With the growing challenge of electronic waste (e-waste), this study explores CO₂-assisted gasification as a valorization method for five typical e-waste resins: PSM, DFR, WPCB, SW, and F. Using TG-MS and TG-FTIR techniques, non-isothermal kinetic modeling was performed under a CO₂ atmosphere to determine activation energies and reaction mechanisms. The findings offer molecular-level insights into pollution control during e-waste gasification and establish a theoretical basis for process optimization guided by gasification kinetics, highlighting its engineering potential for sustainable waste treatment.
{"title":"Gasification mechanism and product analysis of resin wastes: an integrated study of TG-FTIR-MS and kinetic modeling","authors":"Liyan Chen , Qian Liu , Yinsheng Jiang , Wenqi Zhong , Wenli Dong","doi":"10.1016/j.tca.2025.180197","DOIUrl":"10.1016/j.tca.2025.180197","url":null,"abstract":"<div><div>With the growing challenge of electronic waste (e-waste), this study explores CO₂-assisted gasification as a valorization method for five typical e-waste resins: PSM, DFR, WPCB, SW, and F. Using TG-MS and TG-FTIR techniques, non-isothermal kinetic modeling was performed under a CO₂ atmosphere to determine activation energies and reaction mechanisms. The findings offer molecular-level insights into pollution control during e-waste gasification and establish a theoretical basis for process optimization guided by gasification kinetics, highlighting its engineering potential for sustainable waste treatment.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"755 ","pages":"Article 180197"},"PeriodicalIF":3.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681861","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 : 2025-11-30DOI: 10.1016/j.tca.2025.180196
Wei-Le Chen , Jun Deng , Yin Deng , Lan Yin , Cai-Ping Wang , Xia-Dan Duan , Hai-fei Lin
Mining flame-retardant conveyor belts (FRCBs) is a crucial bridge transporting coal in mine, but the occurrence of FRCB fires has seriously affected the safety transportation and mining of coal. To investigate their pyrolysis and combustion characteristics, FRCBs for polyvinyl chloride (PVC) and polyvinyl chloride gum elastic (PVG) were selected, and simultaneous thermal analysis-Fourier transform infrared spectroscopy was adopted to measure their pyrolysis and combustion characteristics, including mass loss characteristics, heat release properties, and gaseous products. Apparent activation energy was received by Kissinger-Akahira-Sunose method. The results indicated that, during combustion, FRCB for PVC and PVG experienced three and two weightlessness stages, respectively. and main functional groups of FRCB for PVC were HCl, chlorinated hydrocarbons, CO2, and aromatic compounds, while FRCB for PVG generated additional gaseous products for cyanate gas. Meanwhile, the average apparent activation energy of FRCBs for PVG was 144.3 kJ·mol-1 in the first stage of combustion, which was higher than that for PVC at 125.6 kJ·mol-1. During pyrolysis, the FRCBs for PVG and PVC experienced two weightlessness stages, the FRCBs for PVC generated the additional CH gas and ester compounds, and PVG also produced ester compounds without cyanate gas. Moreover, their heat releases during pyrolysis were lower than that during combustion. while FRCB for PVG generated additional gaseous products for cyanate gas. The average apparent activation energy of FRCBs for PVG was 162.0 kJ·mol-1 In the first stage of pyrolysis, which was higher than that for PVC at 143.3 kJ·mol-1. These findings confirmed that PVG had superior flame retardancy compared to PVC. The research results provide a theoretical basis for determining key criteria in early intelligent warning.
