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The disadvantage of poor thermal performance of epoxy resin limits its application in special fields, therefore we improve the thermal performance of epoxy resin by copolymerizing it with phthalonitrile resin. A novel self-promoted curing phthalonitrile monomer containing pyridine rings and amino groups (APNH) was successfully synthesized using 2-amino-4-hydroxypyridine and 4-nitrophthalonitril, and characterized by FTIR and NMR spectra. DSC confirmed that the APNH monomer exhibits curing behavior that is self-promoting. Copolymerizing the APNH monomer with epoxy resin enhances the thermal performance of the epoxy resin. The curing behavior of the EPNH copolymer was studied using DSC, which revealed two distinct curing peaks. FTIR analysis showed that the EPNH copolymer has formed structures such as triazine, phthalocyanine, and isoindoline. The presence of cyano groups significantly enhances the thermal properties of the copolymer, surpassing those of traditional epoxy resins. This enhancement in thermal performance amplifies with an increase in the content of the APNH monomer. The research indicates that the EPNH copolymer exhibits superior thermal stability and elevated glass transition temperatures, facilitating the application of epoxy resin in specialized areas. [ABSTRACT FROM AUTHOR]

Bulk tin‐based monochalcogenides are composed of earth‐abundant, low‐cost, and non‐toxic chemical elements, which possess high thermoelectric properties making them candidate for waste heat recovery applications. Bandgap engineering offers opportunity to customize the characteristics of semiconductors as desired applications in microelectronic, thermoelectric, and so on. The bandgap of tin‐based monochalcogenides is systematically regulated by the solid‐solution method. The thermal and optical properties of SnSe(1–x)Sx (0 ≤ x ≤ 1) single crystals, synthesized successfully by a home‐modified Bridgman method, have been systematically investigated. A variety of characterizations, including x‐ray diffraction, electron microscopy, Raman spectroscopy, absorbance spectroscopy, and thermal analyzer, are employed to confirm the precise tuning of the component. As the S compositions increased from 0 to 1, the unit cell parameter, interplanar spacing, and optical phonon frequency exhibited a linear change, aligning with the expected bandgap shifts and calculated results. Our work will promote the advancement of the SnSe and SnS materials in areas including thermoelectricity and photovoltaics. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) oligomers were synthesized through a solution reaction using sulfolane as a solvent, the resultant oligomers were employed to synthesize high melt viscosity PEEK through solid-state polymerization in a twin-roller mixer. The effects of polymerization time on the crystallization properties, thermal properties and flowability of PEEK were investigated. The results indicated that both the degree of crystallinity and crystallization completeness of PEEK decreased with an increase in polymerization time. The degree of crystallinity of PEEK after polymerization for 5 h decreased by about 31. 4 % as compared to that of the oligomers. All samples possessed residual weights greater than 50 % at 900 °C, indicating outstanding thermal stability. In addition, the melt viscosities of PEEKs increased significantly with an increase in the polymerization time, and it reached approximately 13-360 times as high as that of oligomers. [ABSTRACT FROM AUTHOR]

A porous, crosslinked aromatic polyamide having COCl and COOH groups (referred to as PA herein) prepared had a mesoporous structure and comprised agglomerates of particles with average diameters of approximately 30 nm. The PA was found to swell with significant deformation in response to water vapor, but was almost unchanged after exposure to toluene vapor. The polymeric structure returned to its original porous morphology after removal of the solvents, demonstrating that the PA possessed affinity for specific solvents and shape memory. The chemical composition and porous structure of the PA were also not affected by heating to 330 °C. The COCl groups in the PA could be modified by reaction with 2,4,6‐triaminopyrimidine (TAP), resulting in a doubly crosslinked structure based on the reaction with the TAP as well as the existing amide moieties in the polymer. The degree of modification was highly dependent on the reaction solvent used. The porous structure of the PA was essentially unchanged after this modification. The TAP‐based crosslinks in the modified PA could be selectively cleaved along with vaporization of the TAP by heating at 330 °C, which no change to the porous structure. Thus, the PA showed excellent heat resistance and structural stability. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced epoxy resin matrix composite is one of the most important composite materials in the world. Many researchers have conducted a lot of research on epoxy resin matrix systems in recent years, mainly to improve the problem with the short curing time of the matrix system and epoxy resin's high viscosity. The final aim is to enhance various aspects of composites' performance and optimize the production process. A new type of water dispersed epoxy resin matrix system is investigated in this paper and the target is to optimize the mechanical, thermal, and electrical performances of the composites with the water dispersed epoxy resin matrix by varying different doping particles and different resin/catalyst ratios. Through a series of experiments, it is evident that varying the ratio of resin to catalyst in the matrix system will not significantly improve the mechanical as well as thermal properties of the composites. However, increasing the amount of catalyst in the matrix system can greatly improve the electrical properties of its composite samples. In addition to this, the addition of doping particles to the matrix systems has the effect of slightly enhancing the tensile modulus, thermal conductivity, and electrical conductivity of their composites. Highlights: A new water‐dispersed epoxy resin matrix system improves processing technology.Increasing amount of catalyst in the matrix system improves electrical resistivity.Adding particles to matrix systems has a slight effect on different properties. [ABSTRACT FROM AUTHOR]

Multifunctional thermal regulation materials with good thermal properties, efficient magnetic performance, and satisfactory interface bonding on fabrics are highly desirable for protective fabrics, building winter protection materials, medical thermal regulation materials, and special-environment work clothing. Herein, a new class of magnetic phase-change PW@CaCO3@Fe3O4 microcapsules was successfully produced by controlling the content of magnetic Fe3O4 through a self-assembly method. The microstructure, chemical composition, phase-change behavior, and magnetic properties of the products were sequentially characterized and analyzed. The findings revealed that the obtained microcapsules possessed regular spherical structure with uniform size and excellent thermal properties. Furthermore, PW@CaCO3 with Fe3O4 (i.e., 8% mass fraction) showed the highest thermal regulation and magnetic properties and reached an enthalpy value of 94.25 J·g−1, which is clearly superior to the value of 77.51 J·g−1 for PW@CaCO3 microcapsules. At the same time, the encapsulation efficiency of 38.7% and saturation magnetization of 2.50 emu·g−1 were the best among the four given samples. Therefore, the good paramagnetic feature had a significant synergistic effect on the thermal properties of the PW@CaCO3 microcapsules under study. More importantly, multifunctional fabrics loaded with PW@CaCO3@Fe3O4 microcapsules still showed an enthalpy value of 25.81 J·g−1 after several washes and have the potential to be used widely in the field of temperature control. The thermal regulation fabrics in this study exhibited excellent thermal properties and fastness, which contribute to their practical applications in advancing multifunctional textiles and high-technology modern fabrics. [ABSTRACT FROM AUTHOR]

