Fluorinated poly(imide-phthalonitrile) adhesive formulations and related methods

Patent metadata

Field	Value
Publication number	US-12116504-B2
Application number	US-202217829521-A
Country	US
Kind code	B2
Filing date	Jun 1, 2022
Priority date	Jun 1, 2022
Publication date	Oct 15, 2024
Grant date	Oct 15, 2024

Abstract

Adhesive formulations for forming a fluorinated poly(imide-phthalonitrile) thermoset polymer are provided. Such an adhesive formulation may comprise a fluorinated imide-phthalonitrile oligomer having Formula IV

wherein R 1 is an unsubstituted or substituted aryl group and does not comprise an ether group; R 2 is an unsubstituted or substituted aryl group and does not comprise an ether group; at least one of R 1 and R 2 comprises a fluorine substituent; and n has a value of from 1 to 30.

First claim

What is claimed is:

1. An adhesive formulation for forming a fluorinated poly(imide-phthalonitrile) thermoset polymer, the formulation comprising:
a fluorinated imide-phthalonitrile oligomer having Formula IV

wherein R 1 is an unsubstituted or substituted aryl group and does not comprise an ether group; R 2 is an unsubstituted or substituted aryl group and does not comprise an ether group; at least one of R 1 and R 2 comprises a fluorine substituent; and n has a value of from 1 to 30.

2. The adhesive formulation of claim 1 , wherein R 1 is an unsubstituted monocyclic group.

3. The adhesive formulation of claim 1 , wherein R 1 is an unsubstituted polycyclic group comprising at least two unfused aromatic rings connected via a covalent bond.

4. The adhesive formulation of claim 1 , wherein R 1 is a substituted polycyclic group comprising at least two unfused aromatic rings connected via a substituted alkyl group, the substituted alkyl group comprising the fluorine substituent.

5. The adhesive formulation of claim 1 , wherein R 2 is an unsubstituted monocyclic group or a substituted monocyclic group comprising the fluorine substituent.

6. The adhesive formulation of claim 1 , wherein R 2 is an unsubstituted polycyclic group comprising at least two unfused aromatic rings connected via an unsubstituted alkyl group.

7. The adhesive formulation of claim 1 , wherein R 2 is a substituted polycyclic group comprising at least two unfused aromatic rings connected via sulfone group or via a substituted alkyl group, the substituted alkyl group comprising the fluorine substituent.

8. The adhesive formulation of claim 1 , wherein R 1 comprises the fluorine substituent and R 2 does not comprise any fluorine substituent.

9. The adhesive formulation of claim 1 , wherein n is from 6 to 13.

10. The adhesive formulation of claim 1 , wherein the fluorinated imide-phthalonitrile oligomer has Formula IVA

wherein R 1 ′ is a covalent bond or a substituted alkyl group and does not comprise an ether group; R 2 ′ is a sulfone group or an unsubstituted or substituted alkyl group and does not comprise an ether group; at least one of R 1 ′ and R 2 ′ comprises the fluorine substituent and n has the value of from 1 to 30.

11. The adhesive formulation of claim 10 , wherein R 1 ′ is the substituted alkyl group comprising the fluorine substituent.

12. The adhesive formulation of claim 11 , wherein R 1 ′ is hexafluoroisopropyl, 1,1,4,4-tetrakis(trifluoromethyl)cyclohexane in a form of a six-membered ring, 1,4-difluoro-1,4-bis(trifluoromethyl)cyclohexane in a form of a six-membered ring, or 2-phenyl-2-trifluoromethylpropane.

13. The adhesive formulation of claim 10 , wherein R 2 ′ is the sulfone group.

14. The adhesive formulation of claim 10 , wherein the fluorinated imide-phthalonitrile oligomer is

15. The adhesive formulation of claim 14 , wherein n is from 6 to 13.

16. The adhesive formulation of claim 1 , further comprising a catalyst, optionally, a liquid medium, and optionally, a filler.

17. The adhesive formulation of claim 1 , further comprising a polyimide filler.

18. The adhesive formulation of claim 17 , wherein the fluorinated imide-phthalonitrile oligomer is the reaction product of an aromatic dianhydride, an aromatic diamine, and an amine substituted 1,2-dicyanobenzene, and wherein the polyimide filler is a polyimide that is free of ether groups and is the reaction product of the aromatic dianhydride and the aromatic diamine.

19. A method of using the adhesive formulation of claim 1 , the method comprising heating the adhesive formulation according to a curing profile to induce crosslinking reactions between phthalonitrile moieties of fluorinated imide-phthalonitrile oligomers having Formula IV to form a fluorinated poly(imide-phthalonitrile) thermoset polymer.

20. A fluorinated poly(imide-phthalonitrile) thermoset polymer formed by curing the adhesive formulation of claim 1 , the polymer comprising crosslinked phthalonitrile moieties of fluorinated imide-phthalonitrile oligomers having Formula IV.

21. The fluorinated poly(imide-phthalonitrile) thermoset polymer of claim 20 having a degradation temperature of greater than 520° C., an average maximum load of from 300 psi to 6,000 psi, an adhesion loss of no more than 75% after exposure to a temperature of 375° C. in air for 100 hours, or combinations thereof.

22. An adhesive article comprising an aerospace structure and a layer of the adhesive formulation of claim 1 on a surface of the aerospace structure, optionally, wherein the layer is cured to form a fluorinated poly(imide-phthalonitrile) thermoset polymer comprising crosslinked phthalonitrile moieties of fluorinated imide-phthalonitrile oligomers having Formula IV.

23. A fluorinated imide-phthalonitrile oligomer having formula

wherein n has a value of from 6 to 13.

Assignees

• Boeing Co

Inventors

• Dustin Ashley Marie
• Drummey Kevin James
• Bui Phuong
• Nowak Gregory Phillip
• Nowak Andrew P

Classifications

• C09J181/06

  Polysulfones; Polyethersulfones · CPC title

• C09J7/35

  Heat-activated · CPC title

• C09J2203/35

  for aeronautic or naval applications · CPC title

• C09J179/08

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

• C08G73/1064

  containing sulfur · CPC title