{"title":"Comparative analysis on thermal characteristics and microstructures of mining flame-retardant conveyor belts during pyrolysis and combustion","authors":"Wei-Le Chen , Jun Deng , Yin Deng , Lan Yin , Cai-Ping Wang , Xia-Dan Duan , Hai-fei Lin","doi":"10.1016/j.tca.2025.180196","DOIUrl":"10.1016/j.tca.2025.180196","url":null,"abstract":"<div><div>Mining flame-retardant conveyor belts (FRCBs) is a crucial bridge transporting coal in mine, but the occurrence of FRCB fires has seriously affected the safety transportation and mining of coal. To investigate their pyrolysis and combustion characteristics, FRCBs for polyvinyl chloride (PVC) and polyvinyl chloride gum elastic (PVG) were selected, and simultaneous thermal analysis-Fourier transform infrared spectroscopy was adopted to measure their pyrolysis and combustion characteristics, including mass loss characteristics, heat release properties, and gaseous products. Apparent activation energy was received by Kissinger-Akahira-Sunose method. The results indicated that, during combustion, FRCB for PVC and PVG experienced three and two weightlessness stages, respectively. and main functional groups of FRCB for PVC were HCl, chlorinated hydrocarbons, CO<sub>2</sub>, and aromatic compounds, while FRCB for PVG generated additional gaseous products for cyanate gas. Meanwhile, the average apparent activation energy of FRCBs for PVG was 144.3 kJ·mol<sup>-1</sup> in the first stage of combustion, which was higher than that for PVC at 125.6 kJ·mol<sup>-1</sup>. During pyrolysis, the FRCBs for PVG and PVC experienced two weightlessness stages, the FRCBs for PVC generated the additional C<img>H gas and ester compounds, and PVG also produced ester compounds without cyanate gas. Moreover, their heat releases during pyrolysis were lower than that during combustion. while FRCB for PVG generated additional gaseous products for cyanate gas. The average apparent activation energy of FRCBs for PVG was 162.0 kJ·mol<sup>-1</sup> In the first stage of pyrolysis, which was higher than that for PVC at 143.3 kJ·mol<sup>-1</sup>. These findings confirmed that PVG had superior flame retardancy compared to PVC. The research results provide a theoretical basis for determining key criteria in early intelligent warning.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"755 ","pages":"Article 180196"},"PeriodicalIF":3.5,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681860","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 : 2025-11-28DOI: 10.1016/j.tca.2025.180194
Zhuanying Hang , Yan Wang , Jianan Tao , Jingchen Zhang
Carnot battery system, particularly the Organic Rankine Cycle-based system, is an attractive energy storage solution for developing the future carbon-neutral energy system by utilizing low-grade heat (e.g., solar heat). As a cost-effective phase change material (PCM), aluminum potassium sulfate dodecahydrate (KAl(SO4)2·12H2O) offers large heat capacity during melting/solidification at medium-low temperature, which holds a promising prospect in thermal energy storage system in Carnot Batteries. KAl(SO4)2·12H2O is also one of the few types of hydrated salts without phase separation issue. In this study, binary inorganic hydrated salt mixtures of KAl(SO4)2·12H2O and magnesium sulfate heptahydrate (MgSO4·7H2O) with various mass ratios were developed and prepared as a novel energy storage material at medium-low temperatures. The sample with a 6:4 mass ratio (KAl(SO₄)₂·12H₂O:MgSO₄·7H₂O) exhibited a phase-change enthalpy of 181.3 kJ/kg. Optimized mixture was impregnated into expanded graphite (EG) to form shape-stable composites. Results showed that even minimal EG loading prevented PCM leakage (leakage rate < 3%) and enhanced thermal conductivity (up to 5.23 W/(m·K)). The composite containing 8wt% EG exhibited a phase-change enthalpy of 175.7 kJ/kg, enabling rapid heat transfer. Thermal-cycling tests confirmed excellent reliability with negligible enthalpy loss. These properties made the composites highly suitable for thermal storage in Carnot batteries.
