Abstract
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.
Highlights
Aerogels are the type of nanoporous materials possessing extremely low density, low thermal conductivity, high porosity, and high pore volume, and are potentially used in various fields such as environment, energy, cosmetic, transportation, building, catalyst, and biomedicine (Koebel et al, 2012; Ziegler et al, 2017; Vareda et al, 2018; Qie et al, 2020; Wei et al, 2020; Silica-Polyimide Aerogel BlanketWang and Wang, 2021)
The remarkable reduction of the thermal conductivity of PI foam (0.044 W/mK) may be due to the silica aerogels, in which the air in the macropores of the foams was replaced by silica aerogels
The results indicated that the silica–PI aerogels possessed remarkable flameretardant properties
Summary
Aerogels are the type of nanoporous materials possessing extremely low density, low thermal conductivity, high porosity, and high pore volume, and are potentially used in various fields such as environment, energy, cosmetic, transportation, building, catalyst, and biomedicine (Koebel et al, 2012; Ziegler et al, 2017; Vareda et al, 2018; Qie et al, 2020; Wei et al, 2020; Silica-Polyimide Aerogel BlanketWang and Wang, 2021). Silica aerogels synthesized from vinyl-functionalized siloxanes were build up with organic–inorganic double cross-linking networks, and they exhibited remarkable mechanical strength, flexibility, and is capable of ambient pressure drying (APD; Shimizu et al, 2016, 2017; Zu et al, 2018a,b,c) These approaches involve expensive monomers, complicated synthetic processes, and their scale-up productions are yet to be reported. Another strategy is introducing fibers to synthesize silica aerogel blankets (Figure 1A-2), which results in the flexible aerogel blanket that could be bent using polyester and glass fibers as a matrix (Berardi and Zaidi, 2019; Berthon-Fabry et al, 2017; Huang et al, 2019; Talebi et al, 2019; Lakatos, 2019). Though this approach is able to scale-up and commercially available, the interaction between silica aerogel and the fibrous matrix is weak, and the silica aerogel in the blanket can still be cracked and becomes ineffective
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