Ligustrum robustum (Rxob.) Blume was utilized as an natural additive to protect oil quality during the high temperature processing. L. robustum exhibited the remarkable capability to inhibit peroxide value, acid value, viscosity and color deterioration of oil. Meanwhile, L. robustum inhibited the decomposition of unsaturated fatty acids and the formation of trans fatty acids to protect the nutritional value of the oil. In addition, L. robustum increased the initial oxidation temperature of oil and raised its initial decomposition temperature. With high content of total phenols (126.9 g gallic acid equivalent /kg extract) and flavonoids (135.6 g rutin equivalent /kg extract), L. robustum showed the remarkable antioxidant and reducing capacities and was effective in scavenging free radicals and inhibiting lipid peroxidation. Furthermore, Ligurobustoside B was identified as the phenolic component in L. robustum sample with the high amount. All present results suggest that L. robustum has potential to be utilized as the natural additive for protecting oil quality during the high temperature processing. Chemical compounds studied in this article Ligurobustoside B (PubChem CID: 102,316,894). [ABSTRACT FROM AUTHOR]

The thermomechanical coupling of rocks refers to the interaction between the mechanical and thermodynamic behaviors of rocks induced by temperature changes. The study of this coupling interaction is essential for understanding the mechanical and thermodynamic properties of the surrounding rocks in underground engineering. In this study, an improved temperature-dependent linear parallel bond model is introduced under the framework of a particle flow simulation. A series of numerical thermomechanical coupling tests are then conducted to calibrate the micro-parameters of the proposed model by considering the mechanical behavior of the rock under different thermomechanical loadings. Good agreement between the numerical results and experimental data are obtained, particularly in terms of the compression, tension, and elastic responses of granite. With this improved model, the thermodynamic response and underlying cracking behavior of a deep-buried tunnel under different thermal loading conditions are investigated and discussed in detail. [ABSTRACT FROM AUTHOR]

In order to solve the problems that the phase change temperature of fatty acid is higher than the building application requirements, and the existing fatty acid microencapsulated phase change materials have low encapsulation rate and low latent heat, the binary phase change material capric acid-stearic acid was first prepared in this paper. The thermal properties results show that the phase change temperature and latent heat of phase change of capric acid-stearic acid are 24.28 ℃ and 178.21 J/g, which meet the building application requirements. On this basis, CA-SA@SiO2 MPCM (microencapsulated phase change materials) with different core wall mass ratio were prepared by sol-gel method of capric acid-stearic acid with silica as the outer wall material. Micro morphology, particle size, thermal properties, chemical stability and anti-seepage performance of the MPCM were characterized. The results show that core wall mass ratio directly affects the properties of the MPCM. The optimal core wall mass ratio is 50: 50. The MPCM is spherical, smooth and dense, the particle size ranges from 2 to 500 μm, and the mainly concentrated below 50 μm. The wall material covers the core material only by physical action, and the thermal stability of phase change core material can be improved after microencapsulation. Moreover, the thermal decomposition temperature is significantly higher than the use environment of the wall material. The equilibrium leakage rate is only 4.53%, and the phase change temperature is 24.63 ℃, which is within the comfort range of human body. The latent heat of phase change and encapsulation rate is 138.16 J/g and 77%, respectively. It effectively solves the problems of high phase change temperature, low encapsulation rate and low latent heat of phase change, and provides a new material compatible with suitable temperature zone, high energy efficiency density and high stability for phase change energy storage building envelopes. [ABSTRACT FROM AUTHOR]

The comprehensive performance of rubber products could be significantly improved by the addition of functional fillers. To improve research efficiency and decrease the experimental cost, the mechanical and thermal properties of carbon-fiber-reinforced rubber were investigated using finite element simulations and theoretical modeling. The simplified micromechanical model was constructed through the repeatable unit cell with periodic boundary conditions, and the corresponding theoretical models were built based on the rule of mixture (ROM), which can be treated as the mutual verification. The simulation results suggest that, in addition to the fiber volume fraction Vfc increasing from 10% to 70%, the longitudinal Young's modulus, transversal Young's modulus, in-plane shear modulus, longitudinal thermal expansion coefficient, and transversal thermal expansion coefficient changed from 2.31 × 1010 Pa to 16.09 × 1010 Pa, from 0.54 × 107 Pa to 2.59 × 107 Pa, from 1.66 × 106 Pa to 10.11 × 106 Pa, from −4.98 × 10−7 K−1 to −5.89 × 10−7 K−1, and from 5.72 × 10−4 K−1 to 1.66 × 10−4 K−1, respectively. The mechanism by which Vfc influences the properties of carbon-fiber-reinforced rubber was revealed through the distribution of Von Mises stress. This research will contribute to improving the performance of carbon-fiber-reinforced rubber and promote its application. [ABSTRACT FROM AUTHOR]

