contribution in the model. Through analyses of atomic trajectories, molecular rotational angles, and phonon density of states, we mechanistically explain the promoting effect of rotation on vibrational heat transport. Furthermore, we find that ammonium ions contribute predominantly to convective heat transport, while perchlorate ions mainly contribute to vibrational transport. The rotational motion of perchlorate ions produces a more pronounced enhancement of vibrational heat transport, indicating that the positive cross TC in the structure primarily originates from the rotation of perchlorate ions. Overall, our work provides a comprehensive analysis of the thermal transport characteristics of ammonium perchlorate and uncovers several distinctive phenomena, offering valuable support for advancing its application in composite solid propellants.
{"title":"The abnormally promoting effect of molecular rotation on vibration thermal transport-a study on the multi-channel coupled thermal transport characteristics of ammonium perchlorate","authors":"Hongfeng Ji , Yufu Chen , Ju Tang , Wei Jiang , Yufei Gao , Fengnan Guo","doi":"10.1016/j.tca.2026.180234","DOIUrl":"10.1016/j.tca.2026.180234","url":null,"abstract":"<div><div>Ammonium perchlorate (AP) possesses a unique molecular crystalline solid structure, giving rise to multi-channel coupled thermal transport characteristics. These properties are closely related to its thermolysis behavior, which has attracted extensive attention due to its role as an oxidizer. Based on this, the present study employs molecular dynamics simulation to analyze the distinctive thermal properties of AP from a microscopic perspective, and further investigates the influence of a copper substrate on its thermal behavior. Our results show that the thermal conductivity (TC) of AP is dominated by convective heat transport arising from molecular rotations, whereas the solid TC contributed by atomic vibrations and the cross TC arising from fluid-solid interactions are both much lower than the convective component. This unique mode of thermal transport causes the overall TC of AP to exhibit fluid-like behavior under varying temperatures and solid-like behavior under varying pressures. In addition, our study reveals several unique phenomena: molecular rotation in AP abnormally enhances the overall heat transport; after introducing a copper substrate, the overall TC of the system abnormally decreases due to interfacial effects combined with the dominant convective contribution in the model. Through analyses of atomic trajectories, molecular rotational angles, and phonon density of states, we mechanistically explain the promoting effect of rotation on vibrational heat transport. Furthermore, we find that ammonium ions contribute predominantly to convective heat transport, while perchlorate ions mainly contribute to vibrational transport. The rotational motion of perchlorate ions produces a more pronounced enhancement of vibrational heat transport, indicating that the positive cross TC in the structure primarily originates from the rotation of perchlorate ions. Overall, our work provides a comprehensive analysis of the thermal transport characteristics of ammonium perchlorate and uncovers several distinctive phenomena, offering valuable support for advancing its application in composite solid propellants.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"758 ","pages":"Article 180234"},"PeriodicalIF":3.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057465","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 : 2026-04-01Epub Date: 2026-01-26DOI: 10.1016/j.tca.2026.180235
Marco Antonio Treviño-Kauffmann, Aarón Rojas-Aguilar
In this work isothermal thermogravimetry (TG) and Knudsen effusion (KE) were applied to determine the enthalpies of sublimation of ten polycyclic aromatic hydrocarbons (PAHs): five C20H12 isomers; four C22H14 isomers and a C16H10 isomer. This was achieved by measuring the rate of mass loss and applying the combined Pieterse-Focke equation with the Clausius-Clapeyron equation for TG and the combined Knudsen and Clausius-Clapeyron equations for KE to calculate the sublimation enthalpies at the experimental temperature which were then corrected to T=298.15 K. The results obtained were compared with those previously reported and an analysis of the crystal structures was done to correlate the sublimation enthalpies results to the different π stackings caused by the many geometries in the crystal arrangements of each of these PAHs.
