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In the context of the extensive application prospect of two-dimensional (2D) chalcogenides, we synthesized layered SnSe2+δ bulks with defects employing a hybrid chemical vapor transport-melt approach. Both the Eg and A1g Raman characteristic peaks in SnSe2+δ are dominated by cubic anharmonicity, coupled with nonlinear temperature dependencies below 140 K. Notably, the reduction in phonon energy observed in these vibrational modes can be ascribed to defect-mediated Raman scattering, irrespective of deficient or excess Se defects. However, the lower consistency in the Raman shifts of the in-plane Eg vibrations compared to the out-of-plane A1g modes suggests that the defects predominantly entail the absence of Se atoms and the substitutions of Sn by Se, delineating a continuum of Se-deficient and Se-enriched compositions. Furthermore, Se defects induce the contraction of the indirect bandgaps, facilitating a transition from medium to narrow bandgap semiconductors in SnSe2+δ, which underscores the tunable nature of the bandgaps through the incorporation of Se defects. These discoveries present an avenue for bandgap engineering and foster a deeper comprehension of the phonon and thermal properties of layered chalcogenides for further advanced technologies. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHAs) have gained interest recently due to their biodegradability and versatility. In particular, the chemical compositions of medium‐chain‐length (mcl)‐PHAs are highly diverse, comprising different monomers containing 6–14 carbon atoms. This review summarizes different feedstocks and fermentation strategies to enhance mcl‐PHA production and briefly discusses the downstream processing. This review also provides comprehensive details on analytical tools for determining the composition and properties of mcl‐PHA. Moreover, this study provides novel information by statistically analyzing the data collected from several reports on mcl‐PHA to determine the optimal fermentation parameters (specific growth rate, PHA productivity, and PHA yield from various structurally related and unrelated substrates), mcl‐PHA composition, molecular weight (MW), and thermal and mechanical properties, in addition to other relevant statistical values. The analysis revealed that the median PHA productivity observed in the fed‐batch feeding strategy was 0.4 g L−1 h−1, which is eight times higher than that obtained from batch feeding (0.05 g L−1 h−1). Furthermore, 3‐hydroxyoctanoate and ‐decanoate were the primary monomers incorporated into mcl‐PHA. The investigation also determined the median glass transition temperature (−43°C) and melting temperature (47°C), which indicated that mcl‐PHA is a flexible amorphous polymer at room temperature with a median MW of 104 kDa. However, information on the monomer composition or heterogeneity and the associated physical and mechanical data of mcl‐PHAs is inadequate. Based on their mechanical values, the mcl‐PHAs can be classified as semi‐crystalline polymers (median crystallinity 23%) with rubber‐like properties and a median elongation at break of 385%. However, due to the limited mechanical data available for mcl‐PHAs with known monomer composition, identifying suitable processing tools and applications to develop mcl‐PHAs further is challenging. [ABSTRACT FROM AUTHOR]

In this study, the microstructure and thermal properties of the plasma-sprayed free-standing Lu 2 Si 2 O 7 coating before and after thermal aging at 1350 °C were investigated. The tri-layer Yb 2 SiO 5 /Lu 2 Si 2 O 7 /Si EBCs were designed and prepared onto SiC f /SiC substrates, and its thermal shocking behaviors were also explored. Results showed that the as-sprayed coating was mainly composed of Lu 2 Si 2 O 7 and amorphous phase, and significant microstructural evolution, such as grain growth and defects reduction, was observed after thermal aging. Plastic deformation and well damage tolerance including twinning and dislocation were confirmed by TEM analysis. The CTE of the coating before and after heat treatment were similar, while the thermal conductivity increased after thermal aging. After 100 thermal cycles, penetrating microcracks in the Yb 2 SiO 5 top layer were mostly stopped at the Yb 2 SiO 5 -Lu 2 Si 2 O 7 interface, implying the excellent crack propagation resistance of the tri-layer EBCs. The thermal shock behaviors were clarified based on microstructure combined with thermal stresses analysis. • Microstructure and thermal property of Lu 2 Si 2 O 7 coating were studied. • Lu 2 Si 2 O 7 exhibited microstructure and thermal property evolution after aging. • The Yb 2 SiO 5 /Lu 2 Si 2 O 7 /Si EBCs possessed excellent thermal shock resistance. • Lu 2 Si 2 O 7 could be a promising interlayer material for tri-layer EBCs. [ABSTRACT FROM AUTHOR]

In this study, a highly dense GdB 6 bulk ceramic material was fabricated using one-step in-situ reaction spark plasma sintering technology. The sample with a relative density of 96.7 % and a purity of 96.9 wt% was successfully obtained by sintering at 1800 °C for 30 min under a uniaxial pressure of 50 MPa. The Vickers hardness, elastic modulus and fracture toughness of the as-obtained GdB 6 bulk ceramics were 18.9 GPa, 209 GPa and 1.6 MPa·m1/2, respectively. The thermal conductivity of GdB 6 at room temperature was 28.68 W·m−1·K−1, 70 % of which was mainly attributed to phonon vibration, while the remaining 30 % to the electrical thermal conductivity. In addition, the as-obtained GdB 6 ceramics showed no phase transformation after heat treatment at a relatively high temperature of 2100 °C for 20 min in Ar atmosphere. The highly covalent octahedral boron framework played a critical role in maintaining the phase stability of the GdB 6 crystal lattice. This suggested that GdB 6 ceramics could be used as potential ultra-high temperature ceramics for aerospace applications and high-power vacuum electronic devices operated at high temperatures. [ABSTRACT FROM AUTHOR]

Rare earth compounds (RE 2 O 3), typically Eu 2 O 3 and Gd 2 O 3 , are considered as absorbing materials due to their long chain neutron absorbing ability and high efficiency of neutron absorption. In this paper, a specifically designed x Eu 2 O 3 -(1-x)Gd 2 Zr 2 O 7 (x = 0.6, 0.7, 0.8, 0.85) composite ceramics with excellent thermal properties were synthesized through direct thermal decomposition reactions followed a high-temperature sintering method under vacuum conditions. X-ray diffraction (XRD) and Raman spectroscopy analysis indicated that the obtained ceramics consisted of monoclinic Eu 2 O 3 and fluorite Gd 2 Zr 2 O 7 phases. The hardness of x Eu 2 O 3 -(1-x)Gd 2 Zr 2 O 7 ceramics (x = 0.8, 0.85) have no significantly changes in the test temperature range (25–350 °C). The thermal expansion coefficients (TECs) (7.3–10 ×10-6 K-1) are lower than Dy 2 TiO 5 (9.3–10.4 ×10-6 K-1), and the thermal expansion rate changes linearly with the increase of temperature, which indicates that the x Eu 2 O 3 -(1-x)Gd 2 Zr 2 O 7 ceramics exhibit excellent high temperature phase stability. Furthermore, the range of thermal conductivities is from 0.96 W·m-1·K-1 to 2.02 W·m-1·K-1 (25–800 °C), which is higher than Dy 2 TiO 5 (0.27–0.55 W/m·K, 220–650 °C). Compared with the state-of-art Dy 2 TiO 5 ceramics, x Eu 2 O 3 -(1-x)Gd 2 Zr 2 O 7 have superior thermal properties and are therefore expected to be the next generational of neutron absorbent materials used in ash rod. [ABSTRACT FROM AUTHOR]

In this article, the potential of employing self-compacting geopolymer concrete in massive elements has been investigated. The main binder consisted of 85% ground granulated blast furnace slag and 15% fly ash. An alkaline solution of sodium hydroxide and sodium silicate was utilised. The effects of four parameters (binder content, water-to-binder [W/B] ratio, Na2O% and coarse-to-fine aggregate [C/F] ratio) on the fresh, mechanical and thermal properties of Massive Self-Compacting Geopolymer Concrete (MSCGC) mixes were evaluated. Taguchi's design of experiments was used to minimise the number of trial mixes. The heat of geopolymerisation of MSCGCs was monitored using a semi-adiabatic chamber and then applied to concrete samples using a temperature match curing system. The maximum compressive and splitting tensile strengths and modulus of elasticity were 62.7 MPa, 5.04 MPa and 33.26 GPa, respectively. Binder content was identified as the most significant parameter affecting the thermal and mechanical properties of the mixtures. The impact of the C/F ratio was greater than the W/B ratio on the thermal characteristics. The results of a numerical analysis reveal that although a higher binder content enhances the mechanical properties of the MSCGCs, it leads to an increased risk of cracking owing to greater heat production. [ABSTRACT FROM AUTHOR]