{"title":"Experimental study of latent thermal energy storage with shape stabilized binary KAl(SO4)2·12H2O-MgSO4·7H2O hydrated salt material for Carnot batteries","authors":"Zhuanying Hang , Yan Wang , Jianan Tao , Jingchen Zhang","doi":"10.1016/j.tca.2025.180194","DOIUrl":"10.1016/j.tca.2025.180194","url":null,"abstract":"<div><div>Carnot battery system, particularly the Organic Rankine Cycle-based system, is an attractive energy storage solution for developing the future carbon-neutral energy system by utilizing low-grade heat (e.g., solar heat). As a cost-effective phase change material (PCM), aluminum potassium sulfate dodecahydrate (KAl(SO<sub>4</sub>)<sub>2</sub>·12H<sub>2</sub>O) offers large heat capacity during melting/solidification at medium-low temperature, which holds a promising prospect in thermal energy storage system in Carnot Batteries. KAl(SO<sub>4</sub>)<sub>2</sub>·12H<sub>2</sub>O is also one of the few types of hydrated salts without phase separation issue. In this study, binary inorganic hydrated salt mixtures of KAl(SO<sub>4</sub>)<sub>2</sub>·12H<sub>2</sub>O and magnesium sulfate heptahydrate (MgSO<sub>4</sub>·7H<sub>2</sub>O) with various mass ratios were developed and prepared as a novel energy storage material at medium-low temperatures. The sample with a 6:4 mass ratio (KAl(SO₄)₂·12H₂O:MgSO₄·7H₂O) exhibited a phase-change enthalpy of 181.3 kJ/kg. Optimized mixture was impregnated into expanded graphite (EG) to form shape-stable composites. Results showed that even minimal EG loading prevented PCM leakage (leakage rate < 3%) and enhanced thermal conductivity (up to 5.23 W/(m·K)). The composite containing 8wt% EG exhibited a phase-change enthalpy of 175.7 kJ/kg, enabling rapid heat transfer. Thermal-cycling tests confirmed excellent reliability with negligible enthalpy loss. These properties made the composites highly suitable for thermal storage in Carnot batteries.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"755 ","pages":"Article 180194"},"PeriodicalIF":3.5,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737253","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 : 2025-11-28DOI: 10.1016/j.tca.2025.180195
Tau Ikuno , Ibuki Tanizawa , Shoichi Tatsumi , Tomonari Wakabayashi , Tadashi Kamiyama , Hal Suzuki
The melting behavior of silicone rubber (VMQ), composed primarily of polydimethylsiloxane (PDMS), was investigated upon the addition of organic solvents using differential scanning calorimetry (DSC) and adiabatic calorimetry. A significant depression in the melting point (Tfus) – greater than 30 K – was observed upon addition of three solvents: hexane (Hex), 2-methylpentane (2MP), and 2-ethoxy-2-methylpropane (ETBE), all showing similar trends. Adiabatic calorimetry enabled precise thermodynamic measurements for the VMQ-2MP system, allowing for accurate determination of fusion enthalpy (ΔfusH) and entropy (ΔfusS) as functions of the 2MP volume fraction (). Both ΔfusH and ΔfusS increased slightly at low (< 0.3), suggesting that the Tfus depression is primarily driven by entropy. This increase in ΔfusS was attributed to mixing entropy between PDMS and 2MP, and was analyzed using the Flory–Huggins and Flory–Rehner models. However, the experimentally observed ΔfusS values were significantly lower than model predictions, indicating that ideal mixing models overestimate the degree of configurational disorder in the VMQ-2MP system. At high (> 0.7), both ΔfusH and ΔfusS decreased markedly, reflecting a reduction in PDMS crystallinity (pcr) with increasing solvent content. Furthermore, analysis of the -dependent fusion enthalpy of 2MP revealed minimal desorption of 2MP during PDMS crystallization. This suggests that a substantial number of 2MP molecules remain trapped around or within PDMS crystallites, remaining unfrozen even below their own melting temperature.
