Polyimide aerogels with novel bimodal micro and nano porous structure assembly for airborne nano filtering applications

Abstract

Aerogels have presented a very high potential to be utilized as airborne nanoparticles' filtration media due to their nanoscale pore size and extremely high porosity.

Novel, flexible, and transparent thin film polyimide aerogels with enhanced thermal insulation and high service temperature

“…104. Compared to the reported data in recent literature, it can be seen that the compressive strength of PI aerogels in this work ( S ∼ 0.35 MPa) is by far greater than those reported for ceramic nanofibrous aerogels 105 ( S = 0.004 MPa), silica nanofibrous aerogels 106 ( S = 0.01 MPa), double-negative-index ceramic aerogels 107 ( S = 0.01 MPa), and it is comparable with PPDA-PMDA PI aerogels 89 ( S < 1 MPa) and ODA-BPDA-TPU aerogels 88 ( S < 1 MPa).…”

“…87 A similar residue was reported in other studies. 61,88,89 A closer look at the decomposition trend of both aerogel backbones, at temperatures of around 135 and 302 ° C, a slight weight drop can be noticed. Having examined the decomposition trend of constituting monomers (ODA, BPDA, and DMBZ), it can be realized that the aforementioned drops could be due to the insignificant monomer residue inside the backbone, which degrades at lower temperatures.…”

“…89,96 The developed PI aerogels exhibited super thermal insulation performance, with thermal conductivity as low as 27.5 mW m À1 K À1 . A comparison of thermal conductivity of fabricated aerogels in this work with previously reported PI aerogels 17,24,44,48,62,89,[97][98][99] and other commercial insulation materials 100 is provided in Fig. 8(C).…”

Graphene/Polyimide Nanofibrous Mat for High-Efficiency Filtration

“…The following characteristic peaks of PI appear in these spectra: 1776 cm −1 of asymmetric imide C=O, 1726 cm −1 of symmetric C=O, and 1373 and 725 cm −1 of imide C-N. Characteristic absorption peaks of the PAA precursor like anhydride at 1860 cm −1 were not observed, 24,28 which indicates that the imidization process is fully complete. The above results demonstrate that after high temperature imidization, regardless of the amount of graphene added, all samples were fully imidized.…”

Magnetic aerogel: an advanced material of high importance

“…3 This was followed by enormous work to bring improvements in the synthesis methods, compositions, properties, and performance of aerogels. [4][5][6][7][8][9][10][11][12] Aerogels have the unique properties of having the least density, high porosity, large surface area, and high capacity of accommodating other materials within their matrix which make them applicable in diverse elds. 6,13,14 The preparation of nanocomposites is in focus due to the fact that their properties can be tuned by changing the composition and size of the incorporated nanoparticles.…”