Transition Enthalpy Research Articles

Thermal studies of hydrogels based on poly(acrylic acid) and its copolymers by differential scanning calorimetry: A systematic literature review

This systematic literature review aims to study the thermal properties (TP) of poly(acrylic acid)-based hydrogels (PAA) by differential scanning calorimetry. The data sources were obtained from Google Scholar via Publish or Perish software from 2018 to 2020. The synthesis results show that most of the analysis of TP in PAA-based hydrogel consists of glass transition temperature ([Formula: see text]), melting temperature ([Formula: see text]), and enthalpy ([Formula: see text]). The subsequent thermal properties analysis is important for a new development and depth study in the future application.

Novel method for microencapsulation of eutectic hydrated salt

Phase change materials (PCMs), as latent thermal energy storage, have received plenty of attention in recent decades due to their excellent performance in energy conservation. Inorganic hydrated salts have many advantages over organic phase change materials, such as higher thermal storage density, low cost, nontoxicity and nonflammability. This work presents a simple and environmentally friendly method for the preparation of microcapsules with inorganic hydrated salts as core materials. Microcapsule using EHS composed of SSD and DHPD as core material and EC/ABS as shell material has been prepared and investigated by various characterization techniques. The scanning electron microscope (SEM) results indicate that the microcapsules are basically spherical with a core-shell structure. In addition, Fourier-transform infrared spectroscopy (FT-IR) analysis results suggest that the microcapsules are only the physical coating of composite shell material to core material. Furthermore, the phase transition enthalpy is 168.3 J/g according to the differential scanning calorimeter (DSC) analysis. Besides, the method of microencapsulation may be extended to other liquid hydrates salts at room temperature.

Method of enthalpy calibration for differential scanning calorimeters

The article describes a new method for enthalpy calibration of differential scanning calorimeters. The method allows you to remove the limitation on the temperature range in which this metrological procedure can be carried out. The proposed method does not require the use of standard samples of heats of fusion, therefore, it is not limited by the thermophysical properties of the certified substances. The developed method solves the problem of increasing the accuracy of measurements of specific enthalpy and heats of phase transitions of various substances for all types of differential scanning calorimeters. The effectiveness of the method in solving this problem is confirmed and illustrated by the authors by comparing the results of measuring the heats of fusion of a number of metals. The results obtained on differential scanning calorimeters calibrated by the new method and on the same instruments, but calibrated in accordance with the generally accepted standardized method of the International Union of Theoretical and Applied Chemistry, were compared. The authors experimentally revealed the advantages of the new method in terms of saving time and money required for calibration. The article will be of interest to those specialists who use differential scanning calorimeters in the development of new materials, control of technological processes, production, input and output control, as well as to those specialists who develop methods for research and measurement of various materials on differential scanning calorimeters.

A novel form-stable phase change material based on halloysite nanotube for thermal energy storage

Halloysite nanotube (HNT), a natural and environmentally friendly low-cost material with significant reserves, has become one of promising candidates for preparation of form-stable composite PCM with satisfactory thermal properties owing to their hollow tubule structure and high surface area. The present work prepared the form-stable composite with HNTs and acid etching HNTs (A-HNTs) and compares the properties closely related to thermal energy storage application. Specifically, the micromorphology, thermal properties, shape-stabilized properties, as well as thermal conductivities of the composite materials were characterized by utilizing SEM, TEM, FTIR, DSC, BET, and Hot-disk wire methods, respectively. The results showed that the n-octadecane can both adhere on the inner lumen and the outer wall of HNTs and A-HNTs, while the A-HNTs possess significantly improved absorption thanks to the fact that the pore volume of A-HNTs was enlarged by 19.2% in comparison with HNT, which empowers the extra 5.8% phase transition enthalpy of n-octadecane@A-HNT. In addition, the composite PCMs have a good long-term thermal stability based on multi-cycle heat absorption and release further highlights the potentials in thermal storage application.

Unsymmetric Dumbbell-Shaped Polyhedral Oligomeric Silsesquioxane (POSS) Compound as a Single-Component POSS Hybrid.