{"title":"Thermodynamic insights into melting point depression in silicone rubber swollen with organic solvents","authors":"Tau Ikuno , Ibuki Tanizawa , Shoichi Tatsumi , Tomonari Wakabayashi , Tadashi Kamiyama , Hal Suzuki","doi":"10.1016/j.tca.2025.180195","DOIUrl":"10.1016/j.tca.2025.180195","url":null,"abstract":"<div><div>The melting behavior of silicone rubber (VMQ), composed primarily of polydimethylsiloxane (PDMS), was investigated upon the addition of organic solvents using differential scanning calorimetry (DSC) and adiabatic calorimetry. A significant depression in the melting point (<em>T</em><sub>fus</sub>) – greater than 30 K – was observed upon addition of three solvents: hexane (Hex), 2-methylpentane (2MP), and 2-ethoxy-2-methylpropane (ETBE), all showing similar trends. Adiabatic calorimetry enabled precise thermodynamic measurements for the VMQ-2MP system, allowing for accurate determination of fusion enthalpy (Δ<sub>fus</sub><em>H</em>) and entropy (Δ<sub>fus</sub><em>S</em>) as functions of the 2MP volume fraction (<span><math><msub><mi>ϕ</mi><mrow><mn>2</mn><mtext>MP</mtext></mrow></msub></math></span>). Both Δ<sub>fus</sub><em>H</em> and Δ<sub>fus</sub><em>S</em> increased slightly at low <span><math><msub><mi>ϕ</mi><mrow><mn>2</mn><mtext>MP</mtext></mrow></msub></math></span> (< 0.3), suggesting that the <em>T</em><sub>fus</sub> depression is primarily driven by entropy. This increase in Δ<sub>fus</sub><em>S</em> was attributed to mixing entropy between PDMS and 2MP, and was analyzed using the Flory–Huggins and Flory–Rehner models. However, the experimentally observed Δ<sub>fus</sub><em>S</em> values were significantly lower than model predictions, indicating that ideal mixing models overestimate the degree of configurational disorder in the VMQ-2MP system. At high <span><math><msub><mi>ϕ</mi><mrow><mn>2</mn><mtext>MP</mtext></mrow></msub></math></span> (> 0.7), both Δ<sub>fus</sub><em>H</em> and Δ<sub>fus</sub><em>S</em> decreased markedly, reflecting a reduction in PDMS crystallinity (<em>p</em><sub>cr</sub>) with increasing solvent content. Furthermore, analysis of the <span><math><msub><mi>ϕ</mi><mrow><mn>2</mn><mtext>MP</mtext></mrow></msub></math></span>-dependent fusion enthalpy of 2MP revealed minimal desorption of 2MP during PDMS crystallization. This suggests that a substantial number of 2MP molecules remain trapped around or within PDMS crystallites, remaining unfrozen even below their own melting temperature.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"755 ","pages":"Article 180195"},"PeriodicalIF":3.5,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681859","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 : 2025-11-21DOI: 10.1016/j.tca.2025.180193
Xingjia Liu , Shanyang Wei , Hongyu Yang , Hao Wang , Xingjie Wu , Peng Wei
This study investigates the fire spread mechanisms and smoke movement in underground utility tunnels using Copper core rubber insulated rubber sheathed cable (YC) and Copper core cross-linked polyethylene insulated polyvinyl chloride sheathed cable (YJV) through thermogravimetric analysis (TG-DTG), cone calorimetry, Raman spectroscopy, and scaled model tests. Results indicate that Copper core cross-linked polyethylene insulated polyvinyl chloride sheathed cable exhibits lower thermal stability than Copper core rubber insulated rubber sheathed cable, with higher initial pyrolysis temperature (314.6–329.1 °C) but greater weight loss (60–63 %) due to crosslinked polyethylene (XLPE) decomposition and polyvinyl chloride (PVC) dechlorination. Under 30–40 kW/m² radiation, Copper core cross-linked polyethylene insulated polyvinyl chloride sheathed cable ignites 67 % faster than Copper core rubber insulated rubber sheathed cable, with reduced the peak heat release rate (peak-HRR), total heat release (THR), total smoke generation (TSP) (18.56 m²), and CO/CO₂ yield. Plugging rate significantly influences temperature distribution, with a maximum ceiling temperature of 684.8 °C at 20 % plugging rate, enhancing flame spread and smoke flow inclination. Ventilation causes asymmetric ceiling temperatures, with the left side exceeding the right by 21–35 %. These findings support fire risk assessment and prevention strategies for urban underground utility tunnels.
