Thermochimica Acta最新文献

英文中文

Thermal and combustion characteristics of Al/AP/HTPB composite propellant after exposure to cryo-thermal cycling Al/AP/HTPB复合推进剂低温-热循环后的热特性和燃烧特性

IF 3.5 2区化学 Q2 CHEMISTRY, ANALYTICAL

Thermochimica Acta

Pub Date : 2025-09-03 DOI: 10.1016/j.tca.2025.180132

Yanwen Zhang , Jianzhong Liu , Xiaohui Xue , Wenke Zhang , Tuanwei Xu , Xianghua Chen

The structural integrity and combustion safety of composite solid propellants under extreme service environments remain critical concerns. In this study, a typical HTPB/AP/Al composite propellant was subjected to 56-day cryo-thermal cycling to investigate the effects on microstructure, thermal decomposition, and combustion behavior. Scanning electron microscopy revealed progressive interfacial debonding, pore coalescence, and AP crystal fracture induced by repeated cryo-thermal cycles. Thermogravimetry-differential scanning calorimetry indicated that the main decomposition stage exhibited intensified heat release, increased mass loss rates, and a shift of the AP high-temperature decomposition peak toward higher values. Combustion tests demonstrated that the burning rate and pressure exponent increased with the severity of cryo-thermal cycling, particularly under long-term exposure. At 1.6 MPa, cycled samples displayed brighter, smokier, and more unstable flames. The findings support the life prediction and combustion safety optimization of propellants in extreme environments.

复合固体推进剂在极端使用环境下的结构完整性和燃烧安全性一直是人们关注的焦点。本研究以典型的HTPB/AP/Al复合推进剂为研究对象，对其进行了56天的低温循环，考察其微观结构、热分解和燃烧性能的影响。扫描电镜显示，在反复冷热循环的作用下，界面逐渐脱粘，孔隙聚结，AP晶体断裂。热重-差示扫描量热分析表明，主要分解阶段表现为放热加剧，质量损失率增加，AP高温分解峰向较高值移动。燃烧试验表明，燃烧速率和压力指数随着低温-热循环的严重程度而增加，特别是在长期暴露的情况下。在1.6 MPa下，循环后的样品显示出更亮、更冒烟、更不稳定的火焰。研究结果支持了推进剂在极端环境下的寿命预测和燃烧安全性优化。

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引用次数: 0

Cure kinetics of aromatic disulfide epoxy vitrimer: influence of epoxy/amine stoichiometry 芳香族二硫化环氧玻璃体固化动力学：环氧/胺化学计量的影响

IF 3.5 2区化学 Q2 CHEMISTRY, ANALYTICAL

Thermochimica Acta

Pub Date : 2025-09-03 DOI: 10.1016/j.tca.2025.180133

F. Spini , I. Marzorati , P. Bettini , A.M. Grande

Disposal of End-of-Life (EoL) thermoset composites, difficult to recycle due to polymer crosslinked structure, presents a significant challenge. Development of thermoset polymers with increased recyclability, self-healing, and reprocessability offers a promising solution for managing composite waste and extending component lifetime. Vitrimers, based on covalent adaptable networks (CANs) that rearrange their topology via reversible exchange reactions, are particularly promising.

Recent research has shown that varying vitrimers stoichiometry can impact properties such as dissolution capability, potentially enhancing recyclability. This study explores the effects of stoichiometry variation on the thermomechanical properties and cure kinetics of epoxy vitrimers incorporating 4-aminophenyl disulfide (4-AFD) as hardener. Knowledge regarding the progression of crosslinking for both stoichiometric and non-stoichiometric mixtures is critical for optimizing processes and predicting behaviour at different curing temperatures.

Vyazovkin’s approach emerged as the most suitable for analysing cure kinetics among the different methods. It revealed that the non-stoichiometric formulation with hardener excess maintained nearly constant activation energy, suggesting that the cure mechanism is primarily driven by interactions between primary amines and epoxy groups. This reduces the availability of epoxy groups for tertiary amine formation, resulting in a less dense network, lower storage modulus, and decreased T_g, as confirmed by DMA and DSC results.

