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As the research for advanced materials suitable for high-temperature uses continues, the need for oxide ceramic micro-nanofibers with outstanding mechanical and thermal properties becomes increasingly important. By incorporating two types of magnesium sources, specifically Mg(CH 3 COO) 2 ·4H 2 O and MgCl 2 ·6H 2 O, into the precursor, a range of fibers made of magnesium silicate ceramics was produced through electrospinning. X-ray diffraction (XRD) analysis verified that the resulting multiple phases included MgO, MgSiO 3 , Mg 2 SiO 4 , and amorphous SiO 2 , with the phase composition being affected by the diffusion reaction of Mg ions. The fibers produced using the dual-precursor method maintained a stable morphology with a uniform and compact structure after undergoing high-temperature treatments ranging from 1000 to 1200 °C. This study is the first to report the tensile strength of magnesium silicate fibrous membranes, which was found to be 1.54 ± 0.27 MPa and 1.21 ± 0.73 MPa after heat treatment at 800 °C and 1000 °C, respectively. Furthermore, these fibrous membranes demonstrated dependable thermal insulation properties within the testing range of 500–1000 °C, along with a low thermal conductivity at room temperature of 0.0301–0.0306 W m−1·K−1. Characterized by their impressive mechanical strength and high temperature stability, magnesium silicate ceramic micro-nanofibers show significant potential for various applications in the targeted field. [ABSTRACT FROM AUTHOR]

Ceramic aerogels are promising candidates for high-temperature thermal resistance and thermal insulation materials. However, their application can be restricted by their brittleness when exposed to harsh conditions. Herein, this study has developed a novel synthesis process based on a sol-gel method and carbothermal reduction-nitridation to produce a porous TiN composite aerogel from an organic/inorganic hybrid. The resulting TiN displays a polyhedral particle size of around 30–60 nm with nanoscale pores. In addition, the TiN aerogel demonstrates a high BET-specific surface area of 653.42 m2/g and a very low thermal conductivity of 0.046 W/(m·K). Furthermore, the TiN aerogel composite displays a good thermal difference with no shrinkage and cracks of the morphology during the butane blazing torch at 1300 °C for 10 min under air environment, demonstrating its excellent thermal insulation property and anti-oxidation characteristics. The gas-solid reaction mechanism of TiN aerogel based on the Gibbs free energy calculations is also proposed. [ABSTRACT FROM AUTHOR]

This study utilizes modulation of ionic disorder and electronegativity differences for targeted component design of high-entropy ceramic compositions. A series of novel multicomponent ceramics with the general formula (LaGdYSm) x 2 Yb x 1 Zr 2 O 7 (x 1 +4x 2 = 2, x 1 = 0.6,0.4,0.2,0) were prepared by solid-state reaction. The evolution patterns of their microstructures were analyzed using XRD and TEM, and the anti-sintering ability and thermophysical properties were evaluated. The results confirm that the multicomponent ceramics gradually transform from the coexistence of pyrochlore/fluorite dual-phase structure to pyrochlore structure with the tuning of the size disorder degree. After 50h of exposure to air at 1500 °C, the ceramics retained excellent phase stability. Segregation of La and Yb elements with large differences in radius size occurs, forming a mixture of the La-rich pyrochlore and the Yb-rich fluorite phases. The specimen with the maximum size disorder exhibits the lowest grain growth rate and the greatest thermal insulation properties. Large lattice distortions and sluggish diffusion effects are responsible for the mutual inhibition of grain growth in the two-phase coexistence zone. The thermal insulation properties of the ceramics show well correlated with the degree of the size disorder, further validating the effectiveness of the component design. Meanwhile, the thermal expansion coefficients of prepared ceramic can reach 11.49 × ∼11.58 × 10−6 K−1 at 1000–1100 °C. The customization principles used in this work fill a gap in the compositional design methodology for multicomponent lanthanum zirconate-based high-entropy ceramics. It is essential for developing rare-earth zirconates with tunable thermophysical properties in the area of thermal barrier coatings. [ABSTRACT FROM AUTHOR]

The ZrO 2 fiber paper exhibits excellent thermal insulation properties, however, its limited mechanical strength and insufficient thermal stability hinder its widespread applications. The composite fiber papers, using mullite fibers possessing a high aspect ratio and exceptional thermal stability combined with ZrO 2 fibers, were fabricated via a vacuum-assisted filtration method. This method involved the successive stacking of composite fibers with alumina sol, using vacuum-induced directed water flow to create a layered structure reminiscent of nacre. The layered structure of the nacre, which demonstrates remarkable strength and hardness, has also served as a source of inspiration for the architectural design of the fiber paper. The tensile strength of pure ZrO 2 fiber paper was significantly enhanced by the addition of 7 wt% mullite fibers, resulting in a remarkable increase to 0.1805 kN/m. The paper exhibited exceptional resistance to bending, maintaining 96 % of its bending strength even after undergoing 100 cycles. The thermal shrinkage of the composite paper, containing 15 wt% mullite fibers, was reduced from 17.75 % observed in pure ZrO 2 fiber paper to a mere 1.32 % after undergoing heat treatment at a temperature of 1300 °C for 2 h. The composite paper, measuring 5 mm in thickness and consisting of 7 wt% compositions, displayed exceptional thermal insulation properties when exposed to a hot side temperature of 1370 °C. It effectively insulated temperatures up to approximately 1000 °C. [ABSTRACT FROM AUTHOR]

Flexible SiC nanowire aerogel felt has excellent foldability, high-temperature resistance, and thermal insulation properties. However, the large-scale and high-efficiency production of SiC nanofiber aerogel felt remains a challenge. In this work, a three-dimensional network-structured short-chopped carbon fiber felt was used as a template for preparing SiC nanowire aerogel felt. The short-chopped carbon fibers were combed and dispersed using an airflow in a carding machine to obtain the desired felt. This method enables rapid and uniform preparation of carbon fiber felt, enhancing the efficiency of SiC nanowire aerogel felt production. The experimental results showed that the aerogel felt was mainly composed of β-SiC nanowires with a density of 5.29 g/cm3. Additionally, the SiC nanofiber aerogel felt exhibited remarkable superelasticity and low thermal conductivity (0.013 W/m·K). This research contributes to the practical application of flexible SiC nanowire aerogel felt in the field of thermal insulation. • Carding machine dispersed carbon fiber. • Fabrication of large size SiC nanofiber aerogel felt. • SiC nanofiber aerogel felt has flexibility and low thermal conductivity. [ABSTRACT FROM AUTHOR]

Among the family of high-quality fiber materials, mullite fiber membrane is a promising one that possesses abilities of both the thermal resistance and oxidation resistance under high temperature. High-purity mullite nanofibrous membranes were prepared by electrospinning method with low-cost aluminum chloride hexahydrate (AC) as the aluminum source. The effects of sintering temperature and AC content on the phase structure, microstructure, thermal and mechanical properties of the mullite nanofibrous membranes were investigated. The results show that the sintering temperature as low as 1000 °C is the very appropriate temperature for obtaining the high-purity mullite nanofibers with smooth surface. The minimum thermal conductivity of 0.029 W m−1 K−1 and maximum tensile strength of 6.11 MPa are gained from the mullite nanofibrous membranes with AC content of 2 mmol. The mullite nanofibrous membranes with excellent properties can be selected as an ideal candidate for thermal insulation and reinforced applications. [ABSTRACT FROM AUTHOR]

