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}
Pub Date : 2025-11-11DOI: 10.1016/j.tca.2025.180180
Roberto Paredes , Enrique Garcia-Franco , Blanca Castells , María-Pilar Martínez-Hernando , Pedro Mora Peris , Marcelo F. Ortega
Gas emissions during the thermal decomposition of lignocellulosic materials are generally predicted using kinetic models. However, these are often limited by complex reaction mechanisms and high computational requirements. This study presents a new methodology that combines thermogravimetric analysis (TGA) with Gibbs Free Energy Minimisation (GEM) using Reaktoro v2, an open-source Python library, to predict the evolution of gaseous species without requiring kinetic parameters. Five lignocellulosic biomass—olive pomace, wood pellets, wheat straw, soybean dust, and cork dust—were characterised and analysed under controlled thermal conditions.
The model accurately estimated the evolution of CO, CO2, H2, and CH4 in the range of 500–700 °C during the devolatilization process in the thermogravimetric test, showing strong agreement with literature data. Results revealed an inverse correlation between the CO/H2 and O/C ratios of the samples and a direct correlation between the lower heating value (LHV) of the solids and that of the gas produced. It was also observed that high ash content catalysed secondary reactions, reducing both the energy content of the gas and duty.
Overall, this study demonstrates a novel methodology that surpasses conventional kinetic-based approaches, providing a reliable, efficient, and versatile framework for predicting gas emissions and optimising biomass processes.
{"title":"Thermodynamic-based prediction of gaseous species evolution in thermogravimetric analysis","authors":"Roberto Paredes , Enrique Garcia-Franco , Blanca Castells , María-Pilar Martínez-Hernando , Pedro Mora Peris , Marcelo F. Ortega","doi":"10.1016/j.tca.2025.180180","DOIUrl":"10.1016/j.tca.2025.180180","url":null,"abstract":"<div><div>Gas emissions during the thermal decomposition of lignocellulosic materials are generally predicted using kinetic models. However, these are often limited by complex reaction mechanisms and high computational requirements. This study presents a new methodology that combines thermogravimetric analysis (TGA) with Gibbs Free Energy Minimisation (GEM) using Reaktoro v2, an open-source Python library, to predict the evolution of gaseous species without requiring kinetic parameters. Five lignocellulosic biomass—olive pomace, wood pellets, wheat straw, soybean dust, and cork dust—were characterised and analysed under controlled thermal conditions.</div><div>The model accurately estimated the evolution of CO, CO<sub>2</sub>, H<sub>2</sub>, and CH<sub>4</sub> in the range of 500–700 °C during the devolatilization process in the thermogravimetric test, showing strong agreement with literature data. Results revealed an inverse correlation between the CO/H<sub>2</sub> and O/C ratios of the samples and a direct correlation between the lower heating value (<em>LHV</em>) of the solids and that of the gas produced. It was also observed that high ash content catalysed secondary reactions, reducing both the energy content of the gas and duty.</div><div>Overall, this study demonstrates a novel methodology that surpasses conventional kinetic-based approaches, providing a reliable, efficient, and versatile framework for predicting gas emissions and optimising biomass processes.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"754 ","pages":"Article 180180"},"PeriodicalIF":3.5,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576507","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 : 2025-11-07DOI: 10.1016/j.tca.2025.180177
Mateusz Dudziak , Birte Riechers , Robert Maaß , Adam Michalchuk , Andreas Schönhals , Paulina Szymoniak
Fast scanning calorimetry (FSC) has emerged as a transformative technique in thermal analysis, enabling the investigation of rapid and kinetically driven thermal transitions that are inaccessible to conventional differential scanning calorimetry. This review highlights the capabilities enabled by FSC for studying a wide range of materials under extreme thermal conditions, including polymers, pharmaceuticals, metallic glasses, nanocomposites, and hydrogels. By employing ultrafast heating and cooling rates, FSC allows for the suppression of crystallization, resolution of weak transitions, and analysis of thermally labile or size-limited samples. The technique is particularly valuable for probing glass transitions, relaxation phenomena, and phase behavior in systems with complex morphologies or confined geometries. Case studies demonstrate the use of FSC in characterizing vitrification, physical aging, and interfacial dynamics, as well as its application in emerging fields such as additive manufacturing, supramolecular systems, and neuromorphic materials. Together, these examples underscore the role that FSC plays in advancing the understanding of structure-property relationships across diverse material classes.
