Organically modified hybrid aerogels
View Patent ↗Disclosed and claimed herein are hybrid aerogels which are compositions of tetraalkoxysilanes and bis-(trialkoxysilyl) imides that exhibit low thermal conductivities and high compressive strengths. Methods for their preparation are also provided.
1. An aerogel comprising a polymeric network which comprises a silica component and diimide component; wherein the diimide component of the polymeric network comprises a compound of Formula I, Formula II, Formula III, Formula IV, or Formula V:
wherein R is selected from an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, or heterocyclic moiety, which can optionally contain one or more heteroatoms such as O, S, N, P, and Se;
A is selected from an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, or heterocyclic moiety, which can optionally contain a carbonyl moiety or one or more heteroatoms such as O, S, N, P, and Se;
X and Y are independently selected from hydrogen, a halogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, or heterocyclic moiety, which can optionally contain one or more heteroatoms such as O, S, N, P, and Se; and
B is an attachment to the silica component of the polymeric network.
2. The aerogel of claim 1 , wherein the diimide component of the polymeric network comprises a compound selected from Formula I; and wherein R is an alkyl moiety.
3. The aerogel of claim 1 , wherein the diimide component of the polymeric network comprises a compound selected from Formula III; and wherein R is an alkyl moiety.
4. The aerogel of claim 1 , wherein the aerogel has a density of 0.40 g/cc or less.
5. The aerogel of claim 1 , wherein the aerogel has a density of 0.25 g/cc or less.
6. The aerogel of claim 1 , wherein the thermal conductivity of the aerogel at ambient pressure and temperature is between 11 mW/m-K and 30 mW/m-K.
7. The aerogel of claim 1 , wherein the thermal conductivity of the aerogel at ambient pressure and temperature is between 11 mW/m-K and 20 mW/m-K.
8. The aerogel of claim 1 , wherein the diimide content of the aerogel is 25 wt % or less.
9. The aerogel of claim 1 , wherein the diimide content of the aerogel is 10 wt % or less.
10. The aerogel of claim 1 , wherein the compressive modulus of the aerogel is between 175 psi and 1200 psi.
11. An aerogel composite comprising the aerogel of claim 1 , and further comprising a fibrous reinforcement material comprising microfibers, mats, felts, woven fabrics, non-woven fabrics, fibrous battings, lofty battings or a combination thereof.
12. A porous material comprising a polymeric network which comprises a silica component and diimide component; wherein the porous material has a density of 0.40 g/cc or less; and wherein the diimide component of the polymeric network comprises a compound of Formula I, Formula II, Formula III, Formula IV, Formula V:
wherein R is selected from an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, or heterocyclic moiety, which can optionally contain one or more heteroatoms such as O, S, N, P, and Se;
A is selected from an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, or heterocyclic moiety, which can optionally contain a carbonyl moiety or one or more heteroatoms such as O, S, N, P, and Se;
X and Y are independently selected from hydrogen, a halogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, or heterocyclic moiety, which can optionally contain one or more heteroatoms such as O, S, N, P, and Se; and
B is an attachment the silica component of the polymeric network.
13. The porous material of claim 12 , wherein the porous material has a density of 0.25 g/cc or less.
14. The porous material of claim 12 , wherein the thermal conductivity of the aerogel at ambient pressure and temperature is between 11 mW/m-K and 30 mW/m-K.
15. The porous material of claim 12 , wherein the thermal conductivity of the aerogel at ambient pressure and temperature is between 11 mW/m-K and 20 mW/m-K.
16. The porous material of claim 12 , wherein the diimide content of the aerogel is 25 wt % or less.
17. The porous material of claim 12 , wherein the diimide content of the aerogel is 10 wt % or less.
18. A composite comprising the porous material of claim 12 , and further comprising a fibrous reinforcement material comprising microfibers, mats, felts, woven fabrics, non-woven fabrics, fibrous battings, lofty battings or a combination thereof.