Energy efficient buildings, propulsion components and thermal protection systems require materials with high thermal protective properties. Traditional polymer composites or ceramic materials have limited comprehensive applications because of their poor thermal protective properties or poor processability. Herein, a novel fire resistant and thermally insulating polymer/ceramic hybrid ceramifiable composite was developed based on low temperature sintering principle and foaming on fire strategy. Specifically, the influences of raw materials of low temperature ceramics, such as glass frit, phosphate, etc, on the properties of ceramifiable ethylene-vinyl acetate (EVA) composites were investigated. Its fire resistance and thermal insulation properties were evaluated by simulating different sintering environments. The results show that the ceramifiable composite exhibits the highest improvement in fire resistance because a crystalline phase was formed at high temperatures. Gas evolution from the thermal decomposition of ammonium polyphosphate (APP) and EVA contributes to the formation of the porous structure in ceramic residues. The optimal system can resist above 1000 °C flame for 30 min without disintegration, and the temperature of the unfired side was maintained around 200 °C. The reliability of the strategy was verified by the effective medium theory model. [Display omitted] [ABSTRACT FROM AUTHOR]

Hollow-structured ceramic fibers with multiple components are ideal as lightweight insulation materials. In this study, tetraethyl orthosilicate, boric acid, and zirconia octahydrate were used as raw materials for fabricating SiZrBOC hollow ceramic fibers through coaxial electrospinning. These ceramic fibers exhibit a low thermal conductivity and an excellent temperature resistance. The electrospun SiZrBOC hollow ceramic fibers display a clean and compact morphology with internal folds. Fourier-transform infrared spectroscopy and thermogravimetric analysis (TGA) were used to assess the transformation process and thermal behavior of the hollow ceramic fibers. The results suggest that the incorporation of B promotes the formation of Si–O–B bonds within the system, leading to a maximum yield of 75.49 wt% for the production of the SiZrBOC hollow ceramic fibers. The phase composition and microstructure of the SiZrBOC hollow ceramic fibers were analyzed via X-ray diffraction (XRD) measurements. The pyrolysis at 1000 °C resulted in the appearance of diffraction peaks corresponding to SiO 2 and SiC in the XRD patterns of the SiZrBOC hollow ceramic fibers. Laser thermal conductivity measurements reveal that the SiZrBOC hollow ceramic fibers exhibit a thermal conductivity of only 0.06 W‧m−1K−1 at 25 °C and 0.124 W‧m−1K−1 at 500 °C, indicating a significantly superior thermal insulation performance compared with conventional solid SiZrBOC ceramic fibers. [ABSTRACT FROM AUTHOR]

Mullite fiber-based porous ceramics is one of the most commonly used high-temperature insulation materials. However, how to further reduce the thermal conductivity and improve the strength of such materials has been a challenge in the field of high-temperature insulation. In this paper, mullite micro/nano fiber-based porous ceramic was prepared by introducing mullite nanofibers into mullite microfiber-based porous ceramics and the effect of microfiber/nanofiber weight ratio on the samples properties were characterized and analyzed. Results showed that the compressive strength and high-temperature thermal insulation properties of the porous ceramics increased significantly with an increase in the nanofiber content. For the porous ceramics with similar density (about 0.50 g/cm3), the compressive strength of the sample with a microfibers/nanofibers weight ratio of 1:2 was 1.43 MPa, which was much higher than that of the porous ceramics prepared with only microfibers (0.26 MPa). Meanwhile, the backside thermal equilibrium temperature of the sample with a microfiber/nanofiber weight ratio of 1:2 at 900 °C environment was 355.8 °C, which was much lower than that of the porous ceramic prepared with only microfibers (476.5 °C). In addition, in order to investigate the temperature resistance of mullite micro/nano fiber-based porous ceramics, the sintering temperatures was increased from 1400 °C to 1500 °C. Results shows that the high-temperature thermal insulation performance of mullite micro/nano fiber-based porous ceramics with high mullite nanofiber content decays more seriously. The back-temperature test showed that the thermal equilibrium temperature of the samples with a mullite micron/nanofiber weight ratio of 1:1 in 900 °C environment increased rapidly from 386.3 °C to 454.2 °C when the sintering temperature was increased from 1400 °C to 1500 °C. The preparation of mullite micro/nanofiber-based porous ceramics provides a new strategy to improve the performance of fiber-based porous ceramics. [ABSTRACT FROM AUTHOR]

Mullite fiber-based porous ceramics is one of the most commonly used high-temperature insulation materials. However, how to further reduce the thermal conductivity and improve the strength of such materials has been a challenge in the field of high-temperature insulation. In this paper, mullite micro/nano fiber-based porous ceramic was prepared by introducing mullite nanofibers into mullite microfiber-based porous ceramics and the effect of microfiber/nanofiber weight ratio on the samples properties were characterized and analyzed. Results showed that the compressive strength and high-temperature thermal insulation properties of the porous ceramics increased significantly with an increase in the nanofiber content. For the porous ceramics with similar density (about 0.50 g/cm3), the compressive strength of the sample with a microfibers/nanofibers weight ratio of 1:2 was 1.43 MPa, which was much higher than that of the porous ceramics prepared with only microfibers (0.26 MPa). Meanwhile, the backside thermal equilibrium temperature of the sample with a microfiber/nanofiber weight ratio of 1:2 at 900 °C environment was 355.8 °C, which was much lower than that of the porous ceramic prepared with only microfibers (476.5 °C). In addition, in order to investigate the temperature resistance of mullite micro/nano fiber-based porous ceramics, the sintering temperatures was increased from 1400 °C to 1500 °C. Results shows that the high-temperature thermal insulation performance of mullite micro/nano fiber-based porous ceramics with high mullite nanofiber content decays more seriously. The back-temperature test showed that the thermal equilibrium temperature of the samples with a mullite micron/nanofiber weight ratio of 1:1 in 900 °C environment increased rapidly from 386.3 °C to 454.2 °C when the sintering temperature was increased from 1400 °C to 1500 °C. The preparation of mullite micro/nanofiber-based porous ceramics provides a new strategy to improve the performance of fiber-based porous ceramics. [ABSTRACT FROM AUTHOR]

Lightweight ablative materials owing to their low density, high efficiency heat insulation and excellent designability, which are considered as the most promising candidate materials in the field of aerospace ablative thermal protection. In this work, a polycarbosilane (PCS) in-situ reinforced carbon felt/phenolic (PR/C f) aerogel composite is reported. The surface of aerogel and carbon fiber was coated with PCS protective layer by sol gel method and secondary vacuum impregnation process. The aerogel composite material possesses low density (0.264–0.307 g/cm3), hydrophobic, low thermal conductivity (0.121–0.178 W/(m·K)) and significant high compressive strength (12.89 MPa). When the oxygen acetylene flame with high heat flow density ablates for 20 s, it shows high efficiency in heat protection and insulation, and the linear ablation rate is as low as 0.089 mm/s. The PL/PR/C f aerogel composite shows competitive and broad application prospects in the field of ablation heat protection in the future. [ABSTRACT FROM AUTHOR]

ZIF-L, a metal-organic framework (MOF) material, has a two-dimensional (2D) foliation, a large specific surface area, excellent thermal stability and CO 2 adsorption performance, respectively. In this work, in order to further improve the thermal insulation performance of SiO 2 aerogel composite fabrics, ZIF-L powder was first prepared as a reinforcing particle, and then added to silica aerogel. Finally, SiO 2 /AF/ZIF-L composites were obtained by solution impregnation method. The influence of different ZIF-L concentrations on the insulation performance of composites and their influencing factors were studied. Furthermore, these composites were fully characterized using BET measurement, Instron 5967, precision transient thermal performance tester, infrared thermal imager, insulation performance test, thermogravimetric analyzer, and dynamic thermomechanical analyzer. The results showed that 0.12% SiO 2 /AF/ZIF-L composites had excellent thermal insulation performance, with a thermal conductivity as low as 0.029 W/(m·K). In addition, SiO 2 /AF/ZIF-L composites fabricated by atmospheric drying method had the best thermal insulation performance under the conditions of gel time of 24 h, hydrolysis time of 5 h, and polycondensation pH value of 5–6. [ABSTRACT FROM AUTHOR]