{"title":"Effects of ventilation and plugging rate on fire spread and smoke migration of cables in an underground utility tunnel","authors":"Xingjia Liu , Shanyang Wei , Hongyu Yang , Hao Wang , Xingjie Wu , Peng Wei","doi":"10.1016/j.tca.2025.180193","DOIUrl":"10.1016/j.tca.2025.180193","url":null,"abstract":"<div><div>This study investigates the fire spread mechanisms and smoke movement in underground utility tunnels using Copper core rubber insulated rubber sheathed cable (YC) and Copper core cross-linked polyethylene insulated polyvinyl chloride sheathed cable (YJV) through thermogravimetric analysis (TG-DTG), cone calorimetry, Raman spectroscopy, and scaled model tests. Results indicate that Copper core cross-linked polyethylene insulated polyvinyl chloride sheathed cable exhibits lower thermal stability than Copper core rubber insulated rubber sheathed cable, with higher initial pyrolysis temperature (314.6–329.1 °C) but greater weight loss (60–63 %) due to crosslinked polyethylene (XLPE) decomposition and polyvinyl chloride (PVC) dechlorination. Under 30–40 kW/m² radiation, Copper core cross-linked polyethylene insulated polyvinyl chloride sheathed cable ignites 67 % faster than Copper core rubber insulated rubber sheathed cable, with reduced the peak heat release rate (peak-HRR), total heat release (THR), total smoke generation (TSP) (18.56 m²), and CO/CO₂ yield. Plugging rate significantly influences temperature distribution, with a maximum ceiling temperature of 684.8 °C at 20 % plugging rate, enhancing flame spread and smoke flow inclination. Ventilation causes asymmetric ceiling temperatures, with the left side exceeding the right by 21–35 %. These findings support fire risk assessment and prevention strategies for urban underground utility tunnels.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"756 ","pages":"Article 180193"},"PeriodicalIF":3.5,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145712183","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 : 2025-11-20DOI: 10.1016/j.tca.2025.180192
Yahya Rharbi, Frédéric Hugenell
The accuracy of absolute heat capacity (cp) measurements in disk-type differential scanning calorimetry (DSC) has been perennially compromised by a fundamental yet unresolved issue: the poor reproducibility of pan-sensor thermal contact resistance (PS-TCR) upon manual repositioning. This systematic error, frequently treated as random noise, routinely introduces significant uncertainties that limit the reliability of cp data, especially for small samples.
This work introduces a methodological advancement to overcome this limitation. We demonstrate that the isothermal heat flow (Q̇iso), a readily measurable parameter in step-scan protocols, serves as a highly sensitive and quantitative signature of pan-positioning artifacts. By establishing a robust linear correlation between Q̇iso and the integrated enthalpy signal (Qs), we develop a novel correction procedure that effectively isolates and subtracts the positioning-dependent error component.
This strategy, validated experimentally and supported by a refined thermal model, systematically reduces cp measurement uncertainty to below 1 % for sample masses as low as 5 mg, a level of precision previously unattainable in conventional disk-type DSCs without specialized equipment. Crucially, this approach requires no hardware modifications, relying solely on software-based post-processing of existing step-scan data. Our findings provide a practical and universally applicable solution to a decades-old problem, finally enabling high-accuracy cp determination on standard DSC instruments and democratizing precision for the broader materials science community.
圆盘式差示扫描量热法（DSC）中绝对热容（cp）测量的准确性一直受到一个根本的尚未解决的问题的影响：手动重新定位后pan-sensor热接触电阻（PS-TCR）的再现性差。这种系统误差通常被视为随机噪声，通常会引入显著的不确定性，从而限制cp数据的可靠性，特别是对于小样本而言。这项工作引入了一种方法上的进步来克服这一限制。我们证明等温热流（Q o iso）是步进扫描协议中易于测量的参数，可作为泛定位伪像的高灵敏度和定量特征。通过建立Q / iso与积分焓信号（Qs）之间的鲁棒线性相关性，我们开发了一种新的校正程序，可以有效地分离和减去与位置相关的误差分量。该策略经过实验验证，并得到了精细热模型的支持，系统地将样品质量低至5mg的cp测量不确定度降低到1%以下，这是以前在没有专门设备的传统磁盘型dsc中无法达到的精度水平。至关重要的是，这种方法不需要硬件修改，仅依赖于基于软件的现有步进扫描数据的后处理。我们的研究结果为几十年前的问题提供了一个实用且普遍适用的解决方案，最终实现了在标准DSC仪器上的高精度cp测定，并使更广泛的材料科学界的精度民主化。
{"title":"Turning pan-sensor contact variability into a calibration tool for Sub-1% accuracy in heat capacity measurements with disk-type DSC","authors":"Yahya Rharbi, Frédéric Hugenell","doi":"10.1016/j.tca.2025.180192","DOIUrl":"10.1016/j.tca.2025.180192","url":null,"abstract":"<div><div>The accuracy of absolute heat capacity (c<sub>p</sub>) measurements in disk-type differential scanning calorimetry (DSC) has been perennially compromised by a fundamental yet unresolved issue: the poor reproducibility of pan-sensor thermal contact resistance (PS-TCR) upon manual repositioning. This systematic error, frequently treated as random noise, routinely introduces significant uncertainties that limit the reliability of c<sub>p</sub> data, especially for small samples.</div><div>This work introduces a methodological advancement to overcome this limitation. We demonstrate that the isothermal heat flow (Q̇<sub>iso</sub>), a readily measurable parameter in step-scan protocols, serves as a highly sensitive and quantitative signature of pan-positioning artifacts. By establishing a robust linear correlation between Q̇<sub>iso</sub> and the integrated enthalpy signal (Q<sub>s</sub>), we develop a novel correction procedure that effectively isolates and subtracts the positioning-dependent error component.