CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
He Huang,Yanhong Lv,Xiangyu Jin,Hebing Wang,Can Wu,Yiwu Pan,Xiaojie Yan,Changqing Hong,Wenbo Han,Xinghong Zhang
Lightweight and flexible aerogels are highly demanded for thermal management in the burgeoning aerospace and artificial intelligence (AI) fields. However, the design and preparation of thermal insulating aerogels integrating good flexibility, low density, and superior thermostability through environmentally friendly methods remains challengeable. Herein, by introducing bifunctional silicone, a strategy of chain elongation assisted with pore structure adjustment is developed to achieve the flexibility of thermostable phenolic resin aerogel (PRA). The silicone introduction effectively suppresses the drying shrinkage, thus enabling the employment of ambient pressure drying (APD). The obtained flexible PRA combining high softness (elastic modulus 0.05 kPa), superior deformability (cyclic compressive strain > 60%, damage strain up to 80%), and good fatigue-resistance (compression at 40% strain > 1000 cycles) exhibits low bulk density (0.058 g·cm −3 ), and low thermal conductivity (0.033 W·m −1 ·K −1 ). With these superior properties, it can effectively serve for static thermal insulation below 200 °C with a thickness of 2–3 mm; more attractively, it can perform dynamic thermal management as a regulator through compressing and releasing (eg. temperature 41.9–57.6 °C, 0–40% compression strain, thickness of 30 mm). These merits make the material promising for AI thermal management in fields like outdoors, aerospace, and infrared camouflage.
研究领域:
材料科学
·
航空航天工程
·
热能工程
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2023
·Vol. 30
·期 15
·9563-9574
·
IF 5.7
Wang Zhixin,E Yuyu,Li Jie,Du Tingting,Wang Kun,Yao Xi,Jiang Jianxin,Wang Meng,Yuan Shengguang
Bacterial cellulose (BC) aerogels with ultralight, low density, and low thermal conductivity are hopeful candidates for environmentally friendly heat insulating materials. However, the application of BC in packaging and building as a heat nonconductor is seriously limited by its flammable characteristics. Hence, we report a moderate approach to fabricating a flame retardant and heat-insulating composite aerogel by introducing zinc borate (ZnB) particles into BC via an ultrasound-assistant deposition process. The in situ synthesis of ZnB particles resulted in the separation of single fibers from fiber bundles in BC instead of damaging its homogeneous porous structure, improving its thermal stability by weakening the convective intensity of heat rays. The heat release capacity of the prepared composite aerogel was only 8 J g −1 k −1 , exhibiting excellent flame retardancy. The probable mechanism proposed to be that the dehydration of ZnB particles lowered the surface temperature by releasing the bound water, and simultaneously produced metallic oxides (ZnO and B 2 O 3 ) for retarding the spread of heat and isolating the flammable fibrils within the combustion area. Besides above scientifical meaning on understanding the thermal insulation process, because of the natural and renewable substrate and the following simple modification process, the present approach has potential applications for industrial-scale production of green and flame retardant material.
研究领域:
材料科学
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环境科学
·
生物技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·Vol. 107
·期 12
·8572-8582
·
IF 3.5
Lei Han,Yu Chen,Huifang Wang,Haijun Zhang,Shaowei Zhang
A combined theoretical and experimental approach was used to investigate high-entropy carbonitride. Density functional theory (DFT) calculations suggest that the [N]/([C]+[N]) ratio in (Ti 1/6 Cr 1/6 V 1/6 Mo 1/6 Nb 1/6 Ta 1/6 )(C 1− x N x ) affects its lattice thermal conductivity which could be decreased by 89% by increasing the ratio from 0 to 1/2. Moreover, a robust, flame-retardant and high-temperature resistant (Ti 1/6 Cr 1/6 V 1/6 Mo 1/6 Nb 1/6 Ta 1/6 )(C 0.64 N 0.36 ) high-entropy carbonitride aerogel (6-HECNA) was synthesized. It exhibited a porosity of 94.3%, a compressive strength of 0.9 MPa, and a good high-temperature stability up to 1673 K. These properties, along with its outstanding fire-retardancy, and low thermal conductivity (0.122 W·m −1 ·K −1 at 298 K), make it a promising candidate material for thermal insulation applications under harsh conditions.