A novel quinoxaline-based phthalonitrile monomer, namely, 4,4′-(((quinoxaline-2,3-diylbis (oxy))bis (3,1-phenylene))bis (oxy))di-phthalonitrile (QDOP), was successfully synthesized by nucleophilic substitution reaction, which exhibits a low melting point (85°C) and a wide processing window (150°C). The QDOP monomer was cured with 4-aminophenoxy phthalonitrile (APPH) as catalyst by different temperature programs, and the curing process and kinetics were discussed in detail by non-isothermal differential scanning calorimetric (DSC). The QDOP polymer mainly forms triazine, isoindoline and phthalocyanine structure, as revealed by Fourier transform infrared (FTIR) spectroscopy, and its properties improved with the increase of post-curing temperature and curing time. After post-curing at 380°C, the polymer exhibited high storage modulus (3731 MPa), high glass-transition temperature (>400°C), and outstanding thermal stability and thermal oxidation stability. [ABSTRACT FROM AUTHOR]

This study reports the fabrication of quartz fabric reinforced phthalonitrile composite possessing good thermal and wave-transmitting properties. Phthalonitrile-terminated oligomer PN-SF curing behavior was investigated using differential scanning calorimetry (DSC) and dynamic rheological analysis (DRA), revealing a good processability pre-curing temperature of only 175°C. The thermoset exhibited the 5% loss temperature about 462°C, and after the temperature rising to 400°C and 400°C/2 h aging, the weight loss was only 10%, indicating that the resulting thermoset possessed outstanding thermal property. Moreover, the resulting thermosets possessed extremely high glass transition temperature (Tg) about 420°C. Besides, the quartz fabric/phthalonitrile composite possessed extremely excellent mechaical properties. Importantly, the transmission efficiencies can reach 87% at a certain frequency at the incident angle of 0°∼35°, indicating its well waving-transmitting performance. Meanwhile, the composite exhibited stable and relatively low dielectric constant and dielectric loss at the range of 12∼18 GHz. This study can serve as a basis for rapid evaluation of the high heat resistance and waving-transmitting phthalonitrile resin-based composite in various application environments. [ABSTRACT FROM AUTHOR]

This study aims to develop sustainable, renewable and biodegradable biocomposite films from environmentally friendly materials. For this purpose, completely biodegradable polymer composites were prepared by mixing polylactic acid (PLA) with a new source, quince peel (QP), by solvent casting method, and their structural, mechanical and thermal properties were examined. The tensile strengths of the composites prepared using QP in proportions varying between 5% (P5Q) and 30% (P30Q) by weight vary between 21.13 ± 0.80 and 12.01 ± 0.10 MPa, and their elongations at break vary between 11.33 ± 0.38 and 4.08 ± 1.06 %. As the QP contribution increased, the tensile strength and breaking elongation of these composites generally decreased, while the elastic modulus also increased. Among these composites, whose elastic modulus varies between 1040.00 ± 140.01 and 811.33 ± 13.31 MPa, it was determined that the elastic modulus (1040.00 ± 140.01 MPa) of the 20% QP added composite (P20Q) was higher than the others. When the thermal analysis of PLA/QP films were examined, it was observed that the glass transition temperatures (Tg) were between 58.54 and 51.45°C and the melting temperatures (Tm) were between 167.71 and 164.28°C, and these temperatures generally decreased with increasing QP doping. When the T50 values, which represent the temperature at which 50% of the composite materials decompose, were examined, it was found that the QP-added ones were higher than the pure composites. While this value was 317.96°C in pure PLA composite, T50 values varied between 327.92 and 340.80°C depending on the varying QP ratios. According to the XRD results performed to evaluate the crystalline properties of PLA composites containing quince bark, the crystallinity of pure PLA was determined as 19.5% and the crystallinity of composites containing 5, 10, 20 and 30 wt % QP additives was determined as 19.3, 18.3, 16.4 and 14.6%, respectively. [ABSTRACT FROM AUTHOR]

The metal cross-linking fluorinated polyacrylate colloid has a high cross-linking density, high transparency, high heat resistance and hydrophobicity. In this paper, the metal cross-linking fluorinated polyacrylate colloid is synthesized via the semi-continuous seeded emulsion polymerization technology, which uses the self-made magnesium acrylate, calcium acrylate and zinc acrylate as metal crosslinker and dodecafluoroheptyl methacrylate as a fluorine monomer. In this study, the ablation effect of the metal ions is weakened by the increased amount of environmentally friendly and polymerizable anion emulsifier DNS-86. The demulsification phenomenon of emulsion is successfully overcome through destroying the double layer structure of micelles or colloid particles by polyvalent metal ions. The colloidal particle size is smaller and the particle size distribution of the colloid is more uniform. Colloidal film has a good hydrophobicity and the glass transition temperature and the thermal decomposition temperature are high. [ABSTRACT FROM AUTHOR]

Summary: In frozen part‐baked bread technology, starch is influenced by various processing factors. This study aimed to investigate the effect of part‐baking time, freezing rate and frozen storage time on pasting, thermal and structural properties of part‐baked bread. Wheat dough was part‐baked for 0, 3 or 6 min and frozen at −20 °C using two freezing rates: slow (0.15 °C min−1) or fast (1.45 °C min−1). Next, samples were stored in frozen conditions for 56 days and analysed every 14 days for starch damage, pasting properties, thermal and X‐ray analysis. The level of damaged starch increased with 3 min (69.3%), and 6 min (88.8%) of part‐baking time for both freezing rates compared to no part‐baked. In pasting analyses, peak viscosity decreased 27.3% and 38.4% for 3 and 6 min of part‐baking time, respectively, at 0 days of frozen storage; however, this tendency was observed for all frozen storage time. The gelatinisation enthalpy (ΔHg) decreased as part‐baking time increased, showing the maximum reduction at 6 min of part‐baked (94.9%). In X‐ray diffraction analyses at 3 and 6 min of part‐baking, the intensity of the signal increased 4.4% and 10.9%, respectively, probably due to the starch gelatinisation. These results can serve as a valuable guide for developing strategies to enhance the quality of part‐baked bread and improve production performance. [ABSTRACT FROM AUTHOR]

Foam-forming technique imparts ceramic fiber paper with excellent uniformity, low density, and high porosity, but its strength loss must be compensated. Herein, a flexible and rigid foam-formed ceramic fiber network was manufactured by using different strength improvement methods and simultaneously investigated their strength and thermal insulation properties. Sufficient strength (1136 kPa) was achieved by combining Polyvinyl alcohol (PVA) 2 % and Polyester (PET) 3 %. However, the tensile strength of fiber networks would decrease under the contribution of inter-fiber bonding area reduced when the fiber length was longer than 24 mm. Benefiting from the developed flocculation system (aluminum sol-anionic polyacrylamide-carboxymethylcellulose), the strength of the foam-formed ceramic fiber network was 20 kPa, the retention rate increased from 75 % to 88 %, and the average aggregation factor of fillers in the Z direction was 0.67. By adjusting the ratio and Z-directional distribution of functional fillers, the sintered foam-formed paper with a tensile strength of 1300 kPa and compressive strength of 1000 kPa could be obtained. The thermal insulation performance (thermal conductivity 0.03252 W/(m·K)) was similar to the quartz fiber paper reinforced silica airgel, and the flame resistance was better than the commercialized aluminum silicate wool board. [ABSTRACT FROM AUTHOR]

