Thermal and Mechanical Performances of the Superflexible, Hydrophobic, Silica-Based Aerogel for Thermal Insulation at Ultralow Temperature

Abstract

A superflexible hydrophobic silica-based aerogel (FHSA) was prepared via a facile sol−gel process and ambient pressure drying method. The FHSA was treated at different temperatures varying from −196 to 450 °C to evaluate its thermal and mechanical performances. The evolutions of the physical property, hydrophobicity, microstructure, pore structure, and chemical structure of the FHSA with the various treatment temperatures were investigated comprehensively. The structure of the FHSA did not show an obvious change after treatment in the liquid nitrogen. The bulk density of the FHSA increased from 0.047 to 0.077 g cm −3 when the thermal treatment temperature increased from 25 to 450 °C. The specific surface area and pore volume of the FHSA increased with the treatment temperature owing to the decomposition of the organic moieties. The Fourier transform infrared spectra showed that the methyl groups in the FHSA had excellent thermostability up to 400 °C. The water contact angles of the FHSA after treatment at

Facile and environment-friendly preparation of high-performance polyimide aerogels using water as the only solvent

“…This was because the thermal conductivity of non-metals increases with the increase in temperature. 44…”

“…This was because the thermal conductivity of non-metals increases with the increase in temperature. 44 We placed the PI aerogels on a heating platform at a temperature of up to 300 °C, to visually observe the thermal insulation performance of the aerogel. The dynamic conduction of heat was observed by using an infrared thermal imager.…”

Multilevel Structural Design and Heterointerface Engineering of a Host–Guest Binary Aerogel toward Multifunctional Broadband Microwave Absorption

“…The functional groups of the pure BPSi and rGO-BPSi2 aerogels were validated by ATR-FTIR spectroscopy. As shown in Figure 2d, Si−O−Si groups (1105, 1015, and 767 cm −1 ), −CH 3 (2930 cm −1 ), Si−CH 2 − (1265 cm −1 ), Si−CH 3 (825 cm −1 ), and a small amount of unreacted Si−OH groups (918 cm −1 ) 39 are observed in pure BPSi aerogel. An additional C=C group from reduced graphene oxide located at 1565 cm −1 is observed in the rGO-BPSi2 hybrid aerogel.…”

Thermal Insulation and Flame Retardancy of the Hydroxyapatite Nanorods/Sodium Alginate Composite Aerogel with a Double-Crosslinked Structure

“…4−6 A typical inorganic aerogel (SiO 2 ) exhibits extremely low thermal conductivity, but the poor mechanical properties limit wide practical applications. 7 Some organic aerogels (for example, RF, PU, PI, etc) with good formability are suitable choices, but the synthesis processes are complex and involve toxic solvents and raw materials, which will cause environmental pollution problems. 8,9 Compared to these traditional aerogels, development of aerogels based on natural polymers has attracted extensive attention to partially replace petroleum-based derivatives.…”