{"title":"Sublimation enthalpies of polycyclic aromatic hydrocarbons by isothermal thermogravimetry and Knudsen effusion method","authors":"Marco Antonio Treviño-Kauffmann, Aarón Rojas-Aguilar","doi":"10.1016/j.tca.2026.180235","DOIUrl":"10.1016/j.tca.2026.180235","url":null,"abstract":"<div><div>In this work isothermal thermogravimetry (TG) and Knudsen effusion (KE) were applied to determine the enthalpies of sublimation of ten polycyclic aromatic hydrocarbons (PAHs): five C<sub>20</sub>H<sub>12</sub> isomers; four C<sub>22</sub>H<sub>14</sub> isomers and a C<sub>16</sub>H<sub>10</sub> isomer. This was achieved by measuring the rate of mass loss and applying the combined Pieterse-Focke equation with the Clausius-Clapeyron equation for TG and the combined Knudsen and Clausius-Clapeyron equations for KE to calculate the sublimation enthalpies at the experimental temperature which were then corrected to <em>T</em>=298.15 K. The results obtained were compared with those previously reported and an analysis of the crystal structures was done to correlate the sublimation enthalpies results to the different π stackings caused by the many geometries in the crystal arrangements of each of these PAHs.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"758 ","pages":"Article 180235"},"PeriodicalIF":3.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190922","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 : 2026-04-01Epub Date: 2026-01-29DOI: 10.1016/j.tca.2026.180237
Wenyan Zhang , Qin Xu , Chunhua Feng , Faqiang Su , Ze Zhou
Rigid polyurethane foam (RPUF) is widely used in insulation but remains highly flammable and smoke-producing. Existing flame-retardant systems often require high additive loadings or rely on environmentally problematic components, which limit their practical applicability. A bio-based composite coating of chitosan and graphitic carbon nitride (CS/g-C3N4) was designed to enhance the fire safety of RPUF through a simple surface modification strategy. The coated RPUF exhibited enhanced flame retardancy and smoke suppression, with the limiting oxygen index increasing from 19.4% to 26.3%. Cone calorimetry revealed reduced heat release and smoke production, including a 26.8% decrease in total smoke release and a 23.9% reduction in peak smoke production rate. Residual char analysis and TG–IR results demonstrated a combined gas-phase and condensed-phase flame-retardant mechanism, involving nonflammable gas release and the formation of a compact char layer. This study presents an efficient and environmentally friendly coating strategy to mitigate fire hazards in polymer foams.
{"title":"A bio‑based chitosan/g‑C3N4 coating for improved fire safety of rigid polyurethane foam","authors":"Wenyan Zhang , Qin Xu , Chunhua Feng , Faqiang Su , Ze Zhou","doi":"10.1016/j.tca.2026.180237","DOIUrl":"10.1016/j.tca.2026.180237","url":null,"abstract":"<div><div>Rigid polyurethane foam (RPUF) is widely used in insulation but remains highly flammable and smoke-producing. Existing flame-retardant systems often require high additive loadings or rely on environmentally problematic components, which limit their practical applicability. A bio-based composite coating of chitosan and graphitic carbon nitride (CS/g-C<sub>3</sub>N<sub>4</sub>) was designed to enhance the fire safety of RPUF through a simple surface modification strategy. The coated RPUF exhibited enhanced flame retardancy and smoke suppression, with the limiting oxygen index increasing from 19.4% to 26.3%. Cone calorimetry revealed reduced heat release and smoke production, including a 26.8% decrease in total smoke release and a 23.9% reduction in peak smoke production rate. Residual char analysis and TG–IR results demonstrated a combined gas-phase and condensed-phase flame-retardant mechanism, involving nonflammable gas release and the formation of a compact char layer. This study presents an efficient and environmentally friendly coating strategy to mitigate fire hazards in polymer foams.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"758 ","pages":"Article 180237"},"PeriodicalIF":3.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081686","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}
An electrically controlled solid propellant (ECSP) using lithium perchlorate/sodium nitrate as the oxidizer was prepared. The ECSP was verified to be capable of continuous and stable combustion under a 280 V voltage using the established electrically-controlled combustion test system, while it extinguished rapidly after power cutoff. The thermal decomposition properties of the ECSP and its raw materials were analyzed using TG-DSC-FTIR-MS coupled techniques. Comparative analysis of the combustion residues after flame burning and electrically controlled ignition was performed via separate FTIR tests. The results revealed that β-cyclodextrin significantly lowers the thermal decomposition temperature of the propellant system without leading to heat accumulation. Based on these findings, the formation mechanism of the high-temperature desensitization characteristics of this ECSP was further elucidated.
