Hydrophobic aerogel materials
View Patent ↗The present disclosure provides an aerogel composition which is durable and easy to handle, which has favorable performance in aqueous environments, and which also has favorable combustion and self-heating properties. Also provided is a method of preparing an aerogel composition which is durable and easy to handle, which has favorable performance in aqueous environments, and which has favorable combustion and self-heating properties. Further provided is a method of improving the hydrophobicity, the liquid water uptake, the heat of combustion, or the onset of thermal decomposition temperature of an aerogel composition.
1. A method for preparing a fiber- or foam-reinforced aerogel composite, comprising:
Providing a reinforced aerogel composition comprising a silica-based aerogel framework including aerogel material, a fiber or foam reinforcement material, and at least one hydrophobic-bound silicon; and
Exposing the reinforced aerogel composition to a heat treatment in a reduced oxygen atmosphere to form a reinforced, silica-based aerogel composite, wherein the heat treatment comprises exposure to one or more temperatures between 515° C. and 700° C., for at least 1 minute, wherein
the reinforced aerogel composition is not exposed to a temperature above 700° C. for more than 1 minute,
the reinforced, silica-based aerogel composite after the heat treatment has a liquid water uptake of 40 wt % or less, and
the reinforced, silica-based aerogel composite after the heat treatment has a heat of combustion of less than 750 cal/g.
2. The method of claim 1 , wherein the total duration of the heat treatment is between 1 minute and 60 minutes.
3. The method of claim 1 , wherein the total duration of the heat treatment is between 1 minute and 30 minutes.
4. The method of claim 1 , wherein the duration of the heat treatment in a reduced oxygen atmosphere between 515° C. and 700° C. is between 1 minute and 30 minutes.
5. The method of claim 4 , wherein the duration of the heat treatment in a reduced oxygen atmosphere between 515° C. and 700° C. is between 1 minute and 20 minutes.
6. The method of claim 4 , wherein the fiber reinforcement material comprises a sheet of fiber reinforcement material.
7. The method of claim 1 , wherein the reduced oxygen atmosphere is 0.01% to 5% oxygen by volume.
8. The method of claim 1 , wherein the reduced oxygen atmosphere is 0.01% to 1% oxygen by volume.
9. The method of claim 1 , wherein the reinforced aerogel composition before the heat treatment comprises hydrophobic organic material, including aliphatic hydrophobic groups; and wherein the aliphatic hydrophobic groups comprise at least 50% of the hydrophobic organic material.
10. The method of claim 1 , wherein the reinforced aerogel composition before the heat treatment comprises hydrophobic organic material, including methyl hydrophobic groups; and wherein methyl hydrophobic groups comprise at least 50% of the hydrophobic organic material.
11. The method of claim 1 , wherein the aerogel material has a hydrophobic organic content between 2 wt % and 12 wt % before the heat treatment and after the heat treatment.
12. The method of claim 1 , wherein the aerogel material has a hydrophobic organic content between 2 wt % and 10 wt % before the heat treatment and after the heat treatment.
13. The method of claim 1 , wherein the aerogel material has a hydrophobic organic content between 2 wt % and 8 wt % before the heat treatment and after the heat treatment.
14. The method of claim 1 , wherein the aerogel material has a hydrophobic organic content between 2 wt % and 6 wt % before the heat treatment and after the heat treatment.
15. A reinforced aerogel composition produced by the method of claim 12 .
16. The reinforced aerogel composition of claim 15 , wherein the reinforced aerogel composition has the following properties: i) an onset of thermal decomposition of hydrophobic organic materials between 515° C. and 635° C.; ii) a heat of combustion between 265 cal/g and 717 cal/g; and iii) a thermal conductivity between 15 mW/M*K and 30 mW/M*K.
17. The reinforced aerogel composition of claim 16 , wherein the reinforced aerogel composition has a heat of combustion between 265 cal/g and 600 cal/g.
18. The reinforced aerogel composition of claim 16 , wherein the reinforced aerogel composition has a heat of combustion between 265 cal/g and 550 cal/g.
19. The reinforced aerogel composition of claim 16 , wherein the reinforced aerogel composition has a heat of combustion between 265 cal/g and 500 cal/g.
20. The reinforced aerogel composition of claim 16 , wherein the reinforced aerogel composition has a heat of combustion between 265 cal/g and 450 cal/g.
21. The reinforced aerogel composition of claim 16 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials between 525° C. and 635° C.
22. The reinforced aerogel composition of claim 16 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials between 550° C. and 635° C.
23. The reinforced aerogel composition of claim 16 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials between 575° C. and 635° C.
24. The reinforced aerogel composition of claim 16 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials between 600° C. and 635° C.
25. The reinforced aerogel composition of claim 16 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials between 615° C. and 635° C.