由于聚合物交联结构，热固性复合材料难以回收利用，其处理提出了重大挑战。热固性聚合物的发展具有更高的可回收性、自愈性和再加工性，为管理复合材料废物和延长组件寿命提供了一个有前途的解决方案。基于共价自适应网络（can），通过可逆交换反应重新排列其拓扑结构的Vitrimers尤其有前景。最近的研究表明，不同的玻璃体化学计量可以影响溶解能力等性能，从而潜在地提高可回收性。本研究探讨了化学计量学变化对以4-氨基苯基二硫化（4-AFD）为硬化剂的环氧树脂的热力学性能和固化动力学的影响。了解化学计量和非化学计量混合物的交联过程对于优化工艺和预测不同固化温度下的行为至关重要。在不同的方法中，维亚佐夫金的方法是最适合分析固化动力学的方法。结果表明，固化剂过量的非化学计量配方保持了接近恒定的活化能，表明固化机制主要是由伯胺和环氧基之间的相互作用驱动的。正如DMA和DSC结果所证实的那样，这降低了环氧基形成叔胺的可用性，导致网络密度降低，存储模量降低，Tg降低。

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引用次数: 0

Study on the melting characteristics of iron ore sintering mixtures using spent carbide slag and white mud as calcium-based fluxes 以废电石渣和白泥为钙基助熔剂的铁矿石烧结混合物熔融特性研究

IF 3.5 2区化学 Q2 CHEMISTRY, ANALYTICAL

Thermochimica Acta

Pub Date : 2025-09-03 DOI: 10.1016/j.tca.2025.180131

Laiquan Lv, Hanxiao Meng, Jiankang Wang, Jianguo Zhao, Hao Zhou

Iron ore sintering is essential in steelmaking, but traditional fluxes like limestone contribute to CO₂ emissions. Alternative calcium-based fluxes such as carbide slag (CS) and white mud (WM) offer environmental benefits, though their melting behaviors are less understood. This study investigates the effects of flux type, magnetite concentrate addition, and reducing atmosphere on the melting characteristics of sintering mixtures using high-temperature microscopic heating and thermal analysis. At basicity 4.0, mixtures with CS and WM showed critical melting temperatures (T_cm) 1.6 % and 3.8 % higher than those with limestone. Adding 20–30 % magnetite raised T_cm by 25–35 K, and 6–10 % CO further increased T_cm by 15–20 K. Microstructural analysis showed more dendritic and needle-like crystals with CS and WM. While CS and WM are viable alternatives, their inferior melting performance requires further optimization for industrial use.

铁矿石烧结在炼钢过程中至关重要，但石灰石等传统助熔剂会导致二氧化碳排放。替代的钙基助熔剂，如电石渣（CS）和白泥（WM）提供了环境效益，尽管它们的熔化行为尚不清楚。采用高温显微加热和热分析的方法，研究了助熔剂类型、磁铁矿精矿添加量和还原气氛对烧结混合物熔化特性的影响。在碱度4.0时，CS和WM混合物的临界熔融温度（Tcm）分别比石灰石高1.6%和3.8%。添加20 - 30%的磁铁矿可使Tcm提高25-35 K，添加6 - 10%的CO可使Tcm进一步提高15-20 K。显微组织分析显示，CS和WM中有更多的枝状和针状晶体。虽然CS和WM是可行的替代品，但它们较差的熔化性能需要进一步优化才能用于工业用途。

引用次数: 0

Determination of the kinetic parameters of condensed phase reactions under nonisothermal conditions 非等温条件下缩合相反应动力学参数的测定