Dumbbell-shaped polyhedral oligomeric silsesquioxane (POSS) derivatives, in which two POSS units are linked through a bridge, have attracted attention in the last decade. Here, we prepared an unsymmetric dumbbell-shaped POSS derivative (3Ph-iBu) in which isobutyl- and phenyl-substituted POSS units are linked by a disiloxane unit and compared its thermal properties with those of the corresponding symmetric isobutyl- and phenyl-substituted dumbbell-shaped POSS derivatives (3iBu-iBu and 3Ph-Ph, respectively). The symmetric isobutyl- and phenyl-substituted dumbbell-shaped POSS derivatives, 3iBu-iBu and 3Ph-Ph, were almost completely phase-separated during a mixing process. This phase separation is due to the limited solubility of phenyl-substituted POSS compounds, which are only soluble in tetrahydrofuran (THF) and insoluble in hydrocarbons such as n-hexane and toluene, while the isobutyl-substituted POSS derivatives exhibit a wider spectrum of soluble solvents. The unsymmetric dumbbell-shaped POSS, 3Ph-iBu, showed hybrid properties of solubility in solvents and thermal behaviors. Differential scanning calorimetric (DSC) analysis showed that enthalpy of the phase transition of 3Ph-iBu was significantly lower than those of the mixture of 3iBu-iBu and 3Ph-Ph. No apparent melting behavior was observed above the phase transition. The thermal degradation of the weakest isobutyl substituents improves in the present single-component hybrid structure.

Polymer/expanded graphite-based flexible phase change material with high thermal conductivity for battery thermal management

Phase change materials, as smart, ideal latent heat storage, and passive technology, have become the promising option for thermal management. However, the melting leakage, poor mechanical property, and intrinsic low thermal conductivity are long-standing bottlenecks for practical applications. In this study, a synergetic method is proposed to fabricate phase change composites with excellent shape stability, flexible property, and high thermal conductivity. Here, paraffin is used as thermal energy storage material, styrene-ethylene-propylene-styrene served as supporting material provides a cross-linked network to restrict paraffin molecular and endow the composite with thermal-induced flexibility, and expanded graphite with lamellar structure constructs an interconnected thermally network. The thermal conductivities of composites reach up to 2.671–10.019 W m−1 K−1 with EG loading of 5–30 wt%. Simultaneously, the phase transition enthalpy is measured as high as 155.4–211.9 kJ kg−1, indicating that the composites have good thermal properties. In addition, the composites exhibit superior thermal management behavior by controlling the operating temperature of battery to below 50 °C under normal discharge-charge and dynamic stress test cycles. Therefore, this work offers a convenient and efficient method to synthesize scalable form-stable composite with promising performance for battery thermal management and other advanced thermal management applications.

Experimental investigation of the U-rich region and thermodynamic re-assessment of the U–Ti system

• The eutectoid reactions in the U-rich region were experimentally determined. • The congruent reaction γ(U,Ti) →δ-U 2 Ti was experimentally re-investigated. • The phase diagram of U-Ti system was thermodynamically re-assessed. • A set of more rational thermodynamic parameters were obtained. • A new two-phase region αU + βU was predicted. The U–Ti binary system was investigated via experimental measurements and thermodynamic modeling. In order to clarify the disputed phase equilibria of the U–Ti system, 11 alloys with different contents of Ti were prepared by arc melting. The investigated Ti content covers the U-rich portion within the composition range from 1 at.% Ti to 33.3 at.% Ti. All samples were annealed at the temperatures of 640, 720 and 730 °C, and then analyzed by optical microscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and differential scanning calorimeter. The phase equilibria associated with γ(U,Ti), αU, βU, and δ-U 2 Ti were experimentally determined in detail. The reaction temperature and composition of the invariant reaction γ(U,Ti) → βU + δ-U 2 Ti were precisely determined, and the invariant reaction temperature of the reaction βU→ αU + δ-U 2 Ti was updated. The solid solubility of Ti in αU at low temperatures was also revised by experiments. The temperature and the enthalpy of transition δ-U 2 Ti to γ(U,Ti) were newly measured by the differential scanning calorimeter. Finally, a set of self-consistent thermodynamic parameters were obtained by taking into account the present experimental findings and reliable literature data using CALPHAD (Calculation of phase diagrams) technique, and all calculated results are in good agreement with the experimental ones.