{"title":"Thermal decomposition characteristics of lithium perchlorate-based high-temperature insensitive electrically controlled solid propellant","authors":"Yiming Zhang, Xiaolong Fu, Xu Xia, Qihang Chen, Hanwen Liu, Shaocong Zhen, Lianpeng Cui, Suhang Chen, Jiangning Wang","doi":"10.1016/j.tca.2026.180238","DOIUrl":"10.1016/j.tca.2026.180238","url":null,"abstract":"<div><div>An electrically controlled solid propellant (ECSP) using lithium perchlorate/sodium nitrate as the oxidizer was prepared. The ECSP was verified to be capable of continuous and stable combustion under a 280 V voltage using the established electrically-controlled combustion test system, while it extinguished rapidly after power cutoff. The thermal decomposition properties of the ECSP and its raw materials were analyzed using TG-DSC-FTIR-MS coupled techniques. Comparative analysis of the combustion residues after flame burning and electrically controlled ignition was performed via separate FTIR tests. The results revealed that β-cyclodextrin significantly lowers the thermal decomposition temperature of the propellant system without leading to heat accumulation. Based on these findings, the formation mechanism of the high-temperature desensitization characteristics of this ECSP was further elucidated.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"758 ","pages":"Article 180238"},"PeriodicalIF":3.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190924","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 : 2026-04-01Epub Date: 2026-02-05DOI: 10.1016/j.tca.2026.180241
Jürgen E.K. Schawe, Nicolas O. Wyler
The study of crystallization using various scanning calorimetry techniques is often used to investigate the solidification processes of melts or the crystallization behavior of glassy materials. The classic Kolmogorov-Johnson-Mehl-Avrami (KJMA) approach is usually applied for this purpose. Conventional evaluation methods using the linearized KJMA equation or direct fitting can in some cases lead to larger errors. These include crystallization processes with unknown incubation times, rapid crystallization with greater uncertainties regarding crystallinity and time due to transition effects, overlapping crystallization processes, crystallization with changing mechanisms, or incomplete measurements.
In such cases, alternative evaluation methods such as the time-independent and derivative methods are more robust. These methods are presented here and discussed using the example of unfilled polypropylene (PP) and PP highly filled with carbon nanotubes (CNTs). The measurements were performed using conventional differential scanning calorimeter (DSC). As expected, PP exhibits heterogeneous nucleated three-dimensional growth of the crystalline superstructure in the temperature range investigated. The CNT-filled PP exhibits heterogeneous, nucleated two-dimensional growth in the early stage of crystallization, which corresponds to the formation of a shish-kebab structure. Interestingly, the filled material shows a longer incubation time, which is probably caused by the formation of equidistant nuclei on the surface of the nanotubes.
{"title":"Advanced evaluation methods of isothermal crystallization kinetics with consideration of incubation time and changes in the crystallization mechanism","authors":"Jürgen E.K. Schawe, Nicolas O. Wyler","doi":"10.1016/j.tca.2026.180241","DOIUrl":"10.1016/j.tca.2026.180241","url":null,"abstract":"<div><div>The study of crystallization using various scanning calorimetry techniques is often used to investigate the solidification processes of melts or the crystallization behavior of glassy materials. The classic Kolmogorov-Johnson-Mehl-Avrami (KJMA) approach is usually applied for this purpose. Conventional evaluation methods using the linearized KJMA equation or direct fitting can in some cases lead to larger errors. These include crystallization processes with unknown incubation times, rapid crystallization with greater uncertainties regarding crystallinity and time due to transition effects, overlapping crystallization processes, crystallization with changing mechanisms, or incomplete measurements.</div><div>In such cases, alternative evaluation methods such as the time-independent and derivative methods are more robust. These methods are presented here and discussed using the example of unfilled polypropylene (PP) and PP highly filled with carbon nanotubes (CNTs). The measurements were performed using conventional differential scanning calorimeter (DSC). As expected, PP exhibits heterogeneous nucleated three-dimensional growth of the crystalline superstructure in the temperature range investigated. The CNT-filled PP exhibits heterogeneous, nucleated two-dimensional growth in the early stage of crystallization, which corresponds to the formation of a shish-kebab structure. Interestingly, the filled material shows a longer incubation time, which is probably caused by the formation of equidistant nuclei on the surface of the nanotubes.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"758 ","pages":"Article 180241"},"PeriodicalIF":3.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190920","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 : 2026-04-01Epub Date: 2026-02-05DOI: 10.1016/j.tca.2026.180240
Mi Xu , Chenjie Gong , Jin Jia , Jiasheng Ru , Xiang Li , Yuefang Li , Anxin Ding
Precise modeling of curing kinetics is essential for thermosetting composite manufacturing, yet traditional phenomenological models exhibit limited accuracy and poor transferability across diverse thermal histories. In this study, a unified deep neural network (DNN) framework was developed and trained on differential scanning calorimetry (DSC) dataset encompassing both non-isothermal and isothermal curing conditions. The unified model achieved remarkably high predictive accuracy (R² = 0.9998) across all unseen validation cases. For benchmarking, the well-established Prout-Tompkins models and multi-term Kamal models were fitted using various strategies, but they exhibited poor extrapolation performance beyond their calibration domains, underscoring the DNN's superior generalizability. Finite element simulations further verified that accurate kinetic representation is critical, as the choice of model significantly impacts predicted temperature profiles and cure evolution. The proposed data-driven framework thus provides a reliable and generalizable approach for high-fidelity kinetic modeling in advanced composite manufacturing.