In this study, Schiff bases (SCH-1 and SCH-2) were synthesized from the condensation reaction of 2-aminobenzothiazole with 3-hydroxy-4-methoxybenzaldehyde and 3-hydroxy-4-ethoxybenzaldehyde. Poly(phenoxy-imine)s were synthesized from Schiff bases via oxidative polycondensation by NaOCl (6–14% aqueous solution) as oxidant in alkaline medium and H2O2 (35% aqueous solution) as oxidant in THF medium. The structures characterizations of Schiff bases and poly(phenoxy-imine)s were confirmed by FT-IR, 1H and 13C NMR, CV, UV–Vis and TGA analyses. Limit oxygen index (LOI) and the heat resistance index (THRI) temperature were determined from thermogravimetric measurements of compounds. P-SCH-2-A showed the highest LOI as 45.50 with self-extinguishing according to other polymers (18–30). The optical band gap of P-SCH-2-A was determined to be 1.99 eV. Additionally, the optical band gap energy of compounds were calculated by using the Tauc method. According to the Tauc method, the optical band gap (Eg) value of P-SCH-2-A was calculated to be 2.20 eV. The glass transition temperatures (Tg) and surface properties of poly(phenoxy-imine)s were determined from DSC and SEM analyses, respectively. The weight average molecular weight (Mw) values of P-SCH-1-O, P-SCH-2-O, P-SCH-1-A and P-SCH-2-A were calculated to be 7400, 8400, 3100 and 19,100 g mol−1 from gel permeation chromatography (GPC) measurements. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the impact of poly (ethylene glycol) (PEG) on the properties of nanocomposites consisting of polylactic acid (PLA) and 3-aminopropyltriethoxysilane-modified bacterial cellulose (MBC) nanofibers. Differential scanning calorimetry (DSC) studies indicated that the presence of PEG enhanced the chain mobility of PLA during crystallization, thereby enabling the MBC to act as efficient nucleation agents. Furthermore, DSC and X-ray diffraction (XRD) analyses provided evidence for the formation of two distinct crystal structures, namely α and α,' as well as various spherulitic dimensions. Finally, the toughening of PLA was occurred by adding PEG to PLA and ternary nanocomposites. [ABSTRACT FROM AUTHOR]

Ceramic thermal barrier coatings (TBCs) with high toughness and low thermal conductivity are important for developing aero engines with high thrust‐to‐weight ratio and thermal efficiency. In this work, the properties of tantalate Y1/6Yb5/6TaO4 (YYT) were optimized by introducing 8 wt.% yttria‐stabilized zirconia (8YSZ), synthesized using spark plasma sintering, as a second‐phase ceramic. The highest toughness (3.57 MPa m1/2) of the YYT/8YSZ composite ceramics was due to multiple toughening mechanisms. The underlying mechanisms of these processes were revealed based on the microstructures and residual stress of the YYT/8YSZ composite ceramics. A shift from an intergranular fracture to a transgranular fracture was caused by the difference between soft‐grain YYT and hard‐grain 8YSZ, which consumed the fracture energy. Furthermore, the formation of microcracks, crack deflection, bridging, and branching were analyzed based on the differences in Young's moduli and thermal expansion coefficients of YYT and 8YSZ. Internal defects and weak connections between the YYT and 8YSZ grains reduced the thermal conductivity of the composites until it reached its lowest value at 1.4 W m−1 K−1. The studied toughening mechanisms could be applied to various composites. Moreover, herein, we provide a new strategy to design and synthesize TBCs with enhanced performance. [ABSTRACT FROM AUTHOR]

The order-disorder transition (ODT) of RE zirconate (RE 2 Zr 2 O 7) has received much attention due to its potential applications in the design of thermal barrier coatings (TBCs). A series of high entropy RE zirconates (RE = La, Sm, Gd, Er and Lu) were designed and synthesized in order to regulate the fluorite-pyrochlore phases, and to investigate the effect of phase composition on the microstructures and performances. The results showed that the sintering temperature, as well as equivalent ion radius, played an important role in regulating the phase transformation of fluorite-pyrochlore. The coexistence of pyrochlore-fluorite phases not only can result in the decrease in grain size but also increased the lattice strain of each phase, thereby enhancing the phonon scattering and contributing to the reduction in the thermal conductivity. The CMAS corrosion resistance was mainly related to phase compositions, and the thicknesses of reaction layer decreased gradually with the increasing fluorite phase content. The results will provide theoretical guidance for the microstructural design of high entropy RE zirconates as next generation TBC materials in future. [ABSTRACT FROM AUTHOR]

Dy 2 O 3 –Sm 2 O 3 co-doped transparent glass ceramics (GCs) containing NaBi(WO 4) 2 crystalline phase were prepared by melt-curing-crystallization method. The optimal heat treatment condition is 580 °C/2 h. The optimum incorporation concentration of Dy 2 O 3 is 0.4%, exceeding which a quenching phenomenon dominated by quadrupole-quadrupole interactions emerges. Meanwhile, when the concentration of Dy 2 O 3 was fixed, the chromaticity coordinate of the sample moved the cool white light region to the warm white light region as the concentration of Sm 2 O 3 increased. The temperature-dependent emission spectra of the 0.4% Dy 2 O 3 -0.7% Sm 2 O 3 co-doped GC samples show that emission intensity at 575 nm at 185 °C still reaches 80% of the room temperature. The thermal quenching activation energy was 0.1537 eV and the activation energy after the addition of Mo6+ was 0.1957 eV. This study indicates that Dy 2 O 3 –Sm 2 O 3 co-doped GCs containing NaBi(WO 4) 2 crystalline phase can achieve light-color tunable emission, which is potentially valuable for solid-state color rendering and illumination applications. [ABSTRACT FROM AUTHOR]

This paper discusses the fracture analysis of FG structures reinforced by CNT exposed to thermo-mechanical load by means of the XIGA framework. The equivalent properties of functionally graded structures reinforced by CNT (SWCNT & MWCNT) are computed using micro-mechanics models. The volume fraction of CNT has an impact on the mechanical and thermal properties. Then, a preexisting crack is considered in the CNT reinforced FG square structure to perform the fracture analysis. The SIFs are calculated by the interaction integral method. It is noted that delaying of the fracture is possible with the increase of CNT content in FG structure. [ABSTRACT FROM AUTHOR]

Physical parameters are necessary to determine the suitability of the chalcogenide materials for specific applications. The present study reports the physical characteristics of the multicomponent GeTe2-x(SeSb)x (x = 0, 0.2, 0.4, 0.6) chalcogenide glasses synthesised by the melt-quench technique. The differential scanning calorimetric (DSC) technique has been used at separate heating rates β = 5, 10, 15, 20 °C / min. XRD and SEM–EDX studies have been carried out for structural and morphological analyses. The average coordination number and constraints of the compound have been calculated which indicates that the composition forms a glassy system. Lone pair electrons present in the composition have been evaluated. R parameter has a value greater than 1, indicating that the composition has sufficient chalcogen, chalcogen–chalcogen and heteropolar bonds. The overall bond energy of the compound has been calculated using the chemical bonding approach to understand the fine-structure properties of the compound. Cohesive energy has been observed to increase with composition. Thermal stability, glass transition temperature and glass forming ability of the compound have been calculated using different relations like Saad and Poulin relation, Dieztal relation, Hurby parameter (Hr) and reduced glass transition temperature (Trg) and studied theoretically to examine the thermal stability of the composition that shows that the prepared samples are suitable for data storage. [ABSTRACT FROM AUTHOR]