Benzoxazine dimers are a group of compounds with a variety of properties, such as anticancer properties and good chelating behaviors. The modification of the benzoxazine dimers can be carried out on the OH groups as well as the benzene moiety. There are several works reported on the property adjustment involving the use of different substituent groups on the benzene ring. Only a few works described the properties and crystallographic studies of the OH-modified benzoxazine dimer. The repulsion forces between two bulky benzoyl groups push them to be more distant compared to the unmodified benzoxazine dimer. According to the crystallographic information, the C—H···O, C—H···π, and π···π interactions hold neighbor molecules together, which consequently stabilize the crystal structure. Thermal analyses (TGA and DSC) reveal that the synthesized benzoated benzoxazine dimer is stable up to 175 °C. Hirshfeld surface analysis confirmed the presence of the C—H···O and C—H···π interactions as seen from the high contributions of the following contacts: H···H (60.6%), H···C/C···H (25.1%), and H···O/O···H (12.3%). Moreover, the observed π···π interaction is supported by the shape-index property of the corresponding Hirshfeld surface. For the solid-state photoluminescence of the di-benzoated benzoxazine dimer recorded at the excitation wavelength range from 265 to 320 nm, the emission peak at 490 nm is observed together with another peak or shoulder in the range of 440–480 nm. For all the excitation wavelengths studied, the di-benzoated dimer emits the fluorescence in the blue color shades (CIE coordinate of x at 0.137–0.142 and y at 0.200–0.262). The photoluminescence property is found to originate by the benzoate modification of the benzoxazine dimer. [ABSTRACT FROM AUTHOR]

Hafnium-based ceramic with low thermal expansion is suitable for thermal and environmental barrier coating materials. However, the fracture toughness is relatively low. In this work, GdAlO 3 is doped into Gd 2 Hf 2 O 7 , increasing the fracture toughness by 31 %. The increase originates from crack deflecting, crack branching and more tortuous crack route. Meanwhile, GdAlO 3 -Gd 2 Hf 2 O 7 has lower thermal expansion, making it more compatible with environmental barrier coating systems. The thermal conductivity increases from Gd 2 Hf 2 O 7 to GdAlO 3 -Gd 2 Hf 2 O 7 , which can be expected to reduce by controlling the content of GdAlO 3. [ABSTRACT FROM AUTHOR]

To verify the anisotropic effect on the thermal properties of hen egg white lysozyme crystals, we measured the thermal conductivity and thermal diffusivity of lysozyme crystals, the c-axis of which was magnetically oriented along the wire direction. We used the transient short hot-wire method in a horizontally tilted superconducting magnet bore. The crystals were magnetically levitated at the solution interface by the radial component of the magnetic force. The crystals' thermal properties grown in the horizontal bore were consistently smaller values than those of the crystals grown in the vertical bore and randomly grown crystals without applying magnetic force. [ABSTRACT FROM AUTHOR]

The construction of extraterrestrial bases has become a new goal in the active exploration of deep space. Among the construction techniques, in situ resource-based construction is one of the most promising because of its good sustainability and acceptable economic cost, triggering the development of various types of extraterrestrial construction materials. A comprehensive survey and comparison of materials from the perspective of performance was conducted to provide suggestions for material selection and optimization. Thirteen types of typical construction materials are discussed in terms of their reliability and applicability in extreme extraterrestrial environment. Mechanical, thermal and optical, and radiation-shielding properties are considered. The influencing factors and optimization methods for these properties are analyzed. From the perspective of material properties, the existing challenges lie in the comprehensive, long-term, and real characterization of regolith-based construction materials. Correspondingly, the suggested future directions include the application of high-throughput characterization methods, accelerated durability tests, and conducting extraterrestrial experiments.

Although rare earth zirconates (RE2Zr2O7) have garnered attention as viable candidates for thermal barrier coatings (TBCs), they suffer from low fracture toughness and accelerated calcium–magnesium–alumina–silicate (CMAS) melt corrosion at high service temperatures, which impedes their practical application. In this work, we developed a series of REAlO3/RE2Zr2O7 (RE = La, Nd, Sm, Eu, Gd, and Dy) composites with a eutectic composition that not only significantly enhanced the fracture toughness by more than 40% relative to that of RE2Zr2O7 but also exhibited improved resistance to CMAS corrosion. The increase in toughness arises from multiple mechanisms, such as ferroelastic toughening, fine-grain strengthening, and residual stress toughening, all of which trigger more crack defects and energy consumption. Additionally, the CMAS penetration depth of the REAlO3/RE2Zr2O7 composites is approximately 36% lower than that of RE2Zr2O7. Al–O constituents in composites can capture CaO, SiO2, and MgO in CMAS melts and increase their viscosity, resulting in enhanced CMAS corrosion resistance. The thermophysical properties of the REAlO3/RE2Zr2O7 composites were also investigated, and their coefficient of thermal expansion and thermal conductivity are comparable to those of 7–8 wt %Y2O3 partially stabilized ZrO2 (YSZ), indicating their potential as TBC materials.

Li 2 O–ZnO–B 2 O 3 -WO 3 (LZBW) sealing glasses for Si substrates were prepared and the effect of WO 3 on the structure, thermal properties, and sintering behaviour was investigated. As the WO 3 increases from 0 to 12 mol%, the glass transition temperature and softening temperature reach the lowest values of 448 °C and 479 °C, respectively, at which time the glass network has the lowest degree of polymerization. The thermal expansion coefficient increases from 6.959 × 10−6/°C to 8.476 × 10−6/°C with increasing WO 3 contents. It is verified that the introduction of WO 3 can effectively improve the conductivity. The sealing property of the glasses was evaluated by the wetting angle of the glasses after co-sintering with Si substrate for 10 min at 860 °C, and the 25Li 2 O-7ZnO-2.7Bi 2 O 3 -1.3P 2 O 5 -55B 2 O 3 -9WO 3 glass had the minimum wetting angle of 34.07°. The excellent thermal properties, conductivity, and wetting behaviour of the LZBW glasses make it a potential material as a binder material for positive silver pastes. [ABSTRACT FROM AUTHOR]