</div><div>This strategy, validated experimentally and supported by a refined thermal model, systematically reduces c<sub>p</sub> measurement uncertainty to below 1 % for sample masses as low as 5 mg, a level of precision previously unattainable in conventional disk-type DSCs without specialized equipment. Crucially, this approach requires no hardware modifications, relying solely on software-based post-processing of existing step-scan data. Our findings provide a practical and universally applicable solution to a decades-old problem, finally enabling high-accuracy c<sub>p</sub> determination on standard DSC instruments and democratizing precision for the broader materials science community.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"755 ","pages":"Article 180192"},"PeriodicalIF":3.5,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145616911","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 : 2025-11-17DOI: 10.1016/j.tca.2025.180183
Si-yu Zhong , Yu-nong Liu , Ya-jun Ding , Shi-ying Li
The denitration process of waste nitrocellulose (NC) using hydrazine hydrate presents potential thermal risks. This study systematically evaluated the process safety through Simultaneous Thermal Analysis, reaction calorimetry coupled with in situ Raman spectroscopy, ARC, and DFT calculations. Results indicated a significant temperature-dependent increase in heat release. Under adiabatic conditions starting at 85 °C, the MTSR reached 124.69 °C, exceeding the boiling point of hydrazine hydrate (113.5 °C) and suggesting a risk of boiling and ejection. Kinetic analysis yielded an apparent activation energy of 157.8 kJ/mol, confirming that the reaction is controlled by chemical steps. Real-time Raman monitoring, combined with DFT calculations, revealed the key exothermic pathway involving an unstable nitrohydrazine intermediate and the formation of nitrite. Finally, based on ΔTad and TMRad, risk matrix assessment classified the process risk as Level Ⅰ. This study identifies the critical temperature threshold for safe operation and provides a crucial theoretical basis and important safety guidance for industrial denitrification processes.
{"title":"Process hazard evaluation and exothermic mechanism study of nitrocellulose denitration","authors":"Si-yu Zhong , Yu-nong Liu , Ya-jun Ding , Shi-ying Li","doi":"10.1016/j.tca.2025.180183","DOIUrl":"10.1016/j.tca.2025.180183","url":null,"abstract":"<div><div>The denitration process of waste nitrocellulose (NC) using hydrazine hydrate presents potential thermal risks. This study systematically evaluated the process safety through Simultaneous Thermal Analysis, reaction calorimetry coupled with in situ Raman spectroscopy, ARC, and DFT calculations. Results indicated a significant temperature-dependent increase in heat release. Under adiabatic conditions starting at 85 °C, the <em>MTSR</em> reached 124.69 °C, exceeding the boiling point of hydrazine hydrate (113.5 °C) and suggesting a risk of boiling and ejection. Kinetic analysis yielded an apparent activation energy of 157.8 kJ/mol, confirming that the reaction is controlled by chemical steps. Real-time Raman monitoring, combined with DFT calculations, revealed the key exothermic pathway involving an unstable nitrohydrazine intermediate and the formation of nitrite. Finally, based on Δ<em>T</em><sub>ad</sub> and <em>TMR</em><sub>ad</sub>, risk matrix assessment classified the process risk as Level Ⅰ. This study identifies the critical temperature threshold for safe operation and provides a crucial theoretical basis and important safety guidance for industrial denitrification processes.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"755 ","pages":"Article 180183"},"PeriodicalIF":3.5,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145616913","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 : 2025-11-17DOI: 10.1016/j.tca.2025.180181
Robert Kahlenberg , Georg Falkinger , Roman Schuster , Bernhard Miesenberger , Nicolás García Arango , Emad Maawad , Erwin Povoden-Karadeniz , Benjamin Milkereit , Ernst Kozeschnik
The present work describes a systematic approach to improve mean-field simulations of dissolution and precipitation of precipitates from the late stages in the precipitation sequence in AlMgSiCu alloys for processing simulations. In addition to metastable precipitates, it considers the evolution of two populations (coarse and fine) of the thermodynamically stable phases in EN AW-6061 and EN AW-6016, β-Mg2Si and Si respectively. The setup is based on two previous publications using heterogeneous nucleation site energies and their distribution. The simulations are calibrated using data from continuous cooling and heating experiments obtained with differential scanning calorimetry (DSC) and high-energy X-ray diffraction (HEXRD). We show that mean-field simulations combined with DSC and HEXRD can provide valuable information to eliminate uncertainties related to, for instance, the thermodynamic description of metastable precipitates. The method described in this paper also delivers very reasonable results for the evolution of the individual phase fractions. It potentially facilitates the assessment of the influence of different types of nucleation sites and their densities.