Recent advances have shown the beneficial impact of adding nanoparticles to thermal oil. Diamond and boron nitride nanoparticles have superior thermal conductivity and excellent thermal and optical properties. In the current study, thermal conductivity, specific heat, and rheological behavior of diamond and boron nitride-based hybrid nanofluids in thermal oil are experimentally investigated for 0%, 0.2%, 0.4%, and 0.6% weight concentrations and a wide range of temperatures. The proportion between diamond and boron nitride utilized in the study is 1:1. A two-step method is applied to prepare stable hybrid nanofluids. The obtained data indicate that the hybrid nanofluids' thermal conductivity and specific heat enhance with increasing temperature and weight concentration. Almost 37.4% and 48.1% enhancement is observed in the thermal conductivity and specific heat, respectively, at 65 °C and 0.6% weight concentration. Thermal oil-based hybrid nanofluids display Newtonian behavior at low shear rates and an inverse relationship with temperature. Shear-thinning non-Newtonian behavior is observed at high shear rates and temperatures. A maximum increase in viscosity up to 22.0% is observed at 65 °C and 0.6% wt. concentration. The relative change indicates that all investigated properties have a significant impact, where the increasing trend of thermal conductivity and specific heat with increasing temperature and weight concentration of thermal oil-based hybrid nanofluids make them suitable for high-temperature heat transfer applications. [ABSTRACT FROM AUTHOR]

This experimental study aimed to investigate the potential control of microstructural-mineralogical characteristics on thermal properties and its relation with the deformational behaviour in mild to high temperature (25°–800°C) regime of coal-bearing sandstone from an underground coal mine fire region. Barakar sandstone from Jharia Coalfield, India, one of the world's largest underground coal mine fire regions, was chosen. The thermal parameters and their relations to the mineralogical, microstructural, and damage characteristics of Barakar sandstone have been discussed. Thermal conductivity (λ), thermal diffusivity (κ), and specific heat capacity (Cp) of heat-treated samples were determined using the transient plane source method. Additionally, detailed petrography, scanning electron microscopy, and electron probe micro-analyser were used to understand the thermal effect on mineralogy and microstructures. The deformational behaviour with elevated temperature was investigated through the universal testing machine. The obtained results suggest three characteristic temperature regimes: mild temperature regime (25°–300°C), transitional temperature regime (300º–500°C) and high temperature regime (500º–800°C). Moreover, prediction models for thermal properties have also been developed using multi-gene genetic programming (MGGP), considering physical properties as input parameters. In view of experimental constraints to determine the thermos-elastic properties of a rock due to tedious experimental processes, the proposed prediction models shall be very useful to indirectly estimate the thermal properties of sandstone rocks using easily determined physical parameters. The outcome of the present study may be useful to understand the subsidence induced by underground coalmine fire, which is a distressing issue in the Jharia region due to persistent coalmine fire. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs-), graphene (GNs)-natural rubber (NR) composites were prepared by wet mixing process and dry mixing process, respectively. Thermal conductivity, 300% tensile stress, tear strength and elongation at break of the samples were measured experimentally. The effects of mixing process, carbon materials content and type on thermal properties and mechanical properties of composites were studied. The experimental results show that, the thermal conductivity of the mixed rubber, the 300% tensile stress and the tear strength of the vulcanizate all increase first and then decrease slightly with the increase of the carbon material content, regardless of the mixing process. However, the elongation at break of vulcanizate showed an opposite trend. When the carbon material content is 2.0% (w.t.%), thermal conductivity, 300% tensile stress and tear strength all reach their maximum, while elongation at break obtains minimum. Under the same amount of addition, GNs is more conducive to improving the thermal conductivity and elongation at break of composites, while CNTs are more conducive to improving the tensile strength and tear strength of composites. For CNTs-, GNs-NR composites, the wet mixing process can greatly improve the thermal conductivity, tensile strength and tear strength of composites, while the dry mixing process can greatly improve the elongation at break of composites. Therefore, when preparing CNTs-, GNs-NR composites, it is necessary to select a suitable mixing process according to the performance requirements of the final product. [ABSTRACT FROM AUTHOR]

This study aimed to develop environmentally friendly PVC composites for automotive by incorporating plantain fiber (PF) and calcite particles (CP) as reinforcements. Different weight percentages of PF and CP (ranging from 3% to 15%) were utilized. The mixtures underwent compounding and compression molding at 150°C for 10 min. The mechanical and thermal properties of the resulting composites were analyzed, and their fracture surfaces were examined using SEM. Results indicated that the inclusion of these reinforcements significantly enhanced the properties of the composites compared to unreinforced samples, with the hybrid composites exhibiting the best performance. Optimal compositions were identified within the range of 6-8 wt% PF and 3-4 wt% CP. The composite containing 6 wt% PF/3 wt% CP showcased the highest ultimate tensile strength (63.77 MPa), optimum elongation at break, and best insulating property (0.24 W/Mk). The composite with 8 wt% PF/4 wt% CP demonstrated the highest tensile modulus (4.79 GPa), flexural strength (91.35 MPa), and flexural modulus (8.2 GPa). Impact strength peaked at 10 wt% PF/5 wt% CP, reaching 107.02 J/m2. These findings indicate that the developed hybrid reinforced biocomposite compositions hold great promise for various automotive applications, including instrument panels, sun visors, headlining, seals, floor coverings, and protective strips [ABSTRACT FROM AUTHOR]

The copolymer precursor, poly [4-(4-vinylbenzyl)oxy)phthalonitrile]-co-methyl methacrylate (poly (VBOPN-co-MMA)), was synthesized through copolymerization of VBOPN and MMA at a temperature of 110°C. Subsequently, a single-chain polymer complex of cobalt phthalocyanine (SCP-CoPc) was formed at 150°C by intramolecular macrocyclization between the cobalt and the phthalonitrile group in poly (VBOPN-co-MMA), using excess cyclohexanol. The formation of the SCP-CoPc complex was confirmed through various spectroscopic techniques such as UV/Vis, FT-IR, 1H-NMR, and 13C-NMR. In particular, the disappearance of -CN band at 2232 cm−1 from FT-IR indicated the formation of the SCP-CoPc complex, while the presence of specific absorption bands in the UV/Vis spectrum further confirmed its creation. The electrical, dielectric, optical, and thermal properties of the SCP-CoPc complex and SCP-CoPc/ZnO 5% composites were investigated. The SCP-CoPc/ZnO 5 wt% nanocomposite exhibited improved dielectric and DC conductivity with increasing temperature. The activation energy (Ea) was found to be 0.35 eV for SCP-CoPc and 0.25 eV for SCP-CoPc/ZnO 5 wt% nanocomposite, indicating that the electrical conductivity followed the Arrhenius equation. The optical properties, including band gap, dielectric constant, and refractive index, were calculated for the SCP-CoPc/ZnO 5 wt% nanocomposite. The SCP-CoPc complex possessed a band gap of 2.89 eV, while the SCP-CoPc/ZnO 5 wt% nanocomposite had a slightly reduced band gap of 2.36 eV. The refractive indices of SCP-CoPc and SCP-CoPc/ZnO 5 wt% were also determined. [ABSTRACT FROM AUTHOR]

Composites synthesized from natural waste and recycled plastic is quite a promising and interesting field for scientists and polymer industries. In the present study, bio-composites based on agriculture residue Sesamum indicum L. and recycled-low density polyethylene were synthesized by extrusion and injection molding technique at a fiber loading of 10–40 wt%. Additionally, 3% of maleic anhydride grafted low density polyethylene was used as a compatibilizer. The prepared composites were irradiated at 25 kGy, 75 kGy and 125 kGy doses of gamma rays. The effects of different fiber content and gamma doses on mechanical properties were studied statistically by Design Expert software. Response surface methodology was employed to depict the interaction among various factors and optimization was done by desirability index method. Findings indicated that composites having 30% Sesamum indicum L. irradiated at 125 kGy demonstrated best mechanical properties. A significant enhancement in tensile and flexural properties of irradiated composites can be explained effectively in terms of the cross-linking effect. The fiber–matrix adhesion and modifications in composite structure was characterized by fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and X-Ray diffraction (XRD) analysis. Furthermore, thermal stability of the composites was also found to be increased. In addition, gamma-irradiated composite exhibited the highest storage modulus and a decrease in mechanical loss factor was also observed. [ABSTRACT FROM AUTHOR]