{"title":"Beyond conventional calorimetry: Unlocking thermal characterization with fast scanning techniques","authors":"Mateusz Dudziak , Birte Riechers , Robert Maaß , Adam Michalchuk , Andreas Schönhals , Paulina Szymoniak","doi":"10.1016/j.tca.2025.180177","DOIUrl":"10.1016/j.tca.2025.180177","url":null,"abstract":"<div><div>Fast scanning calorimetry (FSC) has emerged as a transformative technique in thermal analysis, enabling the investigation of rapid and kinetically driven thermal transitions that are inaccessible to conventional differential scanning calorimetry. This review highlights the capabilities enabled by FSC for studying a wide range of materials under extreme thermal conditions, including polymers, pharmaceuticals, metallic glasses, nanocomposites, and hydrogels. By employing ultrafast heating and cooling rates, FSC allows for the suppression of crystallization, resolution of weak transitions, and analysis of thermally labile or size-limited samples. The technique is particularly valuable for probing glass transitions, relaxation phenomena, and phase behavior in systems with complex morphologies or confined geometries. Case studies demonstrate the use of FSC in characterizing vitrification, physical aging, and interfacial dynamics, as well as its application in emerging fields such as additive manufacturing, supramolecular systems, and neuromorphic materials. Together, these examples underscore the role that FSC plays in advancing the understanding of structure-property relationships across diverse material classes.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"754 ","pages":"Article 180177"},"PeriodicalIF":3.5,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576519","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 : 2025-11-07DOI: 10.1016/j.tca.2025.180178
Xiaoan Song , Lulu Teng , Ruina Zhang , Lijie Yin , Dezhen Chen , Shanping Chen
In the process of fuel pyrolysis, direct pyrolysis using high-temperature gas is currently the most economical method. For larger fuel particles, shape exerts a significant influence on the rate of temperature increase and the completion time of decomposition. In this study, an experimental apparatus for single-particle pyrolysis was designed, and a back propagation (BP) neural network model was constructed. Based on experimental and prediction results, the influences of the sphericity, characteristic length, and windward area ratio of the particles on the intra-particle temperature during the pyrolysis process were analysed. The rates of temperature increase and weight loss of near-spherical particles were higher than those of nonspherical particles; the weight loss ratios (mass loss per unit time divided by initial mass) of the cylinder and the quadrangular prism were 54.62 % and 44.67 % of those of the sphere. Additionally, the windward area ratio had the greatest impact on the intra-particle temperature and weight loss ratio.