研究领域:
材料科学
·
理论计算
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
ACTA ASTRONAUTICA
·
2025
·
IF 3.4
Chunlei Sun,Guihua Tang,Rui Yang,Mu Du,Cong Wang,Zhigang Liu
Constructing a lunar base is strategically vital for deep space exploration, resource development, and future interstellar migration. However, the absence of atmospheric protection exposes the lunar surface to extremely complex thermal management issues and intense ultraviolet (UV) radiation challenges. For the first time, this study presents a multifunctional composite silica aerogel to enhance UV shielding, thermal insulation, and plant photosynthesis for sustainability in lunar base. The doping scheme is based on the numerical simulation combining Mie scattering, discrete dipoles approximation (DDA) and Monte Carlo method. The optimized UV-opacifier TiO 2 has 0.005% volume fraction and 30 nm particle radius. ITO infrared opacifiers, with volume fraction of 0.05% and radius of 20 nm, reduce infrared radiative dissipation, thereby enhancing thermal insulation. Ag nanorods with volume fraction of 0.001%, length-to-diameter ratio of 3.5, and radius of 10 nm, can filter green light, promoting plant photosynthesis and sustainability. Synthesized with a one-step base-catalyzed sol-gel method, this composite aerogel demonstrates 18.4% improvement in UV resistance compared with traditional transparent aerogels, while maintaining visible light transmittance of 75.2%. The thermal conductivity is 0.0409 W/m·K at 400 K. Its exceptional thermal insulation properties achieve energy savings up to 87.1% under extreme temperature fluctuations on the lunar surface. This composite aerogel can provide crucial solution to the sustainable development of lunar bases.
研究领域:
材料科学
·
天体生物学
·
可持续发展
✓ 已验证
产品关联
DOI
高影响因子
Pigment & Resin Technology
·
2024
·Vol. 54
·期 2
·198-207
·
IF 1.3
Qing Jiang,Yuhang Wan,Xiaoqian Li,Xueru Qu,Shengnan Ouyang,Yi Qin,Zhenyu Zhu,Yushu Wang,Hualing He,Zhicai Yu
PurposeThis study aims to evaluate the thermal performance of sodium alginate (SA) aerogel attached to nano SiO2and its radiative cooling effect on firefighting clothing without environmental pollution.Design/methodology/approachSA/SiO2aerogel with refractory heat insulation and enhanced radiative cooling performance was fabricated by freeze-drying method, which can be used in firefighting clothing. The microstructure, chemical composition, thermal stability, and thermal emissivity were analyzed using Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analyzer and infrared emissivity measurement instrument. The radiative cooling effect of aerogel was studied using thermal infrared imager and thermocouple.FindingsWhen the addition of SiO2is 25% of SA, the prepared aerogel has excellent heat insulation and a high radiative cooling effect. Under a clear sky, the temperature of SA/SiO2aerogel is 9.4°C lower than that of pure SA aerogel and 22.1°C lower than that of the simulated environment. In addition, aerogel has more exceptional heat insulation effect than other common fabrics in the heat insulation performance test.Research limitations/implicationsSA/SiO2aerogel has passive radiative cooling function, which can efficaciously economize global energy, and it is paramount to environment-friendly cooling.Practical implicationsThis method could pave the way for high-performance cooling materials designed for firefighting clothing to keep maintain the wearing comfort of firefighters.Originality/valueSA/SiO2aerogel used in firefighting clothing can release heat to the low-temperature outer space in the form of thermal radiation to achieve its own cooling purpose, without additional energy supply.Graphical abstract
研究领域:
材料科学
·
热能工程
·
纺织科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Huaxiu Xu,Pingping Xu,Di Wang,Yang Yang,Xionglei Wang,Ting Wang,Wenli An,Shimei Xu,Yu-Zhong Wang
Hydrogel-born foam materials have been intensively developed because of great potential in various fields and environmental friendliness with water as foaming agent. However, the energy-consuming nature and pore collapse in the preparing and using process limit their application. Herein, a facile strategy is present to fabricate a dimensional stable hydrogel-born foam by simple acid-heat treatment and subsequent fast microwave foaming. The microwave heating rapidly evaporates and expands water into cells in the gel while the heat softening of the hydrogel further facilitates the formation of the cells. Moreover, the hydrophilicity/hydrophobicity and the crosslinking degree of the foam can be regulated by controllable conversion of amide groups of the hydrogel to the imide groups during the acid-heat treatment. As a result, it successfully avoids the pore collapse in both of the preparation and use process. With hierarchical pore structure and controllable moisture absorption, the foam shows with excellent dimensional and thermal insulation. In addition, the foam provides superior mechanical properties and fire retardance over traditional foams. The flame-retardant mechanism was proposed. The fabrication of this hydrogel-born foam is facile, flexible and can be adapted for extensive applications in building structures.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2020
·Vol. 39
·期 5
·566-572
·
IF 3.154
Luo Qi,Pu Hong-Ting,Zhang Zhi-Hua,Zhang Xiong,Yu Cheng-Long
Multilayer membranes prepared via microlayer coextrusion have attracted wide attention due to their unique properties and broad applications. In present study, the foam/film alternating multilayer sheets based on ethylene-vinyl acetate copolymer (EVA) and high-density polyethylene are successfully prepared via microlayer coextrusion. The cells in the sheets are single-cell-array along the foamed EVA layers with uniform cell size. In addition, the effects of layer number and foam relative thickness on morphology, mechanical properties, damping and heat insulation properties are investigated. The cell size decreases significantly with increasing layer number due to the enhanced confine effects. The tensile strength, elongation at break, and heat insulation also increase significantly. However, the mechanical damping properties change little in the observed frequency. Meanwhile, with higher relative thickness of EVA foam, the sheets have lower tensile strength and lower thermal conductivity, while the damping properties are enhanced in a specific frequency scope. The elongation at break of the optimized sample comes to 800% and the thermal conductivity decreases to 61 mW·m −1 ·K −1 , which shows high toughness and low thermal conductivity, indicating a possible method for preparing materials with high toughness and heat-insulating properties.