The thermal and electrical properties of photovoltaic cell (PVC) under linear phenomenological heat transfer law between it and the environment is studied through finite time thermodynamics and the volt-ampere characteristic equation. The properties of PVC are affected by heat transfer between PVC and environment. There are optimal solar radiation intensity and PVC output voltage (OV), which make the photoelectric conversion efficiency (PECE) of PVC reach the highest value. When OV and solar radiation intensity are 28.50 V and 700 W/m2, the maximum PECE is 0.156. There is also the best solar radiation intensity, which makes the open-circuit voltage (OCV) reach the maximum. When solar radiant intensity is 669 W/m2, the maximum OCV is 33.14 V. The values of power output and short-circuit current (SCC) are monotonically increasing with solar radiation intensity. Given solar radiation intensity, the power output and OV exhibit a parabolic shape. The operating temperature falls first and then grows with the OV. However, the change of operating temperature with OV is not much. Band gap is a decreasing function of operating temperature. This article can give theoretical support for the design and use of PVCs. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Particleboards have gained attention in the global market. Understanding their physical–mechanical behavior in the current technological context is essential due to adhesive polymerization, which depends on variables such as pressing time and temperature. Today, the use of nanoparticles has become a plausible option for improving the properties of polymers used in wood-based composites. This study evaluates the influences of the addition of non-commercial 0.5% aluminum oxide (Al2O3) and aluminum oxide copper (CuO) nanoparticles using a greener route with a lower environmental impact obtaining a urea-formaldehyde (UF)-based polymeric adhesive to manufacture particle composites of Eucalyptus urophylla var. grandis wood. Regarding characterizations, the resin properties analyzed were viscosity, gel time, and pH, as well as panel properties, including density, moisture content, thickness swelling, modulus of elasticity, modulus of rupture, and thermal conductivity. The results were compared with scientific publications and standards. The addition of nanoparticles interfered with viscosity, and all treatments indicated a basic pH. It was not possible to determine the gel time after 10 min. Nanoparticles added to the polymers in the internal layer did not cause an improvement in the swelling properties in terms of thickness, with no significant statistical difference for density and moisture content. The increase from 150 °C to 180 °C may have caused an improvement in all physical–mechanical properties, indicating that the higher temperature positively influenced the polymerization of the formaldehyde-based adhesive. Therefore, the additions of both nanoparticles (0.5% in each condition) led to a limitation in the material influence with respect to physical–mechanical performance. [ABSTRACT FROM AUTHOR]

This paper reports the vapor pressure and enthalpy of vaporization for a promising phase change material (PCM) guanidinium methanesulfonate ([Gdm][OMs]), which is a typical guanidinium organomonosulfonate that displays a lamellar crystalline architecture. [Gdm][OMs] was purified by recrystallization. The elemental analysis and infrared spectrum of [Gdm][OMs] confirmed the purity and composition. Differential scanning calorimetry (DSC) also confirmed its high purity and showed a sharp and symmetrical endothermic melting peak with a melting point (Tm) of 207.6 °C and a specific latent heat of fusion of 183.0 J g−1. Thermogravimetric analysis (TGA) reveals its thermal stability over a wide temperature range, and yet three thermal events at higher temperatures of 351 °C, 447 °C, and 649 °C were associated with vaporization or decomposition. The vapor pressure was measured using the isothermogravimetric method from 220 °C to 300 °C. The Antoine equation was used to describe the temperature dependence of its vapor pressure, and the substance-dependent Antoine constants were obtained by non-linear regression. The enthalpy of vaporization (ΔvapH) was derived from the linear regression of the slopes associated with the linear temperature dependence of the rate of weight loss per unit area of vaporization. Hence, the temperature dependence of vapor pressures ln Pvap (Pa) = 10.99 − 344.58/(T (K) − 493.64) over the temperature range from 493.15 K to 573.15 K and the enthalpy of vaporization ΔvapH = 157.10 ± 20.10 kJ mol−1 at the arithmetic mean temperature of 240 °C were obtained from isothermogravimetric measurements using the Antoine equation and the Clausius–Clapeyron equation, respectively. The flammability test indicates that [Gdm][OMs] is non-flammable. Hence, [Gdm][OMs] enjoys very low volatility, high enthalpy of vaporization, and non-flammability in addition to its known advantages. This work thus offers data support, methodologies, and insights for the application of [Gdm][OMs] and other organic salts as PCMs in thermal energy storage and beyond. [ABSTRACT FROM AUTHOR]

This study investigates the impact of Titanium Suboxide (Ti4O7) on the flame retardancy, mechanical properties, thermal stability, and electrical and thermal conductivity of silicone rubber composites. The addition of 1.0 part of Ti4O7 to the silicone rubber composites results in a total heat release (THR) of 45 MJ/m2, which is 45.7% lower than the silicone rubber without Ti4O7, leading to a decrease in the peak of heat release rate (PHRR). Furthermore, Ti4O7 exhibits temperature stability at low temperatures and acts as a physical barrier, inhibiting the early decomposition of silicone rubber and enhancing the thermal stability of the composites. However, at temperatures exceeding 450°C, the catalytic activity of Ti4O7 is activated, promoting the decomposition of the silicone rubber composites and generating more residue. The addition of an appropriate amount of Ti4O7 can further improve the mechanical properties of the silicone rubber composites and enhance their electrical and thermal conductivity. [ABSTRACT FROM AUTHOR]

In this study, a novel fluorine-containing carbon nanosphere was synthesized by high-temperature carbonization of waste fluororubber trimmings, and its mixing method with fluororubber was investigated. It was found that the solution mixing method resulted in the highest tensile strength (7.6 %) and modulus at 100 % strain (13.3 %) of fluororubber compared to the mechanical mixing method. Furthermore, the addition of fluorine-containing carbon nanosphere can significantly enhance fluororubber's heat resistance, inhibit its thermal degradation, and increase its ultimate service temperature (266.3 °C, 2 years). This work provides new insights into the preparation of high-performance fluororubber composites.

Interpenetrating phase composites (IPCs) can combine the distinctive properties of two materials, and customized manufacturing processes are applied to design reinforced skeletons in IPCs. In this study, a porous ceramic featuring diverse structural regions with different direction-aligned pore channels is fabricated by multi-directional freeze-casting. The size of samples can be efficiently adjusted by controlling the size and amount of freezing sources. After infiltration, the resulting multi-directional freeze-casting ceramic/polymer composite (MFCC) has isotropic and satisfactory mechanical properties. Meanwhile, it remains lightweight and performs the highest specific strength (66.7 kN m/kg) and specific energy absorption (19.2 kJ/kg) among tested materials. The vertical-aligned structural regions are responsible for the robust strength, and horizontal-aligned regions prompt energy absorption capacity. Radial-aligned regions induce slant crack propagation and alignment shift between two regions leads to crack deflection, further enhancing energy absorption capacity. Additionally, the MFCC samples with different sizes or pore sizes, demonstrate isotropic thermal conductivity due to the multi-directional alignment of ceramic walls, which provide efficient thermal pathways across different directions. The MFCC and its structural design are promising for enhancing material performance, especially in applications where isotropic mechanical properties and thermal conductivity are important.