AbstractA novel diphenyl monomer, dimethyl 2,2'-(((ethane-1,2-diylbis(oxy))bis(4-acetyl-3,1-phenylene))bis(oxy))diacetate (EDPD), was synthesized from methyl 2-(4-acetyl-3-hydroxyphenoxy)acetate (MAHA), a 2,4-dihydroxyacetophenonederivative, and combined with 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol or p-phenylenedimethanolto afford a series of biodegradable polyesters via melt polymerization. The polyesters were characterized by Fourier transform infrared and proton nuclear magnetic resonance spectroscopy, gel permeation chromatography, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The weight-average molecular weight (Mw) of the polyesters varied from 3.2–4.4 × 104 g/mol, the glass transition temperature (Tg) from 52 to 80 °C, and the 5% decomposition temperature (Td,5%) was in the 334–362 °C range. All the samples exhibited high yield strength (53–68 MPa) and elongation at break (230–330%) values, comparable with poly(ethylene terephthalate) (PET), owing to their aromatic character. Degradability testing of the polyesters in soil yielded mass losses reaching up to 7% after 32 weeks. In ecotoxicity testing, earthworms had a survival rate of more than 80% after 14 d of incubation, indicating relatively low toxicity. Overall, the good thermal and mechanical properties, biodegradability and low ecotoxicity of the polyesters make them promising materials for packaging applications, in replacement for PET, thereby promoting carbon neutrality and sustainable development. [ABSTRACT FROM AUTHOR]

This article presents a comprehensive review of the advancements in the use of Date Palm Fiber (DPF) reinforced composites, highlighting their mechanical, thermal, and morphological properties and the enhancements achieved through various modification techniques. Date palm fibers, a sustainable and biodegradable resource, have garnered significant interest due to their potential in reducing environmental impact across several key industries, including building and construction, automotive, and packaging. The review discusses the effects of hybrid approaches and physical and chemical treatments on the mechanical properties of DPF composites, demonstrating improvements in tensile strength, elasticity, and flexural strength through optimized fiber‐matrix bonding and reduced moisture absorption. Thermal behavior analyses through Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), and thermal conductivity underscore the composites’ suitability for applications requiring high thermal stability and conductivity for insulation applications. Morphological studies reveal that surface‐treated fibers integrate more effectively with various polymeric matrices, leading to enhanced composite performance. The practical applications of DPF composites are explored, emphasizing their role in promoting sustainable manufacturing practices. Challenges such as scalability, cost‐efficiency, and performance consistency are addressed, alongside future perspectives that suggest a promising direction for further research and technological development in the field of natural fiber composites. This review aims to solidify the foundation for ongoing advancements and increase the adoption of DPF composites in commercial applications. [ABSTRACT FROM AUTHOR]

Highlights While improving the thermal conductivity of composites, single‐size carbon nanotubes (CNT) often degrade their mechanical properties due to the agglomerates. To overcome this limitation, this study reported thermoplastic resin matrix composites synergistically reinforced with small, medium, and large‐size carbon nanotubes (S‐CNT, M‐CNT, and L‐CNT). Using the thermal conductivity (λ) and mechanical properties (flexural strength [F], compressive strength [C] and tensile strength [T]) as the response values, we conducted 21 sets of mixing design experiments and developed the associated quadratic term models. Further multi‐objective optimization was carried out for the above response values. Optimized multiscale CNT synergistically modified composites (S‐CNT, M‐CNT, and L‐CNT contents of 1.25, 7.02, and 2.56 wt%) exhibited a λ value of 1.168 W/mK, which was 121% higher than that of pure composite and also superior to the same content of S‐CNT‐ (1.031 W/mK), M‐CNT‐ (1.016 W/mK), and L‐CNT‐modified composites (0.983 W/mK). Additionally, the optimized composite demonstrated excellent mechanical properties (F = 1482 MPa, C = 848 MPa, and T = 1759 MPa), which were 13%, 11%, and 13% higher than those of the pure composites, respectively, and also surpassed those of the S‐CNT‐, M‐CNT‐and L‐CNT‐modified composites. Using three different scales of carbon nanotubes modified CF/PPBESK composites. Polynomial modeling of composite's thermal conductivity and mechanical properties. Synergistic interactions between carbon nanotubes to improve the composite's thermal conductivity and mechanical properties. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the effects of oven, microwave (MW), and infrared (IR) drying technology on the drying kinetics, physicochemical properties, and β-carotene retention of the dried orange-fleshed sweet potato flour (OFSP). Fresh OFSP slices were dried in an oven (40°C), MW (80 W), IR (250 W), MW-IR (80 W + 250 W), and freeze-drying (-45°C, 100 kPa) and milled into flour. Hot air at a constant temperature was applied to all thermal drying technologies (40°C, 4.5 m/s air velocity). The drying rate of the MW-IR drying method was the fastest (45 min), followed by MW (60 min), IR (120 min), and oven (180 min). The Page model was most suitable for the oven-drying method, the Lewis model for IR drying, and Henderson and Pabis for IR and Logarithmic for the MW-IR method. The pasting and thermal properties of the flours were not significantly (p > 0.05) affected by the different drying methods. However, IR- and MW-IR-dried flours showed a higher final viscosity when compared to other drying methods. MW-IR drying methods, IR, and MW showed a higher water solubility index, while the oven and freeze-drying methods showed a lower solubility index. MW-IR drying methods showed a higher retention of β-carotene (85.06%). MW also showed a higher retention of β-carotene (80.46%), followed by IR (66.04%), while oven and freeze-drying methods showed a lower retention of β-carotene. High β-carotene retention in the produced flour is due to the faster drying method, and these flours can be used in food-to-food fortification to address vitamin A deficiency. [ABSTRACT FROM AUTHOR]

Boron cluster sheets are two-dimensional boron atom-based formations called borophene. They are similar to the two-dimensional sheet known as graphene, which is composed of carbon atoms arranged in a hexagonal lattice. The unique electrical, mechanical, and thermal properties of borophene make it a sought-after substance for a variety of uses, such as catalysis, energy storage, and electronics. There are two ways to manufacture borophene: chemical vapor deposition and molecular beam epitaxy. Vertex-edge valency-based topological descriptors are a great example of a molecular descriptor that provides information on the connection of atoms in a molecule. These descriptions are based on the notion that a node's value in a molecular network is the sum of the valency of those atoms that are directly connected to that node. In this article, we discussed some novel vertex-edge (ve) and edge-vertex (ev) topological descriptors and found their formulations for the boron cluster or borophene sheets. Also, we show the numerical and graphical comparison of these descriptors in this article. [ABSTRACT FROM AUTHOR]

Starch is present in high amount in various cereals, fruits and roots & tubers which finds major application in industry. Commercially, starch is rarely consumed or processed in its native form, thus modification of starch is widely used method for increasing its application and process stability. Due to the high demand for starch in industrial applications, researchers were driven to hunt for new sources of starch, including modification of starch through green processing. Thermal properties are significant reference parameters for evaluating the quality of starch when it comes to cooking and processing. Modification of starches affects the thermal properties, which are widely studied using Differential scanning calorimeter or Thermogravimetric analysis. It could lead to a better understanding of starch's thermal properties including factors influencing and expand its commercial applications as a thickener, extender, fat replacer, etc. in more depth. Therefore, the review presents the classification of starches, factors influencing the thermal properties, measurement methods and thermal properties of starch in its native and modified form. Further, this review concludes that extensive research on the thermal properties of new sources of starch, as well as modified starch, is required to boost thermal stability and extend industrial applications. [ABSTRACT FROM AUTHOR]