IF 3.5 2区化学 Q2 CHEMISTRY, ANALYTICAL

Thermochimica Acta

Pub Date : 2025-09-02 DOI: 10.1016/j.tca.2025.180099

Alireza Aghili , Andrei A. Stolov , Amir Hossein Shabani

This study introduces a methodology for determining the kinetic parameters of condensed phase reactions under nonisothermal conditions by factorizing the reaction rate into a temperature-dependent rate constant and a conversion function. The conversion function is approximated using either the discrete cosine transform (DCT) or the Chebyshev series expansion (CSE) reaction models. The proposed method is applicable to both simple and complex reactions. Notably, for the first time, this approach enables the accurate estimation of the conversion function and pre-exponential factor for complex multistage reactions characterized by multiple peaks in their reaction rate profiles. The developed technique was applied to both simulated reactions and experimental data related to the thermal decomposition of polymer coating from a commercial optical fiber. Additionally, GNU Octave/MATLAB codes have been provided to facilitate the application of new methodology to user-specific datasets.

本文介绍了一种确定非等温条件下缩合相反应动力学参数的方法，该方法将反应速率分解为与温度相关的速率常数和转换函数。转换函数用离散余弦变换（DCT）或切比雪夫级数展开（CSE）反应模型进行近似。该方法既适用于简单反应，也适用于复杂反应。值得注意的是，该方法首次能够准确估计以反应速率谱为多峰为特征的复杂多阶段反应的转换函数和指数前因子。所开发的技术应用于与商用光纤聚合物涂层热分解相关的模拟反应和实验数据。此外，还提供了GNU Octave/MATLAB代码，以方便将新方法应用于用户特定的数据集。

引用次数: 0

Advancements in paraffin wax phase change materials: A comprehensive review of enhancement techniques and thermal storage applications 石蜡相变材料的研究进展：增强技术和储热应用综述

IF 3.5 2区化学 Q2 CHEMISTRY, ANALYTICAL

Thermochimica Acta

Pub Date : 2025-09-02 DOI: 10.1016/j.tca.2025.180129

Bharathiraja R , Ramkumar T , Selvakumar M , Radhika N , Praveenkumar N , Mohanraj M , Mohamed Iqbal Shajahan

Rising energy consumption in recent years has put pressure on electrical infrastructure and sustainability concerns. Efficient energy storage offers a solution to support renewable resources and meet increasing energy needs. Phase change materials (PCMs), particularly paraffin wax, have attracted research interest for their thermal storage potential, but their low thermal conductivity limits practical use. This review article begins with a comprehensive examination on the effect of thermophysical properties of paraffin wax PCMs and also explores their characteristics using different morphological techniques. It further evaluates the impact of various thermal conductivity enhancement techniques on Paraffin wax PCM which could significantly enhance heat transfer rate and system efficiency. Additionally, review article also discusses the preparation methods and applications of nano-enhanced PCM (NPCM). By offering unique insights into the fundamentals and applications of NPCM, this review highlights the current research developments and emerging future trends in this field.

近年来不断增长的能源消耗给电力基础设施和可持续性带来了压力。高效能源存储为支持可再生资源和满足日益增长的能源需求提供了一种解决方案。相变材料（PCMs），特别是石蜡，因其储热潜力而引起了人们的研究兴趣，但其低导热性限制了其实际应用。本文综述了石蜡PCMs热物理性能的影响，并利用不同的形态学方法探讨了其特征。进一步评价了各种导热增强技术对石蜡PCM的影响，这些技术可以显著提高传热速率和系统效率。此外，还对纳米增强型PCM （NPCM）的制备方法及其应用进行了综述。通过对NPCM的基本原理和应用提供独特的见解，本综述突出了该领域当前的研究进展和新兴的未来趋势。

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引用次数: 0

Whole-furnace calorimetry reveals phase transformations in aluminum alloys 全炉量热法揭示了铝合金的相变

