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.

The invention relates to an aerogel composite comprising an aerogel component and a silica particle, and being superior in thermal insulation properties and flexibility.

The invention relates to an aerogel composite comprising an aerogel component and a silica particle, and being superior in thermal insulation properties and flexibility.

Provided is an aerogel blanket and a method for producing the same, wherein a catalyzed sol I sufficiently and uniformly impregnated into a blanket in an impregnation tank, and the catalyzed sol is allowed to stay in the impregnation tank for a specific time to control fluidity while achieving a viscosity at which the catalyzed sol can be easily introduced into the blanket, thereby forming a uniform aerogel in the blanket. As a result, the uniformity of pore structure and thermal insulation performance of an aerogel blanket are improved, the loss of raw materials is reduced through the impregnation process, the occurrence of process problems is reduced, and the generation of dust is reduced.

Disclosed herein is a method of preparing a silica aerogel. The silica aerogel is prepared by adding a first water glass solution and an acid catalyst to a reactor to form a first silica wet gel. The method further includes adding a second water glass solution and an acid catalyst to the first silica wet gel. The method further includes adding a surface modifier solution to the first silica wet gel to form a second silica wet gel. The method further includes drying a silica wet gel including the first silica wet gel and the second silica wet gel. The prepared silica aerogel has a tap density of 0.032 to 0.070 g/mL and a carbon content of 11.2 to 12.1 wt %.

Disclosed herein is a method of preparing a silica aerogel. The silica aerogel is prepared by adding a first water glass solution and an acid catalyst to a reactor to form a first silica wet gel. The method further includes adding a second water glass solution and an acid catalyst to the first silica wet gel. The method further includes adding a surface modifier solution to the first silica wet gel to form a second silica wet gel. The method further includes drying a silica wet gel including the first silica wet gel and the second silica wet gel. The prepared silica aerogel has a tap density of 0.032 to 0.070 g/mL and a carbon content of 11.2 to 12.1 wt %.

A method and an apparatus for preparing aerogel by drying under reduced pressure. The gel to be dried is placed into a sealed drying apparatus which can be depressurized by air extraction or/and can be heated to raise the temperature. The methods of reducing pressure by air extraction or/and raising temperature are acted upon the water and solvents within the aerogel to be dried, and an outward force is thus generated for the water and solvents to be volatilized outwards. By controlling the rates of reducing pressure by air extraction or/and raising temperature, the outward force is allowed to be equal to or close to the inward capillary force, such that the pores of the gel may not be collapsed or cracked. At the same time, drying is carried out continuously, and finally the interior water and solvents are removed completely.

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.

A method for producing a plate type metal-silica composite aerogel and a plate type metal-silica composite aerogel produced thereby in which the metal salt concentration and the basic catalyst concentration are adjusted to form a plate type intermediate first, and then an appropriate amount of a water glass solution is added, thereby enabling the plate type metal-silica composite aerogel to be produced in a short time under conditions of low temperature and atmospheric pressure, so that the process is simpler than the conventional production method, and the cost is reduced, which is excellent in economy. Also provided is a plate type metal-silica composite aerogel, which is produced by the claimed method and has excellent dispersibility that requires no additional surface modifier.

A method for producing a plate type metal-silica composite aerogel and a plate type metal-silica composite aerogel produced thereby in which the metal salt concentration and the basic catalyst concentration are adjusted to form a plate type intermediate first, and then an appropriate amount of a water glass solution is added, thereby enabling the plate type metal-silica composite aerogel to be produced in a short time under conditions of low temperature and atmospheric pressure, so that the process is simpler than the conventional production method, and the cost is reduced, which is excellent in economy. Also provided is a plate type metal-silica composite aerogel, which is produced by the claimed method and has excellent dispersibility that requires no additional surface modifier.