{"title":"The influence of material shape on the intra-particle temperature during biomass pyrolysis under direct heating with high-temperature gas","authors":"Xiaoan Song , Lulu Teng , Ruina Zhang , Lijie Yin , Dezhen Chen , Shanping Chen","doi":"10.1016/j.tca.2025.180178","DOIUrl":"10.1016/j.tca.2025.180178","url":null,"abstract":"<div><div>In the process of fuel pyrolysis, direct pyrolysis using high-temperature gas is currently the most economical method. For larger fuel particles, shape exerts a significant influence on the rate of temperature increase and the completion time of decomposition. In this study, an experimental apparatus for single-particle pyrolysis was designed, and a back propagation (BP) neural network model was constructed. Based on experimental and prediction results, the influences of the sphericity, characteristic length, and windward area ratio of the particles on the intra-particle temperature during the pyrolysis process were analysed. The rates of temperature increase and weight loss of near-spherical particles were higher than those of nonspherical particles; the weight loss ratios (mass loss per unit time divided by initial mass) of the cylinder and the quadrangular prism were 54.62 % and 44.67 % of those of the sphere. Additionally, the windward area ratio had the greatest impact on the intra-particle temperature and weight loss ratio.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"754 ","pages":"Article 180178"},"PeriodicalIF":3.5,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526046","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 : 2025-10-31DOI: 10.1016/j.tca.2025.180174
Shuchang Zhang , Meiqian Chen , Bingyang Li , Yuelong Pan , Linjun Yang
The treatment of spent ion exchange resins (CERs) has become a major concern with the development of nuclear industry. The migration and transformation mechanism of Cs in CERs in both pyrolysis and gasification were evaluated based on chemical equilibrium and experimental analysis. The pyrolysis and gasification temperatures should be limited below 813.15 K and 873.15 K, respectively, but after adding the fixatives, ZrO2 or Nb2O5, the temperatures could be extended to 873.15 K, 1233.15 K (ZrO2) or 1153.15 K (Nb2O5). The kinetic and thermodynamic characteristics of CERs with metal ion catalysts in the gasification were evaluated based on thermogravimetric analysis. In 10 % O2/90 % N2, Fe2+ and Mn2+ metal nuclides would urge the decomposition of functional groups and polymer matrices, since they could promote the reaction in the second stage and the advance of the third stage. This study could provide basic data for the thermal treatment of CERs.
废离子交换树脂的处理已成为核工业发展的一个重要问题。基于化学平衡和实验分析,评价了Cs在cer热解和气化过程中的迁移转化机理。热解和气化温度应分别控制在813.15 K和873.15 K以下,但加入固化剂ZrO2或Nb2O5后,温度可扩展到873.15 K、1233.15 K (ZrO2)或1153.15 K (Nb2O5)。基于热重分析,评价了金属离子催化剂在气化过程中的动力学和热力学特性。在10% o2 / 90% N2条件下,Fe2+和Mn2+金属核素会促进官能团和聚合物基体的分解,促进反应进入第二阶段和第三阶段。本研究可为CERs的热处理提供基础数据。
{"title":"Thermal degradation of spent cation exchange resin with fixatives or metal ion catalysts: Insights from experiments, thermodynamics and kinetics","authors":"Shuchang Zhang , Meiqian Chen , Bingyang Li , Yuelong Pan , Linjun Yang","doi":"10.1016/j.tca.2025.180174","DOIUrl":"10.1016/j.tca.2025.180174","url":null,"abstract":"<div><div>The treatment of spent ion exchange resins (CERs) has become a major concern with the development of nuclear industry. The migration and transformation mechanism of Cs in CERs in both pyrolysis and gasification were evaluated based on chemical equilibrium and experimental analysis. The pyrolysis and gasification temperatures should be limited below 813.15 K and 873.15 K, respectively, but after adding the fixatives, ZrO<sub>2</sub> or Nb<sub>2</sub>O<sub>5</sub>, the temperatures could be extended to 873.15 K, 1233.15 K (ZrO<sub>2</sub>) or 1153.15 K (Nb<sub>2</sub>O<sub>5</sub>). The kinetic and thermodynamic characteristics of CERs with metal ion catalysts in the gasification were evaluated based on thermogravimetric analysis. In 10 % O<sub>2</sub>/90 % N<sub>2</sub>, Fe<sup>2+</sup> and Mn<sup>2+</sup> metal nuclides would urge the decomposition of functional groups and polymer matrices, since they could promote the reaction in the second stage and the advance of the third stage. This study could provide basic data for the thermal treatment of CERs.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"754 ","pages":"Article 180174"},"PeriodicalIF":3.5,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474759","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 : 2025-10-31DOI: 10.1016/j.tca.2025.180175