In this study, we synthesize a porous silica nanoparticles (SiO 2) derived from recycled semi-conducting silica sludge via a conventional hydrothermal and microwave-assisted hydrothermal methods for flame-resistant applications. The corresponding thermal properties of as-synthesized SiO 2 nanoparticles are investigated. The effects of reaction temperature and urea concentration are investigated in terms of surface morphology and thermal conductivity. The results of thermal conductivity tests indicate that 180 °C reaction temperature for both conventional hydrothermal reaction and microwave-assisted hydrothermal reaction demonstrated the best thermal insulator performance. The thermal conductivities are determined to be 0.0193 W/m·K and 0.0192 W/m·K, respectively. For flame penetration and combustion tests, microwave-assisted one exhibits much better performance, maintaining a temperature of 34 °C after 600 s of combustion under a butane torch at nearly 800 °C. Furthermore, there is no deformation occurred when direct contact with the flame at a high temperature, proving that microwave-assisted hydrothermal reaction-synthesized silica is a potential candidate for thermal barrier applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Anisotropic layered porous ceramics are crucial to satisfy the demand for devices with directional functions. However, challenges, such as complicated preparation processes and difficulties in regulating the oriented structure, severely limit their application. Here, multilayered mullite ceramics (MLMCs) with specific porosities and strongly anisotropy properties, were prepared by designing porous thin-layered units and an interlayer layout, in combination with a simple gel-casting. Benefiting from the suitable slurry properties, the samples did not show obvious defects, and a perfect bonding was observed between the layers. The optimized MLMCs exhibited a porosity of 65.12%, the differences in compressive and flexural strengths of 14 (± 0.7) and 5 (± 0.2) MPa in different pressure directions respectively, and the anisotropy factor of thermal conductivity up to 0.98, as well as exhibited good high temperature thermal insulation properties. Ultimately, the MLMCs formed transverse heat conductor and longitudinal heat insulation heat-transfer patterns, with promising applications in thermal insulation. [ABSTRACT FROM AUTHOR]

Double ceramic layer (DCL) TBCs consisting of a top 20 wt.% Al 2 O 3 -7YSZ layer and a bottom 7YSZ layer were desirably designed to achieve preferable performance while the thermal, mechanical and thermal cyclic properties were comprehensively investigated. Compared to the conventional 7YSZ TBCs, the thermal insulation properties of the DCL coating were significantly improved due to the increased oxygen vacancy concentration induced by Al 2 O 3 addition while the thickness of the thermally grown oxides was diminished by the decreased oxygen diffusion rate. Furthermore, the improved fracture toughness of the DCL coating also prolonged the thermal cyclic life. [ABSTRACT FROM AUTHOR]

With the increasingly serious issues of energy conservation and emission reduction, hollow fibers have attracted wide attention as materials that have structural advantages in terms of thermal insulation. Herein, we report the preparation of flexible hollow TiO 2 fibrous membranes via coaxial electrospinning. To optimize the thermal-insulation performance of the fibers, hollow fibers with different diameters and pore sizes were prepared by adjusting the feeding rate of the core spinning solution. Optimum conditions were achieved at a feeding rate of 2 mL/h for the shell solution and 0.4 mL/h for the core solution. The hollow fibers had a compact tube wall structure and good mechanical properties, and the tensile strength of the fibrous membranes reached 0.652 ± 0.119 MPa. In addition, the hollow fibrous membranes have excellent thermal insulation properties with an average reflectance of more than 89% and a room temperature thermal conductivity of less than 0.0294 ± 0.00015 W m−1K−1. In practical experiments, the temperature can be reduced from 1174.6 to below 273.6 °C using 15-mm-thick fibrous membranes, which confirms its excellent thermal insulation. Flexible hollow TiO 2 fibrous membranes have a wide range of insulation applications. [ABSTRACT FROM AUTHOR]

In this study, Antimony-doped tin oxide (ATO) fixed and loaded on one-dimensional halloysite nanotubes (HNTs) were fabricated using the co-precipitation method to improve photocatalytic efficiency and dispersion of ATO. After that well dispersed ATO@HNTs nanofiller (AH) modified by monoethanolamine (mAH) was also embedded in the polyvinylidene fluoride (PVDF) coating by solution blend to further broaden the application fields. The results showed the introduction of HNTs accelerates electron transfer and promotes the decomposition of rhodamine B (Rh B). More significantly, with the effect of the well-dispersed mAH nanofillers, PVDF coating containing 15% mAH degraded more than 90% of Rh B under ultraviolet (UV) irradiation for 2 h, which was 1.2 times higher than that of PVDF coating. In addition, the PVDF/mAH-15% coating exhibits excellent antistatic stability under the harsh conditions of photoaging and thermal aging. Moreover, by comparing temperature differences, the thermal insulation performance of PVDF/mAH-15 coating with 70.24% visible light transmittance is significantly improved by reducing heat conduction and radiation at the same time. [ABSTRACT FROM AUTHOR]

In this study, we investigated the tunable porous structure of SiCN(O)-derived ceramic aerogels by changing the molecular structure of the polysilazanes from linear to branched. We also studied the effect of molecular structure on the thermal insulation properties of ceramic aerogels. As the percentage of branched molecular structure in the polysilazane precursor increased, the internal microscopic pore structure of the aerogels changed from macroporous to mesoporous. The specific surface areas and pore volumes of the ceramic aerogels prepared with different precursors increased after pyrolysis at 1000 °C, ranging from 3.7 to 255.9 m2/g and 0.01–0.36 cm3/g, respectively. The corresponding thermal conductivities increased slightly as the aerogels contracted after pyrolysis. The low thermal conductivity (0.046 W/(m·K) at minimum) can be attributed to the decrease in pore size caused by adjusting the precursor structure, which limits the thermal conduction of gas in the porous aerogel materials. [ABSTRACT FROM AUTHOR]

High-performance thermally insulating aerogel with low density, high porosity, and low thermal conductivity characteristics was widely used in heat insulation. However, the large-scale application of aerogel was still limited by its brittleness and infrared radiation transparency at high-temperature. Fiber composite aerogel had achieved significant progress, but its anti-oxidation ability was poor, and its thermal insulation required further improvement at ultra-high temperatures. Herein, inspired by the structure of elytra, nanoparticle fiber (NF) was prepared by electrospinning of coaxial fiber loaded with opacifier and antioxidant nanoparticles. The NF was incorporated into the SiBCN aerogel to prepare NF/SiBCN ceramic fiber aerogel. The mechanical properties were improved by fiber networks. The shell structure increased the antioxidant properties. Heat conduction and heat convection were suppressed by the aerogel, while heat radiation was reduced by the coaxial fiber. The results showed that the ceramic fiber aerogel exhibited superior mechanical, antioxidant, and ultra-low thermal conductivity properties. • A novel 'particle/fiber/aerogel' composites were constructed for thermal insulation. • The composites exhibited fire resistance and ultralow thermal conductivity at 1300 °C. • The composites had low density and excellent mechanical properties. • Coaxial fiber had self-healing and anti-oxidation properties at ultra-high temperatures. [ABSTRACT FROM AUTHOR]

