Heterogeneous silica-polyimide aerogel-in-aerogel nanocomposites

نویسندگان

چکیده

Polymer aerogels are a promising, non-brittle alternative to silica aerogel, but limited by their very poor high-temperature stability. Polyimide is widely known for its high heat-resistance, however, degree of volume shrinkage common polyimide after exposure temperatures above 200 °C. Here, we present the aerogel-in-aerogel composites that comprise aerogel grains with nanoparticulate microstructure embedded in nanofibrous matrix. The mixing procedure and synthesis protocol were optimized avoid excessive infiltration sol into mesopores. display unique, heterogeneous structure surface area, >600 m2 g−1, low thermal conductivity down 17.5 mW m−1 K−1, dielectric constant (∼2.5 at 10-1-106 Hz, ∼1.2 8–12.5 GHz, 26.5–32 GHz) loss (10-3 10-1 all studied frequencies). hydrophobic component contributes water resistance, contact angles (>150°) humidity uptake (<4 wt% 88% relative humidity), much-reduced temperature. imparts excellent mechanical properties composites, including improved compressive modulus, bending strengths. composite offer great potential applications require strength, and/or

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ژورنال

عنوان ژورنال: Chemical Engineering Journal

سال: 2022

ISSN: ['1873-3212', '1385-8947']

DOI: https://doi.org/10.1016/j.cej.2022.136401