Preparation and Characterization of Polyimide Aerogels with a Uniform Nanoporous Framework

Abstract

Polyimide (PI) aerogels were successfully synthesized via a straightforward sol-gel process under room temperature along with the supercritical CO drying method using 4-amino- N-methylbenzamide and 3,3',4,4'-biphenyltetracarboxylic dianhydride. 1,3,5-Triaminophenoxybenzene was used as the cross-linker. The chemical structure, pore structure, morphology, thermal performance, CO adsorption, and mechanical performance of PI aerogels were investigated. The as-prepared PI aerogels had low bulk densities (0.091-0.167 g/cm), low shrinkages (9.73-17.36%), low thermal conductivities (0.0307-0.0341 W/m·K), high specific surface areas (449.76-538.19 m/g), small pore diameter (10.37-22.41 nm), high thermal stability (onset of decomposition above 560 °C), and excellent mechanical property. The CO adsorption capacities of PI aerogels were substantially higher than the values of the previous porous materials reported under the similar conditions, and the CO uptake capacity was as high as 31.19 cm/g at 25 °C and 1.0 bar. The resulting PI aerogels could be potentially used as thermal insulators and CO adsorbents.

Solvent Vapor Strengthened Polyimide Nanofiber-Based Aerogels with High Resilience and Controllable Porous Structure

“…The welded PI-NFAs with various densities (0.96–16.14 mg/cm 3 ) were prepared simply by adjusting the concentrations of the nanofiber dispersions, and their porosities are listed in Table S3. Plotting the porosities of various PI aerogels (sol–gel-derived PI aerogels ,,− and nanofiber-based PI aerogels ,− ) versus their density revealed that the welded PI-NFAs fabricated in this study processed much lower density and higher porosity compared to the sol–gel-derived PI aerogels and nanofiber-based PI aerogels strengthened by cross-linkers (as shown in Figure d).…”

Exploring CO2@sI Clathrate Hydrates as CO2 Storage Agents by Computational Density Functional Approaches

“…CO 2 clathrate hydrates are involved in current potential applications in sustainable industries, such as CO 2 capture technologies, that are necessary to be developed to store this greenhouse gas [1–12] . Thus, both scientific and technological communities, from different fields of chemistry, physics, geology, engineering, etc., have devoted numerous collaborative research efforts, involving investigations at microscopic level using molecular simulation tools, as several processes (hydrate nucleation or growth or cage occupancy) could get hardly accessible though experimentation [12–23] .…”

Mechanically Strong and Tailorable Polyimide Aerogels Prepared with Novel Silicone Polymer Crosslinkers

“…Due to their unique properties, aerogels have been used in adsorption [ 4 , 5 ], catalysts, supercapacitors [ 6 , 7 ], sensors [ 8 ], energy storage [ 9 ], and so forth. Over the past few decades, aerogels made from polymer have been developed, such as phenol-formaldehyde resin [ 10 ], polyurethanes [ 11 ], polyureas [ 12 ], polyamides [ 13 ], and polyimide [ 14 ]. Compared to other aerogels, PI aerogels attracted more attention from researchers due to perfect chemical stability [ 15 ], good mechanical properties [ 16 ], perfect dielectric performance [ 17 , 18 ] and high decomposition temperatures [ 19 , 20 ].…”