Summary: Symmetry analysis is a cutting-edge research approach in physics, yet its application in macroscopic energy systems remains limited. This study demonstrates its potential to provide valuable insights for a deeper understanding and development of thermodynamic cycles. This article first studies the symmetry of the proposed C-P diagrams and finds rich symmetries including reflection symmetry, translation symmetry, and rotational symmetry within Carnot cycles. Then, it emphasizes that one can use symmetry alone to prove that the highest efficiency for any cycle operating in a certain temperature range is the Carnot efficiency, without relying on the entropy concept in the second law of thermodynamics. Lastly, it is found that this symmetry analysis framework can also be used for thermal cycles with phase transitions, as exemplified by applying in Rankine cycles. This research not only contributes groundbreaking insights into unraveling the symmetry inherent in thermodynamic cycles, but also promotes symmetry analysis to be an alternative analysis mean.

In order to investigate the changes in structure and properties of waxy maize starch (WMS) after its nano-starch was prepared by pullulanase enzymolysis-dynamic high pressure micro-fluidization technology (P-DHPM), this paper explored the trends of changes in starch microstructure, crystalline structure, molecular structure, particle size, molecular weight, and thermal properties before and after the treatment. The results showed that spherical starch particles were turned into fragmentization, and the crystalline structures were transferred into amorphous states, the short-range ordered structure was increased, and the molecular weight of starch was decreased with the increment of enzymatic hydrolysis time. In the meantime, the peak gelatinization temperature (Tp) of treated starch was decreased from 71.23 ℃ to 55.81 ℃, and the enthalpy value of pasting (ΔH) was decreased to 4.68 J/g significantly (P

The magnetic-flux-dependent dispersions of sub-bands in topologically protected surface states of a topological insulator nanowire manifest as Aharonov-Bohm oscillations (ABOs) observed in conductance measurements, reflecting the Berry's phase of π because of the spin-helical surface states. Here, we used thermoelectric measurements to probe a variation in the density of states at the Fermi level of the surface state of a topological insulator nanowire (Sb-doped Bi2Se3) under external magnetic fields and an applied gate voltage. The ABOs observed in the magnetothermovoltage showed 180° out-of-phase oscillations depending on the gate voltage values, which can be used to tune the Fermi wave number and the density of states at the Fermi level. The temperature dependence of the ABO amplitudes showed that the phase coherence was kept to T = 15 K. We suggest that thermoelectric measurements could be applied for investigating the electronic structure at the Fermi level in various quantum materials.

With the development of microelectronics products with high density and high power, it is urgent to improve the electrical and thermal conductivity of electronic paste to achieve the new requirements of packaging materials. In this work, a new synthesis method of Ag-MWCNTs was designed: Firstly, carboxylated MWCNTs and stannous chloride were used as raw materials to prepare high-loading-rate Sn-MWCNT composite material to ensure the high loading rate of metal on the MWCNT surface. Then, Ag-MWCNT composite material was prepared by the chemical displacement method to solve the problem of the low loading rate of silver nanoparticles on the MWCNT surface. On the basis of this innovation, we analyzed and compared the electrical, thermal, and mechanical properties of Ag-MWCNT composite electronic paste. Compared with the electronic paste without adding Ag-MWCNTs, the resistivity was reduced by 77%, the thermal conductivity was increased by 66%, and the shear strength was increased by 15%. Therefore, the addition of Ag-MWCNTs effectively improves the electrical, thermal, and mechanical properties of the paste, making it a promising and competitive choice for new packaging materials in the future. [ABSTRACT FROM AUTHOR]

To achieve a green composite product with large range of potential applications, industries are developing nano-sized fillers from biomass material. In the present work, the potentiality of utilizing date palm trunk fiber, as agricultural waste for the development of fire retardant nano-filler, was investigated. Two different nanofiller products (Nanofiller-55 and Nanofiller-99) were prepared from the date palm–derived microfiller through combined chemical process and high-energy ball milling. Characterization was conducted for the produced nanofiller as well as microfiller, through advanced testing analysis. From morphology examination, the nanofiller was revealed as individually dispersed nanoparticles in rectangular-like shape under transmission electron microscopy (TEM). Meanwhile, the field emission scanning electron microscopy (FESEM) presented the nanofiller particles in irregular shapes with rough surface after the breakdown of compact microfiller structure by ball milling process. The particle size analysis also proved that small nanoparticles in the mean size range of 274.5–289.7 nm were generated for both Nanofiller-55 and Nanofiller-99 samples. Furthermore, energy-dispersive X-ray (EDX) analysis presented the presence of carbon and oxygen as the major fiber elements in nanofillers, while the residual silica, sulfur, calcium, potassium elements were detected to decrease after combined treatment process. Additionally, the physico-chemical analysis revealed those nanofillers possessed great crystallinity between 58 and 67%, which could impart them as strong load-bearing agent. As for thermal analysis, both Nanofiller-55 and Nanofiller-99 samples exhibited high decomposition temperature, while showing stable degradation behavior with enhanced heat resistance. Thus, the produced nanofillers in this work can be used as fire retardant material for nanocomposites fabrication in the future. [ABSTRACT FROM AUTHOR]

