Shape memory epoxy polymers
One embodiment includes compositions of shape memory epoxy polymers.
1. An epoxy shape memory polymer composition comprising:
a rigid epoxy;
a flexible epoxy; and
at least one of a crosslinking agent or a catalytic curing agent;
wherein the rigid epoxy is an aromatic epoxy having at least two epoxide groups, the flexible epoxy is an aliphatic epoxy having at least two epoxide groups, and the crosslinking agent is one of a multi-amine, an organic multi-carboxylic acid, or an anhydride; and
wherein the components are present in an amount sufficient to provide, upon curing of the composition, an epoxy shape memory polymer having a change in storage modulus of 2 to 3 orders of magnitude before and after its glass transition, and a glass transition temperature below 100° C. wherein the total molar amount of aromatic epoxy plus aliphatic epoxy is about twice the total molar amount of cross-linking agent.
2. An epoxy shape memory polymer composition as set forth in claim 1 further comprising an epoxy extender having one epoxide group.
3. An epoxy shape memory polymer composition as set forth in claim 1 further comprising a diluent, wherein the diluent is a monoamine or a monocarboxylic acid.
4. An epoxy shape memory polymer composition as set forth in claim 1 comprising an aromatic diepoxy, an aliphatic diepoxy, and a diamine.
5. An epoxy shape memory polymer composition as set forth in claim 4 wherein the total molar amount of aromatic epoxy plus aliphatic epoxy is about twice the total molar amount of diamines.
6. An epoxy shape memory polymer composition as set forth in claim 1 wherein the aromatic epoxy is diglycidyl ether of bisphenol A epoxy monomer with an approximate epoxy equivalent weight of 180.
7. An epoxy shape memory polymer composition as set forth in claim 1 wherein the aliphatic diepoxy is neopentyl glycol diglycidyl ether.
8. An epoxy shape memory polymer composition as set forth in claim 4 wherein the diamine is poly(propylene glycol)bis(2-aminopropyl) ether with an average molecular weight of about 230.
9. An epoxy shape memory polymer composition as set forth in claim 3 wherein the diluent is decylarnine.
10. An epoxy shape memory polymer composition as set forth in claim 3 comprising an aromatic diepoxy, a diamine, and a monoamine.
11. An epoxy shape memory polymer composition as set forth in claim 1 wherein the aromatic epoxy is an aromatic diepoxy.
12. An epoxy shape memory polymer composition as set forth in claim 1 wherein the aliphatic epoxy is an aliphatic diepoxy.
13. An epoxy shape memory polymer composition as set forth in claim 1 wherein the flexible epoxy has a molecular weight equal to or greater than 216.
14. A method comprising:
producing a shape memory polymer from a composition of claim 1 including an aromatic diepoxy, a crosslinking agent, and a diluent comprising:
heating a first amount of the aromatic diepoxy;
adding a second amount of the crosslinking agent and a third amount of the diluent to the aromatic epoxy to form a mixture; and
thermally curing the mixture.
15. A method as set forth in claim 14 wherein the aromatic epoxy is diglycidyl ether of bisphenol A epoxy monomer, the crosslinking agent is poly(propylene glycol)bis(2-aminopropyl)ether, and the diluent is decylamine.
16. A method as set forth in claim 14 wherein the heating comprises melting at about 75° C. for about 0.5 hour.
17. A method as set forth in claim 14 wherein the thermal curing comprises curing at about 100° C. for about 16 hours.
18. A method comprising;
producing a shape memory polymer from a composition of claim 1 including an aromatic epoxy, an aliphatic epoxy, and a crosslinking agent, comprising:
heating a first amount of the aromatic epoxy;
adding a second amount of the crosslinking agent and a third amount of the aliphatic epoxy to the aromatic epoxy to form a mixture; and
thermally curing the mixture.
19. A method as set forth in claim 18 wherein the aromatic epoxy is diglycidyl ether of bisphenol A epoxy monomer, the aliphatic epoxy is NDGE, and the crosslinking agent is propylene glycol)bis(2-aminopropyl) ether.
20. An epoxy shape memory polymer comprising:
a reaction product of a rigid epoxy, a flexible epoxy, and a crosslinking agent;
wherein the rigid epoxy is an aromatic epoxy having at least two epoxide groups, the flexible epoxy is an aliphatic epoxy having at least two epoxide groups, and the crosslinking agent is a diamine;
wherein the aromatic epoxy, the aliphatic epoxy, and the crosslinking agent are present in an amount that provides a total molar amount of aromatic epoxy plus aliphatic epoxy is about twice a total molar amount of diamines;
wherein the epoxy shape memory polymer has a glass transition temperature below 100° C. and a narrowness of the glass transition about 7° C. or less; and
wherein the epoxy shape memory polymer has a change in storage modulus of 2 or 3 orders of magnitude before and after its glass transition.
21. An epoxy shape memory polymer as set forth in claim 20 wherein the aromatic epoxy is diglycidyl ether of bisphenol A epoxy monomer with an approximate epoxy equivalent weight of 180.
22. An epoxy shape memory polymer as set forth in claim 20 wherein the aliphatic diepoxy is neopentyl glycol diglycidyl ether.
23. An epoxy shape memory polymer as set forth in claim 20 wherein the crosslinking agent is poly(propylene glycol)bis(2-aminopropyl) ether with an average molecular weight of about 230.
24. An epoxy shape memory polymer as set forth in claim 20 further comprising an epoxy extender having one epoxide group.