Polyimide Aerogels Cross-Linked through Amine Functionalized Polyoligomeric Silsesquioxane

Abstract

We report the first synthesis of polyimide aerogels cross-linked through a polyhedral oligomeric silsesquioxane, octa(aminophenyl)silsesquioxane (OAPS). Gels formed from polyamic acid solutions of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), bisaniline-p-xylidene (BAX) and OAPS were chemically imidized and dried using supercritical CO(2) extraction to give aerogels having density around 0.1 g/cm(3). The aerogels are greater than 90 % porous, have high surface areas (230 to 280 m(2)/g) and low thermal conductivity (14 mW/m-K at room temperature). Notably, the polyimide aerogels cross-linked with OAPS have higher modulus than polymer reinforced silica aerogels of similar density and can be fabricated as both monoliths and thin films. Thin films of the aerogel are flexible and foldable making them an ideal insulation for space suits, and inflatable structures for habitats or decelerators for planetary re-entry, as well as more down to earth applications.

Synthesis and characterization of flexible and high-temperature resistant polyimide aerogel with ultra-low dielectric constant

“…However, common organic aerogels usually suffer from their low thermal and dimensional stability at elevated temperatures; thus cannot meet the severe demands of interlayer electrical insulation process for ULSI fabrications. Thus, as a representative high-temperature resistant organic aerogels, PI aerogels have been developed rapidly in recent years [18][19][20][21][22]. The dielectric constants and dissipation factors for PI aerogels have also been investigated in detail.…”

Advanced High-Temperature Flexible TPS for Inflatable Aerodynamic Decelerators

“…Insulator materials are necessary to reduce the temperature of outer fabrics to usable structural temperatures. In Figure 19 a comparison of temperature versus insulator conductivities in vacuum for Pyrogel 3350 and PI-POSS polyimide 12 to standard Saffil materials at densities of 48 kg/m 3 , 96 kg/m 3 , and 144 kg/m 3 densities is shown 10 . Saffil was originally considered as a viable candidate due to the excellent thermal conductivity of Saffil as the temperature of the material increases, but was rejected due to manufacturer"s minimum gage thickness of 12 mm, and because the material had very low tensile strength.…”

Preparation and Characterization of Pure Organic Dielectric Composites for Capacitors

“…corresponds to the C=O asymmetric stretching vibration, 1720 cm −1 corresponds to the C=O symmetric stretching vibration, 1370 cm −1 corresponds to the C-N-C stretching vibration, and 720 cm −1 corresponds to the C=O bending vibration [26][27][28]. Furthermore, the absence of the characteristic absorption bands of PAA at approximately 1660 cm -1 corresponds to the amic acid C=O symmetric stretching vibration and 1535 cm -1 corresponds to the amide C-N asymmetric stretching vibration indicates complete imidization in the resulting composites [29,30].…”