The High Sensitivity Terahertz Detection Module (HSTDM) is one of the scientific payloads of the China Space Station Survey Telescope, which mainly conducts terahertz astronomical observations. The core of the HSTDM is the NbN superconducting tunnel junction (Superconductor - Insulator - Superconductor (SIS)) mixer, operating at the temperature ≤ 10 K, cooled by a space-qualified two-stage pulse tube refrigerator. The cryostat, which can minimize the heat load of the refrigerator, is a key component to realize the 10 K refrigeration environment in space, and it needs to adapt to the mechanical vibration during launch. This paper mainly introduces the structural design, mechanical characteristics simulation analysis and actual measurement, and thermal characteristics simulation analysis of this special cryostat. The fundamental frequency of the cryostat is 189.36 Hz. The mechanical analysis results demonstrate that the maximum stress of the support structures is lower than the yield stress of the materials. The vibration test results show that the cryostat can adapt to mechanical environments. The cryostat has a heat leakage of 1800 mW to the first cold stage and 20.6 mW to the second cold stage, both of which are less than the cooling power of the refrigerator. The thermal analysis results show that the thermal design of the cryostat satisfies the thermal insulation requirements. The research results demonstrate that the cryostat design can meet the space application requirements of the HSTDM. [ABSTRACT FROM AUTHOR]

An accurate estimation of the effective thermal conductivity of various insulation materials is essential in the evaluation of heat leak and boil-off rate from liquid hydrogen storage tanks. In this work, we review the existing experimental data and various proposed correlations for predicting the effective conductivity of insulation systems consisting of powders, foams, fibrous materials, and multilayer systems. We also propose a first principles-based correlation that may be used to estimate the dependence of the effective conductivity as a function of temperature, interstitial gas composition, pressure, and structural properties of the material. We validate the proposed correlation using available experimental data for some common insulation materials. Further improvements and testing of the proposed correlation using laboratory scale data obtained using potential LH 2 tank insulation materials are also discussed. [Display omitted] • We develop physics-based insulation property models for cryogenic LH 2 storage tank • Model captures the micro- and macro-features of the insulation system with any gas • We demonstrate the applicability of model to several typical insulation materials • Model performs well against experiment even at extended pressure/temperature range • Model parameters can be evaluated from either physics or experimental measurements [ABSTRACT FROM AUTHOR]

The porous silicon carbide ceramics with multilevel directional pores were prepared by chemical vapor infiltration (CVI) combined with sacrificial template method. Carbon fiber preform with specific structure was used as template, and silicon carbide was deposited by CVI process. Then, the carbon fiber template was oxidized and removed, so that the porous silicon carbide ceramics were obtained. The influence of deposition time on pore structure, mechanical properties and thermal properties was studied. Compared with the traditional pore-making process, the pores formed by sacrificial template method are more regular, which brings excellent mechanical properties and thermal insulation properties. The porosity and flexural strength of the sample deposited for 72 h can reach 66.00% and 67.52 MPa, respectively, the thermal conductivity can be kept below 1 W/(m·K) from room temperature to 1200 °C. [ABSTRACT FROM AUTHOR]

Thermal protection has always been an important issue in the energy, environment and aerospace fields. Porous ceramics produced by the particle-stabilized foaming method have become a competitive material for thermal protection because of their low density and low thermal conductivity. However, the study of porous ceramics for composite systems using particle-stabilized foaming method was relatively rare. Here, silica-alumina composite porous ceramics were prepared by particle-stabilized foaming method, which was achieved by tailoring the surface charges of silica and alumina through adjustment of the pH. Porous ceramics exhibited porosity as high as 97.49% and thermal conductivity (25 °C) as low as 0.063 W m−1 K−1. The compressive strength of porous ceramics sintered at 1500 °C with a solid content of 30 wt% could reach 0.765 MPa. Based on the light weight and excellent thermal insulation properties, the composite porous ceramic could be used as a potential thermal insulation material in the spacecraft industry. [ABSTRACT FROM AUTHOR]

A novel B–Si–Zr hybridized ceramicizable resin(BSZ-PR) was fabricated by chemical reaction of boric acid, zirconium hydroxyl-containing polyhedral oligomeric silsesquioxane(Zr-POSS) and phenolic. The incorporation of boric acid and Zr-POSS improved the thermal stability of the resin effectively, and the residual carbon rate increased to 72.63% at 800 °C under nitrogen atmosphere. The flexural strength of carbon fiber/BSZ-PR and high silica fiber/BSZ-PR composites were increased by 25.7% and 175.5%, and linear ablation rates were reduced by 37% and 44.75%, respectively. It was discovered that the ceramic structures such as SiO 2 , ZrO 2 and SiC can be formed at high temperatures as well as under extreme ablative conditions from both BSZ-PR and its fiber-reinforced composites, which may be the key to the improved thermal, ablative properties. [ABSTRACT FROM AUTHOR]

Ceramic fiber felts are attractive candidates for high temperature insulation due to their lightweight, high porosity and low thermal conductivity. In this work, ceramic felts constructed by γ-Y 2 Si 2 O 7 fibers were prepared by a facile method of Y–Si–O/PVB sol-gel electrospinning combined with subsequent high-temperature calcination. Effects of calcination temperature on the phase composition, microstructure and thermal insulation properties of ceramic felts were systematically studied. Results indicated that the organic components in the sol-gel fibers were removed after high temperature calcination, while the fibers kept the original continuous microtopography with high aspect ratios. Ceramic fiber felts of pure γ-Y 2 Si 2 O 7 phase could be obtained after calcinated at 1300 °C. The as-prepared paper-like γ-Y 2 Si 2 O 7 fiber felt presented low density of ∼120 mg/cm3 and a high porosity up to 97.03%. Combined with the inherent high temperature stability and low thermal conductivity of γ-Y 2 Si 2 O 7 , this light ceramic felts possessed high-temperature resistance and thermal insulating property (low thermal conductivity of 0.052 W m−1 K−1). The successful preparation of this ceramic fiber felt may provide a perspective for insulation materials used in harsh environments. [ABSTRACT FROM AUTHOR]

The microstructure evolution of carbon fiber reinforced carbon aerogel-like matrix (C/CA) composites with carbonization temperature and its influence on their properties were investigated. The removal of residual organo-functional groups of the C/CA precursors is dominant when carbonized at 600–750 °C with a large volume shrinkage difference by 17–22% as compared to that at 1200 °C, while the rearrangement of novolac structures is dominant at 900–1200 °C with a slight volume shrinkage fluctuation of 6%. Resultantly, the amount of micropore first increases and then decreases, while the particle size experiences an opposite change. The microstructure correspondingly transforms from a completely amorphous state to a partially amorphous state with graphite crystallites in low-angle misorientation, and then with graphite-like entangling ribbons. Due to the reduced residual tensile stress and increased interfacial bonding, the resulting composites with a variable bulk density of 0.58–0.64 g cm−3 have much higher compressive strengths of 45.8–96.9 MPa than other reported carbon foams or aerogels with similar bulk densities. The increase of strength and modulus with carbonization temperature is mainly due to the smaller tensile stress, higher particle packing compactness, larger microcrystallite size and less residual organo-functional groups. The composites also present a relatively low thermal conductivity of 0.12–0.59 W m−1 K−1. The increase of thermal conductivity with temperature is related to the synergistic effect of reduced phonon scattering associated with smaller specific surface area, larger microcrystallite size and less organo-functional groups and improved phonon transfer associated with increased inter-particle contact area. [Display omitted] [ABSTRACT FROM AUTHOR]

Aerogels are excellent thermal insulation materials with extremely low thermal conductivity. However, the practical applications of traditional oxide aerogels, such as SiO 2 and Al 2 O 3 aerogels, are limited by the disadvantages of easy sintering and intrinsic brittleness. SiC is a good candidate for new aerogel due to its superior stability and good properties from room to high temperatures. However, it is generally supposed that SiC cannot be employed as thermal insulation material because of its high intrinsic thermal conductivity. We herein developed SiC nanowire aerogel with quite low thermal conductivity using freeze-drying method. The fabricated SiC nanowire aerogel exhibits ultra-high porosity (∼99.5%), excellent high-temperature stability (∼1700 °C), extremely low thermal conductivity (0.035 W/(m⋅K)) and good compressive flexibility. The low thermal conductivity is resulted from ultra-high porosity and multi-level nanostructures. Flexible compression behavior is attributed to the capability of moving and buckling of SiC nanowires, originating from both ultra-high porosity and strong connection between nanowires. This exploration highlights the flexible SiC nanowire aerogel as a promising high temperature thermal insulation material. [ABSTRACT FROM AUTHOR]