{"title":"Deconvolution of superimposing reaction signals from DSC curves in selected Al-Mg-Si-(Cu) alloys by mean-field modeling and HEXRD","authors":"Robert Kahlenberg , Georg Falkinger , Roman Schuster , Bernhard Miesenberger , Nicolás García Arango , Emad Maawad , Erwin Povoden-Karadeniz , Benjamin Milkereit , Ernst Kozeschnik","doi":"10.1016/j.tca.2025.180181","DOIUrl":"10.1016/j.tca.2025.180181","url":null,"abstract":"<div><div>The present work describes a systematic approach to improve mean-field simulations of dissolution and precipitation of precipitates from the late stages in the precipitation sequence in AlMgSiCu alloys for processing simulations. In addition to metastable precipitates, it considers the evolution of two populations (coarse and fine) of the thermodynamically stable phases in EN AW-6061 and EN AW-6016, β-Mg<sub>2</sub>Si and Si respectively. The setup is based on two previous publications using heterogeneous nucleation site energies and their distribution. The simulations are calibrated using data from continuous cooling and heating experiments obtained with differential scanning calorimetry (DSC) and high-energy X-ray diffraction (HEXRD). We show that mean-field simulations combined with DSC and HEXRD can provide valuable information to eliminate uncertainties related to, for instance, the thermodynamic description of metastable precipitates. The method described in this paper also delivers very reasonable results for the evolution of the individual phase fractions. It potentially facilitates the assessment of the influence of different types of nucleation sites and their densities.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"755 ","pages":"Article 180181"},"PeriodicalIF":3.5,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145616910","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}
Amid growing health concerns regarding novel tobacco products, a hybrid device integrating electronic cigarette (EC) and heated tobacco product (HTP) technologies was developed to enable standalone or composite smoking. Comprehensive analysis revealed composite smoking increased total aerosol mass by 32.55 mg versus standalone EC and 9.37 mg versus standalone HTP, while elevating gaseous phase proportion. Particle number concentration rose 7.80 % with 18.39 % larger count median diameter versus HTP alone, and 315.83 % higher concentration with 15.34 % smaller diameter versus EC alone. Compared to standalone HTP, composite smoking demonstrated a 1.42 mg reduction in nicotine release and a 9.42 % decrease in residual key components. An "adsorption-thermal desorption" hypothetical mechanism is proposed to interpret these experimental findings. The results demonstrate that the composite smoking mode integrating electronic cigarettes and heated tobacco products in series can effectively enhance volatile component release while simultaneously reducing nicotine delivery.