研究领域:
材料科学
·
高分子科学
✓ 已验证
产品关联
DOI
高影响因子
CEMENT AND CONCRETE RESEARCH
·
2022
·
IF 11.958
Zhenxing Du,Wenqiang Zuo,Penggang Wang,Wei She
Bubble-templated advanced cellular materials with ultralight and superior thermal insulation properties have shown great potential in energy-saving related applications. However, insufficient bubble stability severely limits the generation of such highly porous structures . Herein, we present an efficient method to produce ultra-stable aqueous foams by combing the amphiphilic Janus nanoparticle (Janus-SiO 2 ) with the surface-active polymer (hydroxypropyl methylcellulose). The life of aqueous foams is dramatically increased from 4 h to over 5 days with 5 wt% Janus-SiO 2 concentration. The dense adsorbed layer formed by the efficient adsorption of Janus-SiO 2 on the bubble film is the main factor for the outstanding foam stability. Owing to the greatly enhanced foam stability, we successfully produce ultralight cellular cement with hierarchical cellular structures and a density as low as 80 kg/m 3 . The ultralight cellular cement exhibits superior mechanical strength , robust fire resistance and excellent thermal insulation with a thermal conductivity as low as 0.038 W·m −1 ·K −1 . This work provides a practical approach for fabricating various advanced porous materials that employ bubbles as templates.
研究领域:
材料科学
·
热能工程
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 13
·4498
·
IF 3.4
Guoshuai Cai,Jiaxuan Wu,Jiayi Guo,Yange Wan,Qingjun Zhou,Pengyu Zhang,Xiaolei Yu,Mingchao Wang
Currently, most thin-layer expandable coatings are polymer-based, with very few inorganic expandable coatings. Due to the high environmental friendliness of inorganic coatings, studying new types of inorganic coatings is of great significance. A novel amorphous aluminum phosphate-based flame-retardant coating was prepared by modifying it with nano-silica, hollow silica beads, hollow glass microspheres, and boron carbide. A comprehensive study was conducted on the flame retardancy and thermal insulation performance, composition and structural evolution under flame and physical and chemical properties, and the mechanisms of flame retardancy and thermal insulation were elucidated. Large-plate combustion testing, bonding strength testing, XRD, IR, TG-DSC, and SEM testing were all applied in this work. The synergistic effect of the four fillers was very obvious, and a series of AP22XY (nano-silica/silica beads/hollow glass microspheres/boron carbide = 2:2:0:4, 2:2:1:3, 2:2:2:2, 2:2:3:1, 2:2:4:0) coatings were prepared. The change in the ratio of glass microspheres to boron carbide had a significant impact on the composition and structural evolution of the coating, thus reflecting its effectiveness as a flame retardant and thermal insulation. Although decreasing the ratio would promote the formation of borosilicate glass and Al18B4O33and improve the thermal stability of coatings, the structure inside of the coating, especially the skeleton, would be dense, which is not conducive to thermal insulation. When the ratio of glass microspheres to boron carbide is 3:1, AP2231 shows the best fire resistance. Under the combustion of butane flame at about 1200–1300 °C, the backside temperature reaches a maximum of 226 °C at 10 min, and then the temperature gradually decreases to 175 °C at 60 min. This excellent performance is mainly attributed to three aspects: (1) the foaming and expandability of coatings when exposed to fire, (2) the multiple endothermic reactions the coating undergoes, and (3) the improvement effect of boron carbide. Additionally, AP2231 shows the best bonding performance with a strength of close to 4.5 MPa after combustion, because of the appropriate content matching between borosilicate glass, Al18B4O33, and hollow glass microspheres. The coating has potential application prospects in the construction and transportation fields, such as the protection of structural steel, fire prevention in subways and tunnels, and the prevention of lithium battery fires.Keywords:flame-retardant coating;thermal insulation;composition and structural evolution;thermal property;bonding performance
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2024
·
IF 6.5
Dongdong Tang,Liangbo Zhu,Xie Li,Yao Ren,Yuan Liu,Qi Wang
The intumescent fireproof coatings (IFC) constructed on the surface of steel can effectively delay the heating rate of the steel under the fire environment, so as to strive for a longer time for personnel evacuation. The char layer formed by the traditional IFC has the disadvantages of easy cracking and falling off. In this work, by using insulating filler hollow glass microspheres (HGM), the I (D) /I (G) value of the coating with the best performance decreased from 1.26 to 0.98. The problem of char layer cracking and falling off was solved. Its 10-minute back temperature is only 181 °C, and the heat insulation effect is significantly improved. In addition, the synergistic effect of HGM and flame retardant system endows the coating with better flame retardant properties. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), cone calorimeter (CCT) and laser Raman spectroscopy (LRS) were used to study the mechanism of improved flame retardant and thermal insulation properties. The HGM uniformly distributed in the coating forms a network structure with Si-O-Si bonds as the skeleton at high temperature. This structure connects the char layer, thereby increasing the strength of the expanded char layer. Therefore, the flame retardant and thermal insulation properties of the coating are improved.