Shangpeng Pan , Hengbin Zhang , Rui Shan , Chengyu Li , Jun Zhang
This study systematically investigates the process of catalytic selective pyrolysis of epoxy resin to high-value aromatics over niobium phosphate-modified ZSM-5 and provides a detailed analysis of the pyrolysis reaction kinetics. The introduction of amorphous niobium phosphate resulted in abundant mesopores and strong acid sites, which enhanced the deoxygenation performance of the zeolite during high-temperature pyrolysis and significantly improved aromatic selectivity. Notably, the niobium phosphate-modified ZSM-5 achieving a maximum aromatic selectivity of 63.5 % at 650 °C significantly outperformed commercial HZSM-5 zeolite, where monocyclic aromatics account for 31.7 % of the total liquid products and polycyclic aromatics account for 31.8 %. Furthermore, the hierarchical pore structure and excellent anti-coking properties of the modified catalyst effectively reduced the activation energy required for epoxy resin pyrolysis, decreasing the apparent activation energy significantly from 325.6 kJ/mol to 240.4 kJ/mol. The findings of this study provide deep insights into metal-modified zeolite-catalyzed pyrolysis of epoxy resin and contribute to the valorization of waste epoxy resin.
{"title":"Hierarchical niobium phosphate-engineered ZSM-5 for selective pyrolysis of epoxy resin toward aromatics: Synergistic effects and kinetic elucidations","authors":"Shangpeng Pan , Hengbin Zhang , Rui Shan , Chengyu Li , Jun Zhang","doi":"10.1016/j.tca.2025.180175","DOIUrl":"10.1016/j.tca.2025.180175","url":null,"abstract":"<div><div>This study systematically investigates the process of catalytic selective pyrolysis of epoxy resin to high-value aromatics over niobium phosphate-modified ZSM-5 and provides a detailed analysis of the pyrolysis reaction kinetics. The introduction of amorphous niobium phosphate resulted in abundant mesopores and strong acid sites, which enhanced the deoxygenation performance of the zeolite during high-temperature pyrolysis and significantly improved aromatic selectivity. Notably, the niobium phosphate-modified ZSM-5 achieving a maximum aromatic selectivity of 63.5 % at 650 °C significantly outperformed commercial HZSM-5 zeolite, where monocyclic aromatics account for 31.7 % of the total liquid products and polycyclic aromatics account for 31.8 %. Furthermore, the hierarchical pore structure and excellent anti-coking properties of the modified catalyst effectively reduced the activation energy required for epoxy resin pyrolysis, decreasing the apparent activation energy significantly from 325.6 kJ/mol to 240.4 kJ/mol. The findings of this study provide deep insights into metal-modified zeolite-catalyzed pyrolysis of epoxy resin and contribute to the valorization of waste epoxy resin.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"754 ","pages":"Article 180175"},"PeriodicalIF":3.5,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474764","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 : 2025-10-31DOI: 10.1016/j.tca.2025.180176
Yuzhen Cai , Xinkun Li , Yicheng Deng , Xiong Zhao , Xueyan Han , Fengjiao Wang , Xuefeng Wang
Impurities in alkali-metal vapor cells were investigated by differential scanning calorimetry (DSC). Comparative analysis of vapor cells fabricated with different types of glass and in various sizes suggests that the observed impurity originates from the formation of a rubidium-sodium alloy, which results from a reaction between rubidium and sodium precipitated from the inner surface of borosilicate glass. This conclusion is further supported by the intentional introduction of sodium atoms into the vapor cells. The presence of sodium precipitation is confirmed by the localized heating of the vapor cells. This study provides a method for characterizing the alkali metal impurities in atomic vapor cells and offers guidance for optimizing the rubidium filling process, thereby improving the performance of vapor cells.
