Highly branched non-crosslinked aerogel, methods of making, and uses thereof
An aerogel that includes an open-cell structure and a polymer matrix is disclosed. The polymer matrix can include a branched polyimide polymer having a degree of branching of at least 0.5. The polymer matrix can contain less than 5% by weight of crosslinked polymers.
1. An aerogel comprising:
(a) an open-cell structure; and
(b) a polymer matrix comprising a polyimide polymer having a degree of branching of at least 0.5, wherein the polymer matrix contains less than 5% by weight of crosslinked polymers.
2. The aerogel of claim 1 , wherein the polymer matrix contains less than 1% by weight of crosslinked polymers.
3. The aerogel of claim 1 , wherein the polymer matrix is not crosslinked.
4. The aerogel of claim 1 , wherein the degree of branching is from 0.5 to 10.
5. The aerogel of claim 1 , wherein the degree of branching is 6.3.
6. The aerogel of claim 1 , wherein the polyimide polymer has a general structure of:
where:
R 1 is a multifunctional amine;
Z is a dianhydride;
R 2 is a diamine;
m is a solution average number per chain ranging from 0.5 to 10; and
n is 1 to 25.
7. The aerogel of claim 6 , wherein the polyimide has a general structure of:
where R 3 and R 4 are each individually a capping group, and are independently selected from a hydrogen, an anhydride, an isocyanate, an acid, or an alkyl group.
8. The aerogel of claim 6 , wherein the dianhydride is 3,3′,4,4′-biphenyltetracarboxylic dianhydride.
9. The aerogel of claim 8 , wherein the dianhydride is 3,3′,4,4′-benzophenone-tetracarboxylic dianhydride.
10. The aerogel of claim 6 , wherein the multifunctional amine is a substituted or unsubstituted multifunctional amine comprising at least three primary amine functionalities.
11. The aerogel of claim 10 , wherein the multifunctional amine is a substituted or an unsubstituted aliphatic multifunctional amine or a substituted or an unsubstituted aromatic multifunctional amine.
12. The aerogel of claim 11 , wherein the aromatic multifunctional amine is 1,3,5,-tris(4-aminophenoxy)benzene, 4,4′,4″-methanetriyltrianiline, N,N,N′,N′-tetrakis(4-aminophenyl)-1,4-phenylenediamine, or a polyoxypropylenetriamine.
13. The aerogel of claim 11 , wherein the diamine is a substituted or unsubstituted aromatic diamine, a substituted or an unsubstituted alkyldiamine.
14. The aerogel of claim 13 , wherein the diamine is 4,4′-oxydianiline or 2,2′-dimethylbenzidine.
15. The aerogel of claim 6 , wherein R 1 is selected from:
and R 2 is selected from:
16. The aerogel of claim 6 , wherein the molar ratio of anhydride to total diamine is from 0.80:1 to 1.2:1.
17. The aerogel of claim 6 , wherein the molar ratio of anhydride to multifunctional amine is 8:1 to 125:1.
18. The aerogel of claim 1 , wherein the polyimide polymer further comprise a mono-anhydride group.
19. The aerogel of claim 1 , wherein the aerogel is a film.
20. The aerogel of claim 1 , wherein the aerogel is comprised in an article of manufacture.
21. The aerogel of claim 20 , wherein the article of manufacture is an automobile.
22. The aerogel of claim 20 , wherein the article of manufacture is an aircraft.