Thermal transport properties of metallic nanowires are crucial to the near-junction heat dissipation of transistors. However, the understanding of the size-dependent thermal conductivity of these advanced interconnect metals is still limited. In this work, we select nine candidate metals and investigate the size effect on thermal transport properties by the mode-level first-principles method combining with the Boltzmann transport equation. Their thermal conductivity, the phonon contribution, and the Lorenz ratio in nanowires with characteristic size from 3 to 30 nm are analyzed. While all these metals have lower bulk thermal conductivity than Cu, we find some of these metals have larger thermal conductivity with characteristic size smaller than 10 nm. We identified that their smaller electron mean free path is the key factor. Moreover, the contribution of phonon thermal conductivity is smaller than 25% to total thermal conductivity. The Lorenz ratio is found to be slightly larger than the Sommerfeld value, mainly due to the phonon contribution. This work can provide important guidance for selecting advanced interconnects in the development of next-generation integrated circuits. [ABSTRACT FROM AUTHOR]

In chemical reactions of copper(II) acetate dihydrate with imidazolium azide salts in ethanol solution several new homoleptic azidocuprates(II) were obtained. In dependency of the used counter cation various different azidocuprate moieties were crystalized. The doubly charged DMMDIm2+ cation facilitates the formation of mononuclear [Cu(N3)4]2− complex anions, while the utilisation of the (PeMIm)+ ion enables the isolation of a dinuclear [Cu2(N3)6]2− salt. By using the unsymmetrical imidazolium ions (BMIm)+ or (EMIm)+ salts with the trinuclear [Cu3(N3)8]2− complex anion are obtained. With the (DML)+ cation an azidocuprate(II) crystallizes, which contains both [Cu(N3)4]2− and the [Cu2(N3)6]2− anion. The anions in the salt with the (PeMIm)+ cation are interconnected through further Cu−N bonds and form layers with a 2D‐honeycomb structure. The trinuclear units in the (BMIm)+ and the (EMIm)+salts form coordination strands of different structures. [ABSTRACT FROM AUTHOR]

Highlights The relationship between interfacial structure and thermal conductivity in epoxy resin/Al2O3 composite is important but is still elusive. Here, we illuminate this issue by investigating the role of four silane coupling agents in thermal conductivity for epoxy resin/Al2O3 composites. The results show that 3‐glycidoxypropyltrimethoxysilane (KH560) is the best silane coupling agent to modify Al2O3, resulting in the lowest viscosity and the highest thermal conductivity of the epoxy resin/Al2O3‐KH560 composite compared with alternative systems. This is attributed to the strong interfacial interaction between Al2O3‐KH560 and epoxy resin, as confirmed by the Fowkes model and broadband dielectric spectroscopy. The interfacial thermal resistance between the epoxy resin and Al2O3 is also quantitatively measured via a photothermal radiometry technique. The epoxy resin/Al2O3‐KH560 also has the lowest interfacial thermal resistance (1.50 ± 0.02 × 10−6 m2 K W−1), compared with the other three systems. This study advances the understanding of the relationship between interfacial structure and thermal conductivity in polymer composites. The relationship between interfacial structure and thermal conductivity in epoxy resin/Al2O3 composite is understood. The interfacial structure is characterized by broadband dielectric spectroscopy. The interfacial thermal resistance is quantitatively measured via a photothermal radiometry technique. [ABSTRACT FROM AUTHOR]

Composite materials have garnered considerable interest in the thermal industry on account of their remarkable mechanical properties and thermal resistance. The objective of this research work is to analyse the impacts of integrating porcelain infill particles into basalt fibre-reinforced polymer (BFRP) composites. Particularly, the study aims to evaluate the consequential modifications in critical thermal and mechanical characteristics. The results of mechanical testing indicate that the incorporation of porcelain fillings significantly influences the composite tensile strength, flexural strength, and impact resistance. Additionally, by employing scanning electron microscopy (SEM), significant knowledge is acquired regarding the interfacial bonding mechanisms and microstructural properties of the filler particles, polymer matrix, and basalt fibres. Utilizing dynamic mechanical analysis (DMA), the maximal values of storage modulus (3429 MPa), loss modulus (489 MPa), and damping factor (0.17) are investigated in relation to the dynamic mechanical properties across a range of temperature conditions. The research additionally illustrates enhancements in thermal characteristics, including heat deflection temperature, thermal conductivity, and coefficient of linear thermal expansion, all of which are improved by 37% when porcelain infill is incorporated into the composite. In addition, thermal gravimetric analysis (TGA) examines the degradation and thermal stability properties of the composites over an extensive temperature spectrum, reaching a maximum of 390 °C. The insights derived from this analysis are particularly pertinent to applications involving thermal insulation. [ABSTRACT FROM AUTHOR]

Biodegradable chitosan-based films containing different concentrations of jatobá fruit peel extract (0.0%, 0.04%, 0.07%, 0.1% and 0.3%) were prepared and evaluated for their antioxidant and antimicrobial activities, physicochemical, morphological and thermal properties. The extract from jatoba fruit peel was obtained and incorporated into formulations of chitosan films. The films were characterized for thickness, moisture, solubility, water vapor permeability, optical properties, color and morphology. Also, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, in vitro antioxidant activity and antimicrobial activity were performed. The addition of extract at increasing concentrations increased the in vitro antioxidant activity by about 9–60 times compared with the film without extract. Films with lower extract concentrations were more effective at inhibiting nine bacterial strains, with emphasis on Escherichia coli (95.0% inhibition), Bacillus cereus (92.5% inhibition), Bacillus subtilis (96.5% inhibition), Pseudomonas aeruginosa (94.4% inhibition), Salmonella Typhimurium (90.4% inhibition) and Salmonella Enteritidis (93.9% inhibition). Addition of the extract improved the physical properties of the film, such as moisture, solubility, WVP and luminosity. The thermal stability of the films was slightly reduced with addition of extract at increasing concentrations. Films incorporating jatobá fruit peel extract showed potential utility as 'green' bioactive, biodegradable packaging, an alternative to packaging containing petroleum derivatives. [ABSTRACT FROM AUTHOR]

This contribution presents the results of structural investigations on the cured and high temperatures of three series of geopolymers. The specimens were synthesized at 80 °C from coal fly ash and three activators of variable composition based on sodium hydroxide and sodium silicate solutions. Structural and microstructural analysis was performed, especially using in-situ measurements of XRD patterns and IR spectra as a function of temperature. The cured compounds' phase content and compressive strength changed slightly depending on the starting chemical composition. All analyzed materials experience a mass loss due to water removal at 300 °C, followed by increased porosity from disintegrating compounds above 300 °C. Higher alkali content improves strength (400–600 °C) possibly due to nepheline formation. The amorphous phase gradually softens during heating, influenced by alkali content. Structural analyses were supported by model calculations of a number of aluminosilicate structures. The cluster analysis using the k-means algorithm was used to divide the PCA space into regions that represent structural similarities, and analyzing specific point positions in the space allowed for several conclusions to be drawn about the studied materials, including that changes in chemical composition and thermal treatment can promote the transformation from sodalite to nepheline and that the glass network has elements that are nepheline-like and may promote its crystallization. [ABSTRACT FROM AUTHOR]

This paper describes the composites of silane cross-linked polyethylene (PEXb) mixed with four different fillers dedicated to improving thermal conductivity, such as multi-walled carbon nanotubes, graphite, boron nitride, and mineral filler. Using the mathematical modeling, the concentration of each filler was estimated to reach the value of 0.675 W m−1 K−1 suitable for the usage PEXb in the production of geothermal pipes. From tested fillers, all improve the thermal conductivity of pure PEXb; however, above the required value, only 28 mass% of boron nitride (0.937 W m−1 K−1). It was associated with its perfect dispersion and the highest gel content achieved, also resulting in the highest flexural modulus. Graphite at 5 mass% and mineral filler at 35 mass% allowed the thermal conductivity to equal 0.622 W m−1 K−1 and 0.624 W m−1 K−1, respectively, with a simultaneous medium effect on the mechanical properties. Carbon nanotubes increased PEX's conductivity to a small extent, due to their occurrence as agglomerates. [ABSTRACT FROM AUTHOR]

