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 comprising:
a) Providing a precursor solution comprising silica gel precursor materials and a solvent;
b) Combining the precursor solution with a reinforcement material;
c) Allowing the silica gel precursor materials in the precursor solution to transition into a gel composition to form a reinforced, silica-based gel composition;
d) Extracting at least a portion of the solvent from the reinforced, silica-based gel composition to obtain a reinforced, silica-based aerogel composition; and
e) Exposing the reinforced, silica-based aerogel composition to heat treatment in a reduced oxygen atmosphere, wherein the heat treatment includes exposure to one or more temperatures between 500° C. and 700° C., and wherein the total duration of heat treatment in reduced oxygen atmosphere of the reinforced, silica-based aerogel composition is between 1 minute and 30 minutes;
wherein the method further comprises incorporating at least one hydrophobic-bound silicon into the reinforced, silica-based aerogel composition prior to step e).
2. The method of claim 1 , wherein the reinforcement material comprises a sheet of fiber reinforcement material.
3. The method of claim 1 , wherein the heat treatment in a reduced oxygen atmosphere of the reinforced, silica-based aerogel composition does not include exposure to a temperature above 700° C. for more than 1 minute.
4. The method of claim 1 , wherein the reduced oxygen atmosphere comprises 0.1% to 5% oxygen by volume.
5. The method of claim 1 , wherein the reinforced, silica-based aerogel composition has a hydrophobic organic content between 1 wt % and 12 wt % before the heat treatment and after the heat treatment.
6. The method of claim 1 , wherein the reinforced, silica-based aerogel composition comprises hydrophobic organic material before the heat treatment, and wherein at least 50% of the hydrophobic organic material in the reinforced, silica-based aerogel composition before the heat treatment comprises aliphatic hydrophobic groups.
7. The method of claim 1 , wherein the hydrophobic-bound silicon is incorporated into the reinforced, silica-based aerogel composition by including in the precursor solution at least one silica gel precursor material having at least one hydrophobic group.
8. The method of claim 1 , wherein the at least one hydrophobic-bound silicon is incorporated into the reinforced, silica-based aerogel composition by exposing the reinforced, silica-based gel or the reinforced, silica-based aerogel composition to a hydrophobizing agent.
9. A method comprising exposing a reinforced, silica-based aerogel composition comprising at least one hydrophobic-bound silicon to heat treatment in a reduced oxygen atmosphere, wherein the heat treatment includes exposure to one or more temperatures between 500° C. and 700° C., and wherein the total duration of the heat treatment in a reduced oxygen atmosphere of the reinforced, silica-based aerogel composition is between 1 minute and 30 minutes.
10. The method of claim 9 , wherein the reinforced, silica-based aerogel composition comprises a sheet of fiber reinforcement material.
11. The method of claim 9 , wherein the heat treatment in a reduced oxygen atmosphere of the reinforced, silica-based aerogel composition does not include exposure to a temperature above 700° C. for more than 1 minute.
12. The method of claim 9 , wherein the reduced oxygen atmosphere comprises 0.1% to 5% oxygen by volume.
13. The method of claim 9 , wherein the reinforced, silica-based aerogel composition has a hydrophobic organic content between 1 wt % and 12 wt % before the heat treatment and after the heat treatment.
14. The method of claim 9 , wherein the reinforced, silica-based aerogel composition comprises hydrophobic organic material before the heat treatment, and wherein at least 50% of the hydrophobic organic material in the reinforced, silica-based aerogel composition before the heat treatment comprises aliphatic hydrophobic groups.
15. The method of claim 9 , wherein the reinforced, silica-based aerogel composition after the heat treatment has a lower liquid water uptake percentage relative to the reinforced, silica-based aerogel composition before the heat treatment.
16. The method of claim 9 , wherein the reinforced, silica-based aerogel composition after the heat treatment has a lower heat of combustion relative to the first reinforced, silica-based aerogel composition before the heat treatment.
17. The method of claim 9 , wherein the reinforced, silica-based aerogel composition after the heat treatment has a higher onset of thermal decomposition temperature relative to the reinforced, silica-based aerogel composition before the heat treatment.
18. A reinforced, silica-based aerogel composition produced by the method of claim 11 .
19. The reinforced, silica-based aerogel composition of claim 18 , wherein the reinforced, silica-based aerogel composition has the following properties:
i) liquid water uptake of 40 wt % or less;
ii) onset of thermal decomposition of hydrophobic organic materials of 500° C. or higher.
20. The reinforced, silica-based aerogel composition of claim 19 , wherein the reinforced, silica-based aerogel composition has the following properties:
iii) heat of combustion of less than 717 cal/g; and iv) thermal conductivity of 40 mW/M*K or less.
21. The reinforced, silica-based aerogel composition of claim 19 , wherein the hydrophobic organic content in the reinforced, silica-based aerogel composition is between 1 wt % and 12 wt %.
22. The reinforced, silica-based aerogel composition of claim 19 , wherein the reinforced, silica-based aerogel composition has a ratio of T 1-2 :T 3 of between 0.01 and 0.4.