IF 3.5 2区化学 Q2 CHEMISTRY, ANALYTICAL

Thermochimica Acta

Pub Date : 2025-09-01 DOI: 10.1016/j.tca.2025.180113

Johannes A. Österreicher, Aurel R. Arnoldt

Differential scanning calorimetry (DSC) is widely employed for analyzing phase transitions in aluminum alloys and steels, offering insights into formation and dissolution of second phase precipitates. However, DSC is a laboratory method and industrial heat treatments are typically performed without direct access to such microstructural information. This study introduces a whole-furnace calorimetry approach that leverages industrial furnace energy intake and temperature data to perform calorimetric analysis in situ without additional experimental effort. Proof-of-concept experiments on EN AW-6082 billets demonstrate the feasibility of whole-furnace calorimetry for detecting phase transformations during heat treatments. The method shows promising agreement with DSC in both peak shape and temperature. By offering microstructural insights during metal processing, whole-furnace calorimetry opens new avenues for process optimization and data-driven prediction of material properties.

差示扫描量热法（DSC）广泛用于分析铝合金和钢的相变，提供了对第二相沉淀形成和溶解的见解。然而，DSC是一种实验室方法，工业热处理通常在没有直接访问这些微观结构信息的情况下进行。本研究介绍了一种全炉量热法，该方法利用工业炉的能量摄入和温度数据在现场进行量热分析，而无需额外的实验工作。EN AW-6082钢坯的概念验证实验证明了全炉量热法在热处理过程中检测相变的可行性。结果表明，该方法与DSC在峰形和温度上都有较好的一致性。通过提供金属加工过程中的微观结构洞察，全炉量热法为工艺优化和数据驱动的材料性能预测开辟了新的途径。

引用次数: 0

Systematic DSC analysis of the melting point depression and the non-freezable layer width in different mesopore sizes in carbon xerogels 碳干凝胶中不同介孔尺寸的熔点下降和非冻结层宽度的系统DSC分析

IF 3.5 2区化学 Q2 CHEMISTRY, ANALYTICAL

Thermochimica Acta

Pub Date : 2025-08-31 DOI: 10.1016/j.tca.2025.180128

Lucie Kořená , Václav Slovák , Samantha L. Flores-López , Ana Arenillas

The individual effect of pore size on the melting behaviour of probe liquid confined in material pores, as well as on parameters used to convert differential scanning calorimetry (DSC) data into pore size distribution (PSD) was systematically investigated. For thermoporometric testing, a tailored series of carbon xerogels with uniform pore shape and surface chemistry but varying pore sizes (10 - 50 nm) was prepared, and water was chosen as a probe liquid. The observed decreasing relation between water melting point depression and carbon xerogels pore radius confirmed the suitability of modified Gibbs-Thomson equation for PSD determination. A good linear correlation was established between the DSC peak area (representing heat of fusion of pore-confined ice) and pore volume, with the relation notably affected by pore size. The experimentally derived Gibbs-Thomson constant (39 nm K) deviated significantly from the commonly accepted one, and the non-freezable layer width (the delta layer) increased with increasing pore size.

系统地研究了孔隙大小对探针液体在材料孔隙中的熔融行为的影响，以及对将差示扫描量热法（DSC）数据转化为孔隙大小分布（PSD）的参数的影响。为了进行热热测试，我们定制了一系列具有均匀孔隙形状和表面化学性质但不同孔径（10 - 50 nm）的碳干凝胶，并选择水作为探针液体。观察到的水熔点下降与碳干凝胶孔隙半径的减小关系证实了修正Gibbs-Thomson方程测定PSD的适用性。DSC峰面积（代表孔隙约束冰的熔合热）与孔隙体积呈良好的线性相关关系，且受孔隙大小的影响显著。实验得到的Gibbs-Thomson常数（39 nm K）与普遍接受的Gibbs-Thomson常数有明显偏差，且非冻结层宽度（δ层）随孔隙大小的增加而增加。

引用次数: 0

New method for quantitative thermal gravimetric analysis per compound - model and numerical processing of TG and MS data 复合模型定量热重分析的新方法及热重、质谱数据的数值处理

IF 3.5 2区化学 Q2 CHEMISTRY, ANALYTICAL

Thermochimica Acta

Pub Date : 2025-08-30 DOI: 10.1016/j.tca.2025.180127

Yves Zerega, Laurence Tortet, Véronique Wernert

A new numerical data-processing method for Thermogravimeter-Mass Spectrometer (TG/MS) coupling data is presented. It enables the determination of quantified desorption temperature distributions and the quantification of each desorbed compound targeted by the MS. Its main advantage is that no calibration of the evolved gases is required.

