scholarly journals Facile Preparation of High Strength Silica Aerogel Composites via a Water Solvent System and Ambient Pressure Drying without Surface Modification or Solvent Replacement

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3983
Author(s):  
Dongxuan Du ◽  
Fengqi Liu ◽  
Yonggang Jiang ◽  
Junzong Feng ◽  
Liangjun Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Surface Modification ◽  
Silica Aerogel ◽  
Ambient Pressure ◽  
High Strength ◽  
Ambient Pressure Drying ◽  
Synthesis Process ◽  
Insulation Material ◽  
Fiber Density ◽  
Solvent Replacement

To further reduce the manufacturing cost and improve safety, silica aerogel composites (SAC) with low density and low thermal conductivity synthesized via ambient pressure drying (APD) technology have gradually become one of the most focused research areas. As a solvent, ethanol is flammable and needs to be replaced by other low surface tension solvents, which is dangerous and time-consuming. Therefore, the key steps of solvent replacement and surface modification in the APD process need to be simplified. Here, we demonstrate a facile strategy for preparing high strength mullite fiber reinforced SAC, which is synthesized by APD using water as a solvent, rather than using surface modification or solvent replacement. The effects of the fiber density on the physical properties, mechanical properties, and thermal conductivities of SAC are discussed in detail. The results show that when the fiber density of SAC is 0.24 g/cm3, the thermal conductivity at 1100 °C is 0.127 W/m·K, and the compressive strength at 10% strain is 1.348 MPa. Because of the simple synthesis process and excellent thermal-mechanical performance, the SAC is expected to be used as an efficient and economical insulation material.

scholarly journals Silica Aerogel Monoliths Derived from Silica Hydrosol with Various Surfactants

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3192 ◽  
Author(s):  
Dong Chen ◽  
Xiaodong Wang ◽  
Wenhui Ding ◽  
Wenbing Zou ◽  
Qiong Zhu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Silica Aerogel ◽  
Low Cost ◽  
Ambient Pressure ◽  
Silica Aerogels ◽  
Ambient Pressure Drying ◽  
Low Thermal Conductivity ◽  
Silica Hydrosol ◽  
High Production Cost

Owing to their ultra-low thermal conductivity, silica aerogels are promising thermal insulators; however, their extensive application is limited by their high production cost. Thus, scientists have started to explore low-cost and easy preparation processes of silica aerogels. In this work, a low-cost method was proposed to prepare silica aerogels with industrial silica hydrosol and a subsequent ambient pressure drying (APD) process. Various surfactants (cationic, amphoteric, or anionic) were added to avoid solvent exchange and surface modification during the APD process. The effects of various surfactants on the microstructure, thermal conductivity, and thermal stability of the silica aerogels were studied. The results showed that the silica aerogels prepared with a cationic or anionic surfactant have better thermal stability than that prepared with an amphoteric surfactant. After being heated at 600 °C, the silica aerogel prepared with a cationic surfactant showed the highest specific surface area of 131 m2∙g−1 and the lowest thermal conductivity of 0.038 W∙m−1∙K−1. The obtained low-cost silica aerogel with low thermal conductivity could be widely applied as a thermal insulator for building and industrial energy-saving applications.

Characterization and comparison of uniform hydrophilic/hydrophobic transparent silica aerogel beads: skeleton strength and surface modification

RSC Advances ◽  
2015 ◽  
Vol 5 (68) ◽  
pp. 55579-55587 ◽  
Author(s):  
Sekai Zong ◽  
Wei Wei ◽  
Zhifeng Jiang ◽  
Zaoxue Yan ◽  
Jianjun Zhu ◽  
...  
Keyword(s):  
Surface Modification ◽  
Industrial Production ◽  
Silica Aerogel ◽  
Large Scale ◽  
Preparation Method ◽  
Ambient Pressure ◽  
Ambient Pressure Drying ◽  
Silica Beads

This preparation method of skeleton improvement of wet silica beads by ambient pressure drying is suitable for economic and large-scale industrial production of silica aerogel beads.

scholarly journals Thermal Conductivity Performance of Silica Aerogel after Exposition on Different Heating under Ambient Pressure

