Polyimide aerogels for ballistic impact protection

Abstract

The ballistic performance of edge-clamped monolithic polyimide aerogel blocks (12 mm thickness) has been studied through a series of impact tests using a helium-filled gas gun connected to a vacuum chamber and a spherical steel projectile (approximately 3 mm diameter) with an impact velocity range of 150–1300 m s−1. The aerogels had an average bulk density of 0.17 g cm−3 with high porosity of approximately 88%. The ballistic limit velocity of the aerogels was estimated to be in the range of 175–179 m s−1. Moreover, the aerogels showed a robust ballistic energy absorption performance (e.g., at the impact velocity of 1283 m s−1 at least 18% of the impact energy was absorbed). At low impact velocities, the aerogels failed by ductile hole enlargement followed by a tensile failure. By contrast, at high impact velocities, the aerogels failed through an adiabatic shearing process. Given the substantially robust ballistic performance, the polyimide aerogels have a potential to combat multiple constraints such as cost, weight, and volume restrictions in aeronautical and aerospace applications with high blast resistance and ballistic performance requirements such as in stuffed Whipple shields for orbital debris containment application.

Direct ink writing of polyimide aerogels for battery thermal mitigation

“…7A highlight that regardless of processing, all aerogels bear stretching frequencies corresponding to the polyimide structure. 4,49 Namely, both spectra show the imide ring deformation peak at 724 cm −1 , aromatic peaks at 816 and 1100 cm −1 , the imide C-N peak at 1362 cm −1 , and the imide CvO peak at 1718 cm −1 . Based on the FTIR spectra, the heat treating and printing processes do not significantly influence the chemical structure of the resulting aerogel.…”

“…Aerogels are a key material in advanced applications because of their unique combination of extremely low density (ranging from 1 to as low as 0.001 g cm −3 ), 1 high porosity (up to and sometimes exceeding 99%), [1][2][3] high specific surface area (500-1000 m 2 g −1 ), 1 and mechanical strength. 4,5 Since their introduction in 1931, 6 aerogels have found application across a variety of disciplines, including energy storage devices, 7 acoustic insulators, 8,9 thermal insulators, [10][11][12][13][14][15] vibration mitigation systems, 16 catalysts and catalyst supports, [17][18][19] and Cherenkov detectors. 20 The light weight of aerogels makes them appealing for space applications, where each kilogram of mass can cost tens of thousands of dollars to launch.…”

“…2 Primary drying methods include critical point drying or freeze drying, although some studies have demonstrated ambient pressure drying by strengthening the nanostructure 28,29 or modifying the surface to enable the nanostructure to "spring back" after drying. 1,2,[30][31][32] Aerogels have a diverse array of compositions, including silica, 1,13,20,22,[30][31][32] titania, 33 and other metal oxides, [34][35][36] along with carbon, 17,[37][38][39][40][41] chalcogenides, [42][43][44][45] polymers, 4,5,8,26,[46][47][48][49][50] and biological materials. 10,[51][52][53][54] Of these, polymer aerogels offer unique opportunities to tailor chemical composition, with polyimide aerogels being of particular interest due to their combination of good mechanical performance and high thermal stability.…”

Acoustic Properties of Aerogels: Current Status and Prospects

“…[34][35][36] Synthetic polymer aerogels, for example, based on resorcinolformaldehyde, are not brittle and follow foam-like stress-strain dependence (Figure 4b); [37] similar trends were reported for other polymer aerogels. [33,38,39] Compressive modulus of synthetic polymer aerogels can reach several tens of MPa at density around 0.1-0.2 g cm À3 .…”

Super‐White Boron Nitride Aerogel‐Enabled High‐Energy Laser Irradiation Protection

“…[ 5 ] Aerogels possess strong potential for high‐temperature thermal protection, [ 6 ] lightweight electromagnetic protection, [ 7 ] solar radiation protection, [ 8 ] and mechanical protection. [ 9 ] Therefore, the structural design of the nanoscale units and their sol‐gel assemblies is crucial for protection applications. However, aerogel protection under extreme conditions involving multienergy field coupling (such as laser irradiation), including the design concept and synthesis regulation of nanoscale unit‐based aerogel protection materials, has rarely been investigated.…”