Modification of thermoplastic polymers

• US 7,538,163 B2
• Filed: 03/24/2006
• Issued: 05/26/2009
• Est. Priority Date: 03/24/2005
• Status: Expired due to Fees

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Higham, Lawrence J., Theron, Jacobus P., Bezuidenhout, Deon, Zilla, Peter P.
• Primary Examiner(s): Gulakowski; Randy
• Assistant Examiner(s): Baumstein; Kyle
• Application Number:
  US11/388,317
• Publication Number:
  US 20060223955A1
• Time in Patent Office: 1,159 Days
• Field of Search: 525/455
• US Class Current: 525/455
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/282 Alkanols, cycloalkanols or arylalkanols including terpenealcohols
• CPC Class Codes: C08G 18/2825 having at least 6 carbon atoms
• CPC Class Codes: C08G 18/718 containing silicon
• CPC Class Codes: C08G 18/7657 containing two or more aromatic rings
• CPC Class Codes: C09D 175/14 Polyurethanes having carbon-to-carbon unsaturated bonds
• CPC Class Codes: C09D 175/16 having terminal carbon-to-carbon unsaturated bonds

Abstract

A method of preparing a polymer involving reacting at least one backbone carbamate (and/or optional urea) nitrogen of a thermoplastic polymer with a modification agent to form a modified polymer.

Claims

1. A method of preparing a polymer, the method comprising:

providing a thermoplastic polymer comprising urethane groups having backbone carbamate nitrogen atoms, and optionally urea groups having backbone urea nitrogen atoms; and

reacting at least one backbone carbamate nitrogen atom and/or optional backbone urea nitrogen atom of the thermoplastic polymer with a modification agent to form a modified polymer;

wherein the modification agent has a formula X—

R—

(Y)_a,

wherein X is —

COR₁, and

wherein R₁ is chlorine;

R is a bond or an organic group;

each Y is independently a crosslinkable group; and

a is 1 to 3;

with the proviso that Y does not include a silane or substituted silane group.

2. The method of claim 1, wherein reacting comprises reacting no greater than 50% of the backbone carbamate nitrogen atoms and/or the optional backbone urea nitrogen atoms with the modification agent.

3. The method of claim 1, further comprising activating the modified polymer to form a crosslinked polymer.

4. The method of claim 3, wherein activating comprises heating, irradiating, moisture treating, or combinations thereof.

5. The method of claim 3, further comprising shaping the modified polymer before or during activating to form a crosslinked polymer.

6. The method of claim 3, further comprising combining the modified polymer with an initiator before activating the modified polymer.

7. The method of claim 6, wherein the initiator is a free radical initiator.

8. The method of claim 7, wherein the free radical initiator is selected from the group consisting of thermal initiators, photoinitiators, redox initiators, and combinations thereof.

9. The method of claim 3, further comprising combining the modified polymer with one or more monomers before activating the modified polymer.

10. The method of claim 9, wherein the monomers comprise mono- or poly-(meth)acrylates, acrylamides, or combinations thereof.

11. The method of claim 1, wherein the reaction of the thermoplastic polymer with the modification agent occurs in a solvent capable of at least partially dissolving or swelling the polymer.

12. The method of claim 1, wherein the thermoplastic polymer comprises:

a soft segment derived from a polyester diol, a polycarbonate diol, a polyether diol, a polysiloxane diol, and/or a hydrocarbon diol; and

a hard segment derived from an aliphatic and/or aromatic diisocyanate and a monomeric diol and/or diamine.

13. The method of claim 12, wherein the thermoplastic polymer comprises a medical grade polyurethane.

14. The method of claim 1, wherein each Y independently comprises a vinyl or substituted vinyl group.

15. The method of claim 14, wherein each Y is independently —

CR₂═

CR₃R₄, wherein;

R₂, R₃, and R₄ are each independently selected from the group consisting of —

H, —

CH₃, —

(CR₆R₇)_bCH₃, —

C₆H₅, —

C(O)R₈, and —

OCH₂R₉;

R₆, R₇, R₈, and R₉ are each independently selected from the group consisting of —

H, a halogen, a linear or branched aliphatic group, aromatic group, and combination of a linear or branched aliphatic group and an aromatic group; and

b is 0 to 10.

16. The method of claim 1, wherein each Y is independently —

CH═

CH₂ or —

(CH₃)C═

CH₂.

17. The method of claim 1, wherein R comprises a linear or branched hydrocarbon group, ester group, amide group, ether group, amine group, or combinations thereof.