2019 ◽  
Vol 16 (3(Suppl.)) ◽  
pp. 0770 ◽  
Author(s):  
Israa F. Al-sharuee
Keyword(s):  
Thermal Conductivity ◽  
Silica Aerogel ◽  
Ambient Pressure ◽  
Ambient Pressure Drying ◽  
Drying Method ◽  
Insulation Property ◽  
M 10 ◽  
Basic Characteristics ◽  
Thermal Insulation Property ◽  
Quality Material

         The varied thermal conductivity (insulation) of silica aerogel with heating for different pH has been investigated, it has been depended on ambient pressure drying method in the preparing silica aerogel samples, also six different pH of samples (1, 2, 3, 7, 8 and 9) were treated under five degree of heating with (50,100,150,200 and 250) ᴼC. This technique is important to test the carry-outs hydrophobic silica to temperature without high-quality material changes in the basic characteristics. The hot-wire technique is used in this work to examine the thermal conductivity, Fourier Transform Infrared Spectroscopy (FTIR) depended to characterize the bonds and their artificial by heating. Results show that the samples affected by heating through decreasing the density leading to obtaining more insulation metal, moreover varied pH is an important role in thermal conductivity. The average thermal conductivity of all aerogel samples in this work is (0.01- 0.0061 mW m-10 C-1) this means that it is still below thermal conductivity for air equals to (0.02257) mW m-10 C-1 . Meanwhile, we concluded that the insulation property of silica aerogel is affected by heat treatment and gives it more thermal insulation property.

Facile synthesis of silica aerogel composites via ambient-pressure drying without surface modification or solvent exchange

Vacuum ◽  
2020 ◽  
Vol 173 ◽  
pp. 109117 ◽  
Author(s):  
Dongxuan Du ◽  
Yonggang Jiang ◽  
Junzong Feng ◽  
Liangjun Li ◽  
Jian Feng
Keyword(s):  
Surface Modification ◽  
Silica Aerogel ◽  
Ambient Pressure ◽  
Ambient Pressure Drying ◽  
Solvent Exchange ◽  
Facile Synthesis

Preparation and Characterization of Silica Aerogels/Glass Wool Composites

2012 ◽  
Vol 534 ◽  
pp. 106-109 ◽  
Author(s):  
Jing Xiao Liu ◽  
Xiao Jie Wang ◽  
Fei Shi ◽  
Jia Yu Luo
Keyword(s):  
Thermal Conductivity ◽  
Silica Aerogel ◽  
Ambient Pressure ◽  
Measurement Instrument ◽  
Conductivity Measurement ◽  
Nitrogen Adsorption ◽  
Ambient Pressure Drying ◽  
Glass Wool ◽  
Silica Source ◽  
Adsorption Desorption

Using industrial water glass as silica source, silica aerogel/glass wool composite heat insulation materials were prepared through the gel moulding, surface modification and ambient pressure drying method. The microstructure and porous characteristics of the silica aerogel/glass wool composites were studied by scanning electron microscopy (SEM) and BET nitrogen adsorption-desorption method. The thermal conductivity of silica aerogel/glass wool composites was measured by the thermal conductivity measurement instrument. The results indicate that the as-prepared silica aerogel/glass wool composites exhibit strong hydrophobicity and excellent thermal insulation performance. The thermal conductivity of the obtained silica aerogel/glass wool composites is 1.1×10-2～2.0 W∙m-1∙K-1, and with the increasing of aerogels content, the thermal conductivity of the composites could be decreased further.

scholarly journals Robust Silica–Polyimide Aerogel Blanket for Water-Proof and Flame-Retardant Self-Floating Artificial Island

2021 ◽  
Vol 8 ◽  
Author(s):  
Riyong Liu ◽  
Jin Wang ◽  
Jianhe Liao ◽  
Xuetong Zhang
Keyword(s):  
Thermal Conductivity ◽  
Flame Retardant ◽  
Silica Aerogel ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Three Dimensional ◽  
Ambient Pressure Drying ◽  
Low Density ◽  
Low Thermal Conductivity ◽  
Sol Gel Transition

