Shape memory polymers

• US 6,720,402 B2
• Filed: 05/08/2002
• Issued: 04/13/2004
• Est. Priority Date: 02/23/1998
• Status: Expired due to Term

• Current Assignee: Gkss-Forschungszentrum Geesthacht GmbH
• Original Assignee: mNemoscience GmbH
• Inventors: Lendlein, Andreas, Langer, Robert S.
• Primary Examiner(s): GORR, RACHEL F
• Application Number:
  US10/141,891
• Publication Number:
  US 20030055198A1
• Time in Patent Office: 706 Days
• Field of Search: 528/80, 528/76, 528/176, 528/272, 528/193, 528/196, 528/271, 525/415, 525/440, 525/450, 525/903
• US Class Current: 528/76
• CPC Class Codes: A61B 2017/00871 polymeric
• CPC Class Codes: B29C 61/003 characterised by the choice of material
• CPC Class Codes: C08L 101/00 Compositions of unspecified macromolecular compounds
• CPC Class Codes: G01K 5/483 using materials with a configuration memory, e.g. Ni-Ti alloys
• CPC Class Codes: Y10S 525/903 Interpenetrating network
• CPC Class Codes: Y10S 977/754 Dendrimer, i.e. serially branching or "tree-like" structure

Abstract

Shape memory polymer compositions, articles of manufacture thereof, and methods of preparation and use thereof are described. The shape memory polymer compositions can hold more than one shape in memory. Suitable compositions include at least one hard segment and at least one soft segment. At least one of the hard or soft segments can contain a crosslinkable group, and the segments can be linked by formation of an interpenetrating network or a semi-interpenetrating network, or by physical interactions of the blocks. Objects can be formed into a given shape at a temperature above the T_trans of the hard segment, and cooled to a temperature below to T_trans of the soft segment. If the object is subsequently formed into a second shape, the object can return to its original shape by heating the object above the Ttrans of the soft segment and below the Ttrans of the hard segment.

Claims

1. A method of using a shape memory polymer composition having at least two shapes in memory to form an article.

2. The method of claim 1 wherein the composition comprises:

a) at least one hard segment which has a T_trans between −

40 and 270°

C.,

b) a first soft segment which has a T_trans at least 10°

C. lower than that of the hard segment(s), which is linked to at least one hard segment,

c) a second soft segment, linked to at least one of the hard segment or first soft segment, which has a T_trans at least 10°

C. less than the T_trans of the first soft segment.

3. The method of claim 2 wherein the T_trans of the hard segment is in the range of between 30 and 150°

C.

4. The method of claim 3 wherein the T_trans of the hard segment is in the range of between 30 and 100°

C.

5. The method of claim 2 wherein the T_trans of the first soft segment(s) is at least 20°

C. below that of the hard segment(s).

6. The method of claim 2 wherein the T_trans of the second soft segment(s) is at least 20°

C. below that of the first soft segment(s).

7. The method of claim 1 wherein the shape memory polymer comprises a thermoplastic polymer.

8. The method of claim 1 wherein the polymer comprises multiple segments, and the molecular weight M_n of at least one of the segments is between about 500 and 10,000.

9. The method of claim 1 wherein the shape memory polymer is selected from the group consisting of graft polymers, linear polymers, and dendrimer polymers.

10. The method of claim 1 wherein the polymer comprises hard and soft segments and the hard segment comprises cyclic moieties.

11. The method of claim 10 wherein the moieties are selected from the group consisting of crown ethers and cyclic oligopeptides.

12. The method of claim 1 wherein the shape memory polymer is biodegradable.

13. The method of claim 12 wherein the polymer comprises hard and soft segments and at least one of the bard and soft segments is selected from the group consisting of polyhydroxy acids, polyorthoesters, polyether esters, polyesters, polyamides, polyesteramides, polydepsidpetides, aliphatic polyurethanes, polysaccharides, polyhydroxyalkanoates, and copolymers thereof.

14. The method of claim 1 wherein the polymer comprises a polyether ester selected from the group consisting of oligo (p-dioxanone) and its copolymers.

15. The method of claim 1 wherein the polymer comprises at least two soft segments and the segments are connected via a linkage that is cleavable by application of a stimuli selected from the group consisting of ultrasound, electric field, magnetic field, and light.

16. The method of claim 1 wherein the polymer comprises at least one hard segment and two soft segments, wherein the ratio by weight of the hard segment:

first soft segment and second soft segment is between about 5;

95 and 95;

5.

17. The method of claim 1 comprising

a thermoset polymer that comprises at least two covalently crosslinked crystallizable soft segments, wherein

a first soft segment has a T_trans between 250°

C. and −

40°

C.; and

a second soft segment linked to the first soft segment has a T_trans at least 10°

C. less than the T_trans of the first soft segment.

18. The method of claim 17 wherein the first soft segment has a T_trans between 200°

C. and 0°

C.

19. The method of claim 17, wherein at least one of the bard and soft segments contains a crosslinkable group, and wherein at least one of the hard and soft segments are linked by formation of an interpenetrating network or a semi-interpenetrating network.

20. The method of claim 17 wherein the hard and soft segments form a mixed interpenetrating network.

21. The method of claim 17 wherein the hard and soft segments form a shape memory semi-IPN consisting of a thermoset polymer having at least one soft segment and a homo- or copolymer.

22. The method of claim 21 wherein the resulting semi-IPN has a highest T_trans in the range of 200 and −

40°

C.

23. The method of claim 21 wherein the thermoset polymer is degradable.

24. The method of claim 21 wherein the homo- or copolymer is degradable.

25. The method of claim 21 wherein the composition has a multi shape memory where the number of shapes in memory is the same as the number of thermal transitions of the polymer.

26. The method of claim 1 wherein the composition comprises a shape memory IPN comprising an interpenetrating network of thermoset polymers.

27. The method of claim 1 wherein the composition comprises a shape memory mixed-IPN comprising a thermoplastic elastomer containing at least one hard segment and at least one soft segment and a thermoset containing at least one soft segment.

31. The method of claim 1 wherein the composition comprises polymer blends.

28. A method of using a shape memory polymer composition wherein the composition comprises:

a) at least one hard segment which has a T_trans between −

30 and 270°

C.,

b) at least one soft segment which has a T_trans at least 10°

C. lower than that of the hard segment(s), which is linked to at least one hard segment,

wherein at least one of the bard or soft segments includes a functional group which is able to form a crosslink that can be cleaved under application of a stimuli selected from the group consisting of light, electric field, magnetic field, and ultrasound, to form an article.

32. The method of claim 28 wherein the composition comprises polymer blends.

29. A method of using a shape memory polymer composition wherein the composition comprises at least a hard segment and a soft segment wherein at least one of the bard and soft segments undergoing solid to solid state transitions, and/or ionic interactions involving polyelectrolyte segments or supramolecular effects based on highly organized hydrogen bonds to form an article.

30. The method of claim 29 wherein a polycationic metal salt links at least two segments, wherein the link formed can be cleaved using an aqueous solvent.

33. The method of claim 29 wherein the composition comprises polymer blends.