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The main goal of this study is to investigate the impact of aramid nanofiber (ANF) on enhancing various properties of poly(lactic acid) (PLA), including thermal stability, crystallization rates, melt-rheological behavior, and mechanical properties. To achieve this, ANF fillers were produced using a modified deprotonation process from commercial aramid fibers, and a masterbatch (PLA/ANF = 90/10 by wt%) was prepared through solution blending and drying. The masterbatch was then combined with neat PLA through meltblending to create a range of PLA nanocomposites containing 1-10 wt% ANF loadings. Microscopic and spectroscopic analyses confirmed the uniform dispersion and intermolecular interaction of ANFs within the PLA matrix, respectively. As a result, the nanocomposites exhibited a slight increase in glass transition temperature with higher ANF loading, while the cold-crystallization temperature decreased due to ANFs acting as nucleating agents during PLA crystallization. Isothermal crystallization analysis confirmed accelerated meltcrystallization rates in nanocomposites with greater ANF content. The introduction of ANFs enhanced the thermal degradation temperature of the PLA matrix and the 700°C residue of the nanocomposites, attributed to ANFs' barrier and flame retardant effects on PLA. Moreover, the nanocomposites with higher ANF loading demonstrated superior tensile strength, strain at break, toughness, and impact strength owing to the effective bonding interactions at the interfaces between the PLA matrix and the ANF fillers. Highlights • ANF-reinforced PLA nanocomposites are prepared by masterbatch meltcompounding. • Uniform dispersion of ANFs in PLA is attained via effective interfacial bonding. • ANFs boost the melt-crystallization of the PLA matrix. • ANFs enhance the thermal stability of the PLA matrix. • Tensile strength and toughness of PLA are improved with higher ANF content. [ABSTRACT FROM AUTHOR]

Owing to the crucial qualities such as strength, stiffness and durability, as well as low-cost manufacturing benefits, the fibre-reinforced composite materials are becoming more popular in structural applications. The current work basically focused on the influence of Pistachio shell particles (PSP) on mechanical performances of kenaf(K)/glass(G)/polyester hybrid laminates. Usual hand layup technique is used to fabricate different stacking order laminates such as KKKK, KGGK, GKKG, KGKG, and GGGG with PSP filler concentration of 1 wt%, 3 wt% and 5 wt%. The experimental findings reflect a noticeable improvement in mechanical properties with gradual inclusion of PSP filler. The KGKG laminate with 5 wt% of PSP shows an optimum tensile strength of 127.35 MPa and highest micro-hardness value of 21.35 HV, whereas KGKG laminate with 3 wt% of PSP exhibits a maximum flexural of 112.42 MPa and impact strength of 75.59 KJ/m2. The numerical analysis is also been carried out to validate the experimental results using ANSYS 19.0 software. On comparing the data of numerical analysis with experimental values, the deviation of result is found to be within the limit of 5% to 10%. Furthermore, the result of Thermo Gravimetric Analysis (TGA) has shown a highest amount of residue of 31.22% at 700°C in case of GKKG laminate with 5% of PSP filler. Again, at 5 wt% of PSP filler, the GKKG laminate has shown a lower water intake capability of 3.5% in comparison to KGKG and KGGK laminates at saturation time of 14 days. The fractography study has been conducted to examine the different mode of failure of laminates during testing by the help of Scanning Electron Microscope (SEM). [ABSTRACT FROM AUTHOR]

A trifunctional active ester curing agent, triacetoxytriphenylmethane (TATPM), which was dissolvable in diglycidyl ether of bisphenol A (DGEBA), was prepared and characterized. Though TATPM/DGEBA mixture was too viscous to flow at room temperature, its viscosity rapidly declined to a very low level when heating above 120 °C, showing great processability. Accelerators 4-dimethylaminopyridine (DMAP), 2-methylimidazole (2MI), and tetrabutylammonium bromide (TBAB) were used to catalyze the reactions between TATPM and DGEBA. DMAP-catalyzed one reached Tpeak and Tendset earlier, and showed higher conversion than 2MI and TBAB-catalyzed one, exhibiting superior accelerating effect. Ea and A of DMAP-catalyzed system were higher than that of 2MI-catalyzed system. Moreover, the properties of cured products depended on accelerator type, and DMAP-catalyzed one had the highest Tg, Td5%, and Td10%, lowest Df, EQUATION and saturated water uptake, making DMAP a better accelerator than 2MI and TBAB. Meanwhile, TATPM cured epoxies showed higher Td, lower Dk and Df than that of phenolic compound THTPM cured epoxies, despite of its lower Tg. [ABSTRACT FROM AUTHOR]

The impact of para‐ and meta‐aromatic amide repeat units on the microstructure, thermal behavior, mechanical properties, rheological characteristics, and dielectric properties of thermotropic liquid crystalline poly(ester amide)s (TPEAs) is reported. For this purpose, two distinct series of TPEAs are synthesized using 75.0 mol% of 4‐hydroxybenzoic acid (HBA) and 25.0–17.5 mol% of 6‐hydroxy‐2‐naphtoic acid (HNA) with 0.0–7.5 mol% terephthalic acid/para‐acetylaminophenol (TPA/PAP) or isophthalic acid/para‐acetylaminophenol (IPA/PAP) are synthesized via bulk polycondensation reaction. Infrared and electron microscopic data reveal the existence of intermolecular hydrogen bonds and associated fibrillar structures of TPEAs with TPA/PAP‐ or IPA/PAP‐based aromatic amide units. Accordingly, the glass transition temperatures, dynamic storage moduli, and melt viscosities of TPEAs increased with the increment of the aromatic amide units, although they are higher for TPEAs with IPA/PAP‐derived units, compared to TPEAs with TPA/PAP‐derived units. The melting temperatures of TPEAs increase with the para‐aromatic amide unit owing to the intermolecular hydrogen bonding and the rigid linearity, whereas the melting points decrease with the meta‐aromatic amide unit due to the structural nonlinearity. Interestingly, the dielectric constants and losses of TPEAs decrease with the aromatic amide unit content, which is even dominant for TPEAs with IPA/PAP‐based repeat units. TPEAs can be thus utilized as super‐engineering plastics, industrial fibers, printed circuit board materials, etc., requiring enhanced mechanical and thermal transition properties but lower dielectric constants and losses. [ABSTRACT FROM AUTHOR]

In this study, a hybrid nanocomposite made of the polyamide 6 (PA6) and nitrile butadiene rubber (NBR) with polyhedral oligomeric silsesquioxanes (POSS) was prepared and mechanical, thermal, and morphology of nanocomposite were tested. The nanocomposite specimens were prepared through the melt mixing method. Tensile and Charpy impact showed that adding the NBR increases the impact strength while decreasing the tensile strength. However, POSS nanoparticles can improve the weakness of adding NBR rubber to the PA6. Additionally, traditional analytical techniques, including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and scanning electron microscopy (SEM) were conducted. [ABSTRACT FROM AUTHOR]