A robust silica–polyimide (PI) aerogel blanket is designed and synthesized using the PI foam as the matrix and silica aerogel as the filler through an in situ method, where sol–gel transition of silica precursor occurs in pores of the PI foam, followed by the hydrophobization and ambient pressure drying. The density of the aerogel blanket ranges from 0.036 to 0.196 g/cm3, and the low density is directly controlled by tailoring the silica concentration. The specific surface area of the aerogel blanket reaches 728 m2/g. These features of the blanket result in a low thermal conductivity of 0.018 W/mK, which shows a remarkable reduction of 59% compared to that of the PI foam (0.044 W/mK). As a result, a remarkable decrease of 138°C is achieved using the silica blanket as the thermal insulator on a hot plate of approximately 250°C. In addition, the temperature degradation of the blanket is around 500°C, and up to 86% of mass remaining at 900°C is obtained. The blanket is resistant at extremely harsh conditions, e.g., 600°C for 30 min and 1,300°C for 1 min, and no open flame is observed, suggesting a significant flame-retardant of the blanket. Owing to the three-dimensional (3D) porous framework of the PI foam, the silica aerogel is encapsulated in the PI foam and the blanket exhibits strong mechanical property. The silica–PI aerogel can be reversibly compressed for 50 cycles without reduction of strain. The contact angle of the blanket is 153°, which shows a superior waterproof property. Combining with the low density, low thermal conductivity, flame-retardant, and strong mechanical strength, the aerogel blanket has the potential as an artificial island, which is safe (waterproof and flame-retardant), lightweight, comfortable, and easy to be moved.

Experimental Study on Cost-Effective Additive Manufacturing of Silica Aerogel

2020 ◽  
Author(s):  
Zipeng Guo ◽  
Ruizhe Yang ◽  
Tianjiao Wang ◽  
Lu An ◽  
Shenqiang Ren ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Silica Aerogel ◽  
Low Cost ◽  
Ambient Pressure ◽  
Cost Effective ◽  
Supercritical Drying ◽  
Ambient Pressure Drying ◽  
Insulation Material ◽  
Market Demand ◽  
Insulation Property

Abstract The conventional manufacturing process of aerogel insulation material relies largely on the supercritical drying, which suffers from issues of massive energy consumption, high-cost equipment and prolonged processing time. With the consideration of large market demand of the aerogel insulation material in the next decade, a low-cost and scalable fabrication technique is highly desired. In this paper, a direct ink writing (DIW) method is used to three-dimensionally fabricate the silica aerogel insulation material, followed by room-temperature and ambient pressure drying. Compared to the supercritical drying and freeze-drying, the reported method significantly reduces the fabrication time and costs. The cost-effective DIW technique offers the capability to print complex hollow internal structures, coupled with the porous structure, is found to be beneficial to the thermal insulation property. The addition of fiber to the ink assures the durability of the fabricated product. The foam ink preparation methods and the printability are demonstrated in this paper, along with the printed samples for characterizing thermal insulation performance and mechanical properties.

Studies on Thermal Property of Silica Aerogel/Epoxy Composite

2007 ◽  
Vol 546-549 ◽  
pp. 1581-1584 ◽  
Author(s):  
Jiu Peng Zhao ◽  
Deng Teng Ge ◽  
Sai Lei Zhang ◽  
Xi Long Wei
Keyword(s):  
Thermal Conductivity ◽  
Thermal Property ◽  
Epoxy Resin ◽  
Silica Aerogel ◽  
Epoxy Composite ◽  
Transfer Model ◽  
Insulation Material ◽  
Thermal Transfer ◽  
Heat Distortion Temperature ◽  
Ft Ir

Silica aerogel/epoxy composite, a kind of efficient thermal insulation material, was prepared by doping silica aerogel of different sizes into epoxy resin through thermocuring process. The results of thermal experiments showed that silica aerogel/epoxy composite had a lower thermal conductivity (0.105W/(m·k) at 60 wt% silica aerogel) and higher serviceability temperature (Martens heat distortion temperature: 160°C at 20 wt% silica aerogel). In addition, the composite doping larger size (0.2-2mm) of silica aerogel particle had lower thermal conductivity and higher Martens heat distortion temperature. Based on the results of SEM and FT-IR, the thermal transfer model was established. Thermal transfer mechanism and the reasons of higher Martens heat distortion temperature have been discussed respectively.

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