[Display omitted] • Macro PPBESK beads with hierarchical pores are fabricated via NIPS approach. • PPBESK beads have a good thermal insulation property in a wide temperature window. • The compression modulus of PPBESK beads is more than 50 times higher than PS foam. • The performance can be controlled by the composition of the coagulation bath. Preparation of porous materials from high-performance polymers holds great promise for various advanced engineering applications like thermal insulation. However, it is still a great challenge to fabricate them due to the difficulties in manufacturing them. Herein, a high performance polymer material poly(aryl ether sulfone ketone)s containing phthalazinone and biphenyl moieties (PPBESK) was utilized to fabricate porous materials via a frequently used and simple method named non-solvent induced phase separation (NIPS). Macro porous PPBESK beads have been fabricated in different non-solvent coagulation baths. The kinetics of the phase inversion processes are visualized by the optical microscope. The multi-scale porous structures formed inside the beads endow them an excellent thermal insulation performance in a wide temperature window and a high mechanical performance that the compression modulus is more than 50 times higher than Polystyrene (PS) foam. Therefore, these PPBESK beads provide an optimized combination of functionalities including high mechanical strength and good thermal insulation, which could turn out to be useful in harsh environmental applications. [ABSTRACT FROM AUTHOR]

In the field of building energy conservation, the development of biodegradable biomass aerogels with excellent mechanical performance, flame retardancy and thermal insulation properties is of particular importance. Here, a directional freeze-drying method was used for fabricating composite sodium alginate (SA) aerogels containing functionalized ammonium polyphosphate (APP) flame retardant. In particular, APP was coated with melamine (MEL) and phytic acid (PA) by a supramolecular assembly process. Through optimizing the flame retardant addition, the SA-20 AMP sample exhibited excellent flame retardant and thermal insulation properties, with the limiting oxygen index of 38.2 % and the UL-94 rating of V-0. Such aerogels with anisotropic morphology demonstrated a low thermal conductivity of 0.0288 (W/m·K) in the radial direction (perpendicular to the lamellar structure). In addition, as-obtained aerogels displayed remarkable water stability and mechanical properties, indicating significant potential for practical applications. [Display omitted] • A high-efficiency flame retardant was synthesized. • AMP has a good interface compatibility with sodium alginate. • SA-20 AMP reached V-0 rating and the LOI value was 38.2 %. • Directional freezing endows SA-20 AMP with outstanding thermal insulation properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • A method is developed for the regulation of secondary unstable dendrites during ice crystal growth. • The flexible polyimide (PI) aerogels possesses a micro/nano multi-scale porous skeleton. • The PI aerogels are characterized by ultra-low density and exceptional thermal insulation. The freeze-casting is widely utilized as a tool for regulating micro-scale pore structures in the fabrication of flexible polyimide (PI) aerogels for applications in adsorption, filtration, and fire-retardant. Herein, a confinement-controlled freeze-casting method is developed to fabricate PI aerogels with excellent thermal insulation properties by designing multi-scale structural adaptability. In a confinement-controlled system, the enhanced solid/solid and solid/liquid interface interactions in the solution dispersion system induce dendritic evolution of ice crystals. Under the directional freezing, grown dendritic ice crystals squeeze the loaded particles to form polyamic acid salt (PAAs) cryogels. Followed by template removal and thermal imidization, PI aerogels with a micro/nano-scale slit-like porous structure were obtained. The PI aerogels are characterized by ultra-low density (as low as 9.82 mg/cm3) and exceptional thermal insulation performance (25.0 mW/(m·K) at 25 °C). [ABSTRACT FROM AUTHOR]

Pyrochlore ceramics with chemical formula A 2 B 2 O 7 (A= rare earth, B= tetravalent metal) have extremely low thermal conductivities (κ) and are thought to be promising candidates for thermal barrier coatings (TBCs) applications. This study reports κ for nanocrystalline (nc) Gd 2 Ti 2 O 7 pyrochlore fabricated by spark plasma sintering followed by sintering at different temperatures to better understand their thermal properties. The structural analysis confirmed the synthesis of single-phase nc-Gd 2 Ti 2 O 7 pyrochlore. The thermal conductivity investigations displayed a systematic decrease in thermal conductivity from 1.6 Wm−1K−1 to 0.6 Wm−1K−1 for the sample sintered at a lower temperature due to high porosity. The value of the κ is found to decrease sublinearly (κ ∝ T-α, where 0 < α < 1) with temperature for all the nc-Gd 2 Ti 2 O 7 pyrochlore samples. DFT- GGA calculation exhibits that the nc-Gd 2 Ti 2 O 7 is a direct band gap at the Γ point of the Brillouin zone, and its value is increased with the sintering temperature. In addition, the effect of sintering temperature on the specific heat capacity (C p) is insignificant in nc-Gd 2 Ti 2 O 7 structures, as confirmed by the quasi-harmonic approximation. Theoretical and experimentally determined results are in good agreement, and values are compatible with the thermal insulation requirements for various applications. • The thermal conductivity (κ) decreases from 1.6 Wm-1K-1 to 0.6 Wm-1K-1 with lowering sintering temperature. • The thermal conductivity (κ) decreases similarly for the highly dense samples sintered at 1000 ℃ and 1200 ℃. • The κ value decreases sublinearly (κ ∝ T-α, where 0 < α < 1) with temperature for all the nc-Gd 2 Ti 2 O 7 pyrochlore samples. • DFT calculated specific heat capacity (C p) systematically increases with increasing measuring temperature. [ABSTRACT FROM AUTHOR]

The use of bio-based building materials is a sustainable opportunity to reduce the environmental footprint associated with the construction sector. The achievement of this objective is primely achieved through the valorisation of vegetable waste, resulting in a reduction in the use of primary source material and waste generation. Within the scope of this study, the focus is directed towards research concerning the thermal, acoustic, and fire behaviour properties of bio-based building materials. This study conducts a comprehensive bibliometric analysis encompassing all documents meeting these criteria within the Scopus database, spanning two decades, from 2003 to 2023. The comprehensive analysis covered a total of 1081 documents, which were analysed. This analysis furnishes insight into various facets, including the temporal evolution of publications, journals boasting the highest publication counts and impact, influential research areas, countries with substantial contributions and their collaborative patterns, noteworthy affiliations, prolific authors, and seminal documents, alongside recurrent keywords. The objective of this comprehensive study is to provide a detailed analysis of the documents published up to the present day, in order to identify research gaps and potential opportunities in this field, to assist new researchers interested in the subject. The analysis reveals that bio-based building materials have gained substantial attention over the past decade. With each passing year, the published documents have increased their impact and become more specific, underscoring the growing importance of this subject. This evolution has also fostered a broader network of researchers engaged in this field. However, it is noteworthy that the characterization of these materials focuses predominantly on their thermal properties, while research avenues related to acoustic and fire properties remain less explored and present opportunities for future investigation. • This study contributes to identify research gaps and potential opportunities in the field of bio-based building materials. • Studies in bio-based building materials have shown an annual growth of the 25% since 2014, being a topic on the rise. • France and China are the countries with the highest scientific publication on bio-based building materials. • Keywords play a crucial role in making visible the research within bio-based building materials. • "Thermal Conductivity" and "Thermal insulation" are the most repeated keywords in this field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Core-shell mesoporous silica-coated VO 2 (M) nanomaterials (VO 2 @m-SiO 2, VmS) were prepared for the first time. • VmS pore size 3.1769–12.8257 nm, thickness 13–58 nm and structurally controllable. • T c and ΔT c of VmS decrease with increasing mesoporous pore size at suitable thicknesses. • The VmS5/PVB composite film A-T lum up to 62.24%, ΔT sol reach 5.16%. • VmS effectively improves the Mie scattering effect of feedstock VO 2 (M). In this study, a hybrid approach using the Stöber and solvent extraction techniques was employed to synthesize mesoporous silicon-coated VO 2 nanomaterials (VO 2 @m-SiO 2 , VmS) with controllable pore sizes and shell thicknesses. This synthesis was aimed at elucidating the influence of mesoporous silicon coatings on the thermochromic effect and optical properties of VO 2. Experimental findings reveal that the mesoporous silica architecture markedly improve the phase-transition hysteresis of VO 2 while mitigating the Mie effects attributable to particle coarsening, under the appropriate shell thickness. Furthermore, concomitant with the enlargement of the mesoporous aperture, the T lum and ΔT sol of the VmS/PVB films also exhibit upward trends. T lum reaches 73.33% and 62.24% in VmS3/PVB and VmS5/PVB, peak ΔT sol reaches 5.16% in VmS5/PVB. The facile synthesis procedure of VmS, in conjunction with its superior performance across phase transition, optics, and thermal insulation metrics, offers a viable pathway for industrial-scale deployment of VO 2 (M) in smart window applications. [ABSTRACT FROM AUTHOR]