23. A reinforced aerogel composition comprising a silica-based framework; wherein the reinforced aerogel composition has the following properties:
i) liquid water uptake of 40 wt % or less;
ii) onset of thermal decomposition of hydrophobic organic materials of 515° C. or higher;
iii) heat of combustion of less than 717 cal/g; and
iv) thermal conductivity of 40 mW/M*K or less.
24. The reinforced aerogel composition of claim 23 , wherein the reinforced aerogel composition has the following properties:
ii) onset of thermal decomposition of hydrophobic organic materials between 515° C. and 635° C.;
iii) heat of combustion between 265 cal/g and 717 cal/g; and
iv) thermal conductivity between 15 mW/M*K and 40 mW/M*K.
25. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition comprises a sheet of fiber reinforcement material.
26. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has a density of 0.40 g/cm3 or less.
27. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has a thermal conductivity between 15 mW/M*K and 30 mW/M*K.
28. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has a heat of combustion of less than 600 cal/g.
29. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has a heat of combustion of 550 cal/g or less.
30. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has a heat of combustion of 500 cal/g or less.
31. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has a heat of combustion of 450 cal/g or less.
32. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials of 525° C. or higher.
33. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials of 550° C. or higher.
34. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials of 575° C. or higher.
35. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials of 600° C. or higher.
36. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials of 615° C. or higher.
37. The reinforced aerogel composition of claim 24 , wherein the hydrophobic organic content in the aerogel composition is between 1 wt % and 10 wt %.
38. The reinforced aerogel composition of claim 24 , wherein the hydrophobic organic content in the aerogel composition is between 1 wt % and 8 wt %.
39. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition comprises hydrophobic organic material, and wherein at least 50 wt % of the hydrophobic organic material in the reinforced aerogel composition comprises aliphatic hydrophobic groups.
40. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has a ratio of T 1-2 :T 3 of between about 0.01 and 0.4.
41. The reinforced aerogel composition of claim 24 , wherein the reinforced aerogel composition has a ratio of Q 1-3 :Q 4 of between about 0.1 and 1.5.
42. A reinforced aerogel composition comprising a silica-based framework; wherein the reinforced aerogel composition has the following properties:
i) liquid water uptake of 40 wt % or less; and
iii) heat of combustion of less than 460 cal/g.
43. The reinforced aerogel composition of claim 42 , wherein the reinforced aerogel composition has a heat of combustion between 265 cal/g and 460 cal/g.
44. The reinforced aerogel composition of claim 43 , wherein the reinforced aerogel composition comprises a sheet of fiber reinforcement material.
45. The reinforced aerogel composition of claim 44 , wherein the reinforced aerogel composition has a heat of combustion between 265 cal/g and 400 cal/g.
46. The reinforced aerogel composition of claim 44 , wherein the hydrophobic organic content in the reinforced aerogel composition is between 1 wt % and 10 wt %.
47. The reinforced aerogel composition of claim 44 , wherein the reinforced aerogel composition has a ratio of T 1-2 :T 3 of between 0.01 and 0.4.
48. A reinforced aerogel composition comprising a silica-based framework; wherein the reinforced aerogel composition has the following properties:
i) liquid water uptake of 40 wt % or less; and
ii) onset of thermal decomposition of hydrophobic organic materials of 515° C. or higher.
49. The reinforced aerogel composition of claim 48 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials between 515° C. and 635° C.
50. The reinforced aerogel composition of claim 49 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials of 550° C. or higher.
51. The reinforced aerogel composition of claim 49 , wherein the reinforced aerogel composition has an onset of thermal decomposition of hydrophobic organic materials of 575° C. or higher.
52. The reinforced aerogel composition of claim 49 , wherein the hydrophobic organic content in the reinforced aerogel composition is between 1 wt % and 10 wt %.
53. The reinforced aerogel composition of claim 49 , wherein the reinforced aerogel composition has a ratio of T 1-2 :T 3 of between 0.01 and 0.4.
54. The reinforced, silica-based aerogel composition of claim 19 , wherein the reinforced, silica-based aerogel composition has the following properties: ii) onset of thermal decomposition of hydrophobic organic materials between 500° C. and 635° C.; iii) heat of combustion between 265 cal/g and 717 cal/g; and iv) thermal conductivity between 15 mW/M*K and 40 mW/M*K.
55. The reinforced, silica-based aerogel composition of claim 54 , wherein the reinforced, silica-based aerogel composition has one or more of the following properties: ii) onset of thermal decomposition of hydrophobic organic materials between 525° C. and 635° C., or iii) heat of combustion between 265 cal/g and 600 cal/g.
56. The reinforced, silica-based aerogel composition of claim 54 , wherein the reinforced, silica-based aerogel composition has one or more of the following properties: ii) onset of thermal decomposition of hydrophobic organic materials between 550° C. and 635° C., or iii) heat of combustion between 265 cal/g and 550 cal/g.
57. The reinforced, silica-based aerogel composition of claim 54 , wherein the reinforced, silica-based aerogel composition has one or more of the following properties: ii) onset of thermal decomposition of hydrophobic organic materials between 575° C. and 635° C., or iii) heat of combustion between 265 cal/g and 500 cal/g.