Successful preparation of PVA/SrTiO3/CNT polymer nanocomposite films was accomplished via the solution casting method. The structural, optical, and thermal properties of the films were tested by XRD, SEM, FTIR, TGA, and UV-visible spectroscopy. Inclusion of the SrTiO3/CNT nanofillers with a maximum of 1 wt% drastically improved the optical and thermal properties of PVA films. SrTiO3 has a cubic crystal structure, and its average crystal size was found to be 28.75 nm. SEM images showed uniform distribution in the sample with 0.3 wt% of SrTiO3/CNTs in the PVA film, while some agglomerations appeared in the samples of higher SrTiO3/CNT content, i.e., at 0.7 and 1.0 wt%, in the PVA polymer films. The inclusion of SrTiO3/CNTs improved the thermal stability of PVA polymer films. The direct and indirect optical band gaps of the PVA films decreased when increasing the mass of the SrTiO3/CNTs, while the single-oscillator energy (E0) and dispersion energy (Ed) increased. The films' refractive indices were gradually increased upon increasing the nanofillers' weight. In addition, improvements in the optical susceptibility and nonlinear refractive indices' values were also obtained. These films are qualified for optoelectronic applications due to their distinct optical and thermal properties. [ABSTRACT FROM AUTHOR]

In this study, the objective was to optimize energy consumption in the fused deposition modeling (FDM) 3D printing process via a detailed analysis of printing parameters. By utilizing thermal analysis techniques, this research aimed to identify lower printing temperatures that could lead to reduced energy usage. Experimental analysis was conducted using a three-level L9 Taguchi orthogonal array, which involved a systematic combination of different extruder temperatures and cooling fan capacities. Furthermore, the research incorporated differential scanning calorimetry (DSC) and X-ray diffraction (XRD) methods to analyze the thermal properties and crystallinity of the 3D-printed specimens. The results indicated that temperature was a key factor affecting crystallinity, with samples printed at 190 °C and 60% fan capacity showing the highest mean values. By conducting a multi-objective desirability analysis, the optimal conditions for maximizing ultimate tensile strength (UTS), tensile modulus, and elongation at break while minimizing energy consumption for PLA 3D-printed samples were determined to be a temperature of 180 °C and a fan speed of 80%. [ABSTRACT FROM AUTHOR]

This study delineates a methodology for the preparation of new composites based on a photocurable urethane-acrylate resin, which has been modified with (3-thiopropyl)polysilsesquioxane (SSQ-SH). The organosilicon compound combines fully enclosed cage structures and incompletely condensed silanols (a mixture of random structures) obtained through the hydrolytic condensation of (3-mercaptopropyl)trimethoxysilane. This process involves a thiol-ene "click" reaction between SSQ-SH and a commercially available resin (Ebecryl 1271®) in the presence of the photoinitiator DMPA, resulting in composites with significantly changed thermal properties. Various tests were conducted, including thermogravimetric analysis (TGA), Fourier transmittance infrared spectroscopy (FT-IR), differential scanning calorimetry (Photo-DSC), and photoreological measurement mechanical property, and water contact angle (WCA) tests. The modification of resin with SSQ-SH increased the temperature of 1% and 5% mass loss compared to the reference (for 50 wt% SSQ-SH, T5% was 310.8 °C, an increase of 20.4 °C). A composition containing 50 wt% of SSQ-SH crosslinked faster than the reference resin, a phenomenon confirmed by photorheological tests. This research highlights the potential of new composite materials in coating applications across diverse industries. The modification of resin with SSQ-SH not only enhances thermal properties but also introduces a host of functional improvements, thereby elevating the performance of the resulting coatings. [ABSTRACT FROM AUTHOR]

In the realm of thermal interface materials (TIMs), high thermal conductivity and low density are key for effective thermal management and are particularly vital due to the growing compactness and lightweight nature of electronic devices. Efficient directional arrangement is a key control strategy to significantly improve thermal conductivity and comprehensive properties of thermal interface materials. In the present work, drawing inspiration from natural leaf and branch structures, a simple-to-implement approach for fabricating oriented thermal conductivity composites is introduced. Utilizing carbon fibers (CFs), known for their ultra-high thermal conductivity, as branches, this design ensures robust thermal conduction channels. Concurrently, boron nitride (BN) platelets, characterized by their substantial in-plane thermal conductivity, act as leaves. These components not only support the branches but also serve as junctions in the thermal conduction network. Remarkably, the composite achieves a thermal conductivity of 11.08 W/(m·K) with just an 11.1 wt% CF content and a 1.86 g/cm3 density. This study expands the methodologies for achieving highly oriented configurations of fibrous and flake materials, which provides a new design idea for preparing high-thermal conductivity and low-density thermal interface materials. [ABSTRACT FROM AUTHOR]

2,3-dihydro-5,6,7,8-tetranitro-1,4-benzodioxine (TNBD), molecular formula = C8H4N4O10, is a completely nitrated aromatic ring 1,4-benzodioxane derivative. The convenient method of TNBD synthesis was developed (yield = 81%). The detailed structure of this compound was investigated by X-ray crystallography. The results of the thermal analysis (TG) obtained with twice re-crystallized material revealed the onset at 240 °C (partial sublimation started) and melting at 286 °C. The investigated material degraded completely at 290–329 °C. The experimental density of 1.85 g/cm3 of TNBD was determined by X-ray crystallography. The spectral properties of TNBD (NMR, FT-IR and Raman) were explored. The detonation properties of TNBD calculated by the EXPLO 5 code were slightly superior in comparison to standard high-energy material—tetryl (detonation velocity of TNBD—7727 m/s; detonation pressure—278 kbar; and tetryl—7570 m/s and 226.4 kbar at 1.614 g/cm3, or 260 kbar at higher density at 1.71 g/cm3. The obtained preliminary results might suggest TNBD can be a potential thermostable high-energy and -density material (HEDM). [ABSTRACT FROM AUTHOR]

The paper reports on the synthesis, crystal structure, thermal and magnetic properties of spin crossover (SCO) salts containing the [Fe(bpp)2]2+ cation (bpp = 2,6-bis(pyrazol-3-yl)pyridine) and different rigid polycarboxylate anions, such as anthracene-9,10-dicarboxylate (ADC), benzene-1,3,5-tricarboxylate (BTC) and biphenyl-4,4′-dicarboxylate (BPDC). Compound [Fe(bpp)2](ADC)·9H2O (1) shows a porous hydrogen-bonded structure with water molecules sitting in the channels. It contains low-spin (LS) Fe2+ cations that undergo crossover to the high-spin (HS) state upon dehydration. Anhydrous 1 remains HS on cooling at low temperatures. A similar magnetic behaviour is obtained for the partially protonated BTC salt [Fe(bpp)2](HBTC)·5H2O (2), showing a spin change concomitant with dehydration to a HS phase that undergoes gradual and partial SCO on cooling, affecting 25% of the Fe2+ cations. Instead, the BPDC salt [Fe(bpp)2](BPDC)·5H2O (3) has a ground HS state in its fully hydrated form. [ABSTRACT FROM AUTHOR]

Microwave heating has been applied to improve cement-based materials (CBMs) structures deicing efficiency, which reduce the effect of icing on their service life. Moreover, the enhanced thermal properties of CBMs can further improve their deicing efficiency. In this study, silicon carbide (SiC) ceramic particles with favorable thermal properties were used to prepare the SiC cement-based materials (SCBMs). The effect of SiC ceramic on the mechanical strength of CBMs was investigated. Next, the heat transfer and storage ability of CBMs were investigated to analyze the changes in their thermal-physical parameters. Then, the surface thermal responses of the CBMs during microwave heating and off were recorded to characterize their temperature evolution in a low-temperature condition. Furthermore, the deicing efficiency of CBMs was determined using the ice layer shedding time (ILST) as the index. The results show that the filling effect of SiC ceramic on CBMs improved their mechanical strength within a certain content range. However, a large content of SiC ceramic caused an increase in the weak area and porosity within the CBMs, further reducing their mechanical properties. The thermal-physical parameters of CBMs were improved after adding SiC ceramic. The thermal conductivity and thermal effusivity of SCBMs-100 were 13.17 W/(m·K) and 1.44 W/(mm2·K), respectively, 7.90 and 2.35 times higher than the control group. Due to the favorable thermal properties of SCBMs, their heating rate and surface temperature field distribution characteristics were further improved. Furthermore, with the increase of SiC ceramic content, the ILST of SCBMs was further reduced during microwave heating. Therefore, the SiC ceramic was a favorable material, improving the thermal properties and deicing efficiency of CBMs to a certain extent. However, considering its effect on the deterioration of the mechanical properties of CBMs, the optimal content of SiC ceramic might be 75%. [ABSTRACT FROM AUTHOR]