{"title":"Research on impurity in alkali-metal vapor cells by use of differential scanning calorimetry","authors":"Yuzhen Cai , Xinkun Li , Yicheng Deng , Xiong Zhao , Xueyan Han , Fengjiao Wang , Xuefeng Wang","doi":"10.1016/j.tca.2025.180176","DOIUrl":"10.1016/j.tca.2025.180176","url":null,"abstract":"<div><div>Impurities in alkali-metal vapor cells were investigated by differential scanning calorimetry (DSC). Comparative analysis of vapor cells fabricated with different types of glass and in various sizes suggests that the observed impurity originates from the formation of a rubidium-sodium alloy, which results from a reaction between rubidium and sodium precipitated from the inner surface of borosilicate glass. This conclusion is further supported by the intentional introduction of sodium atoms into the vapor cells. The presence of sodium precipitation is confirmed by the localized heating of the vapor cells. This study provides a method for characterizing the alkali metal impurities in atomic vapor cells and offers guidance for optimizing the rubidium filling process, thereby improving the performance of vapor cells.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"754 ","pages":"Article 180176"},"PeriodicalIF":3.5,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474762","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 : 2025-10-29DOI: 10.1016/j.tca.2025.180173
Zhanlin Gong , Xing Liu , Sumei Liu , Jianqing Zhao
The development of polyurethane phase change materials (PUPCMs) integrating high latent heat and good elasticity is a major challenge for thermal management interface materials. Herein, a diol containing octadecyl side groups (MGAE) was synthesized via the thiol-ene click reaction and used to prepare PUPCMs, with the expectation of resolving the inherent contradiction between high latent heat and good elasticity. The effects of MGAE on the chemical structure, thermal stability, thermal reliability, phase change properties, elasticity, thermal conductivity and thermal contact resistance (TCR) of PUPCMs were investigated. All PUPCMs exhibit the excellent leakage resistance characteristic, particularly under pressure conditions. Compared with PUPCMs without MGAE, PUPCMs containing 2.7 wt% MGAE showed a 11.5 % increase in latent heat, a 10.1 °C decrease in phase change temperature, a 26.8 % decrease in Shore hardness, a 147.0 % increase in elongation at break and a 38 % reduction in TCR. These improvements were attributed to the plasticizing effect and heterogeneous nucleation effect of MGAE with octadecyl side groups. This study provides a viable route for the synthesis of PUPCMs with simultaneously enhanced latent heat and elasticity through the introduction of long alkyl side chains, and the resulting PUPCMs have the potential to be used as thermal management interface materials.
{"title":"Synthesis of reliable polyurethane phase change materials with good thermal storage properties and elasticity by introducing long alkyl side chains","authors":"Zhanlin Gong , Xing Liu , Sumei Liu , Jianqing Zhao","doi":"10.1016/j.tca.2025.180173","DOIUrl":"10.1016/j.tca.2025.180173","url":null,"abstract":"<div><div>The development of polyurethane phase change materials (PUPCMs) integrating high latent heat and good elasticity is a major challenge for thermal management interface materials. Herein, a diol containing octadecyl side groups (MGAE) was synthesized via the thiol-ene click reaction and used to prepare PUPCMs, with the expectation of resolving the inherent contradiction between high latent heat and good elasticity. The effects of MGAE on the chemical structure, thermal stability, thermal reliability, phase change properties, elasticity, thermal conductivity and thermal contact resistance (TCR) of PUPCMs were investigated. All PUPCMs exhibit the excellent leakage resistance characteristic, particularly under pressure conditions. Compared with PUPCMs without MGAE, PUPCMs containing 2.7 wt% MGAE showed a 11.5 % increase in latent heat, a 10.1 °C decrease in phase change temperature, a 26.8 % decrease in Shore hardness, a 147.0 % increase in elongation at break and a 38 % reduction in TCR. These improvements were attributed to the plasticizing effect and heterogeneous nucleation effect of MGAE with octadecyl side groups. This study provides a viable route for the synthesis of PUPCMs with simultaneously enhanced latent heat and elasticity through the introduction of long alkyl side chains, and the resulting PUPCMs have the potential to be used as thermal management interface materials.