{"title":"A unified deep learning framework for curing kinetics: surpassing phenomenological models in accuracy and generalizability","authors":"Mi Xu , Chenjie Gong , Jin Jia , Jiasheng Ru , Xiang Li , Yuefang Li , Anxin Ding","doi":"10.1016/j.tca.2026.180240","DOIUrl":"10.1016/j.tca.2026.180240","url":null,"abstract":"<div><div>Precise modeling of curing kinetics is essential for thermosetting composite manufacturing, yet traditional phenomenological models exhibit limited accuracy and poor transferability across diverse thermal histories. In this study, a unified deep neural network (DNN) framework was developed and trained on differential scanning calorimetry (DSC) dataset encompassing both non-isothermal and isothermal curing conditions. The unified model achieved remarkably high predictive accuracy (R² = 0.9998) across all unseen validation cases. For benchmarking, the well-established Prout-Tompkins models and multi-term Kamal models were fitted using various strategies, but they exhibited poor extrapolation performance beyond their calibration domains, underscoring the DNN's superior generalizability. Finite element simulations further verified that accurate kinetic representation is critical, as the choice of model significantly impacts predicted temperature profiles and cure evolution. The proposed data-driven framework thus provides a reliable and generalizable approach for high-fidelity kinetic modeling in advanced composite manufacturing.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"758 ","pages":"Article 180240"},"PeriodicalIF":3.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190918","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 : 2026-04-01Epub Date: 2026-01-27DOI: 10.1016/j.tca.2026.180236
Jonathan L. McNanna, Mysha Momtaz, Mirko Schoenitz, Edward L. Dreizin
Boron is a thermodynamically attractive fuel, and its heterogeneous oxidation is expected to determine its ignition delay in practical configurations. Boron powders are commonly micron-sized aggregates of submicron primary particles. In this work, oxidation is compared for four different commercial boron powders with broad particle size distributions and for the same powders processed using emulsion-assisted milling (EAM) to prepare spherical particles with narrow size distributions. The milled powders were more tightly packed. The observed differences in the oxidation behaviors of commercial powders were reduced after they were EAM-processed. The oxidation proceeded in one step for as-received powders and in two steps for all milled powders. For all powders, the oxidation was incomplete; it slowed down after a smaller mass gain for the milled powders compared to the as-received ones. This was attributed to a lower porosity of the milled powders, which were thus more readily clogged with the formed molten boron oxide, preventing further oxidation. Iron contamination introduced by milling caused the oxidation to begin at a lower temperature; however, it also led to an increase in the activation energy of oxidation. Contamination by zirconia did not affect the oxidation onset temperature or the activation energy.
{"title":"Oxidation of boron powders with distinct particle morphologies","authors":"Jonathan L. McNanna, Mysha Momtaz, Mirko Schoenitz, Edward L. Dreizin","doi":"10.1016/j.tca.2026.180236","DOIUrl":"10.1016/j.tca.2026.180236","url":null,"abstract":"<div><div>Boron is a thermodynamically attractive fuel, and its heterogeneous oxidation is expected to determine its ignition delay in practical configurations. Boron powders are commonly micron-sized aggregates of submicron primary particles. In this work, oxidation is compared for four different commercial boron powders with broad particle size distributions and for the same powders processed using emulsion-assisted milling (EAM) to prepare spherical particles with narrow size distributions. The milled powders were more tightly packed. The observed differences in the oxidation behaviors of commercial powders were reduced after they were EAM-processed. The oxidation proceeded in one step for as-received powders and in two steps for all milled powders. For all powders, the oxidation was incomplete; it slowed down after a smaller mass gain for the milled powders compared to the as-received ones. This was attributed to a lower porosity of the milled powders, which were thus more readily clogged with the formed molten boron oxide, preventing further oxidation. Iron contamination introduced by milling caused the oxidation to begin at a lower temperature; however, it also led to an increase in the activation energy of oxidation. Contamination by zirconia did not affect the oxidation onset temperature or the activation energy.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"758 ","pages":"Article 180236"},"PeriodicalIF":3.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081685","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号