Mechanically strong polyimide aerogels cross-linked with low-cost polymers

Abstract

Polyimide aerogels were prepared using low-cost polymers with different structure capped polyamide oligomers serving as cross-linking agents.

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

“…86 As it can be realized, for the backbone containing DMBZ, the onset of decomposition is lower. As it was demonstrated in previous studies, 43,63 the presence of methyl groups in the DMBZ structure is responsible for such behaviour. 63 Furthermore, at the maximum temperature of 700 8C, it can be noticed that for both backbones, there is a high residual weight percentage in the range of 30-50%.…”

“…Both monolith aerogels with different backbones exhibit a 3D interconnected porous network with fibrous morphology (fiber diameter o 33 nm) similar to other PI aerogels. 14,43,[62][63][64][65][66] Such a morphology with entangled fiber strands is formed during the gelation process, followed by the last stage of polymerization. 61 When the conventional monolith aerogels are translated into 2D thin film aerogels, structural morphology, especially the This suggests that the type of aerogel processing, whether it is mold cast or made via a doctor blade has no significant change in morphology.…”

“…83 The absence of a peak at 1860 cm À1 in aerogels with a BPDA backbone for all samples indicates that all anhydrides have been successfully synthesized. 63 However, in samples containing DMBZ there is a weak appearance of amide CQO bonds at 1660 cm À1 , which contrastingly suggests incomplete imidization of that functional group. 84 Except for the amide CQO bonds, all aerogel samples illustrate similar peaks as seen in the FTIR spectra.…”

Melamine‐Crosslinked Polyimide Aerogels from Supercritical Ethanol Drying with Improved In‐Use Shape Stability Against Shrinking

“…From the plot of MPI-E-50, the characteristic peak centered around 3471 cm −1 is mostly attributed to the stretching vibration of N-H. [25] These peaks at about 740, 1712 and 1774 cm −1 are contributed to the bending, symmetric, and asymmetric stretching vibrations of imide C═O, respectively. [26][27][28] The corresponding peaks for the stretching vibrations of C-N and C═C are located at 1365 cm −1 and 1496 cm −1 . From the whole sight, the FTIR spectrum of MPI-E-50 is almost the same as that of MPI-C-50.…”

Constructing Polyimide Aerogels with Carboxyl for CO2 Adsorption

“…Apart from that, no absorption peaks were observed at 1800 and 1670 cm −1 , indicating the absence of heteroimide ring structure in the structure. Therefore, the above information implies that full imidization of these polyimide aerogels occurs under the polymerization conditions [ 42 , 43 ].…”