Ultrastrong behaviors of a non-equiatomic Ti-Zr-Ni-Cu-Be high entropy metallic glass with ultrahigh glass forming ability

We studied the thermodynamics and kinetics of a non-equiatomic Ti32.8Zr30.2Ni5.3Cu9Be22.7 high entropy metallic glass (HEMG, ΔSconfig.∼1.44R) with a critical size for glass formation over 50 mm. The characteristic transition temperature, enthalpy of transition and specific heat capacity along with the relaxation time at different heating rate were determined using differential scanning calorimeter (DSC) measurements. It reveals that the present HEMG supercooled liquid shows the lowest thermodynamic driving force against the nucleation and growth of crystalline phases with comparing to other typical MG formers. Meanwhile, it exhibits the ultrastrong behavior near glass transition in terms of the Angell's fragility concept. The alloy has a fragility index of D* = 45.2, higher than all the typical MG formers reported so far. Both thermodynamic and kinetic factors are responsible for the ultrahigh glass-forming ability of the HEMG alloys.

Assessment of physical, microstructural, thermal, techno-functional and rheological characteristics of apple (Malus domestica) seeds of Northern Himalayas

In this research, two common apple seed cultivars Viz: ‘Golden Delicious’ (GD) and ‘Red Delicious’ (RD) of Northern Himalayan region were characterized for physical, techno-functional, microstructure, thermal, and rheological properties. Seeds showed a significant difference in width, arithmetic, and geometric mean diameters, volume, and surface area. Proximate analysis results revealed that seed flours have high oil content (> 20%) and are potentially rich sources of protein (> 40%). Color analysis of flours indicated their satisfactory whiter color with higher brightness values (L* ˃ 75), resulting from the reduced particle size which allows greater light penetration and relatively lower a* (< 1.5) and b* (< 11) values. Techno-functional attributes including water/oil absorption capacity, emulsifying capacity, and emulsion stability were significantly higher in RD than GD flour. There was also a significant difference in the average particle size of seed flours. Flour micrographs indicated the presence of oval/spherical-shaped starch granules embedded in dense protein matrix while, Differential Scanning calorimeter (DSC) revealed exothermic transition enthalpies for seed flours. Additionally, seed flours depicted high elastic modulus (G′), suggesting their suitability for modifying food texture. It was concluded that apple seeds exhibit significant potential for use in formulating protein-enriched foods while contributing to reducing industrial wastage.

Curding of milk in incubator utilizing latent heat of lauric acid in winter

AbstractThe maintenance of incubation temperature (30°C‐50°C) for growth of culture is essential during fermentation of milk to curd. This report discusses the issue of maintaining constant temperature of milk for formation of curd using lauric acid (m.p. 45.02°C and f.p. 40.21°C) as phase change material (PCM). Lauric acid possesses phase transition enthalpy, 189.43 kJ kg−1 and was thermally stable till 140°C. A known dimension of a temperature controlling packaging (TCP) box was made by taking 240 g of PCM uniformly distributed inside six polyethylene packets (40 g each) of dimensions identical with that of inner walls of the corrugated box and the packets were placed along inner walls of TCP box. The TCP box containing packets with molten PCM could maintain the temperature of 150 g milk (placed inside box) in between 50°C and 30°C for 160 minutes and helped in curd formation, while the whole assembly was exposed to 1°C of ambient temperature.

Pulmonary surfactant inactivation by β-D-glucan and protective role of surfactant protein A

Pulmonary fungal infections lead to damage of the endogenous lung surfactant system. However, the molecular mechanism underlying surfactant inhibition is unknown. β-D-glucan is the major component of pathogenic fungal cell walls and is also present in organic dust, which increases the risk of respiratory diseases. The objective of this study was to characterize the interaction of this D-glucopyranose polymer with pulmonary surfactant. Our results show that β-D-glucan induced a concentration-dependent inhibition of the surface adsorption, respreading, and surface tension-lowering activity of surfactant preparations containing surfactant proteins SP-B and SP-C. Our data support a new mechanism of surfactant inhibition that consists in the extraction of phospholipid molecules from surfactant membranes by β-D-glucan. As a result, surfactant membranes became more fluid, as demonstrated by fluorescence anisotropy, and showed decreased Tm and transition enthalpy. Surfactant preparations containing surfactant protein A (SP-A) were more resistant to β-D-glucan inhibition. SP-A bound to different β-D-glucans with high affinity (Kd = 1.5 ± 0.1 nM), preventing and reverting β-D-glucan inhibitory effects on surfactant interfacial adsorption and partially abrogating β-D-glucan inhibitory effects on surfactant’s reduction of surface tension. We conclude that β-D-glucan inhibits the biophysical function of surfactant preparations lacking SP-A by subtraction of phospholipids from surfactant bilayers and monolayers. The increased resistance of SP-A-containing surfactant preparations to β-D-glucan reinforces its use in surfactant replacement therapy.