The mathematical formulation of the problem consists in matching the local negative derivative of the mass variation monitored by the TG with the sum of the ion counts monitored by the MS for each compound. This results in an overdetermined system of equations, with a set of delays and proportional factors as unknowns. A least-squares method is employed to solve the system. The desorption temperature distributions are then computed using the delays and proportional factors obtained when the mean square error is minimised. From the distributions, the desorbed quantities, as well as the maximum and mean desorption temperatures, can be calculated.

The numerical method was initially validated using water desorption from FAU-NaX zeolite. Assumptions made to establish the model were confirmed. The transfer of evolved gases to the MS introduces only a pure shift. After mathematical baseline correction, a linear response in the MS amplitude was observed over a sufficiently broad range for our measurements. The treated MS curve matches the -DTG curve with an uncertainty of <0.5 mg/g. The adaptability of the method to variations in MS detection sensitivity was demonstrated. A mass deviation of 10 % is considered acceptable when comparing the desorption temperature distributions of two samples.

提出了一种热重-质谱（TG/MS）耦合数据的数值处理方法。它可以确定定量的解吸温度分布和ms针对的每种解吸化合物的定量。它的主要优点是不需要校准释放的气体。该问题的数学公式包括将TG监测的质量变化的局部负导数与MS监测的每种化合物的离子计数之和相匹配。这将导致一个过度确定的方程组，其中包含一组未知的延迟和比例因子。采用最小二乘法对系统进行求解。然后使用均方误差最小时获得的延迟和比例因子计算解吸温度分布。根据这些分布，可以计算出解吸量、最高解吸温度和平均解吸温度。采用FAU-NaX分子筛解吸水的方法对数值方法进行了初步验证。为建立模型所做的假设得到了证实。演化出的气体向质谱仪的转移只带来纯粹的转变。经过数学基线校正后，在足够宽的测量范围内观察到MS振幅的线性响应。处理后的质谱曲线与-DTG曲线吻合，不确定度为0.5 mg/g。验证了该方法对质谱检测灵敏度变化的适应性。在比较两个样品的解吸温度分布时，10%的质量偏差被认为是可以接受的。

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引用次数: 0

Thermal decomposition of the solid-phase extractant based on dicyclohexano-18-crown-6 and determination of gaseous products of its destruction 基于双环己烯-18-冠-6固相萃取剂的热分解及其破坏气相产物的测定

IF 3.5 2区化学 Q2 CHEMISTRY, ANALYTICAL

Thermochimica Acta

Pub Date : 2025-08-28 DOI: 10.1016/j.tca.2025.180126

A.M. Koscheeva , K.V. Shelamov , I.A. Bolshakova , A.M. Koshcheev , A.V. Ananiev , A.V. Rodin

Given the high selectivity of dicyclohexano-18-crown-6 (DCH18C6) crown ether toward strontium, there is growing interest in its use in radiochemical processes, including as a solid-phase extractant (SPE). In this work, differential scanning calorimetry, gas chromatography-mass spectrometry, and infrared (IR) spectroscopy were used to characterize the processes occurring during heating of SPE-DCH18C6, the crown ether DCH18C6, and the inert styrene-divinylbenzene matrix Porolas-T. Samples of SPE-DCH18C6 were prepared by impregnating Porolas-T with a solution of 0.01 mol/L DCH18C6 in chloroform. As a result of the research, it was found that upon heating in inert atmosphere SPE-DCH18C6 undergoes endothermic decomposition in the temperature range 320-480 °C (593-753 K), as does Porolas-T. The SPE and inert matrix have a similar set of gaseous decomposition products, which includes benzene and a number of its derivatives. In oxidizing atmosphere, SPE-DCH18C6 decomposes exothermically in several stages at temperatures of 180-580 °C (453-853 K) with a total specific heat release of about 10⁴ J/g. The effect of nitric acid on the thermal effects and destruction products of the sample was assessed. A decrease in the intensity of the crown ether bands in the IR spectra was established for the SPE after contact with nitric acid using IR spectroscopy. SPE-DCH18C6 remains thermally stable up to 100 °C and can be used for strontium extraction at radiochemical facilities.