Natural fiber-based foams demonstrate outstanding potential for energy-efficient building and personal protective equipment applications due to their lightweight, high porosity, and sustainability. However, the weak interfacial interaction among fibers, functional additives, and the matrix hampers effective stress dissipation, largely affecting the material performance. Herein, this paper demonstrates a facile strategy for fabricating high-performance collagen fiber-based foams by constructing efficient energy dissipation networks using tannin-modified leather collagen fibers (T-LCF) and waterborne polyurethane (WPU). Tannin acts as a coupling bridge, linking the fiber and polyurethane to create a hydrogen-bonded network, enhancing energy dissipation and imparting excellent mechanical properties. Compared to WPU foam (WPUF), the T-LCF-based foam (WPUF/T-LCF) showed 65%, 34 times, and 35% improvements in tensile strength, compressive strength, and ultimate oxygen index, respectively. This study provides new insights into the cleaner production of high-performance natural fiber-based foam composites and a new way for the high-value utilization of collagen solid waste. [Display omitted] • Innovatively produces high-performance collagen fiber foam with tannin-modified fibers and polyurethane. • Tannin acts as a bridging agent, enhancing mechanical properties and flame resistance. • Foam exhibits significant improvements in mechanical and thermal insulation behaviors. • This innovative approach contributes to the sustainable utilization of collagen solid waste. [ABSTRACT FROM AUTHOR]

Intumescent fireproof coating (IFC) can effectively slow down the temperature rise of base materials by constructing intumescent heat isolation chars. Expandable graphite (EG), combined with a typical intumescent flame-retardant system, shows an excellent expansion effect. However, it is difficult to be evenly dispersed in the coating system due to its low surface energy, thus limiting its application in IFC. In this research, EG encapsulated by polyvinyl alcohol (PVA) film was used in combination with conventional intumescent flame retardants to prepare a fireproof coating. Due to the increased hydrophilicity caused by the hydroxy groups of the PVA, both the dispersion and adhesion of EG can be greatly improved in the coating. Additionally, PVA also plays the role of a charring agent to further upgrade the quality of the produced carbon layer. The prepared IFC displays a satisfying synergistic effect. The experimental results showed that the back-surface temperature of the steel plate coated by PVA@EG was reduced to 232 °C after 20 min, far lower than the 250 °C of the unmodified EG system, and the thermal insulation performance was enhanced significantly. Compared with the untreated EG coating, the HRR, THR, and TSR decreased by 79.5 %, 86.0 % and 24.8 %, respectively, and combustion and smoke suppression performance were improved greatly. All in all, PVA@EG endows the coating with superior flame-retardant and thermal insulation performance and greatly improves the safety of steel structures in buildings. [Display omitted] • The PVA film was encapsulated on the surface of the EG to enhance the dispersion and adhesion of the EG in the coating. • The PVA in PVA@EG can act as a carbon source and increase the residual char. • The PVA @ EG coating exhibits better flame retardant, heat insulation and smoke suppression properties. [ABSTRACT FROM AUTHOR]

Gas absorption capability of material proposes a dominant role in the energy storage, selective gas absorption/capture. Aerogels with ultra-high porosity, ultra-low thermal conductivity have been widely used in gas absorption. However, a persistent limitation of these materials is their static and unalterable gas absorption capacity. In this work, a wrinkled graphene structure is proposed to adjust the gas capability. A series of molecular dynamics (MD) simulations are carried out to propose an atomic-level understanding of the effects of wrinkled structure, including effects of pressure, surface wettability, number of gas molecules, thermal insulation, and mechanical properties. It is found that the gas capability can be reduced by 20% with wrinkle structure. Notably, the linear response between pressure and gas absorption capability is observed. Moreover, wrinkle structure functions as a thermal resistance to restrict solid heat transfer. The mechanical property of the aerogel composite is improved by a doped graphene sheet with a high wrinkle degree. This work will pave the way for the development of aerogel with high and selective gas absorption capability. • MD model of wrinkled graphene doped silica aerogel is built. • A linear response between pressure and gas absorption capability is found. • Wrinkle graphene damages the gas absorption. • High degree of wrinkle graphene improves the mechanical properties. [ABSTRACT FROM AUTHOR]

High-temperature molten vitreous (HTMV), as the primary means of hazardous waste disposal, was produced in large quantities. Exploring its potential in photothermal applications could extend its high-value. Herein, the HTMV was used to explore the photothermal performance potential. It indicates that the HTMV possesses significant photothermal conversion capability, capable of increasing the tested water temperature by 6.65 °C. The HTMV mass and water volume are critical factors affecting the water temperature outcomes. The HTMV exhibits distinct conversion capabilities when applied at different application scenarios on the test object. Application on the bottom primarily focuses on photothermal conversion with high heat production efficiency, while side application additionally demonstrates excellent thermal insulation properties. Based on heat balance and backpropagation neural network predictions, optimal scheme of HTMV on both inside and outside bottom application scenarios of the heated object can achieve a maximum heat input of 660.6 kJ m−2 and 570.1 kJ m−2, respectively, and reduce carbon emissions by 0.062 kg CO 2 m−2 and 0.054 kg CO 2 m−2. This study not only provides a foundation for the further application of HTMV but also opens a new direction for the development of photothermal conversion materials, which is of great significance in advancing sustainable energy technology. [Display omitted] • HTMV from hazardous waste shows photothermal potential. • HTMV Attached as bottom can additionally increase water temperature by 6.65 °C. • 660.6 kJ m−2 heating and 0.062 kg CO 2 /m2 reduction can be realized. [ABSTRACT FROM AUTHOR]

Thermally conductive, insulating thermal interface materials (TIMs) for solving heat transport problems are facing greater opportunities and challenges than ever before. In this study, a three-dimensional boron nitride (BN)/graphene oxide (GO) skeleton prepared by the ice template method ensures the directional motion of the heat flow. The GO is modified by atom transfer radical polymerisation, so that the GO is connected to the BN through hydrogen bonding and π-π interactions；increases the reaction position of the curing agent with the epoxy group, accelerates the curing reaction of the composite, and synergistically reduce the filler-filler and filler-matrix interfacial thermal resistance. The thermal conductivity of the prepared 3D/BN/GO-EP composites can reach 1.07 W m−1K−1 at a low filler content of 20 wt%, as well as good electrical insulation (volume resistivity 2.59 × 1013 Ω cm) and excellent compression properties (compressible up to 60% of deformation). Meanwhile, Dual Network Co-Transmission Heat Strategy provides a new idea for the research of advanced polymer-based thermal management materials. [ABSTRACT FROM AUTHOR]