Controlling thermomechanical behavior of semicrystalline hydrogenated polynorbornene through the cis‐ to trans‐cyclopentylene ratio

AbstractThough polynorbornene synthesized by ring‐opening metathesis polymerization has an intrinsically all‐cis configuration of the cyclopentylene backbone rings, a fraction of these rings can be epimerized to the trans configuration during hydrogenation over suitable catalysts. By varying the method of hydrogenation, semicrystalline hydrogenated polynorbornenes (hPNs) with trans levels between 0 and 36% were obtained. With increasing trans content, the glass transition temperature, melting point, and enthalpy of melting decrease modestly. By contrast, the temperature at which the hPN crystal transitions into a rotationally disordered polymorph varies strongly with trans content, ranging from 126 °C (all‐cis) to 71 °C at 27% trans; at trans contents of 34% and above, no rotationally‐ordered phase is observed at any temperature. The room‐temperature Young's modulus shows no dependence on trans content, while the yield stress drops by 20% at 1% trans content and slowly decreases further with additional epimerization. The temperature dependence of the Young's modulus differs for trans‐containing versus all‐cis polymers, while the temperature dependence of the yield stress is set by the polymorph type (rotationally ordered vs. disordered).

Mesomorphic behaviour, optical and quantum computational study: Effect of electron density on newly synthesized liquid crystalline positional isomers

Effect of position isomer in newly synthesized two liquid crystalline series having nitro and chloro groups at terminal and lateral position, with imine and cinnamoyloxy linkages was studied. The nitro and chloro groups in the aromatic end of the molecule are interchanged with each other at terminal and lateral position, giving rise to positional isomers. All synthesized compounds were characterized with standard spectroscopic techniques, Infrared, Ultra-Violet and Proton magnetic resonance spectroscopy. The mesophase behaviour was observed by a Polarizing optical microscope equipped with a heating stage and was confirmed by Differential scanning calorimetry with respective transition enthalpies of mesophase transition. The mesogenic derivative of both prepared series showed nematic and smectic A mesophase. DFT method was used to obtain optimized geometry of the molecules. The optimized geometry was used to obtain the Molecular electrostatic potential map, dipole moment, HOMO-LUMO and twist angle of the prepared series. The interaction between the molecules was studied on the base of electrostatic potential and HOMO-LUMO. The phase transition of the present two series is compared with each other and with three structurally related compounds to evaluate the effect of planarity, central linkage and position of substitution on their mesophase behaviour.

The composition of edible oils modifies β‐sitosterol/γ‐oryzanol oleogels. Part I: Stripped triglyceride oils

AbstractThe role of the fatty acid (FA) composition of triglycerides (TAGs) on sterol/sterol ester oleogels has been studied. Minor oil components of three vegetable oils with varying degrees of unsaturation (iodine values, IV) were removed. Typical oil quality parameters were determined before and after the treatment, and oleogels were produced using all six oils. Characteristic gel properties such as transition temperatures, mechanical properties and microstructure were tested. The results were compared regarding the impact of IV and the stripping procedure. Minor components were essentially removed during stripping, resulting in significantly different oil properties such as peroxide value, free FA and viscosity. However, peroxides formed rapidly in stripped flaxseed oil. Gel–sol transition temperatures and enthalpies were higher in gels from untreated oils and decreased with IV in samples with stripped oils. In contrast, the sol–gel transition was suppressed due to minor oil components in untreated oils. The effect of IV on gel formation was much less and linked to a lower solvent viscosity in more unsaturated oils. Nevertheless, gel firmness was significantly higher in oleogels from untreated oils and decreased slightly with IV in stripped oils. That was associated with differences in the arrangement of network building blocks, which was confirmed using atomic force microscopy. This study showed that the FA composition of TAGs has a limited effect on oleogel properties compared to those of minor oil components. The next part of this study focuses on modifying oleogel properties by adding selected minor components to stripped oils at varying concentrations.

2H NMR Study of Polymer Segmental Dynamics at Varying Cross-Linking in Poly(N-isopropylacrylamide) Microgels.