鉴于双环己烯-18-冠-6 （DCH18C6）冠醚对锶的高选择性，人们对其在放射化学过程中的应用越来越感兴趣，包括作为固相萃取剂（SPE）。本研究采用差示扫描量热法、气相色谱-质谱法和红外（IR）光谱对SPE-DCH18C6、冠醚DCH18C6和惰性苯乙烯-二乙烯基苯基体Porolas-T加热过程进行了表征。用0.01 mol/L DCH18C6氯仿溶液浸渍Porolas-T制备SPE-DCH18C6样品。研究发现，在惰性气氛中加热后，SPE-DCH18C6在320 ~ 480℃（593 ~ 753 K）范围内发生吸热分解，Porolas-T也发生吸热分解。固相萃取和惰性基质有类似的气体分解产物，包括苯和它的一些衍生物。在氧化气氛中，SPE-DCH18C6在180 ~ 580℃（453 ~ 853 K）的温度下分几个阶段放热分解，总比热释放约为104 J/g。考察了硝酸对样品热效应和破坏产物的影响。用红外光谱法测定了固相萃取与硝酸接触后，其红外光谱中的冠醚带强度降低。SPE-DCH18C6在高达100°C的温度下保持热稳定，可用于放射化学设施中的锶提取。

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引用次数: 0

Research on thermal decomposition and combustion characteristics of ionic liquids 离子液体热分解燃烧特性研究

IF 3.5 2区化学 Q2 CHEMISTRY, ANALYTICAL

Thermochimica Acta

Pub Date : 2025-08-28 DOI: 10.1016/j.tca.2025.180125

Lanyun Wang , Jiahong Yuan , Yongliang Xu , Yao Li , Tingxiang Chu , Hao Shao , Xiaodong Feng , Kun Zhang

Ionic liquids have been widely applied in gas separation, high-temperature lubricants, and rocket propellants, so their thermal stability and combustion characteristics have drawn much attention. The study studied 16 kinds of functionalized imidazolium, quaternary ammonium, and quaternary phosphonium ionic liquids. The thermal decomposition and combustion characteristics were studied systematically by a synchronous thermal analyzer and a conical calorimeter. The results indicate that the thermal stability of ionic liquids is greatly affected by the chemical structures. Larger anions can improve the thermal stability, while bromide ions (Br⁻) may weaken it. Moreover, oxidizing gas environment weakens the thermal stability, resulting in two-stage decomposition. In terms of combustion characteristics, higher hydrocarbon content of ionic liquids leads to more total heat release. Long-chain cations and single-atom anions may promote heat generation during combustion. These research results provide essential theoretical support for predicting the risks of ionic liquids in industrial applications and are crucial for enhancing their intrinsic safety.

离子液体在气体分离、高温润滑剂、火箭推进剂等领域有着广泛的应用，其热稳定性和燃烧特性备受关注。研究了16种功能化咪唑、季铵、季磷离子液体。采用同步热分析仪和锥形量热仪对其热分解和燃烧特性进行了系统的研究。结果表明，离子液体的热稳定性受其化学结构的影响较大。较大的阴离子可以提高热稳定性，而溴离子（Br−）则会削弱热稳定性。此外，氧化性气体环境削弱了热稳定性，导致两段分解。在燃烧特性方面，离子液体的碳氢化合物含量越高，总放热量越大。长链阳离子和单原子阴离子在燃烧过程中会促进热的产生。这些研究结果为离子液体在工业应用中的风险预测提供了重要的理论支持，对提高离子液体的本质安全性具有重要意义。

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