研究领域:
材料科学
·
火灾安全工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2024
·
IF 4.1
Long Ni,Yinfu Luo,Cuiqing Zhou,Haichao Meng,Guanchun Wang,Liwei Yan,Mei Liang,Shaoyu Qiu,Shengtai Zhou,Huawei Zou
Flexible polyimide foams (PIFs) demonstrate a great potential for applications in the fields of thermal insulation, flame retardancy and irradiation tolerance. In this work, mechanically flexible PIFs with anisotropic pore structure were prepared by adopting the copolymerization strategy and microwave-assisted foaming process. The copolymerization reaction was conducted to synthesize polyester ammonium salt (PEAS) precursors using 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) as dianhydride, 4,4′-diaminodiphenyl ether (ODA) and 4,4′-diaminodiphenyl sulfone (DDS) as the copolymerized diamines; afterwards, PEAS powders with particle sizes ranging from 100 to 300 μm were obtained by drying, crushing and sieving treatments, which were used as the feedstock for “bottom-up” microwave-assisted foaming and thermal imidization process, thereby leading to the formation of PIFs with regular three-dimensional near-spherical pores in vertical direction (parallel to the pore growth direction) and the aligned ellipsoidal strip-like pore structure in horizontal direction. The directional growth of foam pores resulted in anisotropic mechanical flexibility and thermal insulation performance. Moreover, PIFs possessed excellent thermal stability and flame retardancy with the initial thermal degradation temperature higher than 545 °C and limited oxygen index up to 58.8%. The PIFs exhibited exceptional thermal insulation performance with thermal conductivity values ranging from 0.0276 to 0.0517 W/(m·K) between 25 and 300 °C. Additionally, the PIFs demonstrated excellent irradiation tolerance, with the mechanical and thermal stability retention rate being above 96% after the irradiation experiment (radiation dosage: 1.15 × 10 5 Gy) using 60 Co source. Thus, lightweight PIFs with superior high temperature thermal insulation performance, flame retardancy and irradiation tolerance were successfully prepared, which showed potential applications in aerospace, medical and nuclear power sectors.
研究领域:
材料科学
·
化学工程
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Advanced Ceramics
·
2022
·Vol. 11
·期 6
·922-934
·
IF 11.534
Liu Wei,Xie Yongshuai,Deng Zhezhe,Peng Ying,Dong Jianhong,Zhu Ze,Ma Dehua,Zhu Luyi,Zhang Guanghui,Wang Xinqiang
Yttria-stabilized zirconia (YSZ) fiber composites are highly efficient thermal insulating materials; however, the poor thermal shock resistance limits their versatile applications. In the present study, YSZ fiber was mixed directly with Al2TiO5 fiber, which had an extremely low thermal expansion coefficient, to prepare YSZ−Al 2 TiO 5 (ZAT) fiber composites by compression molding and heat treatment. The minimum thermal expansion coefficient of the prepared ZAT fiber composites was measured to be 7.74×10 −6 K −1 , which was 26% lower than that of the YSZ fiber composites (10.42×10 −6 K −1 ). It was shown that the prepared ZAT fiber composites maintain the integrity after undergoing 51 thermal shock cycles between 1100 °C and room temperature. Whereas, YSZ fiber composites burst immediately after only one thermal shock cycle under the same condition. In addition, the ZAT fiber composites also exhibit considerable mechanical and thermal insulating performance.
研究领域:
材料科学
·
热力学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）