A microscopic understanding of the internal structure and dynamics of poly(N-isopropylacrylamide) (PNIPAM) chains, in microgel colloids, is developed using deuterium NMR (2H NMR) to study deuterated PNIPAM suspensions as functions of temperature and pressure for four cross-linker molar fractions (f). The PNIPAM polymers were labeled with deuterons at the backbone (d3-PNIPAM) or on side chains (d7-PNIPAM). 2H NMR spectra of the d3-PNIPAM suspensions for all cross-linker molar fractions indicated freely moving chains at low temperature and a nearly immobilized fraction above ∼35 °C. Polymer segments in the collapsed phase of the d3-PNIPAM suspension were more mobile than those in the dry powder. This is direct microscopic evidence that the polymer remains significantly hydrated in the collapsed phase, consistent with strong, indirect evidence from recent light scattering and rheology measurements from our laboratory. However, the observation of a small fraction of immobilized segments in the swollen phase for higher cross-linker molar fraction suggests that, particularly for high levels of cross-linking, some polymer is nonhydrated even in the swollen phase. Finally, variable-pressure NMR (up to 90 MPa) showed a slight increase in transition temperature with pressure for lower cross-linker molar fractions and a larger increase in transition temperature with pressure for higher cross-linker molar fractions. This is consistent with a previously reported dependence of collapse transition enthalpy on cross-linker molar fraction.

Recent advancements in latent heat phase change materials and their applications for thermal energy storage and buildings: A state of the art review

Phase change materials (PCMs) have received substantial interest for their ability to store and release latent heat for energy conservation and thermal control purposes. PCMs are available in a variety of latent heat and melting points but their performance is low due to low value of thermal conductivity which limits its usage. The addition of highly thermal conductivity nanoparticles, porous metal foams and encapsulation methods have been used to address this issue and try to fix the low thermal conductivity of PCMs which is broadly discussed in this manuscript. The ability of PCM to store and release the thermal energy prompted the researchers to use it in potential applications. The energy retained and emitted by PCMs may be used for a variety of purposes, such as in photovoltaic (PV) panels, thermoelectric generators, building air-conditioning, air and water heating systems, heat exchangers, desalination solar stills, textiles, thermal management of electronic equipment and batteries and food packaging. Therefore, in this review, first the advancements in thermal properties of PCMs are thoroughly discussed in terms of enhancement in melting and solidification rates. After that, the use of PCMs in various applications is then explored, and conclusions are drawn accordingly. Based on analysis of recent literature, it was discovered that the phase transition temperature, phase transition enthalpy and thermal conductivity are three important parameters for the selection of an appropriate PCM for use in various applications. The current status of these advanced energy storage materials is also presented in this review. Lastly, some challenges and future recommendation are also proposed for future researchers which will bring a revolution in thermal management field.

Specific heat and thermal history of the Sariçiçek howardite

AbstractMeteorites are excavated fragments from asteroid surfaces and planets, and determining their thermophysical properties is important since they contain valuable information about internal structures of their parent bodies. We investigated thermophysical properties of the Sariçiçek meteorite by differential scanning calorimetry (DSC), measuring phase transition temperatures, enthalpy changes and specific heat capacities of samples and thermogravimetric analysis (TGA), investigating weight change in a sample as a function of temperature or time. DSC results indicate that troilite α/β and β/γ phase transition temperatures of the interior part of the meteorite were at 421.98 ± 0.02 and 581.74 ± 1.71 K, and troilite content of interior and crust parts of the meteorite were 0.28 and 0.02 wt%, respectively. Relict temperatures were calculated as 453 ± 10, 465 ± 17, and 588 ± 55 K; specific heat capacities were measured as 779, 745, and 663 J kg–1 K–1 at 300 K; and predicted as 568, 537, and 480 J kg–1 K–1 at 200 K, for interior, edge, and crust, respectively. TGA results revealed that Sariçiçek's weight loss was 0.98% at 1170 °C, and water content and hydrogen abundance at 200–800 °C were 0.34% and 0.04%, respectively. Obtained results shed light on a thermal history of Sariçiçek’s parent body and provide further knowledge on thermal alteration of 4 Vesta.