• A silicate thermal insulation coating was prepared using water glass, etc. • The properties and structures of the coating were analyzed by various methods. • The coating formed a Si-O three-dimensional network structure at high temperatures. • The optimal preparation parameters and thermal insulation efficiency were determined. Thermal insulation slurry was fabricated using sodium silicate water glass (SSWG) as the film-forming material and hollow glass microspheres (HGM) as thermal insulation fillers. The thermal insulation slurry was coated on 316L stainless steel to fabricate a silicate thermal insulation coating. The results show that SiO 2 phase is formed by SSWG in the thermal insulation coating after sintering at 680 ℃. Through polymerization and dehydration reactions between Si-OH groups, the Si-O three-dimensional network structure develops at 680 ℃. The optimal value of SSWG to aggregate mass ratios is 2.00. Under this condition, the silicate thermal insulation coating exhibits smooth surface, continuous and dense microstructure, high Shore hardness of 50.1 HSD, remarkable thermal insulation efficiency of 21 % at 260 ℃, and excellent resistance to drop and thermal shock tests without any noticeable cracks or detachment. [ABSTRACT FROM AUTHOR]

Using natural porous and fibrous materials for acoustic and thermal conditioning in the construction sector is a solution to achieve a comfort level in buildings. The novelty of this research work lies in employing agricultural and agro-industry waste to solve noise and thermal insulation problems. This study was conducted to investigate a multilayered panel made of fruit stones and coconut fibre from agro-industry waste. Acoustic absorption, and acoustic and thermal transmission, tests were run on four different fruit stone types, olive, cherry, apricot and peach, plus a coconut fibre layer. Although they are not structural elements, bending tests were run to ensure panels' structural integrity. Acoustic tests complied with the recommendations of Standards ISO 10534–2 and ASTM E 2611–09, based on the standing wave tube to obtain the acoustic absorption coefficient and sound transmission loss, respectively. Standard EN 12667 was considered for the thermal test to determine the thermal conductivity coefficient based on the hot plate method. The results show an average sound absorption coefficient above 0.5 and sound insulation over 25 dB within certain frequency ranges. The cherry panels had absorption values of around 0.7 and apricots had sound insulation values of up to 30 dB. Samples' thermal transmittance coefficient values were between 3.0 and 3.4 (W/m2K), which indicate panels' ability to provide thermal insulation. The cherry and olive panels obtained the lowest thermal conductivity (around 0.14 W/mK). The backing effect of the coconut fibre layer improves all the panels' acoustic absorption and thermal properties. [Display omitted] • These natural materials reduce the environmental impact and support a more sustainable construction industry. • Acoustic and thermal properties of multilayer panels composed of fruit stones and coconut fibres. • The panels made of the studied materials, have inherent strength and stiffness that allows them to be structurally stable. • The results show an average sound absorption above 0.5 and sound insulation above 25 dB in certain frequency ranges. [ABSTRACT FROM AUTHOR]

The incorporation of phase change microcapsule (microPCMs) substantially augmented the temperature regulation capacity of foams, endowing it with outstanding application potential in numerous industrial domains. However, interfacial compatibility issues between the capsule and the substrate always exist and affect foam performance. In this study, a milli-meter macrocapsule (macroPCMs) containing microPCMs was prepared using calcium alginate gel as the second layer wall to physically improve the interfacial compatibility. And poly (N-hydroxymethyl acrylamide) was in situ polymerized in the gel layer and provided active alcohol hydroxyl groups to form chemical grafting with the polyurethane raw materials, which further chemically improved the interfacial compatibility. These measures created a significantly improved foam microstructure and a greatly increased foaming capacity, which thus endow the composite foam with excellent thermal insulation performance and mechanical strength. Compared with conventional microPCMs-based foam, the foaming capacity of the macroPCMs-based foam increased by 40 folds, the temperature regulation duration increased by 7 folds, and the mechanical performance increased by 3 folds. Moreover, the insulated incubator fabricated with the macroPCMs-based foam exhibited two-fold greater thermal insulation efficiency than conventional models containing internal ice incubator, which validated the potential of employing macroPCMs-based polyurethane foam in cold chain logistics applications. [Display omitted] • Double-layered macrocapsules with reactive groups on the shell material was synthesized. • The double-layered microcapsules physically and chemically improved the capsules/foams interfacial compatibility. • The improved interfacial compatibility greatly enhanced the macroscopic performances of the composite foams. [ABSTRACT FROM AUTHOR]

Laser technology has made great progress over the past decades. However, corresponding defense systems have lagged slightly behind. Therefore, there is significant room for research with respect to the principles and bases of existing laser protective materials. In this paper, a kind of silica aerogel material is prepared with the acid-base sol-gel process. Considering the influence of thermal conductivity and the porosity of the aerogel materials on the laser irradiation results, the best laser resistance times of the materials were obtained. The concept of the maximum energy transfer radius is proposed to build a preliminary laser irradiation model for porous materials. It indicates that under the irradiation of a continuous wave laser with a power of 7 kW·cm−2, the silica aerogel materials with the thickness of 3, 6, and 9 mm can withstand the laser for maximum times of 26, 61, and 100 s, respectively. After 7 s of irradiation, the surface temperature of 3 mm from the laser incident point is 226.9 °C. Aerogels, especially silica aerogels, should be considered as future laser protection materials. The extremely low thermal conductivity and the strong scattered ability for laser of these materials will provide a good defensive effect against large-energy laser weapons. [ABSTRACT FROM AUTHOR]

High-strength thermal insulation mortar, with its excellent mechanical properties and thermal insulation performance, is commonly used in building structure insulation and reinforcement renovations. In this study, vitrified microbeads and expanded perlite (EP) were used as thermal insulation materials to create high-strength thermal insulation mortar. The effects of the replacement percentage of these materials (50%, 65%, 75%, and 80%) on the density, water absorption, porosity, compressive and flexural strength, and thermal conductivity of the mortar were studied. The results show that increased replacement percentages of vitrified microbead (EP) led to a decrease in the density of the mortar and an increase in the water absorption rate and porosity. Furthermore, when the replacement percentages were increased, the compressive and flexural strength and the thermal conductivity of the mortar were reduced. Comparative analysis of the pore structure of high-strength thermal insulation mortar using scanning electron microscopy and digital microscope revealed the influence of vitrified microbead (EP) on the internal pore structure of high-strength thermal insulation mortar. The influence coefficient (η s) of volume replacement percentage of insulation materials was introduced using the Hamilton and Crosser models. Furthermore, the prediction model of thermal conductivity of high-strength thermal insulation mortar was established under different volume replacement percentages of vitrified microbead (EP). The calculated values of the model matched well with the measured values, with the ratios of the calculated values of the model to the experimental ones ranging from 0.85 to 1.15. • The physical, mechanical, and thermal conductive properties of mortar are found to be influenced by the amount of insulation. • The prediction model of thermal conductivity of high-strength thermal insulation mortar is established. [ABSTRACT FROM AUTHOR]