The 2.5D oxide/oxide composites become attractive for their excellent integrity and mechanical properties. The thermal shock resistance performance of the material is very important in the actual high temperature application. In this work, the evolution of microstructure and mechanical behavior of the 2.5D oxide/oxide composites from thermal shock at different temperatures and cycles was investigated experimentally mainly by optical microscope, X-ray computed tomography and macro-mechanical tests. The thermal shock resistance mechanism of oxide/oxide composites was qualitatively explored. The results showed that cracks propagation was the main manifestation of thermal shock damage in composites. Compared with 2D composites, 2.5D composites exhibited the finite domain effect on crack propagation due to its reinforcement had certain fibers in Z -direction. This directly caused the critical thermal shock temperature difference of the 2.5D composites (∼900 °C) was more than twice that of the 2D oxide/oxide composites (∼400 °C). In addition, the finite domain effect also significantly reduced the damage growth rate of the 2.5D composites from cyclic thermal shock, highlighting its excellent thermal shock damage resistance. [ABSTRACT FROM AUTHOR]

A series of seven stable amide derivatives based on indole‐3‐carboxaldehyde were synthesized with high yields using various aliphatic and aromatic acyl chlorides, triethylamine and DMAP as the catalyst at room temperature. Structural characterization was performed using FT‐IR, 1 H‐NMR, 13C‐NMR and LC–MS techniques. To develop bioactive material, acetalization of water‐soluble polyvinyl alcohol was achieved by reacting one of the N‐acyl derivatives, 1‐propionylindole‐3‐carboxaldehyde, in the presence of a p‐TSA catalyst to form polyvinyl acetal with pendant bioactive groups. The polymer was analyzed using 1 H‐NMR, FT‐IR, TGA, DSC, FE‐SEM and EDX spectroscopic techniques. The polymer was water‐insoluble with enhanced thermal stability compared to pure polyvinyl alcohol. This approach for developing N‐acyl derivatives of indole‐3‐carboxaldehyde and then reacting one of the monomers with polyvinyl alcohol to improve its thermal properties and stability in humid conditions has proven successful. [ABSTRACT FROM AUTHOR]

To improve the thermal and combustion properties of nanothermites, a design theory of changing the state of matter and structural state of the reactants during reaction was proposed. The Al/MoO3/KClO4 (Kp) nanothermite was prepared and the Al/MoO3 nanothermite was used as a control. SEM and XRD were used to characterize the nanothermites; DSC was used to test thermal properties; and constant volume and open combustion tests were performed to examine their combustion performance. Phase and morphology characterization of the combustion products were performed to reveal the mechanism of the aluminothermic reaction. The results show that the Al/MoO3/Kp nanothermite exhibited excellent thermal properties, with a total heat release of 1976 J·g− 1, increasing by approximately 33% of 1486 J·g− 1 of the Al/MoO3 nanothermite, and activation energy of 269.66 kJ·mol− 1, which demonstrated higher stability than the Al/MoO3 nanothermite (205.64 kJ·mol− 1). During the combustion test, the peak pressure of the Al/MoO3/Kp nanothermite was 0.751 MPa, and the average pressure rise rate was 25.03 MPa·s− 1, much higher than 0.188 MPa and 6.27 MPa·s− 1 of the Al/MoO3 nanothermite. The combustion products of Al/MoO3 nanothermite were Al2O3, MoO, and Mo, indicating insufficient combustion and incomplete reaction, whereas, the combustion products of Al/MoO3/Kp nanothermite were Al2O3, MoO, and KCl, indicating complete reaction. Their "coral-like" morphology was the effect of reactants solidifying after melting during the combustion process. The characterization of reactants and pressure test during combustion reveals the three stages of aluminothermic reaction in thermites. The excellent thermal and combustion performance of Al/MoO3/Kp nanothermite is attributed to the melt and decomposition of Kp into O2 in the third stage. This study provides new ideas and guidance for the design of high-performance nanothermites. [ABSTRACT FROM AUTHOR]

Polymer composites with lightweight, ultralow dielectric constant, excellent thermal insulation and mechanical properties are in high demand in aerospace, transport, wireless communications and other fields. In this work, the three‐dimensional woven Kevlar/glass hybrid composites (3DKGC) with lightweight, high strength, excellent dielectric and thermal insulation properties were obtained with the Kevlar fiber and glass fiber as the raw materials. The results showed that the volume content of air in 3DKGC is over 82% and the volume density is as low as 0.29 g·cm−3, while the compression strength is as high as 7.68 MPa. 3DKGC exhibits an ultra‐low dielectric constant of 1.21. The wave transmission performance of 3DKGC was simulated using the CST software. The simulation results showed that 3DKGC has a return loss of 0.036 and a gain of 0.9982. Moreover, the 3DKGC provides superior thermal insulation than three‐dimensional woven Kevlar composites (3DKC) and conventional polystyrene foams. In summary, this work offers an attractive material that holds significant potential for application in aerospace, wireless communications and other fields where lightweight multi‐purpose composites are required. Highlights: 3D woven Kevlar/glass hybrid composites (3DKGC) were proposed and fabricated.3DKGC exhibits low density of 0.29 g·cm−3 but high compression stress (7.68 MPa).3DKGC possesses outstanding dielectric and thermal insulation properties.3DKGC leverages the benefits of cost‐effectiveness and holistic functionality. [ABSTRACT FROM AUTHOR]

Two‐dimensional hexagonal boron nitride (hBN) based nanocomposites exhibit excellent mechanical and thermal properties for various electronics, automotive, and aerospace applications. The present work gives a novel approach to fabricating hexagonal boron nitride/epoxy nanocomposites using isopropanol and dimethyl ketone as dispersants in two different routes and to predict mechanical characteristics employing deep learning and machine learning models. Nanocomposites were fabricated by employing casting techniques with varying concentrations of hBN, spanning from 0.25 to 1 wt%, utilizing dispersing solvents. The nanocomposites were analyzed for mechanical behavior, highlighting a notable improvement in the mechanical properties at 0.5 wt% isopropanol dispersed hBN. It showcased 61% improvement in tensile strength, 38.41% increase in flexural strength, and 35.80% increase in flexural modulus respectively as compared to the pristine epoxy. The Halpin Tsai analytical model showed agreement with the elastic modulus calculated experimentally. The fractured SEM micrograph supported the improved dispersion of the hBN nanocomposite. Thermal stability of 0.5 wt% isopropanol dispersed hBN/epoxy nanocomposite revealed an improvement by 8°C at 50% degradation as compared to the pristine epoxy. Linear regression, random forest regression, support vector regression, and deep neural network (DNN) were employed to predict values. DNN proved better results by showcasing low prediction loss and high R2 values (0.99468–0.99966). Highlights: hBN/epoxy nanocomposite with isopropanol and dimethyl ketone as dispersants.0.5% hBN loading in isopropanol exhibited improved mechanical characteristics.The Halpin Tsai model was employed for evaluating theoretical elastic modulus.Improved thermal stability and filler dispersion by optimized hBN/epoxy combination.Deep neural network showed higher R2 value and lower prediction loss. [ABSTRACT FROM AUTHOR]