An aerogel that includes an open-cell structured polymer matrix is disclosed. The aerogel includes 5 wt. % to 50 wt. % of a polyamic amide polymer, based on the total weight of the aerogel, pores and at least 90% of the pore volume of the aerogel is made up of macropores, a porosity of at least 50%, as measure according to ASTM D4404-10, a density of 0.01 g/cm.sup.3 to 0.5 g/cm.sup.3, and the aerogel is thermally stable to resist browning at 330° C.

Aerogel compositions that include polyamic amides, methods for preparing the aerogel compositions, and articles of manufacture that include or manufactured from the aerogel compositions are described.

The present invention relates to: a method for producing a polyimide aerogel having low dielectric properties, high insulation, and high strength; and a polyimide aerogel prepared therefrom. The present invention has the technical gist of a method for producing a polyimide aerogel having low dielectric properties, high insulation, and high strength, and a polyimide aerogel prepared therefrom, the method including: a first step of preparing a solvent; a second step of preparing a polyamic acid resin by reacting a diamine-based monomer with an acid anhydride monomer in a solvent; a third step of preparing a polyimide resin solution by imidizing the polyamic acid resin at 150 to 200° C.; a fourth step of preparing a polyimide wet gel by mixing a crosslinking agent and an acid with the polyimide resin solution; and a fifth step of preparing a polyimide aerogel by replacing the solvent contained in the polyimide wet gel with a main substitution solvent and a minor substitution solvent and then drying, wherein, in the fifth step, the main substitution solvent and the minor substitution solvent are each added to the polyimide wet gel in a stepwise manner to produce a polyimide aerogel having the porosity of 80 to 85 vol % while forming a skeletal structure having nano-pores through solvent-exchange.

The present invention discloses novel porous polymeric compositions comprising random copolymers of amides, imides, ureas, and carbamic-anhydrides, useful for the synthesis of monolithic bimodal microporous/macroporous carbon aerogels. It also discloses methods for producing said microporous/macroporous carbon aerogels by the reaction of a polyisocyanate compound and a polycarboxylic acid compound, followed by pyrolytic carbonization, and by reactive etching with CO.sub.2 at elevated temperatures. Also disclosed are methods for using the microporous/macroporous carbon aerogels in the selective capture and sequestration of carbon dioxide.

A method of freeze-drying comprising rapidly freezing either liquid or supercritical carbon dioxide in and around a material having pores at a rate of at least 0.2° C./min to limit the size of crystals formed from the carbon dioxide so as to avoid the formation of gas bubbles and damage to the pores and exposure of the material to gas-liquid interfaces. During freezing a solid layer primarily of solid carbon dioxide is formed on and surrounding the material by transferring heat with a cryogenic liquid circulating about the material. This solid layer protects the material from gas-liquid interfaces and surface tension before decreasing pressure about the material by venting carbon dioxide.

Porous three-dimensional networks of polyimide and porous three-dimensional networks of carbon and methods of their manufacture are described. For example, polyimide aerogels are prepared by mixing a dianhydride and a diisocyanate in a solvent comprising a pyrrolidone and acetonitrile at room temperature to form a sol-gel material and supercritically drying the sol-gel material to form the polyimide aerogel. Porous three-dimensional polyimide networks, such as polyimide aerogels, may also exhibit a fibrous morphology. Having a porous three-dimensional polyimide network undergo an additional step of pyrolysis may result in the three dimensional network being converted to a purely carbon skeleton, yielding a porous three-dimensional carbon network. The carbon network, having been derived from a fibrous polyimide network, may also exhibit a fibrous morphology.

The present invention relates to methods of forming aerogels.

An aerogel that includes an open-cell structured polymer matrix that can have 5 wt. % to 50 wt. % of a polyamic amide polymer, based on the total weight of the aerogel is disclosed. The aerogel can have a density of 0.05 g/cm.sup.3 to 0.35 g/cm.sup.3 and can be thermally stable to resist browning at 330° C.

Microporous polyolefin and microporous polydicyclopentadiene (polyDCPD) based aerogels and methods for preparing and using the same are provided. The aerogels are produced by forming a polymer gel structure within a solvent from a olefin or dicyclopentadiene monomer via Ring Opening Metathesis Polymerization (ROMP) reactions, followed by supercritical drying to remove the solvent from the aerogel. Other aerogels are prepared by sequentially (1) mixing at least one dicyclopentadiene monomer, at least one solvent at least one catalyst and at least one inorganic and/or organic reinforcing material, (2) gelling the mixture, (3) aging, and (4) supercritical drying. Aerogels provided herein are inexpensive to prepare, possess desirable thermal, mechanical, acoustic, chemical, and physical properties and are hydrophobic. The aerogels provided herein are suitable for use in various applications, including but not limited to thermal and acoustic insulation, radiation shielding, and vibrational damping applications.

A method of synthesizing aerogels and cross-linked aerogels in a single step and in a single pot without requiring any solvent exchange is described. Porous matrices are synthesized through a modification of hydrolysis condensation of alkoxides in which addition of water is minimized. The reaction occurs in an ethanol-water azeotrope mixture; the water in the azeotrope slowly hydrolyzes the alkoxide. Additionally, after gelation, the porous matrix is dried in supercritical ethanol rather than liquid CO.sub.2, which allows for elimination of solvent exchange steps. These modifications allow for the preparation of aerogel monoliths in any size in one step and in one pot and much faster than conventional procedures. In addition, the method provides for custom aerogel parts with large dimensions, as well as high volume fabrication of aerogels. The custom aerogel parts may be used in a variety of thermal insulation applications.