18. The method of claim 17, wherein R is selected from the group consisting of —

CH₂—

, —

C₆H₄—

, —

(CR₁₂R₁₃)_e—

, R₁₄OC(O)(CR₁₂R₁₃)_e—

, R₁₄C(O)O(CR₁₂R₁₃)_e—

, —

R₁₄C(O)N(CR₁₂R₁₃)_e, —

(CR₁₂R₁₃)_e—

O—

(CR₁₅R₁₆)_f—

, —

(CR₁₂R₁₃)_e—

NH—

(CR₁₅R₁₆)_f—

, —

(CH₂)₂—

O—

C(O)— and

combinations thereof;

wherein;

e is 1 to 5;

f is 1 to 5;

R₁₂, R₁₃, R₁₅, and R₁₆ are independently —

H, a halogen, a linear or branched saturated or unsaturated aliphatic group, an aromatic group, or a combination of the aliphatic and aromatic groups; and

each R₁₄ is independently a linear or branched saturated or unsaturated aliphatic group or an aromatic group.

23. A polymer preparable by the method of claim 1.

24. A medical device comprising the polymer of claim 23.

19. A method of preparing a polymer, the method comprising:

providing a thermoplastic polymer comprising urethane groups having backbone carbamate nitrogen atoms, and optionally urea groups having backbone urea nitrogen atoms; and

reacting at least one backbone carbamate nitrogen atom and/or optional backbone urea nitrogen atom of the thermoplastic polymer with a modification agent to form a modified polymer;

wherein the modification agent has a formula X—

R—

(Y)_a,

wherein;

X comprises an electrophilic center reactive with the backbone carbamate nitrogen and/or optional urea nitrogen on the thermoplastic polymer;

R is —

(CH₂)₂—

, —

(CH₂)₃—

, or —

(CH₂)₂—

O—

C(O)—

;

each Y is independently a crosslinkable group; and

a is 1 to 3;

with the proviso that Y does not include a silane or substituted silane group.

25. A polymer preparable by the method of claim 19.

26. A medical device comprising the polymer of claim 25.

31. The method of claim 19, further comprising combining the modified polymer with one or more monomers and activating the modified polymer to form a crosslinked polymer.

32. The method of claim 31, wherein the monomers comprise mono- or poly-(meth)acrylates, acrylamides, or combinations thereof.

20. A method of preparing a polymer, the method comprising:

providing a thermoplastic polymer comprising urethane groups having backbone carbamate nitrogen atoms, and optionally urea groups having backbone urea nitrogen atoms; and

reacting at least one backbone carbamate nitrogen atom and/or optional backbone urea nitrogen atom of the thermoplastic polymer with a modification agent to form a modified polymer;

wherein the modification agent has a formula X—

R—

(Y)_a,

wherein X—

R—

(Y)_a comprises acryloyl chloride, methacryloyl chloride, 4-pentenoyl chloride, or isocyanatoethylacrylate.

27. A polymer preparable by the method of claim 20.

28. A medical device comprising the polymer of claim 27.

33. The method of claim 20, further comprising combining the modified polymer with one or more monomers and activating the modified polymer to form a crosslinked polymer.

34. The method of claim 33, wherein the monomers comprise mono- or poly-(meth)acrylates, acrylamides, or combinations thereof.

21. A method of preparing a polymer, the method comprising:

providing a thermoplastic polymer comprising urethane groups having backbone carbamate nitrogen atoms, and optionally urea groups having backbone urea nitrogen atoms; and

reacting at least one backbone carbamate nitrogen atom and/or optional backbone urea nitrogen atom of the thermoplastic polymer with a modification agent to form a modified polymer;

wherein the modification agent has a formula X—

R—

(Y)_a,

wherein;

X comprises an electrophilic center reactive with the backbone carbamate nitrogen and/or optional urea nitrogen on the thermoplastic polymer;

R is a bond or an organic group;

each Y is independently a crosslinkable group; and

a is 1 to 3;

with the proviso that Y does not include a silane or substituted silane group; and

treating the thermoplastic polymer with a basic reagent before or during the addition of the modification agent.

22. The method of claim 21, wherein the basic reagent comprises triethylamine, sodium hydride, butyllithium, 1,8-diazobicyclo[5.4.0]undec-7-ene (DBU), 1-4-diazobicyclo[2.2.2]octane (DABCO), Hü

nigs base, dimethylaminopyridine (DMAP), or 1,5-diazobicyclo[4.3.0]non-5-ene (DBN).

29. A polymer preparable by the method of claim 21.

30. A medical device comprising the polymer of claim 29.

35. The method of claim 21, further comprising combining the modified polymer with one or more monomers and activating the modified polymer to form a crosslinked polymer.

36. The method of claim 35, wherein the monomers comprise mono- or poly-(meth) acrylates, acrylamides, or combinations thereof.