A super-hydrophobic multifunctional coating (SMC) was designed and fabricated by combining commercial TiO 2 with polydimethylsiloxane and perfluorodecyltrichlorosilane. The main objective of this research is to enhance the feasibility and effectiveness of SMC coating for building protection. After optimization, the comprehensive performance was significantly improved. The SMC not only significantly improves the water repellency of concrete (decreasing the capillary water absorption by 92.91 %), but also endows concrete with great self-cleaning and photodegradation properties. Additionally, ultraviolet–simulated (90 d) and practical environment (150 d) irradiation tests demonstrate the superior radiative cooling properties of SMC. COMSOL finite element simulation indicates about 20 % of ultraviolet light absorbance and 80 % of visible and near-infrared light reflectance on the SMC. The multifunctional SMC coating not only enhances the water repellency and self-cleaning properties of concrete, but also demonstrates excellent radiative cooling capabilities. These findings highlight the potential of the SMC coating as a promising material for sustainable and energy-efficient building applications. [Display omitted] • A novel multifunctional coating was designed to protect buildings. • The water absorption of concrete can be reduced by 92.91 % with protection (8 days). • The coating possesses great self-cleaning and photodegradation properties. • The coating can protect building against solar radiation and high temperatures. [ABSTRACT FROM AUTHOR]

Aluminosilicate aerogels are promising thermal insulation materials for high temperature applications. In this study, aluminosilicate aerogels were effectively synthesised using affordable precursors: dispersible boehmite powder and waterglass solutions, with subsequent drying achieved by supercritical CO 2 processing. According to the evaluation of their properties, the Al–Si aerogels exhibited low densities (0.11 g/cm3), low thermal conductivities (<0.021 W/m·K) and high specific surface areas (SSA) (516 m2/g for an Al:Si molar ratio of 3:1). When waterglass-based aerogel and aluminosilicate samples were treated at high temperature (1200 °C), the formation of mullite was demonstrated for the aluminosilicate aerogel with a molar ratio of Al:Si 3:1, which showed a higher value for SSA compared to the waterglass-based aerogel. [Display omitted] • Low-cost waterglass and boehmite precursors were employed in aerogel's preparation. • Aluminosilicate aerogels present low densities and low thermal conductivity values. • Aluminosilicate aerogel materials exhibit uniform structure and high specific surface area. • Porosity is retained after heat treatment at 1200 °C for the aerogel with an aluminium: SiO2 molar ratio equal to 3. [ABSTRACT FROM AUTHOR]

• The fabrication process of Ni-P-Al 2 O 3 hollow microlattice is proposed. • The high-temperature antioxidant property of hollow microlattice is improved. • The heat insulation performance can be enhanced up to 13.9%. Hollow microlattice material is a kind of excellent heat insulation material due to its special microstructural characteristics and ultra-low relative density. However, the possibility of oxidation at the temperature higher than 500℃ limits its application in the high-temperature insulation fields, such as rockets and aircraft engines. In order to overcome this obstacle, this study successfully prepared nano-Al 2 O 3 reinforced metallic hollow microlattice materials with an equivalent density of 26.5 mg/cm3. Heat insulation tests and thermogravimetric (TG) experiments were also carried out to investigate the thermal performances of the Al 2 O 3 reinforced metallic hollow microlattice materials, while the effect of the concentration of the Al 2 O 3 was also investigated in accordance with the comparative tests. The results indicate that the Al 2 O 3 plays a significant role in hindering the high-temperature oxidation of hollow microlattice material, especially with Al 2 O 3 concentration in the range of 2 g/L to 4 g/L, and the heat insulation performance can be improved by 13.9%. [ABSTRACT FROM AUTHOR]

Recycled concrete powder (RCP) is a promising supplementary cementitious material, its application in thermal insulation materials is however very limited. In this study, the influence of RCP substitution on the properties of insulation mortars was investigated. The results showed that as the RCP content increased, the compressive strength and thermal conductivity of insulation mortars decreased by 39.8% and 16.8%, owing to the increasing volumes of porous paste and internal air voids. Note that the mortar containing a high content (50 wt%) of RCP struggled to meet the strength requirements of the specification. Therefore, CO 2 curing was further employed here to alleviate the strength loss and successfully increased the compressive strength by 11%∼38%. It was found that since the CaCO 3 particles formed and densified the microstructure (confirmed by the porosity test), the strength reduction derived from the RCP substitution was compensated for. Consequently, insulation mortars incorporating 50% RCP after CO 2 curing for 7 days exhibited satisfactory compressive strength (∼ 0.22 MPa) and relatively low thermal conductivity (∼ 0.048 W/(m∙K)). The mortars showed improved aesthetic appearance and excellent thermal insulation capacity in both hot and cold environments. This study proposed a successful approach to combining reutilization of RCP and CO 2 curing in insulation mortar generation, which effectively improved the sustainability of materials. • A novel and sustainable EPS insulation mortar is developed for energy-efficient buildings. • The synergistic influence of the RCP substitution and CO 2 curing duration is studied. • Remarkably low thermal conductivity is attained through the incorporation of RCP. • Excellent aesthetic appearance and thermal performance are achieved simultaneously. [ABSTRACT FROM AUTHOR]

In this study, a high-entropy approach was employed to design a new single-phase A 2 B 2 O 7 oxide for thermal insulation applications. Multicomponent high-entropy oxides, containing up to seven different cations, were successfully synthesized in a single defective fluorite structure. We observed that the incorporation of the functional cation, Zn2+, effectively blocked the heat radiation phenomenon by reducing the photon mean free path, and further reduced the high-temperature thermal conductivity owing to the larger free carrier concentration originated from the large number of oxygen vacancies. Although a large concentration of Zn2+ caused a slight reduction in thermal expansion, this study suggests that functional cations can be easily incorporated; thus, expanding the material diversity beyond the typical doping levels to develop new thermal barrier materials. [ABSTRACT FROM AUTHOR]

The Al-doped SrZrO 3 perovskite powder with low infrared emissivity at high temperatures was prepared. The infrared radiation performance and thermophysical properties of the perovskites at high temperatures were discussed. As a result, the infrared emissivity of the Al-doped SrZrO 3 perovskite powder is associated with Al3+-doping content, phase composition and particle morphology. The flaky particles SrZr 0.85 Al 0.15 O 2.925 formed by heat treatment at 1000 °C for 6 h have the lowest infrared emissivity of 0.245 in 3–5 μm wavebands at 590 °C. The perovskite powder's infrared emissivity is positively correlated with its electrical resistivity and has no apparent change after heating over 800 °C for long-term. The SrZr 0.85 Al 0.15 O 2.925 perovskite ceramic formed by pressureless sintering still maintains ideal heat insulation performance with the thermal conductivity from 1.17 to 2.21 W m−1 K−1 below 1400 °C. The Al-doped SrZrO 3 perovskite tablet exhibits significant weak radiation intensity due to its characteristics of both low infrared emissivity and thermal conductivity at high temperatures. [ABSTRACT FROM AUTHOR]

To meet demand for lightweight and high-strength ceramic foams, in-situ self-reinforced Si 3 N 4 ceramic foams, with compressive strength of 13.2–45.9 MPa, were fabricated by protein foaming method combined with sintered reaction-bonded method. For comparison, ordinary protein foamed ceramics with irregular block microstructure were fabricated via reaction-bonded method, which had compressive strength of 3.6–20.5 MPa. Physical properties of these two types of samples were systematically compared. When open porosity was about 80%, both types of Si 3 N 4 ceramic foams had excellent thermal insulation properties (<0.15 W m−1 K−1), while compressive strength of in-situ self-reinforced samples increased by more than 158% compared with ordinary samples. Under high-temperature oxidation conditions, microstructures of both types of samples were deformed with increase in oxidation temperature. Moreover, after oxidation temperature was increased to 1400 °C, oxidation weight gain decreased from 18.07% for ordinary samples to only 2.18% for self-reinforced samples. Thus, high-temperature oxidation resistance of Si 3 N 4 ceramic foams was greatly improved. [ABSTRACT FROM AUTHOR]