Modification of thermoplastic polymers

• US 20060223955A1
• Filed: 03/24/2006
• Published: 10/05/2006
• Est. Priority Date: 03/24/2005
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Bezuidenhout, Deon, Zilla, Peter P., Higham, Lawrence J., Theron, Jacobus P.
• Granted Patent: US 7,538,163 B2
• Time in Patent Office: Days
• US Class Current: 525/453
• 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 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.

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 X comprises a carboxylic acid, activated carboxylic acid, acid halide, anhydride, ester, amide, isocyanate, sulfonic ester, succinimidyl ester, 2,3,5,6-tetrafluorobenzoyl, acyl azide, or acyl nitrile group.

15. The method of claim 14, wherein X is selected from the group consisting of —

NCO, —

C(O)R₁, and combinations thereof;

wherein R₁ is selected from the group consisting of a halogen, —

OH, —

OCH₃, —

OCOCH₃, —

NH₂, —

NH₃⁺, —

OH₂⁺, —

OAc, —

(C₆H₅), —

(C₆F₅), —

N₃, —

N-hydroxy-succinimide, —

H, —

OSO₂(C₆H₄)CH₃, —

OSO₂(C₆H₄)Br, —

OSO₂(C₆H₄) NO₂, —

OSO₂CH₃, —

OSO₂CF₃, —

OSO₂C₄H₉, —

OSO₂CH₂CF₃, —

OSO₂(C₆H₄)F, and combinations thereof.

16. The method of claim 15, wherein X is —

NCO or —

COR₁, wherein R₁ is a halogen.

17. The method of claim 16, wherein R₁ is chlorine.

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

19. The method of claim 18, wherein each Y is independently —

CR₂═

CR₃R₄ or —

Si(R₅)₃, wherein;

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

H, —

CH₃, —

(CR₆R₇)_bCH₃, —

C₆H₅, —

C(O)R₈, and —

OCH₂R₉;

R₅ is selected from the group consisting of —

OCH₃, —

O(CH₂)_cCH₃, —

CH₂OCH₃, and —

OCO(CR₁₀R₁₁)_dCH₃;

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;

R₁₀ and R₁₁ are independently a saturated aliphatic or aromatic group;

b is 0 to 10;

c is 0 to 5; and

d is 0 to 5.

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

CH═

CH₂, —

(CH₃)C═

CH₂, or —

Si(CH₂OCH₃)₃.

21. 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.

22. The method of claim 21, wherein R is selected from the group consisting of —

CH₂—

, —

C₆H₄—

, —

(CR₁₂R₁₃)_e—

, R₁₄OC(O)(CR₁₂R₁₃)_e—

, R₁₄C(O)O(CR₁₂R₁₃)_e—

, —

R₄C(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. The method of claim 22, wherein R is —

(CH₂)₂—

, —

(CH₂)₃—

, or —

(CH₂)₂—

O—

C(O)—

.

24. The method of claim 1, wherein X—

R—

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

25. The method of claim 1, further comprising treating the thermoplastic polymer with a basic reagent before or during the addition of the modification agent.

26. The method of claim 25, 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).

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

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

27. 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;

reacting no greater than 20% of the backbone carbamate nitrogen atoms and/or the optional backbone urea nitrogen atoms 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 a carboxylic acid, activated carboxylic acid, acid halide, anhydride, ester, amide, isocyanate, sulfonic ester, succinimidyl ester, 2,3,5,6-tetrafluorobenzoyl, acyl azide, acyl nitrile group, or combinations thereof;

R is a bond or a linear or branched hydrocarbon group, ester group, amide group, ether group, amine group, or combinations thereof;

each Y independently a vinyl, substituted vinyl, silane, or substituted silane group; and

a is 1 to 3; and

activating the modified polymer to form a crosslinked polymer.

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

31. A polymer preparable by the method of claim 30.