Polyimide aerogels having polyamide cross-links and processes for making the same

Patent metadata

Field	Value
Publication number	US-9434832-B1
Application number	US-201514660492-A
Country	US
Kind code	B1
Filing date	Mar 17, 2015
Priority date	May 15, 2014
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

An aerogel and process of making the aerogel is provided. The aerogel is a polyimide aerogel having polyamide cross-links formed using a triacid chloride cross-linker.

First claim

What is claimed is:

1. An aerogel, comprising:
a polyimide oligomer component; and
a polyamide cross-link, the polyamide cross-link connected to the polyimide component, the polyimide oligomer component comprising the reaction product of a diamine and a dianhydride in a ratio of (n+1) to n where n is the number of repeat units in the oligomer.

2. The aerogel of claim 1 , the polyamide cross-link comprising:
a triacid chloride component.

3. The aerogel of claim 1 , the diamine comprising:
4, 4″-oxidianiline.

4. The aerogel of claim 1 , the dianhydride comprising:
biphenyl-3,3′,4,4′-tetracarboxylic dianhydride.

5. The aerogel of claim 1 , the diamine comprising:
a combination of 2, 2′-dimethylbenzidine and 4, 4′-oxidianiline.

6. The aerogel of claim 1 , the diamine comprising:
2, 2′-dimethylbenzidine.

7. The aerogel of claim 4 , comprising:
a density of 0.20 g/cm 3 when the aerogel is preconditioned to 150° C.

8. The aerogel of claim 4 , comprising:
a density of 0.35 g/cm 3 when the aerogel is preconditioned to 200° C.

9. The aerogel of claim 1 , wherein the aerogel has a:
density of 0.100 g/cm 3 .

10. The aerogel of claim 8 , comprising:
a pore size distribution of 20 nm to 40 nm.

11. The aerogel of claim 5 , wherein the 2,2′-dimethylbenzidine, the 4,4′-oxidianiline, and the dianhydride form an alternating backbone.

12. A process for making a polyimide aerogel, comprising:
providing a polyimide oligomer solution;
chemically imidizing the polyimide oligomers of the provided polyimide oligomer solution, the polyimide oligomers comprising amine terminated polyimide oligomers; and
adding triacid chloride to the imidized polyimide oligomer solution to cross-link polyimide oligomers of the polyimide oligomer solution.

13. The process of claim 12 , the providing a polyimide oligomer solution comprising:
generating amine-capped polyimide oligomer solution, the generating comprising:
dissolving diamine in solution;
adding dianhydride to the diamine in solution;
adding acetic anhydride to the dianhydride and diamine solution and mixing, thereby generating amine-capped polyimide oligomer solution.

14. The process of claim 13 , comprising:
adding 1,3,5-benzentricarbonyl trichloride to the amine capped polyimide oligomer solution.

15. The process of claim 14 , comprising:
pouring the solution of 1,3,5-benzentricarbonyl trichloride and amine-capped polyimide into a mold.

16. The process of claim 15 , comprising:
allowing the poured solution to gel for about 5 to about 20 minutes.

17. The process of claim 15 , comprising:
allowing the poured solution to gel for about 10 to about 15 minutes.

18. The process of claim 17 , comprising:
converting the gel to an aerogel by supercritical fluid extraction.

19. The process of claim 13 , wherein the diamine is selected from 4,4′-oxydianiline, 2,2′-dimethylbenzidine, and combinations thereof.

20. The process of claim 13 , wherein the generating comprises:
dissolving 4,4′-oxydianiline in solution;
adding dianhydride to the 4,4′-oxydianiline in solution;
dissolving the dianhydride in the 4,4′-oxydianiline solution;
adding 2,2′dimethylbenzidine to the solution having the dissolved dianhydride and dissolved 4,4′-oxydianiline;
adding acetic acid to the solution having the dissolved dianhydride, the dissolved 4,4′-oxydianiline, and 2,2-dimethylbenzidine, and mixing, thereby generating an amine-capped polyimide oligomer solution;
adding 1,3,5-benzenetricarbonyl trichloride to the amine-capped polyimide oligomer solution;
pouring the solution of 1,3,5-benzenetricarbonyl trichloride and amine-capped polyimide oligomer into a mold; and
allowing the poured solution to gel for about 5 to about 20 minutes.

Assignees

• Nasa
• The Us Administrator Of Nat Aeronautics And Space Administration

Inventors

• Meador Mary Ann B

Classifications

• C08J9/28 Primary

  by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum · CPC title

• C08J2205/026

  Aerogel, i.e. a supercritically dried gel · CPC title

• C08J2205/042

  Nanopores, i.e. the average diameter being smaller than 0,1 micrometer · CPC title

• C08J2201/05

  Elimination by evaporation or heat degradation of a liquid phase · CPC title

• C08J2379/08

  Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors · CPC title