{"title":"Study on the transfer behavior of key components and mainstream aerosol release characteristics from a novel hybrid tobacco product","authors":"Zhonghua Xiao , Dian Li , Qifeng Shen , Huaquan Sheng , Yihui Zhang , Yihan Gao , Naiping Gao","doi":"10.1016/j.tca.2025.180182","DOIUrl":"10.1016/j.tca.2025.180182","url":null,"abstract":"<div><div>Amid growing health concerns regarding novel tobacco products, a hybrid device integrating electronic cigarette (EC) and heated tobacco product (HTP) technologies was developed to enable standalone or composite smoking. Comprehensive analysis revealed composite smoking increased total aerosol mass by 32.55 mg versus standalone EC and 9.37 mg versus standalone HTP, while elevating gaseous phase proportion. Particle number concentration rose 7.80 % with 18.39 % larger count median diameter versus HTP alone, and 315.83 % higher concentration with 15.34 % smaller diameter versus EC alone. Compared to standalone HTP, composite smoking demonstrated a 1.42 mg reduction in nicotine release and a 9.42 % decrease in residual key components. An \"adsorption-thermal desorption\" hypothetical mechanism is proposed to interpret these experimental findings. The results demonstrate that the composite smoking mode integrating electronic cigarettes and heated tobacco products in series can effectively enhance volatile component release while simultaneously reducing nicotine delivery.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"755 ","pages":"Article 180182"},"PeriodicalIF":3.5,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145616912","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 : 2025-11-11DOI: 10.1016/j.tca.2025.180179
João Victor Alves-Laurentino, Fatemeh Pazoki, Luis Felipe Sanz, Juan Antonio González, Fernando Hevia, Daniel Lozano-Martín
For glymes of general formula CH3O(CH2CH2O)uCH3, with u = 1, 2, 3, 4, the densities of the (2-propanol + glyme) systems at temperatures ranging from (293.15 to 303.15) K and at pressure 0.1 MPa were determined using a DSA 5000 densimeter (from Anton Paar). The corresponding excess molar volumes were calculated from these density measurements. In addition, excess molar enthalpies at 298.15 K and 0.1 MPa were measured using a Tian-Calvet micro-calorimeter. The results show that alkanol–ether interactions are strong but do not contribute significantly to the excess molar enthalpy, as the values are large and positive, and comparable to those of (glyme + n-heptane) systems. The excess molar volumes are small or even negative (in the case of the mixture with u = 4), indicating that they are mainly governed by structural effects. Mixtures with 1-propanol or 2-propanol behave similarly, although interactions between unlike molecules become slightly stronger when 1-propanol is involved. On the other hand, effects related to alcohol self-association play a decisive role in the thermodynamic properties when glymes are replaced by di-n-propyl ether. This is supported by the application of the Flory model, which shows that orientational effects are weak in the studied glyme-containing mixtures but become significantly stronger when di-n-propyl ether is considered.
{"title":"Density and excess molar enthalpy of (2-propanol + glyme) liquid mixtures. Application of the Flory model","authors":"João Victor Alves-Laurentino, Fatemeh Pazoki, Luis Felipe Sanz, Juan Antonio González, Fernando Hevia, Daniel Lozano-Martín","doi":"10.1016/j.tca.2025.180179","DOIUrl":"10.1016/j.tca.2025.180179","url":null,"abstract":"<div><div>For glymes of general formula CH<sub>3</sub>O(CH<sub>2</sub>CH<sub>2</sub>O)<em><sub>u</sub></em>CH<sub>3</sub>, with <em>u</em> = 1, 2, 3, 4, the densities of the (2-propanol + glyme) systems at temperatures ranging from (293.15 to 303.15) K and at pressure 0.1 MPa were determined using a DSA 5000 densimeter (from Anton Paar). The corresponding excess molar volumes were calculated from these density measurements. In addition, excess molar enthalpies at 298.15 K and 0.1 MPa were measured using a Tian-Calvet micro-calorimeter. The results show that alkanol–ether interactions are strong but do not contribute significantly to the excess molar enthalpy, as the values are large and positive, and comparable to those of (glyme + <em>n</em>-heptane) systems. The excess molar volumes are small or even negative (in the case of the mixture with <em>u</em> = 4), indicating that they are mainly governed by structural effects. Mixtures with 1-propanol or 2-propanol behave similarly, although interactions between unlike molecules become slightly stronger when 1-propanol is involved. On the other hand, effects related to alcohol self-association play a decisive role in the thermodynamic properties when glymes are replaced by di-<em>n</em>-propyl ether. This is supported by the application of the Flory model, which shows that orientational effects are weak in the studied glyme-containing mixtures but become significantly stronger when di-<em>n</em>-propyl ether is considered.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"755 ","pages":"Article 180179"},"PeriodicalIF":3.5,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145555147","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}
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