Stereochemistry, Conformational Dynamics, and the Stability of Liquid Crystal Phases

Although discotic liquid crystal dimers have been widely targeted as organic semiconductors and as LC-glass formers, the role of conformational dynamics on the self-assembly of these flexible mesogens remains poorly understood. In an effort to probe this effect, we investigated the impact of linker stereochemistry on the phase behavior of discotic liquid crystalline dimers. Diastereomeric dibenzo[a,c]phenazine diesters were prepared from (2R,3R)- and meso-2,3-butanediol. While both dimers form columnar phases, the meso-isomer had a clearing temperature (Tc) that was 31 °C higher than that of its chiral diastereomer. Conformational analysis via DFT calculations, 1H-NMR, and DOSY experiments indicated that both compounds adopt predominantly extended conformations but that the meso-dimer shows a stronger preference to unfold in solution. To probe how conformation alters phase stability, we prepared derivatives in which catechol and hydroquinone act as rigid linkers that lock the dimers in a folded or an extended conformation, respectively. The diester of hydroquinone possessed a Tc that was nearly 100 °C higher than the catechol derivative, consistent with a model where extended conformations stabilize the LC phase. Extended dimers also exhibited higher transition enthalpies at the Tc, an indication that their columnar phases are more ordered than folded structures.

Underutilized horse chestnut (Aesculus indica) flour and its utilization for the development of gluten-free pasta

There has been a growing demand for the production of gluten-free products due to increased occurrence of celiac disease. Thus, different research groups have been investigating the use of various available materials for the development of these functional products to fulfill customer’s needs. Horse Chestnut (Aesculus indica) seeds are underutilized, low-cost, and gluten-free, found in hilly areas of the Himalayan region of Kashmir valley, India. To determine their potential as an alternative to conventional food grains, an investigation was conducted to determine the physicochemical, functional, pasting, and thermal properties of Horse Chestnut (HCN) flour and its compatibility for the development of gluten-free pasta. HCN flour comprised 73.34% carbohydrate, 11.36% protein, 6.34% crude fiber, 3.27% fat, 3.16% ash, 3.15g/g oil absorption capacity, and 4.65% water absorption index. HCN flour showed 505 cp peak, 354 cp trough, 151 cp breakdown, 472 cp final viscosity, and 66.05°C pasting temperature. Transition temperatures (onset, peak, and conclusion) and enthalpy change (ΔH) were 60.12°C, 69.90°C, 81.53°C, and 10.56 J/g, respectively. Pasta prepared from HCN flour using guar gum (0, 0.5, and 1%) was analyzed for color, cooking qualities, and textural and sensory analysis. The present results showed that HCN flour possesses good nutritional quality and has properties comparable to conventional wheat flour. Therefore, HCN-flour-based pasta can act as a nutritious alternative to conventional gluten-free pasta and add variety to the diet of people suffering from celiac disease.

Fabrication of highly thermal conductive and shape-stabilized phase change materials

Poor thermal conductivity and easy leakage in molten state into the surrounding of the thermal energy storage (TES) system are two major problems of organic phase change materials (OPCMs). This study focuses on the heat conduction enhancement and leakage-proof of the OPCM and a novel shape-stabilized OPCM with decyl alcohol (DA) as TES material, expanded graphite (EG) and nanoparticles as additives is developed. The optimal mass fraction of the porous EG, which serves as the shape-stabilizer and heat conduction enhancer, is determined to be 9% through vacuum drying method. Five different kinds of nanoparticles are selected to further improve the thermal conductivity. The experimental results suggest that the composite PCM DA/MgO/EG possesses the highest thermal conductivity, with a value of 1.873 W/(m·K), which is significantly increased by 11.570 times comparing to pure DA and 1.010 times higher than that of DA/EG. The mechanism of strengthening thermal conductivity by the coupling effect of EG and nano additives is revealed. According to DSC tests, the melting temperature and the melting enthalpy of the ternary composite PCM DA/MgO/EG are 1.1 °C and 194.6 J/g, respectively. The effect of additives on the phase transition temperature and enthalpy of PCMs is also investigated. Depending on the cyclic stability experiments, after 300 charging-discharging cycles, both the phase transition temperature and the melting latent heat of DA/MgO/EG have little change by comparison with those of uncirculated composites, which indicates excellent thermal stability of the material. Finally, the applicability of DA/MgO/EG composite is explored by cold insulation experiment. Overall, the composite in this work has promising prospects in cold chain logistics.