This study has been aimed to develop three different knitted denim fabrics (3/1 twill) using cotton (30s) and eri silk (2/80 Nm) yarns in different proportions (100% cotton, 50/50 cotton/eri silk, 100% eri silk). Dimensional, physical and thermal comfort properties have been analysed for the developed samples. Thermal properties of the fabric are analysed using a flat plate thermal conductivity tester, and the wicking ability is measured with a vertical wicking tester. Eri silk knitted denim fabric is found with the excellent dimensional, physical and thermal comfort properties better than that of cotton and 50/50 cotton/eri silk blended knitted denim fabrics. The results indicate that the eri silk knitted denim fabric is more suitable for functional wear applications. [ABSTRACT FROM AUTHOR]

In the rapidly developing microelectronics industry and technology, epoxy resin based electrically conductive adhesives must be urgently improved in terms of aging resistance, especially residual stress caused by thermal cycle aging. In this study, we investigated the stress behavior of rigid and flexible epoxy systems blended with bisphenol F epoxy (BPF) and fatty acid epoxy. The curing processes, thermal, and thermomechanical properties of the modified epoxy systems were assessed comprehensively. Moreover, the residual stress during the thermal cycle was monitored, and the bond strength was characterized. The results pointed out that by introducing soft molecular segments into a rigid system, the modified epoxy resin system had significantly lower residual stress values and exhibited a higher bond strength over a wider temperature range. Finally, we envision the systematic integration of residual stress testing with material strength testing for quantifying the bond failure of adhesive layers in the near future. [ABSTRACT FROM AUTHOR]

We conducted a study to analyze the impact of short aramid fibers (AFs) on the melt-rheological behavior, thermal transition, thermal stability, and mechanical durability of thermotropic liquid crystal polyesters (TLCPs). By using different AF loading contents ranging from 3–15 wt%, we produced TLCP matrix composites through masterbatch-based melt-compounding and injection-molding. The SEM images and FT-IR spectra demonstrate that the AFs are dispersed in the TLCP matrix with a microfibrillar structure through good interfacial adhesion caused by specific intermolecular interactions between the TLCP and AFs. As a result, the complex viscosity, shear storage/loss moduli, and thermal transition (melt-crystallization, glass transition, and melting) temperatures of the composites increase with increasing AF filler content. However, the melt-crystallization and melting enthalpies increase only at low AF loading contents of 3–5 wt%. At high AF contents of 7–15wt%, the enthalpies decrease owing to the partial aggregation of AF fillers. The thermogravimetric analysis proves that the thermal stability of TLCP/AF composites improves when the AF filler is introduced. The dynamic mechanical analysis using the stepped isothermal method shows that the addition of 5 wt% AF to the TLCP leads to an approximately 150% improvement in elastic moduli and long-term mechanical durability at elevated temperatures. Graphical Abstract [ABSTRACT FROM AUTHOR]

Open-cell-type aluminum foam demonstrates excellent heat dissipation owing to interconnected pores. In this study, open-cell-type aluminum foams with various pore sizes and porosities were fabricated using the replication-casting process, which is a relatively simple process. The porosity of the manufactured foams ranged from approximately 55% to 62%. To assess the heat dissipation of the manufactured foams, an air-cooling system was designed. The device could pass a controlled amount of air through the connected pores, simultaneously measuring pressure drop ∆ P and temperature changes. It was confirmed that the open-cell-type aluminum foams exhibited a very high cooling rate in the initial cooling phase, and the thermal behavior is influenced by structural characteristics. At a porosity of 62%, the initial maximum cooling rate was measured to be 1.41 ℃ /s for a pore size of 0.7~1.0 mm, and it was observed to significantly increase to 3.82 ℃ /s for a pore size of 2.8~3.4 mm. Furthermore, for the same pore size, an increase in porosity resulted in an increase in the initial cooling rate. Lager pore sizes and higher porosities led to lower pressure drop ∆ P and improved airflow, enhancing the cooling efficiency of open-cell-type aluminum foams. [ABSTRACT FROM AUTHOR]

Nanocomposite films were prepared by melting and blending nano-MICA powder modified with polylactic acid (PLA), polybutylene adipate-co-terephthalate (PBAT) and aluminate coupling agent. The properties of nanocomposite films were characterized by a Fourier transform infrared spectroscopy (FTIR), a water vapor transmittance tester, an oxygen transmittance tester, and TG-DSC synchronous thermal analysis instrument. The safety of nanocomposites was evaluated by total migration experiments and gas chromatography-mass spectrometry (GC-MS) to determine the specific migration of nanocomposites. The results show that the aluminate coupling agent successfully activates the nano-MICA powder. The glass transition temperature of PLA can be increased by modified nano-MICA powder, while the crystallinity of PLA first increases and then decreases, and the addition of 0.2% modified nano-MICA powder has the best effect. The thermal stability of the PLA/PBAT system decreases slightly with the increase of the amount of modified nano-MICA powder. The addition of 0.2% modified nano-MICA powder reduced the water vapor transmission coefficient of the film by 28%. The addition of nano-MICA powder enhances the interface roughness of the film, and the addition of modified nano-MICA powder can still meet the safety requirements as a food contact material. [ABSTRACT FROM AUTHOR]

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This study explores the potential of untapped lithium hydroxide (LiOH) as a phase change material for thermal energy storage. By overcoming the challenges associated with the liquid LiOH leakage, we successfully thermal-cycled LiOH in a laboratory scale experimentation, and observed its stability (>500 thermal cycles), without chemical decomposition. This step has never been performed to date. Its solid-to-liquid reversible transitions temperatures and related solidification/melting enthalpies values have been verified. Then, the first experimental characterization of LiOH's thermal properties shows unexpected values for its heat capacity, thermal conductivity and diffusivity, in contradiction with the few ones available in literature. This opens avenues for LiOH's applications for the storage of sensible and latent heat, as shown through the increased cycle efficiency potential of a thermal energy storage system if based on its energy storage capacity; up to six times more volumetric energy density compared to traditional Solar Salt-based systems used in the solar tower plant (4.5 GJ/m3 vs. 0.76 GJ/m3 over 1000 thermal cycles). Additionally, we observed a softening phenomenon that occurs inconsistently during heating, but which may account for its excellent melting properties and the interplay with other raw chemicals. This new insight contributes certainly to the underlying mechanisms in the synthesis of another promising heat storage material in development: the peritectic compound Li4Br(OH)3. This pioneering work suggests LiOH as a promising ultra-compact thermal energy storage material for filling the intermediary gap from current to next-generation solar power plants, although its large-scale application requires further investigation to achieve economic viability.