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"754 ","pages":"Article 180173"},"PeriodicalIF":3.5,"publicationDate":"2025-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474760","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 : 2025-10-26DOI: 10.1016/j.tca.2025.180171
Jianjie Wang , Yifan Li , Wenzhe Zhang , Dahai Zhu , Naici Bing , Huaqing Xie , Wei Yu
The development of passive, energy-efficient thermal regulation materials is crucial for improving the cold chain logistics of perishable foods. By mixing tetradecane (TD), decyl alcohol (DOL), and styrene-ethylene-butylene-styrene (SEBS) triblock copolymer, a eutectic phase change gel was prepared. The optimized TD/DOL eutectic composition (molar ratio = 0.3) exhibits a high melting enthalpy of 205.1 J/g and a crystallization enthalpy of 201.2 J/g, indicating excellent reversible phase change performance. SEBS forms a continuous three-dimensional elastic network, effectively preventing leakage and providing mechanical reinforcement. Under conditions where SEBS content is 30 wt.%, the gel maintains a melting enthalpy value of 94.4 J/g after 100 thermal cycles, with a decrease of only 10.7 %, demonstrating good thermal stability. When the SEBS content is increased to 30 wt.%, the tensile strength reaches 3.0 MPa and the compressive strength reaches 0.727 MPa, which are 15 times and 60 times higher than those at 10 wt.%, respectively, confirming the reinforcing effect of the SEBS network. The 30 wt.% formulation achieves the optimal balance between thermal performance and structural integrity. In actual testing, 500 g of TD/DOL-SEBS-30 maintains a stable cooling range of 6–10 °C for an extended period without external power in an insulated container. Compared to the no-cooling-source group and the semiconductor-cooling group, the phase-change material group better preserved the appearance and freshness of strawberries, with minimal weight loss and no spoilage. The TD/DOL-SEBS gel thus combines high latent heat, thermal reliability, shape stability, and strong mechanical properties, demonstrating significant potential in cold chain food transportation, wearable thermal management, and other low-energy refrigeration applications.
{"title":"A SEBS-stabilized eutectic phase change gel for passive cold chain preservation of perishable produce","authors":"Jianjie Wang , Yifan Li , Wenzhe Zhang , Dahai Zhu , Naici Bing , Huaqing Xie , Wei Yu","doi":"10.1016/j.tca.2025.180171","DOIUrl":"10.1016/j.tca.2025.180171","url":null,"abstract":"<div><div>The development of passive, energy-efficient thermal regulation materials is crucial for improving the cold chain logistics of perishable foods. By mixing tetradecane (TD), decyl alcohol (DOL), and styrene-ethylene-butylene-styrene (SEBS) triblock copolymer, a eutectic phase change gel was prepared. The optimized TD/DOL eutectic composition (molar ratio = 0.3) exhibits a high melting enthalpy of 205.1 J/g and a crystallization enthalpy of 201.2 J/g, indicating excellent reversible phase change performance. SEBS forms a continuous three-dimensional elastic network, effectively preventing leakage and providing mechanical reinforcement. Under conditions where SEBS content is 30 wt.%, the gel maintains a melting enthalpy value of 94.4 J/g after 100 thermal cycles, with a decrease of only 10.7 %, demonstrating good thermal stability. When the SEBS content is increased to 30 wt.%, the tensile strength reaches 3.0 MPa and the compressive strength reaches 0.727 MPa, which are 15 times and 60 times higher than those at 10 wt.%, respectively, confirming the reinforcing effect of the SEBS network. The 30 wt.% formulation achieves the optimal balance between thermal performance and structural integrity. In actual testing, 500 g of TD/DOL-SEBS-30 maintains a stable cooling range of 6–10 °C for an extended period without external power in an insulated container. Compared to the no-cooling-source group and the semiconductor-cooling group, the phase-change material group better preserved the appearance and freshness of strawberries, with minimal weight loss and no spoilage. The TD/DOL-SEBS gel thus combines high latent heat, thermal reliability, shape stability, and strong mechanical properties, demonstrating significant potential in cold chain food transportation, wearable thermal management, and other low-energy refrigeration applications.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"754 ","pages":"Article 180171"},"PeriodicalIF":3.5,"publicationDate":"2025-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474758","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 : 2025-10-26DOI: 10.1016/j.tca.2025.180172
Hui-Sheng Peng
To reveal the relationship between anion structure and thermal decomposition property, an experimental system integrating comprehensive thermal analysis and Fourier-transform infrared spectroscopy is constructed to investigate the thermal decomposition mechanisms of four 1-ethyl-3-methyl imidazolium-based ([EMIM]+) ionic liquids with anion structures of thiocyanate ([SCN]-), dicyanamide ([DCA]-), tetrafluoroborate ([BF4]-), and bis(trifluoromethylsulfonyl)imine ([NTF2]-). Results show that the thermal stability follows the order of [EMIM][NTF2] > [EMIM][BF4] > [EMIM][DCA] > [EMIM][SCN] by decomposition temperature. Spectrum analyses reveal that the anion structures are thoroughly disrupted, forming different gas products, while the cation structure only undergoes substitution and elimination reactions on the imidazole ring. Due to the differences in anion structure, methyl isothiocyanate, trifluoromethanesulfonamide and sulfur dioxide, ammonia, and boron trifluoride are found as key products during the decomposition of [EMIM][SCN], [EMIM][NTF2], [EMIM][DCA], and [EMIM][BF4], respectively. Following designs of anion structure for propellant may start from [SCN]- and [DCA]- to obtain better decomposition property.
{"title":"Experimental investigation on the influence of anion structure on the thermal decomposition properties of EMIM-based ionic liquids","authors":"Hui-Sheng Peng","doi":"10.1016/j.tca.2025.180172","DOIUrl":"10.1016/j.tca.2025.180172","url":null,"abstract":"<div><div>To reveal the relationship between anion structure and thermal decomposition property, an experimental system integrating comprehensive thermal analysis and Fourier-transform infrared spectroscopy is constructed to investigate the thermal decomposition mechanisms of four 1-ethyl-3-methyl imidazolium-based ([EMIM]<sup>+</sup>) ionic liquids with anion structures of thiocyanate ([SCN]<sup>-</sup>), dicyanamide ([DCA]<sup>-</sup>), tetrafluoroborate ([BF<sub>4</sub>]<sup>-</sup>), and bis(trifluoromethylsulfonyl)imine ([NTF<sub>2</sub>]<sup>-</sup>). Results show that the thermal stability follows the order of [EMIM][NTF<sub>2</sub>] > [EMIM][BF<sub>4</sub>] > [EMIM][DCA] > [EMIM][SCN] by decomposition temperature. Spectrum analyses reveal that the anion structures are thoroughly disrupted, forming different gas products, while the cation structure only undergoes substitution and elimination reactions on the imidazole ring. Due to the differences in anion structure, methyl isothiocyanate, trifluoromethanesulfonamide and sulfur dioxide, ammonia, and boron trifluoride are found as key products during the decomposition of [EMIM][SCN], [EMIM][NTF<sub>2</sub>], [EMIM][DCA], and [EMIM][BF<sub>4</sub>], respectively. Following designs of anion structure for propellant may start from [SCN]<sup>-</sup> and [DCA]<sup>-</sup> to obtain better decomposition property.</div></div>","PeriodicalId":23058,"journal":{"name":"Thermochimica Acta","volume":"754 ","pages":"Article 180172"},"PeriodicalIF":3.5,"publicationDate":"2025-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474757","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}