Shrimp shell is the most significant chitin source among bio-based materials since a huge quantity of crustacean wastes has been expelled out as a waste material from various shrimp processing industries/zones. The carapaces were treated by 2 M HCl for demineralization (DM), 2 N NaOH for deproteinization (DP), and 50 % NaOH for deacetylation (DA) to extract chitosan, without destroying the inherent microstructure of native shells. Then grafting was carried out by 2‑hydroxy ethyl methacrylate (HEMA) by using a redox initiator K2S2O8/FeSO4 to produce environmentally friendly strength bio-composite. Meanwhile, maximum yield was found when the concentration of monomer and initiator were 2.55 × 10−1 mol/L, 8.48 × 10−3 mol/L, at 70°C whereas the value has been recorded around 73.33±0.03 %. Besides the honeycomb microstructure of chitosan could enhance the overall properties of the fabricated biocomposites by using mechanical interlocking mechanism during compounding. The samples were characterized by fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), solid-state 13C cross-polarization magic-angle-spinning nuclear magnetic resonance (CPMAS-NMR) and tensile strength (TS) techniques. The microstructure and thermo-mechanical profile exhibited noteworthy changes on the bulk property of the CS-g-HEMA composites. Result suggested that the shrimp waste shell would be an attractive source of strength bio-composites that retains outstanding physicochemical, thermomechanical, morphological properties. Thus the grafted products would be significantly utilized in various engineering, and bulk scale industrial applications as a suitable replacement of fossil based synthetic ones for the sustainable environmental protection.

Aerogel/fiber composites have shown a wide range of applications in aerospace, defence, environmental management and biomedicine due to their high porosity, low bulk density, high specific surface area and low thermal conductivity.The thermal and mechanical properties and interfacial compatibility of aerogel/fiber composites was reviewed, the heat transfer mechanism, mechanical property enhancement mechanism and interfacial compatibility bonding mechanism was introduced, and the effect of different fiber embedding on the final properties of the composites considering different fiber volume fractions and fiber multiscale i.e. different fiber diameters (aspect ratio) and pore diameters between fibers was summarized in this paper. Finally, the prospective future of the research directions of aerogel/fiber composites were proposed, including heat resistance, improved mechanical properties and material interface bonding.

Al–50Si alloys were prepared by powder extrusion and characterized for electronic packaging. The optimization of powder size, extrusion temperature, and heat treatment parameters was performed to enhance the microstructure and thermo-physical properties. The alloy exhibits a high relative density >99 %, a low coefficient of thermal expansion (CTE)

Copper-based powder metallurgy materials are frequently utilized in fabricating brake pads for high-speed trains. The preparation process involves mixing, ball milling, pressing, and sintering. Among these steps, hot-pressed sintering stands out as a rapid and efficient method that significantly influences the properties and performance of the products. In this study, four samples (S700/S750/S800/S850) were prepared using hot-pressed sintering at various temperatures, as follows: 700 °C, 750 °C, 800 °C, and 850 °C. The mechanical and physical properties of the four samples were tested, and the microstructure and compositions were investigated using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The findings highlighted the close relationship between sintering temperature and the mechanical and physical properties of the samples, as it impacts the porosity and interfacial bonding of the particles. Notably, Sample S800 demonstrated superior mechanical and thermal conductivity. Furthermore, the coefficient of friction (COF), friction heat, and wear rate of the four samples were also tested under different braking speeds ranging from 150 km/h to 350 km/h. The results indicated that the COFs of the four samples remained relatively stable below 300 km/h but decreased notably above 300 km/h due to heat fading. Sample S800 displayed consistent and high COF under varied braking speeds and exhibited the lowest wear rate. The observed wear mechanisms included abrasive wear and oxidation wear. Additionally, the friction test results underscored the close correspondence of the COF curve of S800 with the standard of the Ministry of Railways of the People’s Republic of China.

Multifunctional thermal regulation materials with good thermal properties, efficient magnetic performance, and satisfactory interface bonding on fabrics are highly desirable for protective fabrics, building winter protection materials, medical thermal regulation materials, and special-environment work clothing. Herein, a new class of magnetic phase-change PW@CaCO3@Fe3O4 microcapsules was successfully produced by controlling the content of magnetic Fe3O4 through a self-assembly method. The microstructure, chemical composition, phase-change behavior, and magnetic properties of the products were sequentially characterized and analyzed. The findings revealed that the obtained microcapsules possessed regular spherical structure with uniform size and excellent thermal properties. Furthermore, PW@CaCO3 with Fe3O4 (i.e., 8% mass fraction) showed the highest thermal regulation and magnetic properties and reached an enthalpy value of 94.25 J·g−1, which is clearly superior to the value of 77.51 J·g−1 for PW@CaCO3 microcapsules. At the same time, the encapsulation efficiency of 38.7% and saturation magnetization of 2.50 emu·g−1 were the best among the four given samples. Therefore, the good paramagnetic feature had a significant synergistic effect on the thermal properties of the PW@CaCO3 microcapsules under study. More importantly, multifunctional fabrics loaded with PW@CaCO3@Fe3O4 microcapsules still showed an enthalpy value of 25.81 J·g−1 after several washes and have the potential to be used widely in the field of temperature control. The thermal regulation fabrics in this study exhibited excellent thermal properties and fastness, which contribute to their practical applications in advancing multifunctional textiles and high-technology modern fabrics.